Emerson SEMPELL User manual

SEMPELL DEWRANCE BLEED STEAM CHECK VALVES
InstallatIon and maIntenance InstructIons
GENERAL
• This covers bled steam check valves fitted
with pneumatic actuator and external limit
switches.
• For spare parts, refer to sheet giving details
of classification. When ordering spare parts,
quote full product number stamped on
nameplate.
• Refer to Appendix 2 for specific product
numbers.
VCIOM-01422-EN 15/05
Before installation these instructions must be fully read and understood
Nr. D129
1 SAFETY NOTICE
Proper installation, operation and maintenance
are essential to the safe and reliable operation
of all valve products. The relevant procedures
recommended by Dewrance 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.
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 Dewrance product, or render it
unsafe. It is also important to understand that
these ‘safety messages’ are not exhaustive.
Dewrance cannot possibly know, evaluate,
and advise any customer of all the conceivable
ways in which tasks might be performed, or
of the possible hazardous consequences of
each way. Consequently, Dewrance has not
undertaken any such broad evaluation and,
thus, who uses a procedure and/or tool, which
is not recommended by Dewrance, or deviates
from Dewrance recommendations, must be
thoroughly satisfied that neither personal
safety, nor valve safety, will be jeopardised
by the method and/or tools selected. If not so
satisfied, contact Dewrance if there are any
questions relative to tools/methods. Some
of the products manufactured by Dewrance
may be used in radioactive environments.
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 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 Dewrance
products, and the possible hazardous
consequences of each way, Dewrance can
not possibly evaluate all conditions that might
injure personnel or equipment. Nevertheless,
Dewrance does offer the safety precautions
listed on page 5 for customer information only.
It is the responsibility of the purchaser or user
of Dewrance 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 any additional copies of this manual be
required, they can be purchased by contacting
Dewrance.
Consequently, prior to starting any operation in
a radioactive environment, the proper “health
physics” procedures should be consulted and
followed, if applicable.
Emerson.com/FinalControl © 2017 Emerson. All rights reserved.

2
4 DESIGN FEATURES AND NOMENCLATURE
This range of valves has been specifically
designed for installation in bled (extraction)
steam lines between steam turbines and feed
water heaters but are equally applicable to
reheater connections and bleed on pass-out
lines in process plants.
Their function is to prevent the reverse flow
of stored steam and water from the heater or
its bled steam pipe to the turbine. Installation
would be in a horizontal pipe as near to the
turbine as possible. These valves are free
acting whereby the disc moves to the closed
position when flow in the forward direction
ceases. Gravity action on the disc provides a
closing moment from the fully open to fully
closed position. Where power assistance is
required, a spring return pneumatic cylinder
is accommodated whilst still maintaining the
automatic gravity closing feature.
All Dewrance bled steam check valves are
based on the same seat geometry of a conical
seated disc in a conical body seat. The seating
intensity is high enough to give a good seal
and yet low enough not to cause any surface
scuffing. The position of the hinge pin ensures
that the disc opens and closes without a
rubbing action to effect a tight seal over the
fullrange of pressures.
The combination of disc geometry and the body
shape produce a seat angle which gives a short
disc travel as the flow falls progressively with
decreasing flow. This disc will be on the seat
when flow ceases and before reversal takes
place without slamming. This arrangement
gives a low pressure drop and flow under the
disc assists in keeping the valve fully open
overa wide range of flows.
2 SAFETY PRECAUTIONS
• Do not attempt to remove the packing gland
nuts while valve is under pressure.
• Do not attempt to eliminate cover seal
leakage, by tightening the cover nuts, while
the valve is under pressure.
• The cover should never be removed while the
valve is under pressure.
• Do not attempt to remove the Actuator while
the valve is under pressure.
• No alteration and/or modification should
be made to any Dewrance valve, except as
sanctioned and/or authorized by Dewrance.
• Never install, or attempt to use, any valve
thatis not properly identified as to its material
and pressure class.
3 INTRODUCTION
Dewrance bled steam check valves are built to
high standards of precision and accuracy, and
must pass rigid inspection before leaving the
factory. It is imperative that these valves are
properly installed, maintained and operated to
ensure optimum performance.
The purpose of this service manual is to
instruct installation crews maintenance
personnel and operators in these
fundamentals. This manual should be made
available to these personnel at all times, so
thatthey can become, and remain, familiar
withthe details of these valves.
