®
Consolidated
INSTALLATION, OPERATION
AND MAINTENANCE MANUAL
®
Consolidated Safety Valve
Type 1700-2-S and 1700-3-S
Type
1700
Series
Industrial Valve Operation
Dresser Valve and Controls Division
Alexandria, Louisiana 71309-1430 (USA)
CON-1
9/12/00
Product Safety Sign and Label System
1.
DANGER — Immediate
hazards which WILL result
in severe personal injury or
death.
If and when required, appropriate safety labels have been included in the
rectangular margin blocks throughout this manual. Safety labels are vertically
oriented rectangles as shown in the representative examples (below), consisting
of three panels encircled by a narrow border. The panels can contain four
messages which communicate:
2.
WARNING — Hazards or
unsafe practices which
COULD result in severe
personal injury or death.
•
•
•
•
3.
The top panel of the format contains a signal word (DANGER, WARNING,
CAUTION or ATTENTION) which communicates the level of hazard seriousness.
CAUTION — Hazards or
unsafe practices which
COULD result in minor
personal injury.
The center panel contains a pictorial which communicates the nature of the
hazard, and the possible consequence of human or product interaction with the
hazard. In some instances of human hazards the pictorial may, instead, depict
what preventive measures to take, such as wearing protective equipment.
4.
The bottom panel may contain an instruction message on how to avoid the
hazard. In the case of human hazard, this message may also contain a more
precise definition of the hazard, and the consequences of human interaction with
the hazard, then can be communicated by the pictorial.
ATTENTION — Hazards or
unsafe practices which
COULD result in product or
property damage.
1
The level of hazard seriousness.
The nature of the hazard.
The consequence of human or product interaction with the hazard.
The instructions, if necessary, on how to avoid the hazard.
2
3
4
! CAUTION ▲
! ATTENTION
▲
Know all valve
exhaust/leakage points
to avoid possible
severe personal injury
or death.
CON-6
Wear necessary
protective equipment
to prevent possible
injury.
Do not drop or strike
valve.
CONSOLIDATED
MAXIFLOW SAFETY VALVE
WELDED INLET
2500 PSIG (175.8 Kg/cm2) CLASS
Part
No.
1
1a
2
3
4
5
5a
5b
5c
6
7
8
9
10
11
*12
12a
12b
12c
13
13a
13b
13c
14
15
16
**17
**18
19
20
21
22
Nomenclature
Base
Inlet Neck
Disc Holder
Guide
Upper Adj. Ring
Spring Assembly
Top Washer
Bottom Washer
Spring
Seat Bushing
Disc
Lower Adj. Ring
Disc Collar
Lift Stop
Overlap Collar
Cover Plate Assy.
Cover Plate
Floating Washer
Washer Retainer
Top Plate Assy.
Top Plate
Washer Retainer
Floating Washer
Spindle
Compression Screw
Yoke
Yoke Rod
Lifting Gear
Upper Adj. Ring Pin
Lower Adj. Ring Pin
Release Nut
Compression Screw
Lock Nut
* Includes Pin Screws
** See Figure 7 on page 19
CON-1
MAXIFLOW SAFETY VALVE
FLANGED INLET
900 PSIG (63.3 Kg/cm2) CLASS
Part
No. Nomenclature
1
2
3
4
5
5a
5b
5c
6
7
8
9
10
11
*12
12a
12b
12c
13
13a
13b
13c
14
15
16
**17
**18
19
20
21
22
Base
Disc Holder
Guide
Upper Adj. Ring
Spring Assembly
Top Washer
Bottom Washer
Spring
Seat Bushing
Disc
Lower Adj. Ring
Disc Collar
Lift Stop
Overlap Collar
Cover Plate Assy.
Cover Plate
Floating Washer
Washer Retainer
Top Plate Assy.
Top Plate
Washer Retainer
Floating Washer
Spindle
Compression Screw
Yoke
Yoke Rod
Lifting Gear
Upper Adj. Ring Pin
Lower Adj. Ring Pin
Release Nut
Compression Screw
Lock Nut
* Includes Pin Screws
** See Figure 7 on page 19
CON-1
Page 1
Contents
Section
I.
II.
III.
IV.
V.
VI.
VII.
VIII.
IX.
X.
XI.
XII.
XIII.
XIV.
XV.
XVI.
XVII.
XVIII.
XIX.
XX.
XXI.
Subject
Safety Notice.......................................................................................
A. Safety Precautions .......................................................................
B. Warranty Information ....................................................................
Introduction .........................................................................................
Safety Valve Terminology ...................................................................
Design Features..................................................................................
Operating Principles............................................................................
Storage and Handling Prior to Installation...........................................
Recommended Installation Practices..................................................
A. General Requirements..................................................................
B. Outdoor Safety Valve Installation .................................................
C. Indoor Safety Valve Installation ....................................................
D. Cover Plate Vent Piping ...............................................................
Hydrostatic Test Plug Removal - Domestic and Export ......................
A. General Information ......................................................................
B. Domestic Plugs.............................................................................
C. Export Plugs .................................................................................
Field Testing........................................................................................
A. General Information ......................................................................
B. Popping Point Adjustment ............................................................
C. Ring Adjustments, Blowdown and Overlap Collar Adjustments ...
D. Restricted Lift Valves ....................................................................
E. Hydroset/EVT Testing...................................................................
F. Sealing Valves After Test .............................................................
Disassembly Instructions ....................................................................
A. General Information ......................................................................
B. Specific Steps ...............................................................................
Inspection............................................................................................
A. General Information ......................................................................
B. Specific Steps ...............................................................................
Maintenance Instructions ....................................................................
A. General Information ......................................................................
B. Lapping Procedure .......................................................................
C. Reseating Machine Information ....................................................
D. Spindle Runout .............................................................................
E. Disc Replacement and Disc/Spindle Bearing Requirements........
F. Grinding the Compression Screw.................................................
G. Thrust Bearing Surfaces ...............................................................
H. Grinding the Lower Spring Washer ..............................................
Re-Assembly.......................................................................................
A. General Information ......................................................................
B. Specific Steps ...............................................................................
Hydrostatic Testing & Gagging ...........................................................
Trouble Shooting the Type 1700 Valve...............................................
Maintenance Tools & Supplies............................................................
Service Parts Inventory Philosophy ....................................................
Genuine Dresser Parts........................................................................
Recommended Spare Parts................................................................
Manufacturer’s Field Service & Repair Program.................................
Page
2
3
3
4
5
7
8
11
12
12
16
17
17
18
18
19
20
21
21
22
22
27
27
28
28
28
28
34
34
34
36
36
36
39
41
41
45
45
45
46
46
46
54
56
57
59
61
62
63
CON-1
Page 2
I.
▲
Safety Notice
Proper installation, operation and maintenance is essential to the safe and
reliable operation of all valve products. The relevent procedures
recommended by Dresser Valve and Controls Division (DVCD), and
described in this manual, are effective methods of performing the required
tasks. Some of these procedures require the use of tools specifically
designed for an intended purpose. These special tools should be used
when, and as, recommended.
Know nuclear “health
physics” procedures,
if applicable, to avoid
possible severe injury
or death.
! CAUTION
▲
Wear necessary
protective equipment
to prevent possible
injury.
It is important to note that this manual contains various “safety messages”
which should be carefully read in order to minimize the risk of personal
injury, or the possibility that improper procedures will be followed which
may damage the involved DVCD product, or render it unsafe. It is also
important to understand that these “safety messages” are not exhaustive.
DVCD can not possibly know, evaluate, and advise any customer of all of
the conceivable ways in which tasks might be performed, or of the possible
hazardous consequences of each way. Consequently, DVCD has not
undertaken any such broad evaluation and, thus, anyone who uses a
procedure and/or tool, which is not recommended by DVCD, or deviates
from DVCD recommendations, must be thoroughly satisfied that neither
personal safety, nor valve safety, will be jeopardized by the method and/
or tools selected. If not so satisfied, contact DVCD (at 318/640-2250) if there
are any questions relative to tools/methods. Some of the products
manufactured by DVCD may be used in radioactive environments.
Consequently, prior to starting any operation in a radioactive environment,
the proper “health physics” procedures should be consulted and followed,
if applicable.
The installation, operation and maintenance of valves and/or valve products
may involve proximity to fluids at extremely high pressure and/or
temperature. Consequently, every precaution should be taken to prevent
injury to personnel during the performance of any procedure. These
precautions should consist of, but are not limited to, ear drum protection,
eye protection, and the use of protective clothing. (i.e., gloves, etc.) when
personnel are in or around a valve work area. Due to the various
circumstances and conditions in which these operations may be performed
on DVCD products, and the possible hazardous consequences of each
way, DVCD can not possibly evaluate all conditions that might injure
personnel or equipment. Nevertheless, DVCD does offer the safety
precautions listed on page 3 for customer information only.
It is the responsibility of the purchaser or user of DVCD valves/equipment
to adequately train all personnel who will be working with the involved
valves/equipment. Further, prior to working with the involved valves/
equipment, personnel who are to perform such work should become
thoroughly familiar with the contents of this manual. Accordingly, should
additional copies of this manual be required, they can be purchased, at a
minimal cost, by contacting DVCD (in writing) at P.O. Box 1430, Alexandria,
LA 71309-1430, or (telephonically) at 318/640-2250.
CON-1
Page 4
III. Introduction
The “safety valve” is the final safeguard between a controlled boiler and a
catastrophic explosion. In an over-pressure situation, the pressure in the valve
inlet increases until the force on the disc exerted by the system pressure equals
the force exerted by the spring. This causes the safety valve to pop, or lift,
relieving the excess steam until the system pressure is reduced to the desired
level.
The Type 1700 Maxiflow Safety Valve represents the state of the art in pressure
relief products. As well as its back pressure assisted closing feature, the
Maxiflow Safety Valve incorporates a pressure assisted/temperature stabilizing
THERMOFLEX™ disc for improved seat tightness. This design has been
proven in hundreds of installations world wide.
The Type 1700 Maxiflow Safety Valve is sold with a flanged outlet and either a
flanged or buttwelded inlet. Other variations include a thrust bearing assisted
compression screw for high pressure valves, a spring cover and a lifting gear
cover for outdoor installations. All export and weld inlet valves are shipped with
a hydro plug for protecting the internal parts of the valve and to provide a means
for the end user to hydrostatically test his system without damaging the disc or
nozzle seats.
The information contained in this manual provides the customer with basic
concepts required in maintenance of the Maxiflow Safety Valve, but in no way
is it intended to take the place of experience and technical knowledge required
to perform adequate valve repair work and maintenance.
Page 5
IV. Terminology for Safety Valves
(Paraphrased from PTC 25.3)
•
Back Pressure
Back pressure is the static pressure existing at the outlet of a safety valve
device due to pressure in the discharge system.
•
Blowdown
Blowdown is the difference between actual popping pressure of a safety
valve and actual reseating pressure expressed as a percentage of set
pressure, or in pressure units.
•
Bore Area
Bore area is the minimum cross-sectional area of the nozzle.
•
Bore Diameter
Bore diameter is the minimum diameter of the nozzle.
•
Chatter
Chatter is abnormal, rapid reciprocating motion of the moveable parts of
a safety valve, in which the disc contacts the seat.
•
Closing Pressure
Closing pressure is the value of decreasing inlet static pressure at which
the valve disc re-establishes contact with the seat, or at which lift becomes
zero.
•
Disc
A disc is the pressure containing moveable member of a safety valve
which effects closure.
•
Inlet Size
Inlet size is the nominal pipe size of the inlet of a safety valve, unless
otherwise designated.
•
Leak Test Pressure
Leak test pressure is the specified inlet static pressure at which a
quantitative seat leakage test is performed in accordance with a standard
procedure.
•
Lift
Lift is the actual travel of the disc away from closed position when a valve
is relieving.
•
Lifting Device
A lifting device is a device for manually opening a safety valve, by the
application of external force to lessen the spring loading which holds the
valve closed.
•
Nozzle/Seat Bushing
A nozzle is the pressure containing element which constitutes the inlet flow
passage and includes the fixed portion of the seat closure.
