4034650/5
BCV31
DN20 - Blowdown Control Valve
Installation and Maintenance Instructions
IM-P403-37
AB Issue 5
Printed in the UK
1. Safety information
2. Application
3. Technical data
4. Operation
5. Installation
6. Adjustment
7. Maintenance
8. Spare parts
© Copyright 2004
2
1. Safety information
WARNING
Your attention is drawn to Supplementary Safety Information Leaflet (IM-GCM-10), as well as to any National or Regional regulations concerning boiler blowdown.
In the UK, guidance is given in HSE Guidance Note PM60.
WARNING
The actuator must be isolated both pneumatically and electrically before any maintenance is carried out.
The actuator must be vented before dismantling.
Safe operation of these products can only be guaranteed if they are properly installed, commissioned, used and maintained by qualified personnel (see
Section 1.11) in compliance with the operating instructions. General installation and safety instructions for pipeline and plant construction, as well as the proper use of tools and safety equipment must also be complied with.
1.1 Intended use
Referring to the Installation and Maintenance Instructions, name-plate and
Technical Information Sheet, check that the product is suitable for the intended use / application. The products listed below comply with the requirements of the
European Pressure Equipment Directive 97/23/EC and carry the mark when so required. The products fall within the following Pressure Equipment Directive categories:
BCV30
BCV31
Product
DN20
DN40
DN20
DN40
Group 1 Group 2 Group 1 Group 2
Gases Gases Liquids Liquids
-
SEP
1
-
-
SEP
SEP
-
SEP
1 -
SEP
SEP i) The products have been specifically designed for use on steam, air or condensate which are in Group 2 of the above mentioned Pressure Equipment Directive.
The products’ use on other fluids may be possible but, if this is contemplated,
Spirax Sarco should be contacted to confirm the suitability of the product for the application being considered.
ii) Check material suitability, pressure and temperature and their maximum and minimum values. If the maximum operating limits of the product are lower than those of the system in which it is being fitted, or if malfunction of the product could result in a dangerous overpressure or overtemperature occurrence, ensure a safety device is included in the system to prevent such over-limit situations.
iii) Determine the correct installation situation and direction of fluid flow.
iv) Spirax Sarco products are not intended to withstand external stresses that may be induced by any system to which they are fitted. It is the responsibility of the installer to consider these stresses and take adequate precautions to minimise them.
v) Remove protection covers from all connections before installation.
IM-P403-37 AB Issue 5
1.2 Access
Ensure safe access and if necessary a safe working platform (suitably guarded) before attempting to work on the product. Arrange suitable lifting gear if required.
1.3 Lighting
Ensure adequate lighting, particularly where detailed or intricate work is required.
1.4 Hazardous liquids or gases in the pipeline
Consider what is in the pipeline or what may have been in the pipeline at some previous time. Consider: flammable materials, substances hazardous to health, extremes of temperature.
1.5 Hazardous environment around the product
Consider: explosion risk areas, lack of oxygen (e.g. tanks, pits), dangerous gases, extremes of temperature, hot surfaces, fire hazard (e.g. during welding), excessive noise, moving machinery.
1.6 The system
Consider the effect on the complete system of the work proposed. Will any proposed action (e.g. closing isolation valves, electrical isolation) put any other part of the system or any personnel at risk?
Dangers might include isolation of vents or protective devices or the rendering ineffective of controls or alarms. Ensure isolation valves are turned on and off in a gradual way to avoid system shocks.
1.7 Pressure systems
Ensure that any pressure is isolated and safely vented to atmospheric pressure.
Consider double isolation (double block and bleed) and the locking or labelling of closed valves. Do not assume that the system has depressurised even when the pressure gauge indicates zero.
1.8 Temperature
Allow time for temperature to normalise after isolation to avoid danger of burns.
1.9 Tools and consumables
Before starting work ensure that you have suitable tools and / or consumables available. Use only genuine Spirax Sarco replacement parts.