Dewrance bled steam check valves are
intended for high-pressure service in fluids
approved by Dewrance. When shipped from the
Dewrance factory, they are guaranteed to be
in good condition; however, Dewrance cannot
assume responsibility for damage to valves
due to faulty installation, improper operation
orother conditions beyond its control.
SEMPELL DEWRANCE BLEED STEAM CHECK VALVES
InstallatIon and maIntenance InstructIons

3
PARTS LIST (REFERRING TO FIGURES 1 AND 2)
Ref. no. No. off Description Ref. no. No. off Description
1 1 Body 78 ** Cover nut
3 1 Cover 78a 4Gland nut
4 1 Stem 78b 8Side flange nut
5 1 Gland 80 1Neck bush
17 1Cover gasket 80a 1Guide bush
17a 2Side flange gasket 88 1Adaptor plate
24 2Side flange 96 2Hinge pin bush
28 ** Cover stud 99 2Hinge pin housing
28a 4Gland stud 160 1Stem guide
28b 8Side flange stud 160a 1Limit switch striker plate
39 1Stem indicator 200 4Cap head screw
48 4Pillar 200a 4Safety washer
51 1Disk 200b 1Set screw
58 1Hinge pin A 1 Pneumatic actuator
68 ** Gland packing B 2 Limit switch
FIGURE 1
Main air supply in
Filter
regulator
View of limit switches
indirectionofarrow ‘X’
Do not use eyebolts
forlifting valve
Only use for lifting
pneumatic actuator
Safety guard (fitted only
whensolenoid valve has
manual push button)
FIGURE 2
Scrap view of hinge pin area in
directionof arrow ‘A’ (Figure 1)
Assembly check
Clearance gap between bushes 96 and 99 with
dickin shut position to be 0.6 to 1.0mm
Radial clearance
(cold)
Max. 0.35mm
Min. 0.18mm
** Quote product number for quantity
SEMPELL DEWRANCE BLEED STEAM CHECK VALVES
InstallatIon and maIntenance InstructIons

4
5 COMMISSIONING
A. Connecting to electrical supply
For single acting pneumatic actuator with
solenoid valve wired for normally closed
positions.
1. Ensure that the adjusting nut on the filter
regulator is fully out (anti-clockwise) then
turn on the air supply to the inlet supply of
the filter regulator.
2. Connect the electrical supply to the
solenoidvalve.
3. Energize the solenoid valve.
4. Screw in the adjusting nut on the filter
regulator (clockwise) until the working
pressure is obtained (Refer to certified
General Arrangement drawing for details of
air pressure requirements). The valve stem
(4) will go to the fully instroked position.
5. To ensure correct and safe operation, check
the outstroke by de-energizing the solenoid
valve. As the air pressure is relieved, the
stem (4) will move to the fully outstroked
position.
WARNING!
Care must be taken when exhausting the solenoid
valve that the area close to the valve is kept clear.
Do not attempt to obstruct exhausting orifices
byhand.
6 STORAGE
Indoor storage of valves is recommended.
Ifprolonged storage is anticipated, the valves
should be stored in humidity controlled
storageareas.
If valves are ordered to a more stringent
cleaning and storage procedure, the
recommendations in that procedure should
befollowed.
7 INSTALLATION AND WELDING
When valves are received, an enclosed ‘Packing
Note’ will provide an itemised statement of all
valves and parts included in the shipment. The
recipient should check and account for each
item on the list, and then keep this packing note
as a permanent record for these valves/parts.
Unloading the valves should be done with care.
Remember that, although the valve is a rugged
piece of equipment, it may still be damaged by
abusive handling. Skidded or chocked valves
should not be unskidded until immediately
before installation.
Improper installation of a valve can have very
serious consequences, resulting in a possible
malfunction, which may result in extensive
and costly repairs. Compliance with the
following recommendations will do much to
assure optimum performance of the valve
afterinstallation.
It is essential that precautions be taken to
prohibit the entry of foreign debris inside
the valve, which could damage the seating
surfacesbefore and/or after installation.
B. Solenoid valve check
Next, it is necessary to check the functional
operation of the solenoid to ensure that it
responds correctly via the control system.
1. With solenoid valve energized, the stem (4)
and the indicator plate (39) will move to a
fully instroked position. This will indicate the
correct operation of the solenoid. Open limit
switch operation can also be checked at this
stage.