•
Outlet Size
Outlet size is the nominal pipe size of the outlet passage of a safety valve,
unless otherwise designated.
•
Overpressure
Overpressure is a pressure increase over the set pressure of a safety
valve, usually expressed as a percentage of set pressure.
CON-1
Page 6
IV. (Continued)
CON-1
•
Popping Pressure
Popping pressure is the value of increasing inlet static pressure at which
the disc moves in the opening direction at a faster rate as compared with
corresponding movement at higher or lower pressures. It applies only to
safety or safety relief valves on compressible fluid service.
•
Pressure Containing Member
A pressure containing member of a safety valve is a part which is in actual
contact with the pressure media in the protected vessel.
•
Pressure Retaining Member
A pressure retaining member of a safety valve is a part which is stressed
due to its function in holding one or more pressure containing members in
position.
•
Rated Lift
Rated lift is the design lift at which a valve attains its rated relieving
capacity.
•
Safety Valve
A safety valve is a pressure relief valve actuated by inlet static pressure
and characterized by rapid opening or pop action.
•
Set Pressure
Set pressure is the value of increasing inlet static pressure at which a
safety valve displays the operational characteristics as defined under
“Popping Pressure.” It is one value of pressure stamped on the safety
valve.
•
Seat
A seat is the pressure containing contact between the fixed and moving
portions of the pressure containing elements of a valve.
•
Seat Diameter
Seat diameter is the smallest diameter of contact between the fixed and
moving members of the pressure containing elements of a valve.
•
Seat Tightness Pressure
Seat tightness pressure is the specific inlet static pressure at which a
quantitative seat leakage test is performed in accordance with a standard
procedure.
•
Simmer
Simmer is the audible or visible escape of fluid between the seat and disc
at an inlet static pressure below the popping pressure and at no measurable
capacity. It applies to safety valves on compressible fluid service.
•
Warn
See “Simmer” (definition above).
Page 7
V. Design Features
•
Blowdown
The Consolidated ® Maxiflow Safety Valve is the valve with 3% attainable
blowdown certified by the National Board of Boiler and Pressure Vessel
Inspectors. Adjusting rings are preset at the factory to give slightly longer
blowdown. If a verified value of 3% blowdown is required, this can be
obtained by actuating the valve on the installation where sufficient capacity
is available, and where system operating parameters will permit such
blowdown.
•
Body and Neck Materials
All pressure retaining parts, with the exception of reheat valves rated to 900
psi (62.1 Bar) and lower, are made of forged materials. Forged welded inlet
neck valves have the three-piece weld construction. Flanged inlet valves
and cast neck welded inlet valves have a top-inserted seal-welded bushing.
•
Design Life
For most service conditions, pressure retaining parts subject to mechanical
stresses, such as valve necks, yoke rods, etc., are designed for a design life
equivalent to the boiler, and are well in excess of the requirements of the
Power Boiler Code.
•
Operating Gap
The operating gap is defined as the difference between the operating
pressure and the valve set pressure. Consolidated Safety Valves are tested
and proven tight for operating gaps of 6%. Although tightness is a function
of design, it should be realized that with smaller operating gaps it is also
necessary to increase maintenance. Increase in incidents of valve lift,
simmer, etc. can be expected with a small operating gap, because there is
less allowance for system pressure transients and other unidentified
variables.
•
Supercritical Valves
Maxiflow Supercritical Valves are used for steam at pressures above
approximately 3200 psig. Its internal design is similar to that used in
subcritical boiler safety valves.
The springs for supercritical valves are made from alloy steel, the discs from
Inconel "X" and the seating surface of the bushing from Stellite. These
materials have been found to work very well under the high temperatures
and pressures to which the valves are subjected. A ball thrust bearing is
used on the compression screw in all of the valves for better adjustment.
•
Thermal Compensation
The yoke rod design, together with proper selection of yoke rod and spindle
materials, renders the valve relatively free from changes in pressure
settings due to inlet temperature variations. High ambient temperatures
adjacent to the valve spring and yoke rods may cause set pressure
variations, and need to be considered when adjusting the valve. Temperature
stabilization is always necessary prior to adjusting a valve for set pressure.
•
THERMOFLEX™ disc
The THERMOFLEX™ disc design, by allowing for the rapid equalization of
temperature around the valve seat, provides a degree of tightness far above
that offered by competitive valves. Selection of materials provides desired
“Thermal Flexibility” and “Mechanical Flexibility”. THERMOFLEX™ discs
are now giving excellent results at 5500 psi (379.3 Bar) and 1150° F (621°C).
CON-1
Page 8
VI. Operating Principles
The 1700-S series Maxiflow valve operates during closing on a back pressure
principle, that is, the force of trapped steam on the upper side of the disc holder
is utilized to assist the spring in forcing the disc back down onto its seat.
In Figure 1 (below), 100 percent lift is attained by proper location of the upper and
lower adjusting rings (G) and (O), respectively. When full lift is attained, as in
Figure 2 (see next page), lift stop (M) rests against coverplate (P) to eliminate
hunting, thus adding stability to the valve. When the valve discharges in an open
position, steam is bled into chamber (H) through two bleed holes (J) in the roof
of the disc holder. Similarly, the spindle overlap collar (K) rises to a fixed position
above the floating washer (L). The area between the floating washer and the
spindle is thereby increased by the difference in the two diameters on the overlap
collar.
CON-1
Page 9
VI. (Continued)
Under this condition, steam in chamber (H) enters into chamber (Q) through the
secondary area formed by the floating washer (L) and the overlap collar (K) on
the spindle, then through orifice (N), and escapes to atmosphere through the
pipe discharge connection (R).
CON-1
Page 10
VI. (Continued)
When closing, as in Figure 3 (below), the spindle overlap collar (K) is adjusted
so that it moves down into the floating washer (L), thereby effectively reducing
the escape of steam from chamber (H).
The resulting momentary pressure building-up in chamber (H), at a rate controlled
by orifice (N), produces a downward thrust in the direction of spring loading. The
combined thrust of the pressure and spring loading results in positive and precise
closing. Cushioning of the closing is controlled by the lower adjusting ring (O).
CON-1
Page 11
VII. Storage and Handling Prior to Installation
Safety valves should be stored in a dry environment to protect them from the
weather. They should not be removed from the skids or crates until immediately
prior to installation. Flange protectors and sealing plugs should remain installed
until just prior to installation.
Safety valves, either crated or uncrated, should never be subjected to sharp
impact. This would be most likely to occur by bumping or dropping during loading
or unloading from a truck or while moving with a power conveyor, such as a fork
lift truck. The valve, either crated or uncrated, should always be kept with the inlet
down (i.e., never laid on its side), to prevent misalignment and damage to
internals. Even crated valves should always be lifted with the inlet down.
Uncrated valves should be moved or hoisted by wrapping a chain or sling, around
the discharge neck, then around the upper yoke structure, in such manner as will
insure that the valve is in vertical position during lift, (i.e., not lifted in horizontal
position). Never lift the full weight of the valve by the lifting lever. Never hook to
the spring to lift. When safety valves are uncrated and the flange protectors
removed, immediately prior to installation, meticulous care should be exercised
to prevent dirt from entering the outlet port while bolting in place.
While hoisting to the installation, care should be exercised to prevent bumping
the valve against steel structures and other objects.
CON-1
Page 12
VIII. Recommended Installation Practices
A.
General Requirements
1. The valve should be installed to meet all the requirements of Figure
4 (below).
2. The safety valve shall be connected to the header independent of any
other connection, and attached as close as possible to the header,
without any unnecessary intervening pipe or fitting. “Necessary”
intervening pipe or fitting shall not be longer than the face-to-face
dimension of the corresponding tee fitting of the same diameter and
pressure, per ANSI Standards.
3. No valve of any description should be placed between the safety valve
and the header, nor on the discharge pipe between the safety valve
and the atmosphere.
4. In no case may the inlet piping to the valve have a flow area less than
the area of the valve inlet.
5. Excessive pressure loss at the inlet of the safety valve will cause
extremely rapid opening and closing of the valve, which is known as
“chattering”. Chattering may result in lowered capacity as well as
damage to the seating surface of the valve. Severe chattering can
cause damage to other parts of the valve.
CON-1
Page 13
VIII.A. (Continued)
The following recommendations will assist in eliminating the factors that produce
chatter:
a. Header nozzle corners must be rounded to a radius of not less than
1/4 of the opening diameter.
b. Pressure drop due to friction flow to the inlet of the valve should not be
greater than 50% of the expected blowdown of the safety valve.
6. To decrease the effects of a phenomenon known as “sonic vibrations,” the
following recommendations are made.
a. Safety valves should be installed at least eight to ten pipe diameters
downstream from any bend in a steam line. This distance should be
increased when the valve is installed on the horizontal section of a
header which is preceded by an upward section.
b. Safety valves should not be installed closer than eight to ten pipe
diameters either upstream or downstream from a diverging, or a
converging, “Y”.
c. In cases where a piping configuration renders the above two
recommendations impractical, or impossible, the downstream corner of
the header nozzle inlet should be rounded to a greater extent than the
upstream corner. The header nozzle entrance should be rounded so the
radius at the downstream corner will be equal to a minimum of 1/4 of the
nozzle diameter. The radius should be reduced gradually, leaving only
a small portion of the upstream corner with a smaller radius.
d. Safety valves should never be installed, in a steam line, in a position
directly opposite to a branch line.
7. Excessive line vibrations are known to produce shifts in safety valve set
pressures. Vibrations may possibly introduce chatter, causing damage to
the valve, and reduce its capacity. This vibration also contributes to increased
incidents of seat leakage. Considerations should be given to eliminating this
problem prior to installing the valve on the unit.
8. Steam flowing vertically out a discharge elbow produces a downward
reaction on the elbow. Bending stress in the valve is determined by the
product of this reactive force and the moment arm between the point of
steam exhaust and the section being analyzed for bending stress. The
effects of reaction force, vibration, and seismic loads, on all valve components
and discharge piping, should be considered when designing the valve
system.
9. For optimum performance, safety valves must be serviced regularly and
otherwise maintained. So that servicing can be properly performed, valves
should be located in a manner that allows for easy access. Sufficient working
space should be provided around and above the valve to permit access to
adjusting rings. If two or more valves are located close together, the outlets
should be parallel so as to offer as much protection as possible to personnel
repairing, or working close to, the safety valve.
10. Because foreign material passing into, and through, a safety valve is
damaging, the system on which the valve is tested and finally installed must
also be inspected and cleaned. New systems are prone to contain welding
beads, pipe scale, and other foreign materials which are inadvertently
trapped during construction, and destroy the valve seating surfaces the first
few times the valve opens. Therefore, the system should be thoroughly
purged before the safety valve is installed.
CON-1
Page 14
VIII.A. (Continued)
11. With regard to weld-end inlet valves, completely assembled valves may be
installed without disassembly being necessary at the time of welding. During
welding, the valve neck should be insulated to reduce thermal stresses.
When stress relieving, insulation should also be utilized to reduce thermal
stresses. In service, the valve neck should be insulated at least to the point
of the inlet neck/valve body-bowl juncture.
12. Safety valves should be installed in a vertical position. Nominal tolerance on
vertical installation is plus or minus 1 degree.
13. The discharge area of the outlet piping from a safety valve should not be less
than the area of the outlet connection. Where more than one safety valve is
connected to a common outlet pipe, the area of the pipe should not be less
than the combined area of the outlet connections to the safety valves.
14. All safety valve discharges should be piped so that the effluent is discharged
clear from running boards or platforms. Ample provision for gravity drain
should be made in the discharge pipe at, or near, each safety valve where
water, or condensation, may collect. Each valve has an open gravity drain
through the body, below the level of the valve seat, and this drain should be
piped to a safe discharge area.
15. If a silencer is used on a safety valve, it should have sufficient outlet area to
prevent back pressure from interfering with the proper operation and
discharge capacity of the valve. The silencer or other piping components
should be constructed so as to avoid the possibility of creating corrosion
deposit restrictions in the steam passages.
