Double Duty® 12 Steam Trap/Pump Combination

Double Duty® 12 Steam Trap/Pump Combination
Double Duty® 12
Steam Trap/Pump Combination
Installation and Operation Manual
IB-117
ARMS
Copyright C
DO NOT SCALE DRAWING
DD12 TRAP
TOLERANCES UNLESS
OTHERWISE SPECIFIED
FRACTIONAL
ANGULAR:
DECIMAL
1/64
2
IN.
MM
.XXXX
.0005 ----.XXX
.005 .010 DRAWN
.XX
.015 .10
.X
---------- .3
RELEASED
NAME
Emily Fritts
DATE
01/14/2011MATERIAL
Installation and Set Up Overview
Warning: This bulletin should be used by experienced personnel as a guide to the installation and
maintenance of the Armstrong Double Duty® 12 or Double Duty® 12 package. Selection or installation
of equipment should always be accompanied by competent technical assistance. We encourage you to
contact Armstrong or your local representative if further information is required.
Double Duty®12 Overview...........3
Product Information........................4
Operation....................................6
Installation..................................7
Start-up......................................9
Maintenance................................10
Spare Parts..................................11
Adjustment Procedure.....................13
Troubleshooting............................14
Double Duty® 12 Overview
Product Information:
The Armstrong Double Duty® 12 is a flanged fabricated steel vessel, which is pressure rated for 200 psi, full
vacuum, and has an ASME Sec. VIII “U” stamp. It is a steam trap with integral pump with the capability of
switching between trapping and pumping automatically. The Double Duty® 12 is designed to be operated by
steam in a closed system and used to evacuate condensate from steam systems. It can also use air or inert
gas as the motive fluid in a vented system.
Typical Application:
Heat exchange equipment with modulating control has the possibility that the system could stall (no longer be
able to drain condensate). If only a steam trap is used, condensate could flood the heat exchange equipment
causing corrosion, water hammer and poor process temperature control. The Double Duty® 12 is a steam
trap with an integral pump, which automatically takes over when the steam trap stalls. If condensate can not
be discharged by the steam trap, the Double Duty® 12 body will fill with water until the level is high enough
for the pump to take over and push the condensate into the return system using high pressure steam as the
motive fluid.
Suggested Optional Accessories:
• Receiver
• Inlet and discharge check valves
• Gauge glass assembly Double Duty® 12
• Gauge glass assembly receiver
• Pressure gauge assembly Double Duty® 12
• Pressure gauge assembly receiver
• Pressure gauge assembly motive
• Pressure gauge assembly condensate discharge
• Pressure gauge assembly heat exchange equipment
3
Product Information
Materials
Body and Cap
Fabricated steel 200 psi
ASME Sec. VIII design
“U’’ stamped
Cap Gasket
Flexible graphite
Mechanism Assembly
Stainless steel
Springs
Inconel X-750
Float
304 Stainless steel
Recommended Check
Valves
Wafer style; carbon steel
body w/stainless steel
trim
Specifications
Motive Fluid
Steam
Max. Operating Pressure
200 psig @ 400 deg F
(14 bar @ 204 deg C)
Max. Allowable Pressure 200 psig @ 400 deg F
(14 bar @ 204 deg C)
Min. Motive Differential
10 psig
Physical Data
in
mm
“B”
34
864
“C”
24
610
“D”
13
330
“E”
16
406
“F”
15-1/2
394
“G”
5-1/4
133
“H”
28
712
“P”
1-5/8
41
“R”
5-1/4
133
“T”
16
406
“U”
2-1/4
57
“V”
7/8
22
“W”
1-1/8
29
“X”
1-1/16
27
Face to
Face
42*
1067
Weight
Check
3
Valve
Connection
*Tolerance +/- 1/2”
348 (158)
75
4
Product Information Continued
Capacity
Needed to size the Double Duty®12:
1. Space constraints: height, width or length restrictions
2. Motive fluid available and pressure to be used (psig) P1
3. Total back pressure
= (vertical lift L + pressure in return P4 + friction loss) (psig)
4. Heat exchange equipment maximum operating pressure (psig) P2
5. Heat exchange equipment maximum condensing rate (lbs./Hr.) CL
6. Incoming media temperature (deg. F) T1
7. Outgoing media temperature (deg. F) T2
8. P2 - P3 = pressure drop across equipment
The vent/equalizing line from the Double Duty®
12 may be plumbed to the steam inlet side of the
equipment being drained, if the pressure drop
across the equipment is less than 1/2 psi and the
fill head is a minimum of 24’’. If these conditions
do not exist, the default is to equalize to the
discharge side of the heat exchange equipment.