2. Select the ‘close valve’ position via the
control system (for on-load testing) i.e.
solenoid de-energized and check the
actuator has moved to the fully outstroked
position. Closed limit switch operation can
also be checked at this stage.
3. Select the ‘open valve’ position via the
control system (for on-load testing) and
check that the actuator has moved to the
fully instroked position.
4. With the working air pressure still set, a
simulated turbine trip should now be carried
out via the control system to ensure the
correct solenoid response.
5. Local on-load testing can be achieved by
operating the push button on the solenoid
valve. When the actuator is fully outstroked,
release the push button and the pneumatic
actuator will return to the fully instroked
position.
6. After satisfactory completion of the above
steps, fully screw out (anti-clockwise) the
adjusting nut on the filter regulator and de-
energize the solenoid valve. The stem (4) will
move to the fully outstroked position.
When the valve is required to be put into
service, screw in (clockwise) the adjusting
nut on the filter regulator until the working
air pressure is obtained. The stem (4) will
move to the fully instroked position when
the valve is ready for service.
SEMPELL DEWRANCE BLEED STEAM CHECK VALVES
InstallatIon and maIntenance InstructIons

5
Caution
Provisions should be made for supporting the
valve and adjacent piping so that the pipeline
stresses will not be transmitted to the valve
body during site welding of the pipe to the valve.
Welding and stress relieving procedures should
conform to the applicable code or standard.
Weld with care and beware of weld splatter
damaging internal parts
Cleaning of pipelines in which the valve is
installed, and all connecting lines, is essential
before the unit is put into operation. Welding
beads, scale and foreign debris in the line can
cause damage to the valve seats and can result
in leakage.
When raising pressure at any time in the
pipeline system, the valve gland nuts should be
tightened or ‘followed up’ at regular intervals.
8 DISASSEMBLY (REFER TO FIGURES 1 AND 2)
WARNING!
Ensure that there is no pressure in the pipeline
or valve. The pipeline should be drained prior to
dismantling the valve.
1. Fully retract the regulating nut on the filter
regulator to zero pressure.
2. De-energize the solenoid to exhaust the air
in the pneumatic cylinder (A).
3. Isolate the compressed air and electrical
supplies.
4. Label and record cables before
disconnecting electrical connections to
solenoid valves and limit switches.
FIGURE 3
Cover (3)
Stem guide (160)
Peened over to retain
guide bush as shown
Guide bush (80a)
5. Disconnect compressed air connection.
6. Loosen gland nuts (78a) then utilizing the
eyebolt in the top of the actuator (A) and
suitable lifting equipment, support the
weight of the actuator. Unscrew and remove
the lower actuator nuts that secure the
actuator to the adaptor plate (88). Carefully
raise the actuator to the half way position.
Slacken set screw (200b). Utilizing the hole
in stem (4) and the flat portion on the piston
rod, unscrew stem (4) from the actuator
piston rod and remove stem indicator (39).
Protect actuator from ingress of foreign
matter.
(See Appendix 1 for actuator maintenance
instruction).
7. Screw three suitable eyebolts into the
threaded holes on the side of the cover(3).
Thread size is stamped adjacent to the
holes.
8. Unscrew all cover nuts (78).
9. Utilizing the eyebolts and suitable lifting
equipment, lift off the cover assembly.
10. Remove gland nuts (78a)
11. Remove gland (5), gland flange (30) and
gland packing (68).
12. Refer to the diagram below. Check guide
bush (80a) for wear or scoring. Should a new
bush be required, then first remove the old
bush. Do this by knocking back the places
where the stem guide has been peened over
the bush and then knocking guide out with
suitable punch.
SEMPELL DEWRANCE BLEED STEAM CHECK VALVES
InstallatIon and maIntenance InstructIons

6
13. Ensure that the disk (51) is in the closed
position.
14. Referring to Figure 2 check and record the
gap between hinge pin bush (96) and hinge
pin housing (99).
15. Remove indicator locking nut (78) and
indicator bracket (160). Refer to Figure 1
Appendix 1.
16. Unscrew and remove side flange nuts (78b).
17. Remove side flange (24).
18. Remove hinge pin housing (99). A tapped
hole is provided in the end of the housing
tofacilitate the removal.
19. Withdraw the hinge pin (58). A tapped hole
is provided in both ends of the hinge pin to
facilitate the removal. This tapped hole is
the same size as the one in the hinge pin
housing(99).
20. To remove the disk (51), place a nylon sling
through to hinge pin bush holes (96) in lugs
on the disk then, using lifting equipment,
hoist out the disk.