16. Exhausts, drains, and vents must be installed so that they will not impose
undue stresses on the safety valve. Any such stresses can produce body
distortion and leakage. Therefore, the following recommendations are
provided:
a. Discharge piping should not be supported by the valve. The maximum
weight on the outlet of the valve should not exceed the weight of a short
radius elbow and flange, plus a twelve (12) inch (304.8 mm) straight
length of standard weight thickness pipe (with drip pan).
b. Clearance between the valve exhaust piping and the discharge stack
should be sufficient to prevent contact when considering thermal
expansion of the header, valve, and discharge stack. Movements due
to vibration, temperature changes, and valve reaction forces should also
be considered, to insure adequate clearance between the exhaust
piping and the discharge stack.
c. Flexible metal hoses are not generally recommended, but if used to
connect valve outlets to discharge stacks, they must be of sufficient
length, and be configured/installed in such a manner, that they will not
become “solid” in any one position. Better results are obtained if the
hoses are installed so that they will permit movement by bending, rather
than by stretching and compressing along their length.
17. When liftinga valve, the valve should always remain in a vertical position.
The valve may be lifted by using a sling around the valve yoke and the valve
outlet neck. In no case should the valve be lifted by the lifting lever.
The valve should not be bumped or dropped during installation. If the valve
is dropped, an inspection for damage should be made, and the set pressure
of the valve rechecked.
CON-1
Page 15
VIII.A. (Continued)
18. At the time of installation, all protective covers on the valve should be
removed. The internals of the valve are to be checked for cleanliness. No
foreign matter is permitted in the valve inlet or outlet, since it may possibly
damage the valve components, or be dropped into the header.
All face surfaces which require gaskets, to seal pressure, shall be inspected
for cleanliness, or any defects that can cause leakage. Burrs, mashed
serrations, uneven surfaces, etc., are all possible leakage producing defects.
Proper gasket sizes and pressure ratings should be checked prior to starting
valve installation.
19. It is of utmost importance that the gaskets used be dimensionally correct for
the specific flange, and that they fully clear the valve inlet and outlet
openings. Gaskets, flange facings, and bolting should meet the service
requirements for the pressure and temperature involved. Other valve
installation considerations include:
a. Install the inlet gasket, if required, on the header mounting flange. Check
for cleanliness, surface alignment condition, gasket condition, etc.
When possible, inlet studs on the mounting flange should be used to
guide the valve on the header mounting flange. Inlet studs should be
lubricated with the appropriate lubricant.
b. When installing flanged valves, the flange bolts must be pulled down
eveningly to prevent body distortion, misalignment, and leakage.
c. With valve in position,screw on the stud nuts until all nuts are finger tight.
An initial torque shall be placed, in turn, on each stud nut. Increase the
torque progressively until the final torque is applied. Upon completion,
recheck each stud nut’s torque. Required torque will vary with bolting
material and gaskets used. See your company engineering or
specification department for details.
As an extra precaution, the gap between the two mating flanges should
be checked during the torquing process to insure that the flanges are
being pulled together evenly. Calipers may be used for this verification.
A final inspection and review should be made to insure that all of the
requirements for bolting the valve inlet have been implemented.
d. In like manner, the outlet piping may now be installed. A complete
inspection of components and their cleanliness is to be made prior to
further work. Studs are to be lubricated with an appropriate lubricant.
e. Install the outlet gasket, studs and nuts. Stud nuts are to be pulled down
finger tight. An initial value of torque is to be applied. The additional
procedures outlined, in Step 19.c., (above), are also to be followed.
20. After being assured that the valve is properly installed, the drainage piping
from the valve body-bowl is to be connected. This line also must be flexible,
so it will not create loads on the valve under operating conditions.
21. Prior to completing the installation, a visual check should be made to insure
that the valve lifting lever is free to operate.
22. At the time of installation, an inspection of the valve should be made to
confirm that all adjustment components (i.e., ring pins, cap, etc.) are properly
locked and sealed, as required by the ASME Code.
23. Flanged valves may be installed without insulation.
24. For operational hydrostatic tests at the valve inlet, which do not exceed valve
CON-1
Page 16
VIII.A. (Continued)
set pressure (1.0 x design pressure), the valve may be gagged. Refer to the
“Field Testing” portion of this manual (i.e., Section X) for proper techniques.
Insure that the gag is removed upon completion of the inlet hydrostatic test.
25. Prior to startup of the unit on steam, the sections of this manual which specify
requirements for set pressure testing should be reviewed. For conditions
where the valve is subjected to high steam pressures (i.e., those exceeding
normal operating conditions), preparations should be made to gag the
valves. These preparations should then be cleared with the boiler
manufacturer and DVCD Engineering. Refer to Section XV of this manual for
the proper gagging techniques.
26. The safety valve should be tested with full steam pressure to insure that the
safety valve installation has been properly accomplished. In some cases this
is not practical, thus the use of the CONSOLIDATED® Hydroset, or the
Electronic Valve Tester (EVT), should be considered. For valves being
tested for set pressure by using a Hydroset or EVT, only the set pressure
is being verified. Other factors such as blowdown, lift, reaction force, proper
discharge stack sizes and effects of thermal expansion cannot be determined.
27. Vent and drain piping should have a union connection to facilitate valve
removal.
B.
Outdoor Safety Valve Installation
Safety valves operating under the best possible conditions (i.e., of favorable
operating gap, relatively stable ambient temperatures, the absence of dirt and
in relatively still air) will provide the maximum degree of safety, tightness and
dependability.
When a safety valve is installed in an outdoor location, it may be exposed to wind,
rain, snow, ice, dirt and varying temperatures. Therefore, the following
recommendations are made for proper protection, and to insure that operational
dependability can be restored to a level near that of the valve installed under ideal
conditions:
1.
2.
3.
CON-1
The inlet neck of the safety valve and safety valve body, up to the bottom
of the cover plate in the Maxiflow Safety Valve, should be insulated. The
exterior surface of any such insulation should be made weather-proof by
any suitable means. In addition to maintaining a more even temperature
within the valve body, especially during widely fluctuating ambient
temperatures, this insulation will effectively reduce thermal stresses, due
to high temperature gradients, through the walls of the safety valve nozzle.
Spring covers should be used to stabilize (as nearly as possible) the
temperature of the spring, to prevent the accumulation of snow and ice
between the coils of the spring, and to prevent dirt and fly ash from
accumulating between the coils of the spring.
Lifting gear covers should be installed to prevent ice, dirt and fly ash from
accumulating in areas inside the safety valve cap.
appropriate considerations
should be made for draining
any condensate which may
accumulate in the cover plate
vent piping
Page 18
IX. Hydrostatic Test Plug RemovalDomestic and Export
A.
General Information
Flanged inlet safety valves should be removed from the boiler during
hydrostatic tests and boiler nozzles blanked off to prevent possible valve
damage.
All valves shipped outside the continental United States are shipped with an
export hydroplug. All welded inlet valves shipped within the continental United
States are shipped with a domestic hydroplug, unless the customer specifically
requests otherwise. All flanged inlet valves shipped within the continental United
States are shipped without a hydroplug, unless one is specifically re-quested by
the customer.
Valves shipped with either type of hydroplug are identified by a Red on White
CAUTION TAG which is attached to the valve by wires extending through the
drain hole in the valve body. See Figure 6 (below).
The hydrostatic plugs are placed in the bore of the valve, inside the seating
surface. Their purpose is twofold. First they effect closure at a point differing from
the seating surface of the valve so that, if the valve is lifted on hydrostatic test,
the seating surface is not as likely to be damaged. Second, by raising the disc
of the valve off its seat and increasing spring compression, the set pressure of
the valve is increased to a point where the valve will not leak at one and one-half
times design boiler pressure. It is not necessary to gag safety valves tightly when
hydrostatic plugs are used.
These plugs must, of course, be removed from the valves prior to placing the
boiler in service. However, they should be retained, and reinstalled, whenever
a hydrostatic test exceeding the low set valve pressure is conducted.
CON-1
Page 19
IX. (Continued)
B. Domestic Plugs
1. Disassemble the valve as outlined in Section XI of this manual.
2. Remove the hydrostatic test plug from the seat bushing, and lap disc
and bushing seat.
3. Always be certain that all parts are clean and free of dirt and foreign
material. Dirt trapped on seating surfaces or in the inlet, when the
valve is reassembled, will damage the seats. Reassemble the valve
as outlined in Section XIII of this manual. The lug on the top spring
washer should be on the left side of the valve when facing in the same
direction as the outlet. (See Figure 7, below.)
4. Replace the cap, and locate the drop lever vertically on the center line
of the valve.
5. Remove the top lever from the cap, and reassemble in position in
accordance with Figure 7. If properly positioned, the top lever should
have 1/8" (3.175 mm) of vertical movement prior to engaging bottom
surface of release nut. The valve is now ready for the initial field test,
on steam, to check valve set point and blowdown.
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Page 20
IX. (Continued)
C. Export Plugs
When hydrostatic plugs are installed in Maxiflow Valves scheduled for shipment
to foreign countries, the disc is removed and dipped in preservative, then packed
in a box. The package is then inserted into the valve outlet and taped to the floor
of the valve body.
To remove the special export plug, Figure 8 (below), the following steps must be
followed.
1. Disassemble the valve as outlined in Section XI of this manual.
2. Remove the export plug by turning it counterclockwise, until it is
disengaged from the spindle thread.
NOTE:
Hold the disc holder against the disc adjusting collar during this
step, otherwise the disc holder will fall from the spindle and
become damaged.
3. Remove the seal peel preservative from the disc and thoroughly clean
the disc seat with a clean cloth. Then, lap the disc and bushing seat.
Lubricate the spindle tip with "Anti-Seize", and assemble the disc and
disc holder to spindle by turning the disc clockwise until the dropout
thread disengages. Reassemble the valve as outlined in Section XIII
of this manual. The lugs on the top spring washer should be on the left
side of the valve when facing in the same direction as the outlet.
(Again, see Figure 7 on the preceeding page.)
4. Remove cotter pin from release nut and position release nut so that
1/8 in. (3.175 mm) of clearance is visible between lifting fork and
release nut, then install cotter pin.
5. Install lifting gear as outlined in Section XIV of this manual.
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Page 21
X. Field Testing
A.
General Information
All 1700 Maxiflow Safety Valves are steam tested at the factory to verify set
pressure adjustability and seat tightness. Every valve is set to have a clean
popping action and to reseat tightly. However, because the boiler used in setting
the valves has a small capacity, compared to the capacities of the Maxiflow type
of valves, adjustments on the actual installation are necessary to ensure proper
valve action and “adjusting ring” settings.
When supplied for pressures over 2500 psi (172.4 Bar), the compression screw
lock nut will be locked to the compression screw with a 1/4-20 Allen screw, in
order to locate the exact amount of compression screw engagement in the valve
yoke. The compression screw has then been backed out to decrease the spring
load on the seat by 75%. See Red Letter Warning Tag, attached to compression
screw of each Maxiflow Valve by means of double strand sealing wire, which
reads as follows:
WARNING
This valve has been steam tested and set to the proper set
pressure; however the compression on the spring has been
relaxed by backing out the compression screw.
Before the hydrostatic test on the boiler the compression screw
must be turned clockwise until the lock nut makes up on the yoke.
Remove the 1/4-20 allen screw to allow the lock nut to turn on
compression screw for future adjustments.
(Note attached tag for hydrostatic plug removal).*
Upon completion of hydrostatic testing of the boiler, but prior to placing the boiler
in service, insure that the hydrostatic plugs are removed from all valves. (Note:
See Figure 6 on page 18 of this manual). The use of a DVCD Hydroset or EVT,
unit can serve to establish set pressure but cannot be used for verifying
blowdown, lift, etc. (For additional information, see Section X.E., of this manual).
Gagging of other valves not being set will not generally be necessary; however,
for setting of high pressure valves, depending on system pressure being used,
it may be necessary to gag the lower set valves.
Boiler safety valve tests can be conducted with the unit either on or off the line.
However, with the unit on the line under full load, a sudden load drop could be
dangerous as most of the safety valves will be gagged. Therefore, it is
recommended that the safety valves be tested and adjusted with the boiler
isolated, or with light load. Boiler control can then be maintained, with little or no
outside influence due to load change.
