Flowserve Valtek Guide

12-1
Valtek Metal Bellows
Seal Valves
Rev. 6/97 Valtek No. 49022
GENERAL INFORMATION
The following instructions are designed to assist in
disassembling, reassembling and troubleshooting
Valtek valves equipped with a metal bellows seal.
Productusersandmaintenancepersonnelshouldthor-
oughly review this bulletin in conjunction with Mainte-
nance Instructions 1 (Mark One and Two Control
Valves) before installing, operating or performing any
maintenance on the valve.
ThispublicationdoesnotcontaininformationonValtek
positioners. Refer to the appropriate Maintenance
Instructionsforinstalling,maintaining,troubleshooting,
calibrating, and operating Valtek positioners.
Three styles of metal bellows seal exist: Guardian,
Guardian II and Formed. Guardian II and Formed
bellows are constructed of flat material, which is rolled
intoatubeandthenseamwelded. Thewallsofthetube
are then mechanically formed into convolutions.
Guardian bellows are constructed from a series of
matched pairs of metal discs that are welded together.
To avoid possible injury to personnel or dam-
age to valve parts, WARNING and CAUTION
notes must be strictly adhered to. Modifying
this product, substituting non-factory or infe-
rior parts, or using maintenance procedures
otherthan outlined could drastically affect per-
formance and be hazardous to personnel and
equipment, and may void existing warranties.
GUARDIAN METAL BELLOWS SEAL
Disassembling Guardian Metal Bellows
Seal
To disassemble the Guardian metal bellows seal, refer
to Figure 1 and proceed as follows:
WARNING: Sincetoxicorhazardousmaterialsmay
be present, depressurize the line to atmospheric
pressure. Drain all process fluids and decontami-
nate the valve. Failure to do so can cause serious
personal injury. Keep hands, hair and clothing
awayfrommovingvalvepartsatalltimes. Faceand
eye protection should be worn; otherwise, serious
personal injury may occur.
1. Remove bonnet flange bolts and nuts.
2. Removetheentireactuator/bellowssealassembly,
bonnet and bonnet flange by lifting them straight
out of the body.
WARNING: Thesleeve maystick tothebellows
seal and fall from the assembly during removal
of the actuator assembly from the body, which
could cause damage or possible injury. To
remove a sticking sleeve, lightly tap on the
sleeve while lifting the actuator assembly.
NOTE: Heavy assemblies may require a hoist. A
lifting ring is provided on most actuators for this
purpose;otherwise,liftbytheyokelegsusinglifting
straps and a hoist.

12-2
Figure 1: Guardian Metal Bellows Seal with Integral Flange Design
Note: Item numbers correspond directly to the valve's bill of material. Refer to bill of material for specific numbers.
Seal Ring
Gasket
(Item No. 59)
Sleeve
Gasket
(Item No. 56)
Retainer
(Item No. 30)
Packing Spacers
(Item No.s 93 - 99)
Bonnet
(Item No. 40)
Bonnet Flange Bolt
(Item No. 108, 114)
Lower Guide
(Item No. 82,83)
Upper Stem Guide
(Item No. 86, 87)
Packing
(Item No. 88)
Tell-tale Tap (Purge Plug)
(Item No. 42)
Bonnet Flange
(Item No. 70)
Bonnet Gasket
(Item No. 58)
Sleeve
(Item No. 31)
Metal Bellows
Plug Assembly
(Item No. 50)
Seat Ring
(Item No. 20)
Seat Ring
Gasket
(Item No. 55)
Body
(Item No. 1)
3. Remove the sleeve from the body, then the seat
retainer and seat ring.
4. Remove the bonnet gasket, seal ring gasket,sleeve
gasket and seat gasket.
5. Loosen the actuator stem clamp and remove the
packing box bolting.
WARNING: If there has been a bellows failure,
process fluids may be trapped in the packing
box; therefore, be extremely cautious when re-
moving the packing box bolting and packing.
6.Remove the yoke clamps.
7.Removeactuatorassemblybyturningitoffplugstem.
CAUTION: Although the valve incorporates an
anti-rotation pin, care should be taken not to put
excessive torque on the plug stem/bellows as-
sembly. Excessive torque can damage bellows
and/or shear the anti-rotation pin.

12-3
8.Remove the bonnet flange, then carefully slide the
plug/bellows assembly out of the bonnet without
stretchingthebellows. Becarefulnottolosetheanti-
rotation pin from the plug/bellows assembly. The
packing, packing spacer and stem guides can now
be removed for inspection or replacement.