Maximum average instantaneous discharge rate
is approximately 160 gpm
Note: The Double Duty® 12 is a steam trap
with integral pump. It replaces a single steam
trap. Do not use for group trapping of multiple
pieces of heat exchange equipment.
Materials
Number
Part
Material
1
Body
Fabricated Steel
2
Mechanism
Stainless Steel
3
Cap
Fabricated Steel
4
Vent Seat
Stainless Steel
5
Motive Seat
Stainless Steel
6
Gasket
Flexible Graphite
7
Springs
Inconel X-750
8
Float
304 Stainless
Steel
9
Float
304 Stainless
Steel
10
Steam Trap
Stainless Steel
11
Gasket
Flexible Graphite
5
Operation
Figure 4: As the body pressurizes the inlet check valve
closes. The condensate generated during this time will need
to be stored in a receiver or pipe reservoir to prevent water
from flooding the heat exchange equipment. When the body
pressure is greater than the back pressure, the condensate
will be pushed through the trap mechanism and external
discharge check valve into the return line.
Figure 1: Acting as a steam trap, when the system pressure
is greater than the back pressure, condensate enters the body
through an external inlet check valve and lifts the steam trap
float to allow condensate to leave the body and in to the return
line through an external check valve.
Figure 2: If the system modulates, it may be possible for the
back pressure to be greater than the system pressure. This will
cause the trap to stall (stop discharging condensate) and the
condensate will flood the body.
Figure 5: Condensate is pushed from the body by motive
steam until the water level reaches the pump’s lower trip
point. Motive steam is turned off and the vent valve is
opened, allowing pressure equalization to occur.
Figure 3: Once the condensate level reaches the pump trip point,
the equalization line shuts off and the motive valve opens, allowing high pressure steam into the body.
Figure 6: After the pressure equalizes with the system
pressure, condensate will begin entering the body through
the external inlet check valve. The DD12 is ready to begin
another pump cycle or begin trapping.
6
Installation
Typical Closed Loop System Drawings
Notes:
1. Standard fill head 12’’. Other fill heads may be used, refer to the fill head
adjustment multiplier chart in literature.
2. The Double Duty® 12 steam trap with integral pump system can only replace one
steam trap. Multiple pieces of heat exchange equipment cannot drain to a single
double duty system.
3. The PRV should be plumbed a minimum of 10 ft. of 1’’ pipe away from the Double
Duty® 12 motive inlet.
7
Installation
Fill head: The fill head is the dimension from the top of the cap to the bottom of the
receiver. The standard fill head is 12’’. The fill head can be reduced to 0’’ at a reduction
in capacity. The fill head can also be increased above 12’’ with a corresponding increase
in capacity. A receiver or reservoir should not be installed next to the Double Duty® 12
(causing negative fill head). A fill head less than zero may cause the receiver to flood prior
to the pump mechanism tripping.
Liquid Reservoir: Liquid flowing from the heat exchange equipment must be stored while
the inlet check valve is closed during the pump discharge cycle. A liquid reservoir or receiver
should be installed above the unit to prevent flooding of the equipment.
Vent piping (Equalization Line): The vent is the 1’’ npt connection on the top of the cap. The
equalization line should be self draining and plumbed to the condensate discharge side of the
heat exchange equipment. In order to prevent a water seal, the equalization line should be
plumbed to a vapor space. A union or flange should be installed on the equalization line near
the cap for convenient maintenance.
Motive piping: The motive pipe is 1/2’’ npt
connection on the top of the cap. It should be
properly trapped with an Armstrong steam
trap and have an Armstrong 100 mesh strainer
with blowdown. The motive pressure should
be regulated as needed by an Armstrong
PRV located a minimum of 10 ft. of 1’’ pipe
away from the DD12 to give downstream
accumulation space for the PRV. The optimum
motive pressure is 20-30 psi above the back
pressure. It is recommended that a pressure
gauge be installed in the motive line and a
union or flange installed near the cap for
convenient maintenance.
Inlet Piping: The condensate inlet connection is a 3” 150# flange located on the same end
as the (2) ½” npt gauge glass connections. An external check valve needs to be installed on
the inlet for proper operation. Important Note: The condensate inlet and outlet connections
should not be reversed. Failure to function will result.
Discharge Piping: The condensate outlet connection is a 3” 150# flange located on the same
end as the circular hand hole. An external check valve must be installed on the outlet for proper
operation. The discharge piping should be sized for the full load of the heat exchange equipment
along with its flash load. If other equipment is also entering the return line, these loads should
also be used in the line sizing to prevent excessive return line pressures or water hammer.