It is important to note that all adjustments of adjusting rings are DVCD initial
adjustments only, and are not intended to be final adjustments. This final
adjustment must be made on the operating system with conditions approximately
those that will be realized under actual operating conditions. Valves are factory
set for long blowdown to prevent chattering under initial setting conditions.
* This parenthetical statement is a reference to the tag shown in Figure 6, on page 18 of this manual.
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Page 22
X.A. (Continued)
Factors which can affect valve operation, and which should be considered when
initially setting a valve, are as follows:
1. Ambient temperature near the valve and valve temperature stabilization.
2. Line vibration.
3. Line capacity at time when the valve must lift.
4. Discharge stack or drain piping binding.
5. Fluid flow vibrations set up by upstream bends and other disturbances.
B. Popping Point Adjustment
NOTE:
Prior to beginning this procedure, lower the operating pressure
on the boiler to a point which ensures that the valve will not
open during adjustment of the compression screw.
To change the popping pressure of the valve, remove the cap and lever
assembly, loosen the compression screw locknut and turn the compression
screw clockwise to increase the pop point, or counterclockwise to decrease the
pop point.
After each adjustment of the compression screw, the lock nut should be
tightened. The arm of the top spring washer should always be free from bearing
against the yoke rod. This can be accomplished by holding a screw driver
between the arm and the rod to prevent any movement of the top spring washer
while adjusting the compression screw. Install the cap and lever assembly after
set pressure adjustments have been completed, as outlined in the Re-assembly
instructions (see Section XIV of this manual).
C.
Ring Adjustments, Blowdown and
Overlap Collar Adjustments
1. General
The positions of the upper adjusting ring and the lower adjusting ring
are locked by means of the upper adjusting ring pin and the lower
adjusting ring pin, respectively. These pins are threaded into the valve
body and engage notches which are cut into the rings. To adjust either
ring, the corresponding ring pin must be removed. A screw driver (or
other suitable tool), inserted through the ring pin hole, can be used to
turn the rings.
NOTE:
Always gag the Safety Valve for protection. This will ensure that the
disc is not accidentally lifted from the seat by the adjusting tool
during ring adjustment. This will also ensure that an unexpected rise
in system pressure will not be a hazard to service personnel.
CON-1
Page 23
X.C.
(Continued)
2. Lower Ring Adjustment
If the lower adjusting ring position is in question, the factory position
can be attained as follows:
a. Gag the safety valve to prevent the disc from being accidentally
lifted from the seat.
b. Remove the service port plugs.
c. Remove the lower adjusting ring pin.
d. Move the lower adjusting ring up until it contacts the disc holder.
e. Refer to Figure 9 (below), and move the lower adjusting ring down
the number of notches indicated in Column A, plus 1 additional
notch for each 600 psig increment of set pressure, not to exceed
six notches (see Table I, also below).
TABLE I
Final Factory Positions
(Field Starting Positions)
ORIFICE
1
2
3
5
4
6
7
Q
8
R
LOWER RING
UPPER RING
HOLDER TO SEAT HOLDER TO SEAT
IN NOTCHES
IN NOTCHES
(Column A)
(Column B)
7
8
12
12
12
30
30
30
37
38
10
12
16
16
16
45
45
45
45
47
CON-1
Page 24
X.C. (Continued)
WARNING
f.
Lock the lower adjusting ring into position by installing the lower
adjusting ring pin, clockwise, until tight.
g.
Remove the gag.
h.
Test the valve on the system and adjust the lower ring to the lowest
position which does not produce simmer.
The ideal ring position must then be found by test for the set of
operating conditions present. If simmer is present or the valve fails
to lift, the lower ring should be moved upward slowly, one notch at
a time, to remove the simmer. The most ideal position for the lower
ring is the lowest position that does not introduce simmer or a
buzzing sound.
3.
Relationship Between Upper Ring and Overlap Collar Adjustments
and Blowdown
The correct method of obtaining proper blowdown adjustment can be
best explained by reference to Figure 10 (below).
The upper ring is used to obtain full lift at the popping pressure.
However, its position also determines the point at which the valve
begins to drop out of full lift and starts the closing portion of its cycle. For
example, if the upper ring is in such a position that the valve barely
attains full lift at the popping pressure, and starts to drop out of full lift
at a slight reduction of boiler pressure, the first portion of the valve cycle
will be represented by the line ABF. If it were not for the lift stop, the
action of the valve would be represented by the line ABCF. If the upper
ring is in a more positive position (lower setting), the action of the valve
would be represented by the line ABG and, if it were not for the lift stop,
the line ABDG. If the upper ring is in a still lower position, the action of
the valve is represented by the line ABH and, if it were not for the lift
stop, ABEH. From this it can be seen that a lower position of the upper
ring causes that valve to remain in full lift for a longer period of time and
over a greater period of pressure reduction.
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Page 25
X.C. (Continued)
It will further be noted that there is a distinct difference between the
actual overlap setting on the valve and the point at which the overlap
begins to take effect. This can be understood since the area in the
overlap vent begins to reduce considerably ahead of the point where
the upper corner of the overlap bevel actually enters the floating
washer. This has the effect of rounding off the corners of the diagram
at points J, K & L. If the upper ring is in a position to produce the line
ABH, the overlap will have to be set considerably higher to obtain a
short blowdown than if the upper ring is set at such a position as to
produce the line ABF. Excessive overlap settings may cause seat
damage when the valve closes. It is therefore desirable to set the upper
ring in such a position as to cause the valve to stay in full lift for as short
a time as possible. The most desirous complete cycle is represented
by the line ABFJM.
NOTES:
•
When steam safety valves are subjected to an excessively high
water level, the valve can be expected to have a long blowdown
which the upper adjusting ring position will be unable to correct.
It is recommended that the cause of high water level be corrected,
so valves may function correctly at the ordered condition.
•
If a superheater valve is set with low temperature steam, it is
advisable to increase the blowdown to compensate for the change
in density and other thermal effects taking place when the steam
is brought up to working temperature. An approximate rule is to
add 1/2 of 1% of set pressure to the blowdown for each 100°F
(37.8°C) of steam temperature below the final temperature.
4. Upper Ring Adjustment
If the upper adjusting ring position is in question, the factory position
can be attained as follows:
a. Gag the safety valve to prevent the disc from being accidently lifted
from the seat.
b. Remove both service port plugs.
c.
Remove upper adjusting ring pin.
d. Move the upper adjusting ring until it is level with the disc holder.
A flashlight may be needed to provide adequate lighting for this
observation.
If so, the observation can be made from one of the service ports
while the flashlight is positioned to shine through the other service
port.
e. From this point, move the upper adjusting ring down the number of
notches indicated by Column B of Table I (see page 23). This is
also Dimension B in Figure 9 (again, see page 23).
f.
Lock the upper adjusting ring into position by installing the upper
adjusting ring pin.
g. Remove the gag.
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Page 26
X.C. (Continued)
5.
Blowdown Adjustments
When further adjustments are required to obtain final blowdown setting,
the upper adjusting ring should be moved 5-10 notches at a time as
follows:
a.
To reduce blowdown - MOVE RING UP - TURN COUNTERCLOCKWISE.
b.
To increase blowdown - MOVE RING DOWN - TURN CLOCKWISE.
It is possible to raise the upper ring too far and prohibit attainment of full
lift. When this occurs, lower the upper adjusting ring to the point where
full lift is attainable and finalize the blowdown setting with the overlap
collar adjustments (see Section X.C.6., below). If the valve fails to lift,
the lower adjusting ring requires further adjustment (see Lower Ring
Adjustment on page 23).
In attempting to obtain blowdown of 4%, it is important to be sure that
the upper and lower adjusting ring positions are not so far apart as to
cause loss of control of the valve. The first indication of reaching this
condition is a slow “up and down hunting” action of the valve immediately
before closing. If this action occurs at a blowdown longer than desired,
moving both rings downward a small amount will generally produce a
slightly shorter blowdown. When making this adjustment, move the
upper ring twice as many notches as the lower.
After adjustments are complete, check the ring pins to see that they
engage the ring grooves, but without touching the bottom of the groove.
The pins should not bear against the rings.
6.
Overlap Collar Adjustment
The overlap collar is a secondary adjustment point for blowdown
control. It is utilized in conjunction with the upper adjusting ring. There
will be some field conditions where it may not be necessary to use the
overlap collar. However, in no case should the overlap collar be used
exclusively for blowdown setting without first giving due adjustment
attention to the upper adjusting ring.
The overlap collar is moved downward to shorten blowdown and
upward to lengthen blowdown. After final setting, be sure to lock the
overlap collar in position by installing the cotter pin.
A guide to how movement of the overlap collar assists in making final
blowdown adjustments is as shown in Table II on the next page.
CON-1
Page 28
X. (Continued)
F. Sealing Valves After Test
After testing the valve for proper set point and blowdown, the ring pins, overlap
collar and top lever pin will be sealed to conform with the applicable ASME Code.
In addition, the cover plate is sealed on restricted lift valves.
Means are provided in the design of all 1700 Maxiflow valves, for use under
Section I of the ASME Code, for sealing all external adjustments. Seals are
installed by DVCD at the time of shipment. It is also required that seals be
installed, after field adjustment or repair of the valves, by the manufacturer, its
authorized representative, or the user.
Seals should be installed in such a manner as to prevent changing the
adjustment without breaking the seal. They also serve as a means of identifying
the manufacturer, repairer, or user making the adjustment. Unauthorized
breakage of the seals will void the valve warranty.
XI. Disassembly Instructions
A.
General Information
The Type 1700 Maxiflow Safety Valve can be easily disassembled for inspection,
reconditioning seats, or replacing internal parts. The initial spring load can be
established after reassembly. (Again, refer to Figure 7, on page 19, for parts
nomenclature.)
NOTES:
B.
•
Before starting to disassemble the valve, be sure that there is
no steam pressure in the drum or header.
•
Parts from one valve should not be interchanged with parts
from another valve.
Specific Steps
1. Remove the top lever pin and top lever.
2. Loosen cap set screw and lift off cap and drop lever assembly.
3. Remove the cotter pin which retains the release nut, and then remove
the release nut.
CON-1
Page 29
XI.B. (Continued)
4. Refer to Figure 11 (below), and measure and record Dimension A, as
this information will be required to correctly re-assemble the valve.
5. Remove the two top yoke rod nuts evenly, so as to prevent binding of
the yoke.
6. Carefully lift the yoke over the spindle, and away from the valve.
Remove the thrust bearing assembly (if applicable) and the top
spring washer.
7. Ensure that the bottom spring washer is not stuck to the spring. If the
bottom spring washer is stuck to the spring it may accidentally jar
loose and fall. Next, mark the top of the spring, in order to correctly
install the spring during re-assembly. Finally, lift the spring over the
spindle and away from the valve, and then remove the bottom spring
washer.
8. Remove the overlap collar cotter pin from the collar and spindle
assembly. Note which overlap collar notch is opposite the cotter pin
hole in the spindle. (See Figure 12, below.) Carefully counting each
collar notch that passes in front of the cotter pin hole in the spindle,
begin rotating the collar counterclockwise until the bottom line (of the
four lines) on the collar is even with the upper floating washer. Record
the number of overlap collar notches that passed in front of the cotter
pin hole in the spindle, as this information will be required to correctly
re-assemble the valve.
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Page 30
XI.B. (Continued)
9.
Mark the cover plate vent to establish its relationship to the valve
base, as this will ensure correct alignment during re-assembly, then,
remove the cover plate stud nuts, and lift the cover plate over the
studs.
10.
Remove the spindle, disc and disc holder assembly from the valve
by lifting the spindle. Take care to insure that the disc seating
surface is not damaged when the assembly is placed on the ground
or some other work surface.
11.
To remove the disc and disc holder from the spindle, first insert the
spindle into a vise (see Figure 13, below) being careful not to
damage the threaded end of the spindle. Then, lift up on the disc
holder and turn the disc/disc holder counterclockwise to engage the
"drop-thru" threads. Once the threads are engaged, release the disc
holder and continue to unthread and remove the disc. After the disc
is removed, lift the disc holder from the spindle.