Reassembling Guardian Metal Bellows Seal
To reassemble the Guardian metal bellows seal, refer
to Figure 1 and proceed as follows:
1. Check metal bellows for signs of wear or damage.
If the bellows shows signs of fatigue or cracking,
obtain a replacement before reassembling and
operatingthe valve. Make sure allgasket surfaces
are clean and free of damage.
2. If the packing has been removed, replace packing,
packingspacerandstemguides(refer toFigure1).
3. Insert the plug stem into the bonnet.
4. Place the bonnet flange on the bonnet.
5. Place the gland flange over the plug stem and the
stem clamp on the actuator stem and reinstall the
actuator assembly by screwing it onto the plug
stem. Three or four plug stem threads should be
exposed below the actuator stem to ensure proper
seating.
CAUTION: Although the valve incorporates an
anti-rotationpin,careshouldbetakennottoput
excessive torque on the plug stem/bellows as-
sembly. Excessivetorque can damagebellows
and/or shear the anti-rotation pin.
6. Insert the seat gasket, seat ring and seat retainer
into the body; then install the sleeve gasket and
metal bellows sleeve.
7. Install the seal ring gasket and the bonnet gasket.
8. Retract the plug and carefully lower the bellows/
bon-netassemblyintothesleeve. Makecertainthe
anti-rotation pin is in place before installing the
bellows.
WARNING: Careshouldbetakennottodamage
the bellows or plug and seat ring seating sur-
faces when installing the bellows. Damage to
the bellows may cause faulty operation and/or
injury to personnel.
9. On air-to-close valves, leave three or four threads
exposed. For correct plug engagement on air-to-
open valves, make certain the plug does not rotate
in the body/bonnet assembly and screw the actua-
tor assembly onto the plug as far as possible.
WARNING: Rotation of the plug while clamped
in the body/bonnet assembly will damage the
bellows seal, which could cause personal
injury.
10. Applyair pressureabovethepiston todriveitto the
bottomoftheactuatorcylinder. Withoutrotatingthe
plug, back the actuator assembly off of the plug
stemuntilthereis1/32-inchgapbetweenthebottom
of the yoke and bonnet. Then back the actuator
assemblyoffofthe plugstemexactlyonecomplete
turn. This provides the correct seating force.
11. Apply air below the actuator piston, retracting the
plug. Install the yoke clamp.
12. To properly align the seat ring and plug, first bring
the bonnet bolting to finger tightness. Apply air
above the piston to seat the plug in the seat ring.
NOTE: Step 12 applies only to valves with pneu-
matic actuators. If an hydraulic or mechanical
actuator is used, return the plug to the midstroke
position and proceed to tighten.
WARNING: Failure to return the plug to the
midstroke position (mechanical or hydraulic
actuatorsonly)will causedamage tothe actua-
tor and/or the valve during the bonnet tighten-
ing sequence. This is due to the inability of
most mechanical/hydraulic actuators to ac-
commodate the 1/16-inch back driving during
the tightening sequence.
13. With the plug in the extended (or closed) position,
tighten two opposing bonnet flange bolts or nuts
1/6-turn (one flat). Tighten each bonnet bolt in this
manner until the bonnet, seat, sleeve and seal ring
gaskets are compressed and the bonnet, sleeve
and body are seated metal-to-metal.
CAUTION: Undertightening may not fully com-
press the gaskets, which may cause leakage.
Overtightening may damage interior parts.
Tighten only to the point that metal-to-metal
seating occurs.
14. Removeair fromtheactuator.Adjustthepositioner
camandstemclampaccordingto instructions con-
tained in the appropriate positioner maintenance
bulletin. Then adjust the stroke plate to indicate
proper air-action (air-to-open valves should be ad-
justed so the stem clamp points to “closed” on the
stroke plate; air-to-close valves should point to
“open”).
15. Installthe packing boxbolting. Packingboxbolting
shouldbeslightlymorethanfingertightwhenTeflon
packing is used.
CAUTION: Do not overtighten packing. Over-
tightened packing can cause high stem friction
and excessive packing wear, which may im-
pede stem movement.
16. Strokethevalveandcheckforsmooth,trouble-free
operation.