8
Start-Up
Valve Opening Sequence:
Open isolation valve(s) in condensate
discharge.
Replace all temporary plugs and fittings with
appropriate permanent fittings.
Make sure piping is clean and free of debris. Debris
can affect proper operation and performance.
Open isolation valve(s) in equalization line.
Open isolation valve(s) in motive line.
The DD12 must be installed with the condensate inlet
and outlet horizontal and the motive and vent vertical.
The product will not function properly if it is not
installed in correct orientation.
Confirm no steam leakage by checking
pressure gauges.
Open isolation valve(s) on thermostatic air
vent.
Connect all pipe securely.
Open isolation valve(s) on condensate inlet.
Open all valves slowly to reduce chance of water
hammer. Water hammer could injure personnel or
damage equipment.
9
Start-up is complete and operation can be
confirmed by use of the gauge glass and
pressure gauges.
Maintenance
Removal of Cap Assembly:
Warning!: Before starting inspection and repair make
sure the unit is completely isolated from the system
and all residual pressure has been dissipated.
Disconnect all piping plumbed to the cap
and remove all bolts, then lift the cap off
the body. A withdrawal distance of 18’’ is
needed. The cap will need to be tilted as it is
lifted for the float to exit the body.
Visually inspect the mechanisms for obvious
problems. Move the floats up and down
manually, checking for free movement and
the mechanism snapping back and forth.
Check the floats to make sure they are
undamaged and free of corrosion and pin
hole leaks.
Check pivot points and springs for damage
and free movement.
Check adjustments to make sure they are in
the proper range.
Plumb air to the motive and check that the
motive seat properly seals (a small amount
of air leakage is normal).
Trip the mechanism by hand to check that
the mechanism operates properly and is able
to open the motive valve against the testing
air pressure.
Spare Parts:
Cap Assembly:
Steam Trap Assembly:
A. Cap Assembly
B. Gasket
C. Float
D. Steam Trap Float
E. Steam Trap
F. Nut (2)
G. Lock Washer (2)
H. Steam Trap Gasket
J. Gasket
10
Spare Parts
Pump Rebuild Kit
Item No. Description
QTY.
1
Washer Flat
4
2
Bolt Hex 1/4-20 X 1’’ LG 18-8SS
2
3
Seat Vent 1’’ NPT for DD12
1
4
Valve Vent DD12
1
5
Spring Assembly Kit DD12
1
6
Pin Pivot
1
7
Pin Pivot
1
8
Pin Pivot
2
9
Arm Spring
2
10
Spacer
2
11
Pivot
1
12
Nut Hex Jam
2
13
Valve Inlet
1
14
Seat motive 1/2 NPT
1
15
Gasket Body
1
16
Bushing long
6
17
Bushing short
4
18
Retaining Ring
4
*Spring assembly kit includes: Spring assemblies(2), (4) bushings, and (6)
retaining rings (2 extra).
Note: The number of washers that were taken out of the cap should equal the
number to be installed. Three are supplied for the motive, but may not be the
number used.
Mechanism Rebuild Kit
Item No.
Description
QTY.
1
Bolt Hex 1/4-20 X 1’’ LG 18-8SS
1
2
Pin, Pivot
1
3
Pin, Pivot
1
4
Pin, Pivot
2
5
Arm Spring
2
6
Spacer
2
7
Pivot
1
8
Nut Hex Jam 1/4’’-20 18-8SS
1
9
Gasket Body
1
10
Bushing long
6
11
Bushing short
4
12
Retaining ring
10
Note: 2 extra retaining rings included
11
Spare Parts Continued
Motive Valve Assembly Replacement
Item
No.
Description
QTY.
1
Washer Flat
3
2
Valve Inlet
1
3
Seat motive 1/2 NPT
1
}
Note: The number of washers that were taken out of the cap
should equal the number to be installed. Three are supplied with
each motive valve assembly, but may not be the number used.
Vent Valve Assembly Replacement
}
Item
No.
Description
QTY.
1
Washer Flat
1
2
Seal Vent 1’’ NPT for
DD12
1
3
Valve Vent
1
Spring Assembly Replacement
Item
No.
Description
QTY.