IM-P403-37 AB Issue 5 3
1.10 Protective clothing
Consider whether you and / or others in the vicinity require any protective clothing to protect against the hazards of, for example, chemicals, high / low temperature, radiation, noise, falling objects, and dangers to eyes and face.
1.11 Permits to work
All work must be carried out or be supervised by a suitably competent person.
Installation and operating personnel should be trained in the correct use of the product according to the Installation and Maintenance Instructions.
Where a formal 'permit to work' system is in force it must be complied with. Where there is no such system, it is recommended that a responsible person should know what work is going on and, where necessary, arrange to have an assistant whose primary responsibility is safety.
Post 'warning notices' if necessary.
1.12 Handling
Manual handling of large and / or heavy products may present a risk of injury. Lifting, pushing, pulling, carrying or supporting a load by bodily force can cause injury particularly to the back. You are advised to assess the risks taking into account the task, the individual, the load and the working environment and use the appropriate handling method depending on the circumstances of the work being done.
1.13 Residual hazards
In normal use the external surface of the product may be very hot. If used at the maximum permitted operating conditions the surface temperature of some products may reach temperatures of 250°C (482°F).
Many products are not self-draining. Take due care when dismantling or removing the product from an installation (refer to 'Maintenance instructions').
1.14 Freezing
Provision must be made to protect products which are not self-draining against frost damage in environments where they may be exposed to temperatures below freezing point.
1.15 Disposal
Unless otherwise stated in the Installation and Maintenance Instructions, this product is recyclable and no ecological hazard is anticipated with its disposal providing due care is taken.
1.16 Returning products
Customers and stockists are reminded that under EC Health, Safety and
Environment Law, when returning products to Spirax Sarco they must provide information on any hazards and the precautions to be taken due to contamination residues or mechanical damage which may present a health, safety or environmental risk. This information must be provided in writing including
Health and Safety data sheets relating to any substances identified as hazardous or potentially hazardous.
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2. Application
The BCV31 is a pneumatically actuated control valve for the blowdown of steam boilers.
It is normally used with a controller as part of an automatic TDS control system, though it can also be used for other high pressure drop, low flowrate applications.
3. Technical data
Valve maximum pressure
Valve maximum temperature
Actuator maximum ambient temperature
Minimum air pressure
Maximum air pressure
Air consumption (20 mm travel)
Air supply connection
32 bar g
239°C
110°C
2.5 bar g
6 bar g
0.33 litres
1 /
8
" BSP
(464 psi g)
(462°C)
(230°F)
(36 psi g)
(87 psi g)
(0.01 Cu. ft.)
4. Operation
The valve is spring loaded to the closed position (spring retract), and is also held closed by the boiler pressure. The valve is supplied with a low flowrate 10 mm (0.4") stroke, but can be adjusted to give 15 mm (0.6") or 20 mm (0.8") stroke for increased flowrates if required (see Fig. 1 below).
The actuator has a rolling diaphragm and a stroke indicator on the spindle.
Actuator spindle
Actuator yoke
Travel indicator
Closed position
Anti-rotation/ indicator plate
Open position -
Factory set to
10 mm stroke
Fig. 1 Adjustment (For further information see Section 6)
IM-P403-37 AB Issue 5 5
5. Installation
Caution
Do not pressurise the spring side of the actuator housing.
Do not restrict the housing plastic vent cap.
The BCV31 will operate at any pressure between 2.5 bar g (36 psi g) and 6 bar g (87 psi g).
A regulated supply of filtered air is required, which should be free of oil and water. A suitable filter / regulator is the Spirax-Monnier MP2, fitted with a spring to provide a pressure range of 2.5 bar g
(36 psi g) to 6 bar g (87 psi g). A solenoid valve is also required. See separate literature for regulator details. The BCV31 may be mounted horizontally or vertically.
For boiler blowdown applications the ideal take-off point for the blowdown is from a boiler side connection (Figs. 2 and 3), to reduce the possibility of scale entering the blowdown valve.
If the bottom connection has to be used, make a 'T' connection upstream of the main bottom blowdown valve as shown in Fig. 4. We recommend that where possible the 'T' is taken off the top of the blowdown line to reduce any problems of scale.