CAUTION
When lifting out the disk (51), the tendency is for
the disk to swing away from the body seat. Care
must be taken not to damage the body and disk
seating faces when lifting.
9 RE-ASSEMBLY (REFER TO FIGURES 1 AND 2)
A. Pre-assembly checks
Ensure the following checks are performed
prior to assembling the valve.
Should it be necessary to replace the hinge
pin bushes. Push the bushes into position and
‘peen’ over in three places as shown below.
Note: it is not recommended to re-use any
packings or gaskets.
In case of defects considered to be outside
the acceptable standards, replacement parts
should be fitted.
Dewrance provide in-house factory repair
facility and a fast response spare parts service.
FIGURE 4 Hinge pin
bush(96)
Disk (51)
Disk to be peened
over in 3 places
Note: ensure bush is fully
pushed in before peening
• Body (1)
Check the finish of the stem, which operates
through the gland. The stem must be smooth
and free from scoring.
• Cover (3)
Ensure that the body is cleaned of any other
foreign debris, which may have accumulated
inthe valve body.
1. Inspect the gasket sealing face for damage.
2. Inspect the internal walls of the gland box
for steam cuts or pitting.
• Studs (28, 28a and 28b)
Check for wear or damage; replace with new
ones as necessary.
• Hinge pin (58)
It is important that the pin is straight within
0.06mm, if greater that this pin must be
straightened.
Caution: take care not to damage pin during
this operation.
• Neck bush (80)
Inspect bore of bush for wear or scoring,
replace with as necessary.
• Hinge pin bush (96)
Check Bush for wear, if damaged, bush must
be replaced in the following manner:
Using suitable punch, knock back the peened
metal and tap out the bush.
Press in new bush and secure by peening in
three places as shown below.
SEMPELL DEWRANCE BLEED STEAM CHECK VALVES
InstallatIon and maIntenance InstructIons

7
FIGURE 5
Material to be removed
fromthisface by grinding
Hinge pin housing (99)
B. Assembly procedure
1. Ensure that the disk (51) and body (1)
seating faces are clean. Place a nylon sling
through hinge pin bushes (96) located in
disk and using lifting equipment, lower disk
into body (1). As the disk is being lowered, it
will have to be pushed over at the same time
until the disk comes into contact with the
body seat.
Caution: care must be taken to prevent
damage to disk and body seating faces, the
angle of the seat to disk faces will keep the
disk in position.
2. Align hinge pin bushes (96) and slide in
hinge pin (58).
3. Ensure gasket faces on body (1) and hinge
pin housing (99) are clean, fit new side
flange gasket (17a), slide in hinge pin
housing (99).
4. Fit side flange (24) over side flange
studs(28a).
5. Screw on side flange nuts (78b) and tighten
in a diametrically opposing sequence to a
torque value shown in Appendix 2.
6. Using feeler gauges, check that the
minimum clearance gap between hinge
pin bush (96) and hinge pin housing (99) is
0.6mm to 1mm (0.024” to 0.040”). The valve
is designed to these tolerances. In the event
of tolerances being outside the above limits,
proceed as follows:
Remove the hinge pin housing (99) on the
affected side/s referring to diagram below,
remove by grinding sufficient metal from
face shown to achieve above tolerances.
Ensure that the face is machined square
toC/L. Refit hinge pin housing (99).
7. Ensure gasket faces on cover (3) to body(1)
are clean. Fit new cover gasket (17) into
recess in body (1).
8. If guide bush (80a) has been replaced,
ensure that the stem guide (160) has been
peened over to retain the guide bush (80a),
refer to section VII (page 14).
9. Slide stem (4) through guide bush (80a,) and
into stem guide (160) and neck bush (80).
10. Fit new gland packing (68), gland (5), gland
flange (30) and gland nuts (78a).
11. Using eyebolts and lifting equipment fit
cover assembly over cover studs (28),
making sure that the location dowel is
linedup correctly.
Caution: care should be taken not to
damage cover studs (28). Support stem (4)
during this operation as it could become
dislodged.
12. Lightly lubricate cover studs (28) with a high
temperature anti seize compound and fit
cover nuts (78). Gasket compression is an
important factor in obtaining a long term
tight joint. It is essential that the gasket
be pulled down evenly. Use feeler gauges
between the cover (3) and body (1) flange
toensure this compression is even.