12-4
Troubleshooting Guardian Metal Bellows Seals
Failure Probable Cause Corrective Action
Leakage through 1. Insufficient compression of 1. Tighten bonnet flange bolting until
bonnet or sleeve bonnet flange leakage stops
gaskets 2. Worn or defective bonnet, sleeve or 2. Disassemble and replace all gaskets,
seat ring gasket including seat ring gasket
Leakage through 1. Failure of metal bellows 1. Disassemble and replace metal bellows
packing box or seal assembly seal assembly and all gaskets
“tell-tale” tap
Valve does not 1. Improper actuator stem engagement 1. Correct stem engagement (refer to step 10
seat or seats in the “Reassembly” section)
too early
GUARDIAN II METAL BELLOWS SEAL
Disassembling the Guardian II Metal
Bellows Seal
To disassemble the Guardian II metal bellows seal
valve, refer to Figures 2 and 3 and proceed as follows:
WARNING: Depressurizeline to atmosphericpres-
sure, drain all process fluids and decontaminate
the valve (if toxic or hazardous materials are
present). Special attention should be given to the
housing packing area and inside the bellows hous-
ingandwhendisassembling theplughead. Failure
to do so can cause serious injury.
1. Loosen the actuator stem clamp.
2. Remove the packing box bolting.
3. Remove the yoke clamps.
4. Remove the actuator by turning it completely off
the bellows seal stem and bellows seal housing.
CAUTION: Although the valve incorporates an
anti-rotation pin, care should be taken not to
put excessive torque on the plug stem/bellows
assembly. Excessive torque can damage bel-
lows and/or shear the anti-rotation pin. Flats
on plug stem should only be used to prevent
stemfrom rotatingwhile removingactutator or
installing plug heads.
CAUTION: Heavyactuatorsmayrequireahoist.
A lifting ring is provided on most actuators for
this purpose; otherwise, lift by the yoke legs
using lifting straps and the hoist.
5. Remove the bonnet flange bolts or nuts.
6. Remove entire bellows seal assembly, plus the
bonnetand plug, by lifting them straight out of body.
WARNING: If there has been a bellows failure,
process fluid may be trapped in the bellows
sealhousing; therefore, be extremelycautious
when disassembling the valve and bellows
assembly.
7. Disassemble the bellows assembly by first remov-
ingtheplughead. Beginbygrindingthetackwelds
offwheretheplugheadmeetstheplugstem. Next,
securely hold the plug stem by the flats, being
carefulnottodamagethethreadsorgallthe shaft.
Usingawrenchontheplugheadflats,turntheplug
head off the stem.
8. Remove the metal bellows assembly by carefully
pulling it out of the housing.
9. Pullthestemguidehousingoffthebellowsassem-
bly. Jack screw holes are provided, if needed.
10. Remove the bellows housing gasket from the bel-
lows housing.
11. Inspect lower stem guide for galling or wear. If
replacement is required, use a dowel and arbor to
press out the soft guide and guide retainer in the
case of soft guides. When hard guides are used,
the entire guide will be pressed out in one piece.
12. Remove the seat ring, seat retainer, seat ring
gasket,andbonnetgasketfromthebody. Referto
Maintenance Instructions 1 for further details.
Reassembling the Guardian II Metal
Bellows Seal
To reassemble the Guardian II metal bellows seal
valve, refer to Figures 2 and 3 and proceed as follows:
1. If bellows failure has been determined, properly
discard the old assembly and obtain a new one.
Inspect all parts for wear and replace. All gaskets
must be replaced.
2. Replace the lower stem guide into the stem guide
housing. With soft guides, insert the Teflon®liner
into the guide retainer and then press this assem-
blyintotheguidehousing. Withhardguides,press
thesolid guide intotheguidehousing. (An arboris
required to press in these parts.)
3. Install the stem guide housing over the stem and
into the lower flange of bellows assembly. Jack
screw threads should be facing outward.

12-5
S
O
Figure 2: Guardian II Metal Bellows Seal with Integral Flange Design
Note: Item numbers correspond directly to the valve's bill of material. Refer to bill of material for specific numbers.