The ¼" BSP plug may be removed and the connection used for boiler water sampling.
Spirax Sarco recommend and can supply a sample cooler and conductivity meter.
Fit a stop valve between the boiler and the BCV31.
A check valve is recommended downstream of the BCV31.
In accordance with UK regulations and guidance notes, for single boiler installations the blowdown may discharge into the main blowdown line downstream of the bottom blowdown valve.
For multi-boiler installations the automatic blowdown lines must be separate from the main bottom blowdown line.
For further information see UK Health and Safety Executive Guidance Note PM60.
Regulations or guidance notes for other countries may differ.
Note: When installing with S11 chamber, use M12 bolts for PN16, 25 and 40 and ANSI 300 flanges.
Use M16 bolts for BS 10 Tables 'H' and 'J' flanges. The holes in the S11 chamber are 19 mm Ø.
Probe elbow TDS probe Boiler
Stop valve
BCV31
To sample cooler
Fig. 2 Installation on a probe elbow
6
Check valve
Blowdown to heat recovery system or blowdown vessel
IM-P403-37 AB Issue 5
BCV31
Stop valve
Boiler Check valve
Blowdown to heat recovery system or blowdown vessel
Sensor in
S11 chamber
To sample cooler
Fig. 3 Installation on a boiler side connection
Boiler
300 mm (12")
Stop valve
Strainer
Pipeline distance between boiler and sensor to be as short as possible
Main blowdown valve
Fig. 4 Installation on a boiler with no suitable side connection
IM-P403-37 AB Issue 5
BCV31
Stop valve
Blowdown to heat recovery system or blowdown vessel
Check valve
Sensor in
S11chamber
Main blowdown to blowdown vessel
7
6. Adjustment
The valve is supplied with a low flowrate setting of 10 mm (0.4") stroke.
To increase the stroke to 15 mm (0.6") or 20 mm (0.8") proceed as follows:-
1.
Isolate the valve from boiler pressure and energise the solenoid valve so that the air supply can be manually controlled by the regulator.
2.
Remove the lower travel indicator using a screwdriver.
3.
Apply just enough air pressure to fully open the valve.
4.
Remove the four socket screws from the anti-rotation/indicator plate, locking plate and valve adaptor.
5.
Turn off the air supply and allow the actuator to retract fully.
6.
Loosen the valve stem locking nut and screw the nut and the valve adaptor as far down the stem as it will go by hand.
Actuator spindle
Actuator yoke
Locking nut
Actuator connector
Anti-rotation / indicator plate
Locking plate Valve adaptor
Socket screws and washers
(4 off 5 /
32
A /F)
Travel indicator
Fig. 5
Locking nut Valve stem
7.
The actuator spindle is factory set flush with the underside of the actuator connector
+/- 0.5 mm ( 1 /
50
"). Check that it has not been moved.
Caution:- If adjustment should be needed, hold the actuator connector to prevent the actuator spindle turning and damaging the diaphragm.
8.
Lift the valve stem up as far as it will go.
9.
Measuring from the top of the stuffing box (Fig. 5), mark the required stroke 15 mm (0.6") or
20 mm (0.8) on the valve stem (use a sharp pencil or fine marker).
Table 1 Blowdown valve capacities
Boiler pressure bar g
5
7
10
15
20
32 psi g
72
102
145
218
290
464
Low flowrates
Blowdown valve capacities
Medium flowrates
10 mm (0.4") stroke 15 mm (0.6") stroke kg / h (Ib /h) kg / h (Ib/ h)
High flowrates
20 mm (0.8") stroke kg / h (Ib/ h)
380
460
(838)
(1 015)
530
710
(1 168)
(1 565)
730
1 150
(1 609)
(2 540)
570
700
780
940
(1 260)
(1 540)
(1 720)
(2 075)
950
1 150
1 250
1 400
(2 100)
(2 540)
(2 760)
(3 090)
1 500 (3 310)
1 650 (3 640)
1 700
1 800
(3 750)
(3 970)
8 IM-P403-37 AB Issue 5
Fig. 6
20 mm (0.8") mark
15 mm (0.6") mark
10 mm (0.4") mark
10 mm (0.4")
Stuffing box
10. Push the valve stem down until the mark lines up with the stuffing box.
11. Apply air pressure to allow the actuator to descend fully.
12. Screw the valve adaptor upwards to fully locate into the actuator connector, and make sure the locking plate will align with the flat on the valve adaptor. Tighten the locking nut.