NOTE:
Removal of the overlap collar, the lift stop and/or the disc collar
from the spindle is usually unnecessary, unless the spindle is to
be replaced.
CON-1
Page 31
XI.B. (Continued)
12.
Measure from the top of the guide to the bushing seat (Dimension
B, Figure 14, below) with a depth micrometer or other suitable
measuring device. Record Dimension B. Place a scale or other
thin flat metal surface against the lower face of the upper adjusting
ring and measure from the top of the guide to the face of the upper
adjusting ring (Dimension C, Figure 14, below). Record Dimension
C.
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Page 32
XI.B. (Continued)
13.
CON-1
Remove the upper adjusting ring pin from the valve base. Remove
the upper adjusting ring and guide assembly from the base by lifting
straight up on the guide being careful not to disturb the upper
adjusting ring adjustment. Mark the radial position of the upper
ring notches relative to the guide by marking or scribing axially on
the guide, then making a corresponding mark axially on the upper
adjusting ring (see Figure 15, below). Recording Dimensions B and
C and marking of the upper adjusting ring and guide will aid in setting
the adjusting ring in exactly the same position it was in prior to
disassembly.
Page 33
XI.B. (Continued)
14.
Loosen the lower adjusting pin until the pin is slightly clear of the
notches in the lower adjusting ring. Being careful not to move the
lower adjusting ring, place a ring lap on top the busing seat. (See
Figure 16, below). Then, using the ring pin as a “pointer”, or
reference point, rotate the lower adjusting ring counterclockwise
and count the number of notches that pass in front of the “pointer”
until contact is made with the ring lap. Record this information, as it
will be required to correctly re-assemble the valve.
FIGURE 16
15.
Next, remove both the lower adjusting ring pin and the lower
adjusting ring from the valve base.
16.
Normally the yoke rods do not have to be removed from the valve
base. If however, it becomes necessary to remove them, the
procedure below should be followed:
17.
a.
Mark each rod relationship to where it contacts the valve base
"ears", and also identifying which rod is to the right and which
rod is to the left of the valve outlet.
b.
Loosen the yoke rod nuts using the appropriate size socket
and handle.
c.
Remove the nuts, and then pull up on each rod to remove it
from the base.
The valve is now ready to be cleaned and the parts inspected for
proper size and condition.
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Page 34
XII. Inspection
A. General
Once the valve is disassembled, appropriate parts can be inspected for damage
and their suitability for reuse.
B. Specific Steps
As a minimum, the following parts should be inspected as specified below:
1. Disc Holder
The surface on the end of the disc holder closest to the disc must be
free from steam erosion. The two small holes must be open to insure
the passage of steam to the chamber above the disc. Make sure the
outside diameter is not egg shaped and the surface is smooth. If any
small indication of galling is present, polish the high spots with an
emery cloth. If serious or large scale galling is present, the disc holder
should be replaced.
2. Guide
Inspect the guide inside diameter for egging, and insure the inside
surface is smooth. The threads on the outside must be in good
condition to insure the upper ring will adjust, even when the valve is
hot. If serious or large scale galling is present, the guide should be
replaced.
3. Clearance
The maximum clearance between the disc holder and guide should be
in accordance with Table III (below):
TABLE III
ORIFICE SIZE
#1
#2
#3
#4
#5
#6
#7
#Q
#8
#R
CON-1
TEMPERATURE
UP TO 750°F
ABOVE 750°F
UP TO 750°F
ABOVE 750°F
UP TO 750°F
ABOVE 750°F
UP TO 750°F
ABOVE 750°F
UP TO 750°F
ABOVE 750°F
UP TO 750°F
ABOVE 750°F
UP TO 750°F
ABOVE 750°F
UP TO 750°F
ABOVE 750°F
UP TO 750°F
ABOVE 750°F
UP TO 750°F
ABOVE 750°F
MAX. CLEARANCE (in.)
.005
.008
.008
.012
.010
.015
.012
.018
.011
.017
.016
.016
.020
.020
.020
.020
.020
.020
.020
.020
Page 35
XII.B. (Continued)
4. Disc
Inspect the disc seat for steam cuts, nicks, or other damage. If the seat
step measure less than dimensions specified in Table IV (below), this
indicates that the thermal lip has been lapped to the minimum
thickness.
Do not machine any THERMOFLEX™ disc; however, a disc which
is not below minimum relief can be lapped to remove minor damage.
(See Figure 18, on page 38 for more information.)
TABLE IV
MINIMUM SEAT RELIEF
ORIFICE
M(MIN.) (in)
1
2
3
5
4
6
7
Q
8
R
.004
.005
.006
.007
.008
.010
.012
.012
.012
.012
5. Overlap Collar
Inspect the outside diameter for nicks, burrs, tears, pitting and signs
of galling. Then, inspect the lugs for bending or damage, and the
threads for signs of galling, tearing, and damage.
6. Cover Plate
Ensure that the floating washers are free to move and are not bent or
deformed. Check the surface of the inside diameter on the floating
washers and the washer retainers for tears, pitting, corrosion, and
signs of galling. Ensure that the bleed hole in the cover plate is not
obstructed.
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Page 36
XIII. Maintenance Instructions
A. General
It is not necessary to remove Type 1700 Maxiflow Safety Valves from the boiler
for maintenance. The normal maintenance required is generally confined to
touching up seats and occasionally replacing the disc.
The following tools are recommended for this work:
1.
Flat lapping plate (Part No. 0439004)
2.
Grinding compounds
3.
High temperature lubricant (Fel-Pro Nickel Ease)
4.
Two (2) ring laps per valve size and type
See Maintenance Tools & Supplies (in Section XVII of this manual).
All of the above tools can be procured from DVCD, with prices being those that
are in effect at the time of delivery. It may not be necessary to use all of the ringlaps at any one time, but having a sufficient supply on hand will save the time of
reconditioning them during a boiler outage. After the boiler is back on the line,
the ringlaps should be reconditioned on the flat lapping plate, or returned to the
factory for reconditioning, at a nominal cost, on a special lapping machine. A lap
should not be used on more than one valve without being reconditioned.
Valves that have been leaking should be disassembled in accordance with prior
instructions. Since the position of the adjusting rings has been recorded, the
rings can be removed for cleaning every time the valve is disassembled. Parts
for each valve should be kept together or marked, to ensure that they are
replaced in the same valve.
Reconditioning of the seat surface of the disc and seat bushing is accomplished
by lapping with a flat cast iron, ring lap, as outlined in the lapping procedure.(See
Section XIII.B, below).
B. Lapping Procedure
1.
General Information
While the finer points of lapping and “grinding-in” may be considered
as a mechanical art, it is not beyond the ability of the average
mechanic to produce good seats with some practice. No effort has
been made in this manual to establish an exact procedure to cover
each and every case, because different persons can get the same
results using their own techniques.
The following precautions and hints will be of assistance when lapping
nozzle and/or disc seats:
a. Two (2) ring laps per valve
b. 1A Clover Grinding Compound per tool list*
c.
1000 Grit Kwik-Ak-Shun Grinding Compound per tool list*
d. Clean, lint free cotton rags
CON-1
*
This tool list is located on page 57 of this manual
Page 37
XIII.B. (Continued)
Before lapping the nozzle and disc seat, the leading edges (inside
diameter of seats) of both must be slightly chamfered as follows:
Use a fine grade sandpaper to lightly break the inner edge and outer
edge of the nozzle seat and disc seat. The purpose of this is to remove
any small metal particles or fins attached to the sharp corner surfaces.
Do not exceed .002 inches (.05 mm) chamfer for this purpose.
2.
To Lap The Bushing Seat
NOTE:
If the bushing seat surface requires extensive lapping or
reconditioning, a reseating machine should be used prior to
lapping. (See “Reseating Machine“, in Section XIII.C., of this
manual.)
Cover the seat lap face with a light coating of 1-A Clover Compound
and gently place the lap on the valve bushing seat.
NOTE:
A heavy coat of lapping compound tends to round off the edges
of the seat.
Lap, using an oscillating motion in various directions, while holding the
lap loosely in the fingers and allowing the weight of the lap to rest on
the seat surface. Control the motion of the lap to prevent either the
inside or outside edge of the lap from crossing the bushing seat
surface. If either edge touches the seat surface, the seat can become
scratched and/or rounded.
NOTE:
Care should be used not to run off the seating surface with the lap,
as this will cause the seat to become uneven.
CON-1
Page 38
XIII.B. (Continued)
Do not lap excessively with a ring lap without resurfacing on a lapping
plate as shown in Figure 17 (below). Use a new ring lap, if further
lapping is required, to remove any defect in the seat. To finish lapping
the bushing seat, apply a light coating of #1000 Grit Compound to the
face of the new lap, and repeat the above lapping motion.
Remove the ring lap and wipe the lap surface with a clean, lint free
cloth, leaving compound on the bushing seat. Replace the ring lap on
the seat and lap as above, but without adding compound. Repeat this
operation until the seat has a mirror finish. Any evidence of defects,
such as gray areas or scratches, will require a repeat of the whole
lapping procedure until a mirror finish is attained.
3.
To Lap Disc Seat
The above lapping method is also used on the disc seat. When lapping
the disc seat, the disc should be held stationery, but not rigidly, and the
lap moved as above. Use care not to strike the cone of the disc, as this
would cause the seat to be high on the inside.
The THERMOFLEX™ disc can not be machined. If, after lapping,
Dimension M , in Figure 18 (below), does not meet the minimum
specified in Table V (on the opposite page), the disc should be
replaced.
CON-1
Page 39
XIII.B. (Continued)
TABLE V
MINIMUM SEAT RELIEF
ORIFICE
M(MIN.) inches
1
2
3
5
4
6
7
Q
8
R
.004
.005
.006
.007
.008
.010
.012
.012
.012
.012
It may not be necessary to use all the laps at any one time, but having
a sufficient supply on hand will save reconditioning time. The laps
should be reconditioned on the flat lapping plate, and a lap should not
be used on more than one valve without being reconditioned. Laps
must be checked for flatness prior to use, and at frequent intervals
during use. A lap that is flat within one-half light band is considered
satisfactory. Information on the Monochromatic Light and optical flat is
available, upon request, from the DVCD Field Service Department.
To recondition a ring lap, wipe all compound from the lapping plate and
ring lap, then move the ring lap in a figure-eight motion on a lapping
plate. If the lap is not flat, a shadow will be apparent. To remove the
shadow, coat the lapping plate with 1000 Grit Compound and lap the
ring, with figure-eight motions covering the lapping plate, as shown in
Figure 17 (on page 38).
C. Reseating Machine Information
A DVCD reseating machine should be used to recondition badly worn, out of
tolerance, bushing seats. This machine can be provided by the DVCD Service
Department, and eliminates the need to remove a valve from the unit. The
machine is mounted in place of the yoke and cuts the top face, inside diameter,
and outside of the bushing, to establish the correct height, angles, and diameters.
CON-1
Page 40
XIII.C. (Continued)
Replace the seat bushing if critical dimension K (Max.) is exceeded. See Figure
19 and Table VI below. Do not remove threads.
TABLE VI
Valve Type
#1
#2
17.35, 36, 37
17.38, 39, 30
#4
#5
#6
#7
#Q
#8
#R
1706RXHPI
and
1707R only
Critical Dimension
K (Max.) inches
3-1/16
3-13/16
4-7/8
5-11/16
5-11/16
5-11/16
4-3/4
5-9/16
5-9/16
5-9/16
5-9/16
7-9/16
The use of the reseating machine is suggested for reconditioning badly worn
seats, or for re-establishing Dimension E per Figure 20 (below). Dimension E
should be re-established when it is less than .010 inches for orifices 9, 1, 2, K,
3, and 5, and 4 or less than .030 inches for orifices 6, 7, 8, R and RR.
FIGURE 20
As a result of machining the bushing seat, the length of disc holder extending
above the disc guide will decrease. Therefore, the top of the disc guide should
be kept to a distance of at least 1/16 in. (1.587 mm), beneath the top of the disc
holder, to facilitate freeing the disc holder, in case a deposit of dirt forms in the
pocket between the two parts. This dimension is obtained by machining the top
of the disc guide (see Figure 21, on opposite page).