Monitoring Port
(optional)
Bellows Seal Housing
(Item No. 5)
Bonnet Flange Bolting
(Item No. 108,114)
Lower Stem Guide
(Item No. 82, 83)
Stem Guide Housing
(Item No. 31)
Seat Ring
(Item No. 20)
Seat Ring Gasket
(Item No. 55)
Body
(Item No. 1)
Actuator / Yoke Assembly
Upper Guide
(Item No. 86, 87)
Packing
(Item No. 88)
Packing Spacer
(Item No. 93 - 99)
Tell-tale Tap
Shrouded Bellows Assembly
(Item No. 6)
Bellows Assembly to
Housing Gasket
(Item No. 58)
Tack Weld
Bellows Plug Head
(Item No. 50)

12-6
4. Place the upper end of the stem into a vice using
the stem flats to hold in place. Use caution to not
damage the stem or its threads. Thread the plug
head into the bellows stem using a wrench on the
flatsof the head. (Torque1/2through2-inchvalves
to 540 in-lbs, and 3-inch valves to 2500 in-lbs.)
5. Attheinsidecornerwheretheplugheadmeetsthe
plug stem, tack weld the head to the stem with two
1/8-inch welds 180 degrees apart.
6. Installanewseatringgasket,seatring,seatretainer
and new bellows assembly gasket into valve body.
7. Insert the bellows assembly into the valve body,
being careful to not damage the plug head.
8. Insert a new bellows housing gasket onto the
bellows assembly. Next, carefully lower the bel-
lows housing over the bellows assembly and onto
thevalvebodyandbonnetflangestuds. Becertain
the tell-tale tap is located opposite of the positioner.
9. Installthebonnetflangenutsandtightenfinger-tight.
10. Insert the packing spacer, lantern ring, new pack-
ing and upper stem guide into the packing box.
11. Turn the actuator back onto the bellows stem,
without turning the stem inside the bellows seal
housing. Be certain the gland flange and bonnet
flange are in place before engaging the bellows
stem and actuator stem threads. Leave approxi-
matelythree to five bellowsstem threads exposed
or until a 1/8-inch gap remains between the yoke
bottom and bonnet. With air-to-open valves, re-
tract the stem by applying air pressure to the
bottom of the actuator. This will allow the yoke
clamp and gland flange bolting to be attached and
tightened firmly. The packing box nuts should be
just over finger tight.
12. For air-to-close valves, skip this step and go to step
13. For air-to-open valves, check for proper plug
seating as follows: When proper seating occurs, the
bonnetflangewillbeforcedupagainstthefingertight
bonnet bolting with such force that it will be impos-
sible to wiggle the flange. If proper seating does not
occur, the bonnet flange can be wiggled with light
hand force. Should this occur, place air under the
actuator piston and retract the actuator to approxi-
mate mid-stroke position. Remove the yoke clamp
andgland flange bolting and turn the actuator off the
bellows stem one additional thread and repeat the
above seating procedure. When the bonnet flange
becomes tight against the finger-tight body bolting,
plug is properly seated. If necessary, repeat above
procedure until proper seating occurs. Re-attach
andtightenthe yoke clamp and gland flangebolting.
13. Movetheplugtotheextended(orclosed)position.
Begin tightening the bonnet flange bolting in a
manner that will keep the bonnet flange square/
parallelwith the body.Tightenthefirstbolt1/6-turn, Figure 3: Exploded view:
Guardian II Metal Bellows Seal
Standard
Mark One
Parts
Hard
Guide
Guide
Housing
Plug
Head
Shrouded
Bellows
Assembly
Soft
Guide
Retainer
Soft
Guide

12-7
Troubleshooting Guardian II Metal Bellows Seals
Failure Probable Cause Corrective Action
Leakage through 1. Insufficient compression of bonnet 1. Tighten bonnet flange bolting until
bellows assembly gasket leakage stops
gasket 2. Worn or defective bonnet gasket 2. Disassemble and replace bonnet gasket
Leakage through 1. Failure of metal bellows seal 1. Disassemble and replace metal bellows
packing box or assembly seal assembly and all gaskets
“tell-tale” tap
Valve does not 1. Loose stem locknut on bellows stem 1. Disassemble, tighten stem locknut
seat or seats 2. Improper actuator stem 2. Correct stem engagement (refer to steps
too early engagement 9 thru 12 in the “Reassembly” section)
Leakage through 1. Insufficient compression of gaskets 1. Tighten bonnet flange bolting until
bellows assembly leakage stops
gasket 2. Worn or defective housing, bellows 2. Disassemble and replace all gaskets,
assembly or seat ring gasket including seat ring gasket
then tighten the bolt directly opposite 1/6-turn and
so on around the flange. Firmly tighten all bolts
evenly and completely to compress the bonnet
gasket and to seat the bonnet. Torque the bonnet
bolts to the suggested torque values in Table I.