Locking plate
Actuator yoke
Fig. 7
Valve adaptor Anti-rotation / indicator plate
Note offset
13. Refit the anti-rotation / indicator plate and locking plate. Note offset on locking plate. Check that the plate aligns with the flat on the valve adaptor. Refit and tighten the four socket screws.
14. Refit the lower travel indicator.
15. Operate the valve and check that the stroke is correct.
16. Reset regulator to the desired pressure range 2.5 - 6 bar g (36 - 87 psi g).
Plate and screws refitted
Valve fully retracted
(after plate removed).
Spindle flush with underside of connection.
Adaptor and lock-nut screwed fully onto stem.
Screws and plate detached with valve fully extended.
Valve stem pulled fully upwards.
Fig. 8 12 sided nut
Adaptor screwed up to meet connector and lock-nut tightened.
Mark on stem aligned with top of stuffing box.
Lower travel indicator removed
Travel indicator refitted
IM-P403-37 AB Issue 5 9
7. Maintenance
We recommend that the valve and actuator are examined annually and parts replaced as necessary.
Full actuator spares fitting instructions are given in the Installation and Maintenance Instructions for PN type actuators.
No routine maintenance is required.
The valve stem is sealed by packing rings, which can be adjusted if any leakage should occur at the valve stem (see Section 7.2).
If you need to replace spring loaded PTFE chevron seals with an adjustable packing ring set read Section 7.3.
7.1 Materials
No.
Description
9
13
7
8
14
15
16
17
18
19
20
5
6
3
4
1
2
Body
Bonnet
Seat
Washer (seat)
Valve cone
Cap
Stem
Wave spring
Gasket (bonnet)
Gasket
M8 lock-nut
Plug
'S' type gasket
Bottom cover
M10 nut
Stud
Guide bush
33
34
40
41
42
43
44
29
30
31
32
No.
21
22
23
26
27
28
Description
M30 nut
'S' type gasket
Plug ¼" BSPT
Actuator yoke
Valve adaptor
Locking plate
Anti-rotation / indicator plate
Socket screw
Washer
Travel indicator
Actuator connector
Locking nut
Bottom support ring
Graphite stem seal (set of 5)
Top support ring
Stuffing box
Gland nut
7.2 To adjust the valve stem packing rings:
-
Turn the adjustable gland nut (44) clockwise one flat (60°) at a time, then operate the valve several times. Repeat if still leaking.
10 IM-P403-37 AB Issue 5
Fig. 9
3
4
16
15
2
1
43
21
41
40
33
28 /29
14
8
IM-P403-37 AB Issue 5
26
34
32
30/ 31
27
44
13
42
19
18
9
7
5
6
22
17
23
11
7.3 To replace spring loaded PTFE chevron seals with an adjustable packing ring set:
-
Remove the actuator.
-
Remove and discard the existing stuffing box, PTFE chevron seals, guide bush, and spring (see inset in Fig. 10).
-
Ensure the valve stem and bonnet are clean.
7.3.1 If the new seal set is supplied assembled into the stuffing box:
-
Fit the bottom support ring (40, see Fig. 10) over the valve stem and locate in the valve bonnet with its small diameter downwards.
-
Fit the stuffing box gasket (13) to the stuffing box (43), and pass the stuffing box assembly over the valve stem (7).
WARNING: Handle the gasket with care - it is fragile, and has a sharp reinforcement.
-
Screw the stuffing box into the valve bonnet and torque to 25 - 30 N m (18 - 22 Ibf ft).