CON-1
Page 41
XIII.C. (Continued)
D. Spindle Runout
It is important that the spindle be kept very straight in order to transmit the spring
force to the disc without lateral binding. Overgagging is one of the common
causes of bent spindles. A method to check the essential working surfaces of the
spindle is illustrated in Figure 22 (below). This may be performed either with or
without the disc collar and lift stop on the spindle.
Using Figure 22 (above) as a reference, clamp a V block (A) made of wood, fiber
or other suitable material onto the platform railing. Imbed the ball end of the
spindle in a piece of soft wood (B) and place the top of the spindle, below the
threads, in the V block (A). Clamp a dial indicator onto the railing and locate at
point (C). The total indicator reading should not exceed .007 in. (.177 mm) when
the spindle is rotated. If it does, the spindle must be straightened prior to reuse.
To straighten the spindle, place the unthreaded portion of the small and large end
in padded V blocks, with the point of maximum indicator readout upward, and
then apply a downward force with a padded press or jack as required, until the
spindle is within the specifications.
CON-1
Page 42
XIII.D. (Continued)
Other parts of the spindle not used as working surfaces may run out considerably
more than .007 in. (.177 mm), but this should not be regarded as unacceptable.
Although the upper thread end is not a working surface, excessive bending in this
area could effect the accuracy of the DVCD Hydroset device and/or the DVCD
Electronic Valve Tester, if either of these devices is used to verify valve set
pressure.
E. Disc Replacement and Disc-Spindle Bearing Requirements
To replace the disc, disassemble the valve in accordance with the instructions
provided in Section XI of this manual.
Apply a small amount of lapping compound (1A) on the tip of the spindle. Install
the disc - without the disc holder - onto the spindle tip, turning it clockwise until
the disc threads drop out. Place a ring lap on a table, or similar flat surface, and
wipe the exposed surface of the lap clean. Insert the disc nose into a ring lap, so
that the seat contacts the lap surface. Oscillate the spindle using 360 degree
oscillations for approximately 15 seconds, then check the spindle tip and disc
“pocket” to determine progress. (See Figure 23, below).
CON-1
Page 43
XIII.E. (Continued)
The desired band width for subcritical valves is shown in Table VII (below), and
the desired band width for supercritical valves is shown in Table VIII on the next
page. In addition, the finished machine size of the spindle nose radius, and the
flat diameter for each orifice size and valve type are also shown in these two (2)
tables.
TABLE VII
SUB CRITICAL
ORIFICE
NOSE
RADIUS “R”
FLAT DIA.
BEARING
BAND WIDTH
IN.
MM
IN.
MM
IN.
MM
0.277
1
7.038
0.371
2
9.423
0.495
3
12.573
0.485
4
12.573
0.495
5
12.573
0.485
6
12.573
0.582
7
17.323
Q
0.582
17.323
8
0.713
18.118
R
0.713
18.118
+.000
-.004
+.000
-.102
+.000
-.004
+000
-.102
+.000
-.005
+.000
-.127
+000
-.005
+.000
-.127
+.000
-.005
+.000
-.127
+.000
-.005
+.000
-.127
+.000
-.005
+.000
-.127
+.000
-.005
+.000
-.127
+.000
-.005
+.000
-.005
+.000
-.005
+.000
-.127
1/8
1/8
3.175
3.175
3/16
1/8
4.783
3.175
1/4
7/32
9.358
5.556
1/4
7/32
8.350
5.558
1/4
7/32
6.350
5.556
1/4
7/32
6.350
5.556
1/4
9/32
6.350
7.143
1/4
9/32
6.350
7.143
5/16
5/16
7.938
7.937
5/16
5/16
7.938
7.937
CON-1
Page 44
XIII.E. (Continued)
TABLE VIII
SUPER CRITICAL
NOSE
RADIUS "R"
ORIFICE
IN
MM
FLAT DIA.
BEARING
BAND WIDTH
IN
MM
IN
MM
1
.371
9.423
3/16
4.763
5/32
3.968
2
.371
9.423
3/16
4.763
5/32
3.968
K
.594
15.087
NONE
NONE
1/4
5.35
3
.495
12.573
1/4
6.350
7.32
5.556
4
.495
12.573
1/4
6.350
7/32
5.556
5
.495
12.573
1/4
6.350
7/32
5.556
If the required bearing band cannot be obtained by hand grinding, then this radius
should be checked and remachined if necessary.
If the band extends too high on the radius it will be difficult to rock the disc, and
the disc may lock up under pressure. If the band is too narrow, the spindle may
indent the disc and again the rock will be lost.
When the bearing area is re-established, clean both surfaces. Then apply
lubricant to the spherical surface of the spindle tip, and work it into the surfaces
by rotating the disc on the spindle.
Place the disc holder on the spindle, allowing it to rest on the face of the disc collar
as previously shown in Figure 13 on page 30. Then assemble the disc holder and
new disc. The disc should be free enough to rock on the spindle tip. If there is no
freedom, lower the disc collar until the disc is free to rock slightly initially,
approximately .001 to .002 inches (0.25 to .05mm) rock. The disc collar must
then be lowered two additional notches from this initial position and secured with
a stainless steel cotter pin. (See Figure 25, below).
NOTE:
Failure to provide the recommended disc rock at assembly will result in a
leaking valve.
CON-1
Page 45
XIII. (Continued)
F. Grinding the Compression Screw
Some valve designs feature a compression screw with a spherical radius tip as
shown in Figure 26 (below). For these designs, the compression screw spherical
bearing surface must be ground into the upper washer so that full contact along
the spherical radius is obtained. To grind these items, a 320 grit (Clover 1A)
lapping compound is used for roughing-in and then finish lap with 1000 Grit KwikAk-Shun lapping compound, until a satisfactory bearing band is obtained. Clean
the compression screw, and upper spring washer when completed.
G. Thrust Bearing Surfaces
For those designs utilizing a ball-type thrust bearing, the aligning washer must
match evenly to the lower thrust bearing spherical surface, such that full face
contact is achieved between the parts (see Figure 27, below). Therefore, grind
together, or replace the entire thrust bearing, as necessary.
H.
Grinding The Lower Spring Washer
The lower spring washer bearing surface must be ground to the spindle. To grind
the lower spring washer, a 320 grit (Clover 1A) lapping compound is used for
roughing-in, and then finish lap with 1000 Grit Kwik-Ak-Shun lapping compound
until a satisfactory bearing band is obtained. The bearing width should be 1/8 in.
(3.2 mm) min. to 3/16 in. (4.8 mm) max. Clean the lower spring washer and
spindle when complete.
CON-1
Page 46
XIV. Re-Assembly
A.
General Information
The Type 1700 Safety Valve can be easily re-assembled after required inspection/
maintenance of internal parts has been performed. (Again, refer to Figure 7, on
page 19, for parts nomenclature.) All parts should be clean prior to assembly.
See Section XVII for recommended compounds, lubricants, and tools.
B.
Specific Steps
1.
If they have been removed, the yoke rods are installed into the base,
and then the yoke rod nuts installed. Locate the yoke rods in the
original location in the valve base as recorded during disassembly.
Lubricate all threads. Yoke rod nuts are then to be torqued using the
yoke rod nut torque wrench and socket. Torque nuts in accordance
with Table IX (below).
NOTE:
Use of an impact device to produce required torque values is
not recommended.
TABLE IX
YOKE ROD NUT TORQUES - FOOT POUNDS
ORIFICE
PRESSURE CLASS
5
6
7
8
9
0
1
150
150
150
120
120
120
2
150
120
120
150
150
150
3
250
150
150
300
300
300
5
300
300
300
350
350
350
4
300
300
300
350
350
350
6
300
300
300
500
7
500
350
500
8
500
500
750
8-xhp
R
R-xhp
2.
CON-1
1000
750
500
500
750
750
Prior to reinstalling the lower adjusting ring, lubricate the threads of
the lower adjusting ring pin and partially insert the pin into the valve
body. Now the pin can again serve as a “pointer”, or reference point,
as previously discribed in Section XI.B.14 of “Disassembly” . Next
lubricate the threads of the lower adjusting ring, and install the ring
in the valve body. Then, turn the lower adjusting ring clockwise until
the top of the ring clears the seat.
Page 47
XIV.B. (Continued)
3.
To position the lower adjusting ring, place a clean ring lap on the
nozzle seat and move the lower adjusting ring up until it makes
contact with the ring lap. If the original location of the adjusting ring
was recorded, simply lower the ring, by moving it down, the same
number of notches as was recorded in Step XI.B.12 of “Disassembly”.
If information on the original lower ring position is not available, the
ring should be lowered, by moving it down one notch for every 600
psig (41.38 bar) of set pressure.
NOTE:
For a valve set pressure of 1200 psig (82.76 bar), the ring will
have to be lowered two (2) notches below the bushing seat. This
will be the starting position, with the final position being
determined during field testing (see Figure 28, below).
4.
Once the lower adjusting ring is in its correct location, lock it in place
by screwing in the lower adjusting ring pin. Verify that the lower ring
is capable of a slight movement. If the lower ring does not move, the
pin is too long. Should this be the case, grind the end of the pin
slightly to shorten it, while retaining the original tip contour, then
reinstall the pin.
5.
If the upper adjusting ring has been removed from the guide,
lubricate the ring threads and re-install the ring on the guide.
CON-1
Page 48
XIV.B. (Continued)
6.
CON-1
Install the adjusting ring and guide assembly into the valve base
such that the scribe marks will be visible from the valve outlet or an
inspection port. Place a scale or other suitable thin flat metal object
on the lower face of the upper adjusting ring and measure the overall
length of the upper ring and guide assembly. Adjust the upper ring
to the Dimension C (see Figure 29, below) recorded in Step 12 of
Section XI.B., "Disassembly". Observe the marks made on the ring
and guide and adjust the ring to align the marks (see Figure 30,
below). Recheck the overall length of the adjusting ring and guide
assembly to assure that the upper ring is in its original position.
Page 49
XIV.B. (Continued)
7.
Measure from the top of the guide to the bushing seat with a depth
micrometer. Subtract Dimension B as measured in Step 12, Section
XI.B., "Disassembly", from the dimension previously measured.
The difference is the distance the upper adjusting ring must be
lowered. Refer to Table X, below, to determine the number of
notches that the ring is to be lowered.
TABLE X
ORIFICE
1
2
3
5
4
6
7&Q
8
R
VERTICAL RING TRAVEL FOR EACH
NOTCH OF ADJUSTMENT
inches
.0025
.0020
.0015
.0015
.0015
.0009
.0010
.0016
.0011
8.
Once certain that the upper adjusting ring/guide assembly is properly
set, lubricate the guide seating surface in the valve base, and reinstall the assembly into the base, then, lubricate the threads of the
upper adjusting ring pin, and lock the ring/guide assembly in place
by screwing in the pin. Verify that the upper ring is capable of a slight
movement. If the upper ring does not move, the pin is too long.
Should this be the case, grind the end of the pin to shorten it, while
retaining the original tip contour, then reinstall the pin.
9.
Clamp the spindle in a padded vise, with the “ball end” of the spindle
upward.
10.
Verify that the spindle bearing has been ground to the disc pocket,
as specified in Section XIII.E, “Disc Replacement and Disc Spindle
Bearing Requirements”, of this manual.
NOTE:
This step must be accomplished before proceeding with reassembly.
11.
If the lift stop was removed from the spindle, lubricate the threads
and install the lift stop. Do not install the cotter pin at this time.
12.
If the disc collar was removed, lubricate the threads and install on
the spindle. Do not install the cotter pin at this time. Then, carefully
lower the disc holder onto the spindle, allowing it to sit on the face
of the disc collar.
CON-1
Page 50
XIV.B. (Continued)
13.