14. Apply air over the piston to seat the plug. For all
throttlingvalves,adjustthestemclampsothatwith
fullinstrumentsignaltothepositionerthefullsignal
scribe line on the positioner cam points to the
center of the cam roller bearing.
Tighten the stem clamp bolting. Proper tightness is
importantsincethisadjustmentsecurestheactuator
stem to the bellows stem. Adjust the stroke plate so
that the stem clamp points to the “closed” position.
15. If the valve has been taken out of the line, make
sure the flow arrow indicates proper flow direction
upon reinstallation.
Table I: Suggested Bonnet Bolting
Torque Values (ft-lbs, +10 percent)
Bolt/Stud Material
Bolt
Size Carbon Stainless
(inches) Steel Steel
5/880 50
3/4140 90
1 350 220
11/8510 330
11/4730 460
13/8990 630
3. Loosen the actuator stem clamp.
4. Remove the packing box bolting.
5. Remove the yoke clamps.
6. Remove the actuator by turning it completely off
the bellows seal bonnet and bellows seal stem.
CAUTION: Although the valve incorporates an
anti-rotation pin, care should be taken not to
put excessive torque on the plug stem/bellows
assembly. Excessive torque can damage bel-
lows and/or shear the anti-rotation pin.
7. Removetheboltingfromtheupperhousingclamps
or flanges.
WARNING: If there has been a bellows failure,
process fluid may be trapped in the bellows
seal bonnet; therefore, be extremely cautious
when removing the upper housing bolting.
FORMED METAL BELLOWS SEAL
Disassembling Formed Metal Bellows Seal
To disassemble the formed metal bellows seal, refer to
Figures 4 and 5 and proceed as follows:
WARNING: Depressurizeline to atmosphericpres-
sure, drain all process fluids and decontaminate
the valve (if toxic or hazardous materials are
present). Failureto do so cancause serious injury.
1. Remove the bonnet flange bolts or nuts.
2. Remove the entire actuator/bellows seal assem-
bly, plus the bonnet and plug, by lifting them
straight out of the body.
CAUTION: Heavy assemblies may require a
hoist. A lifting ring is provided on most actua-
torsforthispurpose;otherwise,liftbytheyoke
legs using lifting straps and the hoist.

12-8
8. Remove the upper housing clamps or flanges (if
separable) and slide the bellows seal bonnet off
thebellowssealstem. Careshouldbetakennotto
lose the anti-rotation pin from the upper seal. The
packing,packingspacer,andstemguidescannow
be removed for inspection or replacement.
9. Removetheboltingfromthelowerhousingclamps
or flanges. Remove the clamps or flanges (if
separable) from the assembly.
WARNING: Toxicprocessfluidmaybetrapped
inside the bellows housing. Although previ-
ouslydecontaminated,care shouldbetaken to
prevent exposure to toxic residues.
10. Slide the body bonnet down until it makes contact
with the plug head, exposing the stem locknut
between the body bonnet and bellows seal stem.
Using a wrench on the flats, loosen the stem
locknut.
11. Screw the plug stem out of the bellows seal stem
and separate the bonnet and plug from the metal
bellowsassembly. Remove thebonnetspring guide
retainer and guide for inspection or replacement.
12. Remove the metal bellows assembly by carefully
pulling the assembly through the housing.
13. Remove both upper seal ring gaskets from the
upper seal ring.
14. Removethelowerhousinggasketfrom the housing.
15. Remove the seat ring, seat retainer, seat ring
gasket,andbonnetgasketfromthebody. Referto
Maintenance Instructions 1 for further details.
Reassembling Formed Metal Bellows Seal
To reassemble the formed metal bellows seal, refer to
Figures 4 and 5 and proceed as follows:
1. Check the metal bellows for signs of wear or
damage. If the bellows shows signs of fatigue or
cracking, obtain a replacement before reassem-
bling and operating the valve.
2. Install new upper seal gasket “A” in the recessed
areaoftheupper(orlarger)endofthebellowsseal
housing.
3. Insert the metal bellows seal assembly into the
housing, making sure the upper seal ring gasket
properly engages the upper seal ring.
4. Install the lower guide and spring guide retainer in
the body bonnet.
5. Place the lower housing gasket into the recessed
gasket surface on the lower (or smaller) end of the
housing.