Caution: do not lubricate gasket or gasket
sealing faces. Cover nuts (78) must be
tightened in a diametrically opposing
sequence in a minimum of 3 stages to a
torque value shown in Appendix 2.
13. Using lifting equipment as previously
described, lift up actuator (A) and lower
over valve ensuring that actuator screwed
tie rods locate into adaptor plate (88).
Lower to half way position then fit position
indicator(39) over stem (4) and screw
stem into actuator piston rod, secure
withpin(200b).
Lower actuator all the way down onto
adaptor plate face (88), secure with lower
actuator nuts.
14. Tighten gland nuts (78a).
15. Reconnect electrical and compressed air
connections.
16. Reinstate electrical and compressed air
supplies.
17. Screw in adjusting nut on filter regulator
until the working air pressure is obtained.
18. Stroke valve fully open and close to check
ease of operation.
SEMPELL DEWRANCE BLEED STEAM CHECK VALVES
InstallatIon and maIntenance InstructIons

8
10 INVENTORY PHILOSOPHY
The basic objective in formulating a service
parts inventory philosophy is to provide prompt
valve service capability, thus preventing
maintenance outage time extensions.
Toaccomplish this, it is necessary to have
immediate availability of the proper inventory
of service parts for optimum valve quantities.
This can be achieved at a minimum of cost
by defining the inventory on a frequency of
needbasis.
To assist towards this objective, the field
service and repair organisation of Dewrance
recommends that the following guidelines
be utilized to establish meaningful inventory
levels:
1. Identify the total number of valves in service
by size, type number, pressure/temperature
class, and tag number.
2. Identify the frequency of replacement
tendency of specific parts:
Class I Parts most frequently replaced.
Class II Parts less frequently replaced,
but critical in the event of an
emergency requirement.
Class III Parts seldom replaced.
Class IV Hardware e.g. nuts, bolts,
pinsetc.
Class V Parts practically never requiring
replacement.
3. “Need probability coverage’ is defined as the
probable percent (%) of total, uninterrupted
operational time which can be expected by
stocking predetermined valve component
classifications.
Identification and ordering essentials
When ordering service parts, please furnish
thefollowing information to ensure receiving
the correct replacement parts:
CLASSIFICATION OF SPARE PARTS
Classification Item N° Description
Class I 17 Cover gasket
Parts most frequently replaced 17a Side flange gasket
68 Gland packing
Class II 4Stem
Parts less frequently replaced but critical
in the eventof an emergency requirement
5Gland
51 Disk
80 Neck bush
80a Guide bush
Class III 24 Side flange
Parts seldom replaced 30 Gland flange
39 Stem indicator
48 Pillar
58 Hinge pin
88 Adaptor plate
96 Hinge pin bush
99 Hinge pin housing
Class IV 28 Cover stud
Hardware (e.g. nuts, studs, pins, ect) 28a Gland stud
28b Side flange stud
78 Cover nut
78a Gland nut
78b Side flange nut
Class V Balance
Parts practically never requiring replacement
Parts classification Need probability coverage
Class I 70%
Class I and II 85%
Class I, II and III 95%
Class I, II, III and IV 99%
4. Consult recommended spare parts list by
valve type to determine quantity of parts
valves to be covered by the inventory plan.
5. Select parts and specify quantities.
Identify valve by: Specify parts required by:
1. Full product no. 1. Part name
2. Size. 2. Part number (if known)
3. Type 3. Quantity
4. Pressure/
temperature class
5. Tag number
Determine “need probability coverage”
which is computable with a specific
company’s operational objectives and
service parts inventory investment
philosophy. Then relate “need probability
coverage” to parts classifications, which
willsatisfy that need.
Guidelines are as follows:
SEMPELL DEWRANCE BLEED STEAM CHECK VALVES
InstallatIon and maIntenance InstructIons

9
11 VALVE REPAIR
A. Factory refurbishment
Many customers find it desirable to return
their valves to Dewrance for restoration or
modernising. Products returned to Dewrance
valve repair center are restored to original
specifications and returned with a new valve
warranty.
B. Service warranty
Factory repaired valves carry a warranty that
covers workmanship and new parts installed
during repair, for a period of one year from
dateof repair completion.