Thread the disc onto the spindle, ensuring that the disc is free to
“rock” on the spindle tip as specified in Section XIII.E., “Disc
Replacement and Disc Spindle Bearing Requirements”, of this
manual. If disc “rock” is not satisfactory, correct the cause before
proceeding. When disc “rock” is satisfactory, remove the disc and
disc holder, and secure the disc collar with a stainless steel cotter
pin. Using side cutters, carefully cut off excess cotter pin legs, and
bend the cotter pin for a neat installation.
14.
Lubricate the spindle tip, and assemble the disc holder and disc to
spindle. Recheck the rock.
15.
Remove complete assembly from the vise, being sure to protect the
disc seat surface at all times.
16.
Prior to installing the spindle assembly into the valve base, wipe the
disc seat with a soft, lint-free cloth. Then, carefully install the spindle
assembly into the guide.
17.
Install the cover plate over the spindle assembly, ensuring that the
cover plate is correctly oriented with regard to the valve base, as
previously marked for this purpose during disassembly. (See Step
XI.B.9., in this manual.) Then, install the cover plate nuts, with the
nuts being only hand tightened.
18.
Next, install the yoke and compression screw assembly over the
yoke rods and spindle.
19.
Next, refer to Figure 31 (below) and establish Dimension A.
20.
Pull up on the spindle until the lift stop contacts the cover plate and
repeat the measurement of Dimension A, while the lift stop and
cover plate are in contact. The difference between these two
measurements is the valve lift. The valve lift should be equal to the
nameplate lift, plus the additional recommended lift as shown in
Table XI, on the opposite page.
NOTE:
Do not deviate from stamped nameplate lift.
CON-1
Page 51
XIV.B. (Continued)
TABLE XI
Bore
Diameter
Inches (Metric)
Orifice
1
2
3
5
4
6
7
Q
8
R
K
21.
1.125(28.6mm)
1.350(34.3mm)
1.800(45.7mm)
2.062(52.4mm)
2.250(57.2mm)
3.000(76.2mm)
3.750(95.3mm)
3.948(100.3mm)
4.250(108.0mm)
4.515(114.7mm)
1.531(38.9mm)
.282(7.16mm)
.338(8.59mm)
.450(11.43mm)
.517(13.13mm)
.563(14.30mm)
.750(19.05mm)
.938(23.83mm)
.985(25.02mm)
1.063(27.00mm)
1.129(28.68mm)
.384(9.75mm)
Required
Additional Lift
Inches (Metric)
.020(.508mm)
.020(.508mm)
.030(.762mm)
.040(1.016mm)
.050(1.270mm)
.060(1.524mm)
.070(1.778mm)
.070(1.778mm)
.080(2.032mm)
.090(2.286mm)
.030(.762mm)
If the measured dimension is:
a.
b.
22.
Rated
Liift
Inches (Metric)
Correct:
(1)
Remove the yoke and cover plate.
(2)
If the cotter pin has been removed from the lift stop, lift
the spindle assembly from the valve and disassemble it.
(3)
Install the lift stop cotter pin, re-assemble the spindle
assembly, and re-install the spindle assembly into the
valve guide.
(4)
Install the cover plate and torque cover plate nuts to fifty
(50) ft/lbs. (Do not re-install yoke at this time.)
Incorrect:
(1)
Remove yoke and cover plate.
(2)
Adjust valve lift, as required, in the following manner:
(a)
Increase valve lift by moving the lift stop down one
(1) notch for each .010" increase required.
(b)
Decrease valve lift by moving the lift stop up one (1)
notch for each .010" decrease required.
Verify that the valve lift is now correct by repeating Steps XIV.D.17
through XIV.D.21 (above). If the lift is correct, proceed to Step
XIV.D.21.a (above). If the lift is incorrect, repeat Step XIV.D.21.b
(above).
CON-1
Page 52
XIV.B. (Continued)
23.
If the overlap collar has been removed from the spindle, lubricate
the collar threads and place over the spindle with the notches in the
collar up (i.e., away from the cover plate). Note that the overlap
collar has four circumferential scribe lines. The lower scribe line is
the one farthest away from the notches. (See Figure 32, below.)
Thread the overlap collar onto the spindle by turning in a clockwise
direction, until the lower scribe line is even with the visible floating
washer. Align the nearest overlap collar notch with the drilled hole
in the spindle by moving the overlap collar down.
24.
Refer to Table XII (below) before making the initial overlap collar
adjustment.
TABLE XII
Orifice
1
2
3
5
4
6
7
Q
8
R
Bore Diameter
Inches (Metric)
1.25 (28.6mm)
1.350 (34.3mm)
1.800 (45.7mm)
2.062 (52.4mm)
2.250 (57.2mm)
3.000 (76.2mm)
3.750 (95.3mm)
3.984 (100.3mm)
4.250 (108.0mm)
4.515 (114.7mm)
Adjustments (Notches)
Standard Restricted Lift
6
7
8
9
10
13
16
16
18
20
3
3
4
4
5
6
8
8
9
10
Note that these adjustments differ for each orifice size. (Also note
that restricted lift valves require a different overlap collar adjustment.)
CON-1
25.
To adjust the overlap collar, move the collar down the number of
notches specified in Table XII (above) or, if the original setting is to
be re-established, reset the collar to the position previously recorded
during disassembly. (See Section XI.B.8 in this manual.)
26.
Install cotter pin through overlap collar notches and spindle. Trim
cotter pin to proper length, and bend the ends to secure the overlap
collar and spindle together.
27.
Before installing the spring washer, lubricate the bearing surfaces
on lower spring washer and the spindle. Then, install lower spring
washer onto the spindle.
Page 53
XIV.B. (Continued)
28.
Determine which end of the spring is to be fitted to the lower spring
washer as determined in the disassembly procedure. (See Section
XI.B.7 in this manual.) Lower the spring gently over the spindle until
it is seated on lower spring washer. Install the top spring washer
onto the spring, and insure that the lug engages the left yoke rod
when facing in the same direction as the outlet.
29.
If compression screw has been removed, lubricate the threads of
the compression screw and yoke. Install the lock nut onto the
compression screw and thread the compression screw into yoke,
until the screw is just protruding from lower end of the yoke.
NOTE:
If the valve utilizes a bearing with a compression screw
adaptor as shown in Figure 27 (on page 45 of this manual),
install the adaptor onto the top spring washer. Install the
bottom race and pack the thrust bearing with lubricant, then
install the bearing and the top race into the adaptor.
30.
Lubricate upper yoke rod threads. Carefully position the yoke
assembly over the yoke rods taking care to align the compression
screw with either the bearing or upper spring washer as applicable.
31.
Using the yoke rod nut torque wrench and the socket, torque the
yoke rod nuts as specified in Table IX, on page 46 of this manual.
32.
Next, return the compression screw to its original position recorded
during disassembly (see Section XI.B.4 of this manual), and tighten
compression screw lock nut.
33.
Ensure that the top washer lug does not remain in contact with the
yoke rod, after final compression screw adjustment.
34.
Install the release nut onto the spindle and thread clockwise, until
the release nut is fully engaged on the spindle thread.
35.
Install the cap over the release nut, and seat the cap firmly into
place on the yoke. Install the top lever in the cap and, then, insert
the lever pin through the top lever and cap holes.
36.
Adjust the release nut, until it clears top lever by 1/8 inches
(3.175mm). Remove the lever pin, top lever, and cap. Next, insert
a cotter pin through the release nut slots and spindle, and spread
cotter pin ends. (If spindle has been replaced, a cotter pin hole must
be drilled through the replacement spindle.) Re-assemble the cap
with the drop lever, top lever, and top lever pin. Install a cotter pin
to lock the top pin in place. A final check should be made to ensure
the proper clearance exists between the release nut and the top
lever. Finally, tighten cap set screw to secure the cap.
CON-1
Page 54
XV. Hydrostatic Testing & Gagging
During any hydrostatic test, all safety valves on the unit, which have not been
removed and do not have hydroplugs, must be gagged. This gagging procedure
prevents the possibility of damage to the safety valve internals in the event that
the test pressure exceeds the safety valve set pressure. When adjusting valve
set pressures, other valves in the system should also be gagged.
When valves are subjected to working hydrostatic tests not exceeding the set
pressure of the low set valve, valves may be gagged rather than using
hydrostatic test plugs. For higher pressures, hydrostatic plugs should be used.
Probably the most common source of Safety Valve trouble is over-gagging.
During hydrostatic testing, and during Safety Valve setting, gags should be
applied only hand tight. During setting, overgagging will also cause damage to
the seating surface and result in seat leakage. In applying gags remember that
the valve spring will hold the valve closed against its set pressure.
The additional gag load applied should be only enough to ensure that the valves
do not lift at the expected overpressure.
During start-up, gags should never be applied when the boiler is cold. The
spindle of the Safety Valve expands considerably with the temperature increase.
If it is not free to expand with this temperature change it may become seriously
overstressed and bent.
Except for hydrostatic tests, boiler pressure should be brought up to within 80%
of the pressure of the low set valve before applying gags.
Tighten the gags of drum and superheater valves with only a light force applied
to the gag screw head.
CON-1
Page 55
XV. (Continued)
APPLICATION OF TEST GAGS (All Pressures)
Refer to Figure 7 on page 19. Remove top lever pin and top lever then loosen the
cap screw. Remove cap and drop lever as an assembly. The release nut is fixed
to the spindle by means of a cotter pin. Note that the release nut does not quite
engage top of compression screw.
Center the test gag in the exposed end of the SPINDLE and hook the legs of gag
under the sides of the YOKE as shown in Figure 33 (below).
Do not apply the gag load until the system steam pressure is equal to 80%
of the pressure to which the low set valve is adjusted.
Apply the gag load by turning the gag screw clockwise. If the gag on any valve
has not been tightened sufficiently, the valve will leak. On steam service the
leakage is accompanied by a “sizzling” sound.
If this occurs, the hydrostatic test pressure or steam pressure should be
reduced until the valve becomes tight and, then, the gag should be
tightened still further.
This procedure must be followed exactly, since it is very difficult to stop the leak
by additional gagging once it has started. Any attempt to stop the leakage
through the valve, without first lowering the system pressure, could result in
damage to the valve seats.
After the hydrostatic test or steam test is completed, the gags should be removed
when the hydrostatic pressure has been reduced to 80% to 90% of the pressure
of the low set valve.
NOTE:
Under no circumstances should the gags be left on the valves.
CON-1
Page 56
XVI. Trouble Shooting The 1700 Series Valve
Problem
No Action,
Valve does not go
into full lift.
Possible Cause
A. Upper ring too high.
B. Foreign material trapped
between disc holder & guide.
C. Overlap collar adjusted too
low.
Corrective Action
A. Increase blowdown as outlined in
Section X.C.5. of manual.
B. Disassemble valve and correct any
abnormaility as outlined in Section
XI. of manual. Inspect system for
cleanliness.
C. Reset initial setting per Section
XIV.B.24. of manual, then move
overlap collar from right to left one or
two notches, then retest. Repeat
additional adjustment as necessary.
Simmer
A. Lower ring too low.
B. Steam line vibrtations.
A. Adjust per Section X.C.2. of manual.
B. Investigate and correct cause.
Valve Leaking
and/or exhibits
erratic popping
actions.
A. Damaged seat.
A. Disassemble valve, lap seating
surfaces, replace disc if required, as
outlined in Section XII.B. of manual.
B. Disassemble valve, inspect contact
area of disc and nozzle, lower spring
washer or spindle, compression
screw, spindle straightness, etc.
C. Disassemble valve and check disc
rock per Section XIII.E. of manual.
B. Part misalignment.
C. Disc has insufficient rock.
Hangup, or valve
does not close
completely.
D. Discharge stack binding on
outlet.
D. Correct as required.
A. Lower ring too high.
A. Move lower ring to the left one notch
per adjustment until problem is
eliminated.
B. Disassemble valve and correct any
abnormal condition. Inspect system
for cleanliness.
B. Foreign material.
Excessive
blowdown
A. Upper ring too low.
B. Exhaust pressure too high.
C. Overlap collar too high.
Chatter or short
blowdown
A. Upper ring way too high.
B. Overlap collar way too low.
C. Inlet piping pressure drop too
high.
CON-1
A. Decrease blowdown as outlined in
Section X.C.4. of manual.