-
Ensure the gland nut (44) is finger tight against the top support ring (42), then move the valve stem up and down over its full travel five or six times to bed in the packing rings.
-
Tighten the gland nut by two flats (120°).
-
Reassemble the actuator, pressurise the system, and operate the valve five or six times.
-
Adjust the gland nut to stop any leaks.
7.3.2 If the new seal set is supplied as separate components:
-
Fit the top support ring (42), chamfer first, into the stuffing box (43). (See Fig. 10).
-
Fit the five packing rings (41) into the stuffing box from below, so the thread in the top of the stuffing box cannot damage the rings. Ensure that the splits in the packing rings are staggered.
Tip:- Use the bottom support ring (40) as a temporary tool to push the packing rings into place.
-
Fit the bottom ring support over the valve stem (7) and locate in the valve bonnet with its small diameter downwards.
-
Fit the gland nut (44), and tighten finger-tight only at this stage.
-
Fit the stuffing box gasket (13) to the stuffing box, and pass the stuffing box assembly over the valve stem.
WARNING: Handle the gasket with care - it is fragile, and has a sharp reinforcement.
-
Screw the stuffing box into the valve bonnet and torque to 25 - 30 N m (18 - 22 Ibf ft).
-
Move the valve stem up and down over its full travel five or six times to bed in the packing rings.
-
Tighten the gland nut by two flats (120°).
-
Reassemble the actuator, pressurise the system, and operate the valve five or six times.
-
Adjust the gland nut to stop any leaks.
7.4 Replacing the valve seat:
-
When replacing the valve seat (3), it will be necessary to fit a guide bush (20) into the valve bonnet if one is not already fitted.
-
The bush is a press fit - fit with chamfered end first.
-
It is recommended that a suitable press is used to insert the bush flush into the bonnet.
Note: to avoid damage, the bush must not be hammered.
-
A guide bush is included in the in the 'Valve cone, seat and stem spares set' (see Section 8).
12 IM-P403-37 AB Issue 5
8. Spare parts
Available spares for BCV31 valve
Note: see page 14 for PN6126 actuator spares.
A gasket and packing set, and a valve cone and stem set are available.
An adjustable stuffing box kit is also available, enabling a valve with spring loaded PTFE seals to be converted to the adjustable graphite seal system*.
The spare parts are available as indicated below. No other parts are available as spares.
Available spares
Gasket and packing set Stock No. 4034682 4, 9, 13, 16, 22, 36
Valve cone, seat and stem set Stock No. 4034683
3, 5, 6, 7, 8, 15, 16, 20 +
Gasket and packing set
Note: Stem (7) is supplied with plug (15) tightened to a specific torque (14 N m). Do not loosen as it is a safety critical item.
* Adjustable stuffing box kit Stock No. 4034684
40, 42, 43, 44 +
Gasket and packing set
Note: The adjustable graphite seal system is not currently approved for use on the UL Listed valve
How to order spares
Always order spares by using the description given in the Table above and state the size, and flange type of the blowdown valve.
Example: 1 - Gasket and packing set Stock No. 4034682, for Spirax Sarco BCV31 blowdown control valve flanged BS 4504 PN40.
44
43
13
42
41
40
UL listed valve sealing arangement
5
16
3
4
20
9
7
Fig. 10
IM-P403-37 AB Issue 5
22
15
8
6
13
Available spares for PN6126 actuator
The spare parts available are shown in heavy outline. Parts drawn in broken line are not supplied as spares.
Available spares
Stem seal kit
(Piston guide bearing and 'O' rings)
Diaphragm kit
(Diaphragm, Nyloc nut and washer and 'O' ring)
Travel indicator kit (2 off)
Spring kit
A, C, H
D, E, F, H
G
B, J
How to order spares
Always order spares by using the description given in the column headed 'Available spares' and state the size and type of blowdown control valve.
Example: 1 -Diaphragm kit for PN6126 actuator.
D
F
E
J
J
G
G
B
H
A
C
J
J
Fig. 11
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IM-P403-37 AB Issue 5 15
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