C. Dewrance product repair by unauthorized
sources
Dewrance has not authorized any outside
repair companies, contractors, or individuals
to perform warranty repair service on new
products, or field/factory repaired products
of its manufacture. Therefore customers
contracting for such repair services from
unauthorized sources must do so at their
own risk. Likewise, if any Dewrance product
falls to perform within the scope of its design,
12 TROUBLESHOOTING
The following table indicates the difficulties,
which may be encountered, the most probable
cause and the necessary corrective action.
TROUBLESHOOTING
Problem Probable cause Corrective action
Body/cover joint leakage 1. Gasket damaged 1. Disassemble valve, and fit new gasket as
outlined in manual
2. Cover nuts loose 2. Tighten cover nuts as outlined in manual
Cover gland box leaking 1. Gland packing damaged 1. Disassemble valve, and correct discrepant
condition as outlined in manual
2. Gland nuts loose 2. Tighten gland nuts as outlined in manual
Disk will not open and
fully close
1. Foreign material trapped
between disk and seat
1. Disassemble valve, and correct discrepant
condition as outlined in manual. Inspect
system for cleanliness
2. Air supply low to actuator 2. Check air pressure and filter regulator.
Pressure should be as outlined in manual.
Inspect pipework for leaks
3. Gland nuts too tight 3. Tighten as outlined in manual
4. Clearance between hinge
pin housing/bush incorrect
4. Check clearance as outlined in manual
SEMPELL DEWRANCE BLEED STEAM CHECK VALVES
InstallatIon and maIntenance InstructIons
Dewrance must be notified and given the
opportunity to inspect and correct the problem.
Dewrance will not accept any backcharges
for unauthorized repair sources performing
corrective repairs on its products.

10
APPENDIX 1 - PNEUMATIC ACTUATOR
MAINTENANCE
A. Dismantling procedure
1. Before starting to dismantle cylinder
assembly from its installation, it is
important to note by an appropriate means,
the position of port and pipework in relation
to each other and its installation.
2. Remove cylinder assembly from its
installation and lift clear using the lifting
eyefitted.
3. Place cylinder on a service bench with the
front of the cylinder towards you. (Front of
cylinder refers to piston rod end of cylinder).
4. Undo the elbow fitting pipe ‘nut on the air
supply to the valve, remove the solenoid cap
and undo and remove the F.R.L mounting
plate and F.R.L assembly. Remove the
junction box plate and preserve. - (Preserve
parts means keep for later maintenance
operation).
5. To dismantle the cylinder, the tie rod nuts
on the front end of the cylinder must be
loosened as indicated in Figure 6, until
the installed -compression springs have
reached their free length.
Removal of tie rod nuts
1. Loosen nuts ‘1’ and ‘3’ 5 to 6 turns.
2. Loosen nuts ‘2’ and ‘4’ 5 to 6 turns.
3. Repeat steps 1 and 2 until compression
spring reaches its free length.
Tightening of tie rod nuts
Tightening of nuts is the reverse procedure
ofremoval.
FIGURE 6 FIGURE 7
6. Remove the tie rod nuts and lift the back
cover and tie rods clear. Remove the
compression springs and preserve.
7. Remove tube from front end cover, if
necessary by holding tube (do not clamp)
and lightly tapping on the four corners of the
front cover with a fiber mallet until the tube
is clear of the front spigot ‘O’ ring. Preserve.
8. Wipe the piston rod clean. Remove the
piston rod and piston assembly from the
front end cover bush. Take particular care
not to damage seats or bearings when
passing rod end through bush. Preserve.
9. Grip the piston and rod assembly as
indicated (Figure 7), and tap out the locking
roll pin with a 5mm diameter punch.
Preserve roll pin. Loosen piston rod using
spanner flats. Refer to page 38 for spanner
sizes. No marking or gripping should be
made on the shaft O.D. Undo the remaining
thread engagement by hand supporting both
piston rod and piston. Preserve.
10. Place front-end cover on bench with bush
fixing screws facing uppermost. Remove
screws with a 6mm A/F hex. wrench. Turn
front-end cover over and support it such
that the bush is clear of the bench. Push
bush out from back face of front cover.
Preserve.
Do not grip on or mark in any
waythe piston rod surface
Loosen piston rod using
spanner flats only
Tap out lock roll pin
Grip piston rod/piston assy. by tail rod only
WARNING!
the tie rod fixings on the back face of the cylinder
are welded solid no attempt should be made
to dismantle the cylinder from this end as this
will result in the uncontrolled release of the
compression spring.
SEMPELL DEWRANCE BLEED STEAM CHECK VALVES
InstallatIon and maIntenance InstructIons