B. Decrease exhaust pressure by
increasing discharge stack area.
C. Check initial setting per Section
XIV.B.24. of manual, then move
overlap collar from right to left one or
two notches, then retest. Repeat
additional adjustment as necessary.
A. Lower upper ring.
B. Raise overlap collar. Reestablish in
accordance with Section XIV.B.24. of
manual.
C. Reduce inlet pressure drop to less
than one-half of required valve
blowdown by redesigning inlet piping.
Page 57
XVII. Maintenance Tools and Supplies
LAPPING TOOLS
The following tools are required for proper maintenance of Consolidated® Type
1700 Safety Valve seats:
Ring Lap
The ring lap is used for lapping the nozzle and disc seats.
Rings Laps*
Valve
Orifice**
Lap
Part No.
1
2
3
4
5
6
7 and Q
8, R and RR
1672806
1672807
1672808
1672810
1672809
1672811
1672812
1672813
Lapping Plate
The lapping plate is used for reconditioning the ring laps. Only one 11” diameter
plate is required for all sizes of ring laps.
Resurfacing Plate - 11” Diameter.
Part No. 0439004
Lapping Compound
Lapping compound is used as a cutting medium for lapping and polishing the
seats and bearing surfaces in Type 1700 Safety Valves.
Brand
Clover
Clover
KwikAk-Shun
Grade
Grit
Lapping
Function
Size
Container
Part No.
1A
C
-
320
220
1000
General
Coarse
Polishing
4 oz.
4 oz.
1 lb.
2 oz.
199-3
199-2
199-11
199-12
Gags
Valve
Orifice**
1
2
3
4
5
6
7 and Q
8, R and RR
Gag
Part No.
4363001
4363001
4363001
4217701
4217701
4217701
4217701
4217701
* Note 1: One set of two (2) Ring Laps is recommended for each orifice valve
in service, to assure ample flat laps are available at all times.
** Note 2: Valve orifice number is third digit of valve type number, e.g. a 1737A
valve has a #3 orifice.
CON-1
Page 58
XVII. (Continued)
Lubricant
Location
Lubricant
Bearing Points
1. Spindle/Disc
2. Compression Screw/Top
Spring Washer
3. Spindle/Bottom Spring
Washer
All Threads
All Nut Contact Faces
Fel-Pro Nickel Ease
Wrench Sizes (inches)
Maxiflow
Series
1-7/16 1-5/8
Number
2
2-3/8
2-3/4
3-1/8
Maxiflow
Series
Number
1710
1748
1712
1749
1715
1716
1750
1717
1752
1718
1755
1719
1756
1757
1720
1758
1722
1759
1725
1726
1765
1727
1766
1728
1767
1729
1775
1730
1775Q
1732
1776
1735
1776Q
1736
1777Q
1737
1738
1785
1739
1786
1787
1740
1742
1705R
1745
1706R
1746
1707R
1747
CON-1
1-7/16 1-5/8
2
2-3/8
2-3/4
3-1/8
Page 59
XVIII. Service Parts Inventory Philosophy
The basic objectives in formulating a replacement parts plan are:
•
•
•
•
PROMPT AVAILABILITY
MINIMUM DOWNTIME
SENSIBLE COST
SOURCE CONTROL
Guidelines for establishing meaningful inventory levels:
PARTS CLASSIFICATION
PART
CLASSIFICATION
REPLACEMENT
FREQUENCY
PREDICTED
AVAILABILITY
CLASS I
MOST FREQUENT
70%
CLASS II
LESS FREQUENT
BUT CRITICAL
85%
CLASS III
SELDOM REPLACED
95%
CLASS IV
HARDWARE
99%
CLASS V
PRACTICALLY NEVER
REPLACED
100%
Consult the Recommended Spare Parts list (see Section XX of this manual) to
define the parts to be included in the inventory plan.
Select parts and specify quantities.
CON-1
Page 60
XVIII. (Continued)
Identification and Ordering Essentials
When ordering service parts, please furnish the following information to insure
receiving the correct relacement parts:
Identify valve by the following nameplate data:
1. Size
2. Type
3. Temperature Class
4. Serial Number
Example One: 2“ 1729WA
S/N BG-5171
Example Two: 1 1/2” 1712WD
S/N BH-9547
Specify parts required by:
1. Part Name (See Figure 7 on page 19)
2. Part Number (if known)
3. Quantity
Contact Parts Marketing: 1-318-640-6044
In addition, the serial number is stamped on the top edge of the outlet flange. Be
sure to include the one or two letters preceding the figures in the serial number.
A typical valve nameplate is shown in Figure 34 (below).
FIGURE 34
CON-1
Page 62
XX. Recommended Spare Parts
For 1700 Maxiflow Safety Valves
Quantity Parts/Same Size,
Type, Set Pressure, and
Temperature Class Valves
In Service
Class
Part Name
Drum
Superheater
Reheat
Section
I
1.
2.
3.
Disc
Adj. Ring Pin (Upper)
Adj. Ring Pin (Lower)
1/1
1/1
1/1
1/1
1/1
1/1
1/4
1/4
1/4
II
4.
5.
6.
7.
8.
Adj. Ring (Upper)
Adj. Ring (Lower)
Holder
Spindle
Guide
1/4
1/4
1/4
1/2
1/4
1/4
1/4
1/4
1/2
1/4
1/4
1/4
1/4
1/6
1/4
III
9.
10.
11.
12.
13.
Disc Collar
Lift Stop
Spring
Spring Washers(2)
Compression Screw
1/4
1/4
1/6
1 Set/6
1/4
1/4
1/4
1/6
1 Set/6
1/4
1/6
1/6
1/6
1 Set/6
1/6
14.
15.
16.
17.
Disc Collar Pin
Lift Stop Pin
Compression Screw
Top Plate Screws
1/4
1/4
1/4
1 Set/4
1/4
1/4
1/4
1 Set/4
1/6
1/6
1/6
1 Set/6
IV
YOUR SAFETY IS OUR BUSINESS!!!
DVCD has not authorized any company or any individual to manufacture
replacement parts for it’s valve products.
When ordering replacement valve parts, please specify in your purchase order:
“ALL PARTS MUST BE DOCUMENTED AS NEW AND SOURCED FROM
DRESSER INDUSTRIAL VALVE & CONTROLS DIVISION”
CON-1
BE SURE! BE SURE!
Page 63
XXI. Manufacturer’s Field Service & Repair Program
FACTORY SETTING VS. FIELD SETTING
Every CONSOLIDATED® Safety Valve is set and adjusted on steam before
shipment from the factory. Blowdown adjustments are made as carefully and
accurately as possible on the factory test boiler. However, it must be recognized
that actual field operating conditions may vary considerably from factory test
conditions.
Conditions beyond the manufacturer’s control that affect Safety Valve operation
are:
•
•
•
•
•
•
•
•
Quantity of steam being discharged through the valve, i.e. the actual
installation capacity exceeding that of the test boiler, thus permitting the
valve to flow its full rated capacity.
Quality of steam being discharged.
Discharge piping stresses and back pressure.
Ambient temperature.
Shipping or storage damage.
Improper gagging
Improper bolting of flanges.
Damage due to foreign material in the steam.
Final Safety Valve adjustments made on the actual installation are the best
means of insuring that the valves perform in compliance with the ASME Boiler
Code and/or other applicable code requirements.
FIELD SERVICE
Utilities and Process Industries expect and demand service on a moment’s
notice CONSOLIDATED Field Service can be depended upon for prompt
response, even in extreme off-hour emergency situations.
DVCD maintains the largest and most competent field service staff in the
industry. Service Engineers are located at strategic points throughout the United
States to respond to customer’s requirements for service. Each Service Engineer
is factory trained and long experienced in servicing Safety Valves. DVCD
Service Engineers restore disc and nozzle critical dimensions which effect valve
performance, and are capable of modernizing valves in the field.
It is highly recommended that the professional talents of a DVCD Field Service
Engineer be employed to make final field adjustments during the initial setting of
all CONSOLIDATED Safety Valves.
All Field Service Engineers’ activities are coordinated from the Alexandria,
Louisiana, Field Service Office. Upon receipt of a purchase order number
authorizing the trip, the engineer is dispatched.
Contact: Field Service Dept., Field Service Supv., (318) 640-6055
FACTORY REPAIR FACILITIES
If boiler downtime permits, it may be desirable to return the valves to the factory
for repair or modernizing. The factory at Alexandria, Louisiana, maintains a
complete CONSOLIDATED repair center. The Repair Department is staffed to
provide you rapid repair that meets your needs.
Contact: Repair Dept., Mgr. Valve Repair, (318) 640-6058.
CON-1
Sales Offices Locations
UNITED STATES
IVO Headquarters & Main Factory
LA Hwy. 3225 at U.S. Hwy. 167 North, P.O. Box 1430, Alexandria, Louisiana 71309-1430
Telephone 1-318-640-2250, Telex 586423, Rapifax 1-318-640-6222
Northern Region
3201 North Wolf Road, Franklin Park, Illinois 60131
Telephone 1-708-451-3913, Rapifax 1-708-451-3997
Pacific Region
3931 MacArthur Blvd., Suite 202, Newport Beach, California 92660-3014
Telephone 1-714-752-0455, Rapifax 1-714-752-2561
Southern Region
16503 Park Row, Houston, Texas 77084-5016
Telephone 1-713-579-8720, Rapifax 1-713-579-7844
CANADA
Dresser Canada, Inc., Valve & Controls – Canadian Operations
5010 North Service Road, Burlington, Ontario, L7L 5R5 Canada
Telephone 1-905-335-3529, Rapifax 1-905-336-7628
JAPAN
Dresser Japan, Ltd., Industrial Valve Operation, Room 405, Maersk Bldg.,
18, Nihon-Odori, Naka-ku., Yokohama 231 Japan
Telephone 81-45-651-5601, Rapifax 81-45-651-5606
KOREA
Dresser Korea, Inc., Room #2107, Kuk Dong Building
60-1, 3-KA, Choongmu-Ro Chung-Ku, Seoul, Korea 100-705
Telephone 82-2-274-0792, Telex K22801 DRESSER, Rapifax 82-2-274-0794
MEXICO
Masoneilan Internacional y Compania, S, en N.C., Av. Henry Ford No. 114
Apartado Postal 572, 54030 Tlalnepantla, Mexico
Telephone 52-5-310-9863, Telex (383) 172645, Rapifax 52-5-310-5584
SAUDI ARABIA
Dresser Al Rushaid Valve & Instrument Co., Ltd., P.O. Box 10145
Jubail Industrial City 31961, Kingdom of Saudi Arabia
Telephone 966-3-341-0278, Telex (928) 832108, Rapifax 966-3-341-7624
SOUTH AFRICA
Dresser Limited Valve & Controls Division
P.O. Box 2234, 16 Edendale Road, Eastleigh, Edenvale 1610, South Africa
Telephone 27-11-452-1550/1-7, Rapifax 27-11-452-2903
SWITZERLAND
Dresser Europe, S.A. Industrial Valve Operation
Badenerstrasse 156, P.O. Box 369, CH-8021 Zurich, Switzerland
Telephone 41-1-241-0533, Telex (845) 812429, Rapifax 41-1-241-4218
UNITED KINGDOM
Dresser U.K., Limited, Industrial Valve Operation, Trevithick Works
Gillibrands Estate, Skelmersdale, Lancashire, WN8 9TU England
Telephone 44-695-24234, Telex (851) 627039, Rapifax 44-695-20175
Masoneilan Division Dresser U.K., Ltd., Controls House
Riverside Way, Uxbridge, Middlesex, UB8 2YF England
Telephone 44-895-258161, Telex (851) 935174, Rapifax 44-895-234318
VENEZUELA
RIESE & CIA S.A.
Apartado 372, Caracas, Venezuela
Telephone 58-2-541-1311/541-3812, Telex (395) 24796, Rapifax 58-2-545-2702
Note: Numbers in (
) are codes to be used for calling from U.S.A.
CONSOLIDATED is a registered trademark
of Dresser Industries, Inc.
© 2000 Dresser Industries, Inc.
CON-6