1
Spring Tension Inconel for
DD12
2
2
Bushing long
4
3
Retaining ring
6
}
Note: Kit includes two extra retaining rings
}
12
Cap Assembly
Note: Cap assembly includes gasket
Adjustment Procedure
1. All adjustments must be made while the mechanism is secured to the cap
2. Be sure all lock nuts are tightened (two 11/16’’ wrenches needed)
3. Use a dial-caliper to set dimensions
Step 1
1. Adjust bolt & lock nut to achieve the dimension
Step 2
1. Measure when the mechanism is fully tripped with
the vent valve seated and the motive valve fully
open
2. Pivot should be manually lifted through its entire
range to make sure no binding occurs on the
motive and vent valves
3. If binding is felt, loosen lock nuts and straighten
valve holder and retighten (start measurement
process again)
4. Recommend that compressed air be plumbed to
the motive and the mechanism tripped against
air several times by raising and lowering the float
arm manually
Step 3
1. Measure the point at which the motive valve starts
to lift the motive ball
2. Measure when the mechanism is tripped off with
the vent open and the motive ball on its seat
3. Air should be plumbed to motive so point of valve
contact can be heard and felt
4. Pivot should be manually lifted until the motive
valve contacts the motive ball. This will be evident
by the increased effort and the sound of leaking
air
5. The dimension is adjusted by adding or
subtracting washers under the motive seat
13
Troubleshooting
Important! For safety of personnel – Vent line
piping should be isolated from equipment and
pump pressure should be relieved prior to
breaking connections.
Warning! Water may run out of the vent
connection when the piping is broken. Care
should be taken to avoid danger to personnel or
damage to nearby equipment.
Areas to Check First:
• Are all isolation valves open?
• Are check valves operating properly (correct direction)?
• Have there been any changes to the system?
• Is the motive strainer free of debris?
• Is the motive pressure at least 10 psi above the back pressure but not exceeding 200 psi?
• Is there sufficient fill head?
• Is the equalizing line free of obstructions/water seal?
• Is the flow through the unit the proper direction?
Assessing Check Valve Function:
•Inlet check valve assessment: Isolate the DD12 outlet and allow water to enter body through
inlet check valve. When pump mechanism turns on motive, it should pressurize to full motive line
pressure and the water level in the gauge glass should not go down. If the water level is going
down, the inlet check valve is not holding (water is being pumped backwards through the check
valve and into the receiver) and should be repaired or replaced.
•Outlet check valve assessment: Isolate the inlet. The water level in the body should not change. If the
water level in the gauge glass continues to rise, it is due to the discharge check valve not holding (water
from the return line is filling the body) and should be repaired or replaced.
Check Valve Chatter:
• Are you using an Armstrong supplied/recommended check valve?
*Consider spring assisted non-slam check valve.
• Is the check valve worn?
14
Troubleshooting Continued
Pump does not cycle:
1. Check gauge glass to make sure water is entering body:
• No water is entering:
- Check for blockage of the inlet line (isolation valve, check valve, other obstruction)
- Check equalizing line: unobstructed, does not have a water seal, vents to a vapor space
- Check that the pressure of the body is the same as the receiver/pipe reservoir
• Water is completely filling the body:
- Check to see if motive piping is unobstructed (isolation valve, check valve, strainer, other obstruction)
- Check that motive pressure does not exceed 200 psi
- Check mechanism for damage/wear
- Check floats for damage/corrosion/pin hole leaks
2. Check motive pressure.
•It should be at least 10 psi above back pressure.
3. Check pressure in body:
•While filling, the pressure should be the same as the receiver
•While pumping, the pressure should be approximately 5-25 psi above the back pressure, water level
should be going down as pressure builds, if pump stays pressurized (no water in gauge glass) to full
motive line pressure at end of pump down, consult factory or local factory representative
•If motive turns on pressurizing body to full motive line pressure, but the unit remains full: inadequate
motive, blocked discharge line (check valve, isolation valve, internal steam trap, other obstruction)
Double Duty® 12 cycling, but equipment is flooding:
•Is the DD12 undersized?
•Is there sufficient fill head?
•Is receiver sufficient size to store condensate?
•Is there a sufficient motive pressure?
•Is back pressure greater than anticipated?
•Is condensate return line restricted?
•Is a check valve hanging open?
Double Duty® 12 pressurizes, but does not pump:
•Check that motive and vent piping have been installed correctly: motive 1/2’’ npt, vent 1’’ npt.
•Check the motive seat for debris. If so, clean or replace motive valve and seat.
15
Armstrong International
816 Maple Street, Three Rivers, MI 49093 – USA Phone: (269) 273-1415 Fax: (269) 278-6555
armstronginternational.com
IB-117
Printed in U.S.A. - 4/11
© 2011 Armstrong International, Inc.
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