6. Slide the plug stem through the body bonnet.
7. Makesuretheseparableflangesandhalfringsare
positionedonthehousingandbonnet. Thebonnet
flange should also be positioned on the bonnet.
8. Install the stem locknut on the plug stem. Screw
the plug stem into the bellows seal stem. Proper
engagement of the plug stem is achieved when
there is approximately 1/8-inch of space in the slot
above the anti-rotation pin when the plug is fully
extended or in the seated position (refer to Figure
5). To determine the correct location of the ex-
tended plug, fit the bonnet and housing loosely
togetherusingthelowerhousingclampsorflanges.
Screw the plug clockwise into the bellows stem
until the 1/8-inch clearance is achieved above the
anti-rotation pin. When in the fully extended posi-
tion, measure the distance from the back of the
plug head to the bottom of the bonnet. This
distance should correspond to the stroke of the
valve plus 1/16-inch. These measurements are
found in Table II. If adjustment is needed, turn the
plug head so that the plug stem screws in or out of
the bellows seal stem until the proper measure-
ment is reached. Double check to be sure the 1/8-
inch clearance still remains.
9. Remove the lower housing clamp or flange bolting
and pull the bonnet and housing apart, exposing
the plug stem. Tighten the locknut firmly against
thebellowssealstem,usingtwowrenches:oneon
thenutandtheotheronthebellowssealstemflats.
10. Thehousingcannowbeboltedtothebonnetusing
the lower housing clamps or flanges. At this point,
the bolting should be finger-tight.
NOTE: Be certain the anti-rotation pin is still in
place before proceeding to step 11.
11. After placing upper seal gasket “B” on the upper
seal ring, insert the bellows seal bonnet over the
bellows seal/plug assembly and onto the upper
seal ring.
12. If the packing has been removed for replacement,
replacethepacking,packingspacer,andguidesin
the correct order in the bellows seal bonnet by
referring to Figure 4. For non-standard packing
configurations, refer to Maintenance Instructions
1.
13. Position the upper housing clamps or flanges and
bolt them together. Bolting should be finger-tight.
14. Before turning the actuator back onto the bellows
seal stem, be certain the stem clamp and gland
flange are in place.
15. Forcorrectstemengagementonair-to-openvalves,
turn the actuator stem onto the bellows seal stem
until about 1/16-inch of space is left between the
bottomofthe yoke and the shoulder of the bellows
sealbonnet. Applyairpressureunderthepistonto
driveit up approximately1/4-inch. Thiswillseatthe
yoke on the bellows seal bonnet and provide the
properclearancebetweenthepistonandthetopof
the yoke.

12-9
Figure 4: Formed Metal Bellows Seal with Separable Flange Design
Note: Item numbers correspond directly to the valve's bill of material. Refer to bill of material for specific numbers.
Packing Spacers
(Item No. 93 - 99)
Bellows Seal Bonnet
(Item No. 7)
Upper Seal Ring
Gasket "B"
(Item No. 59)
Upper Seal Ring
Gasket "A"
(Item No. 59)
Bellows Seal Assembly
(Item No. 6)
Lower Housing Bolt
(Item No. 110)
Half Ring
(Item No. 13)
Lower Housing Flange
(Item No. 72)
Body Bolting
(Item No. 108, 114)
Packing Spacers
(Item No. 93 - 99)
Seat Retainer
(Item No. 30)
Seat Ring
(Item No. 20)
Seat Ring Gasket
(Item No. 55)
Body
(Item No. 1)
Tell-tale Tap
Upper Housing Bolt
(Item No. 106)
Bellows Seal Housing
(Item No. 5)
Stem Jam Nut
(Item No. 113)
Lower Housing Gasket
(Item No. 60)
Spring Guide Retainer
(Item No. 90)
Body Bonnet
(Item No. 40)
Lower Guide
(Item No. 82, 83)
Bonnet Gasket
(Item No. 58)
Half Ring
(Item No. 11)
Bellows Seal Plug
(Item No. 50)
End Flange
(Item No. 10)

12-10
Figure 5: Plug Thread Adjustment
(Refer to Step 8 in
"Reassembly" Section)
Plug Stem
Jam Nut
Anti-rotation Pin
Bellows Seal Assembly
Bellows Seal Plug
Stroke + 1/16-inch
1-inch to less stroke
stroke +1/32-inch
(See Table II)
Spring Guide Retainer
should compres
approximately 1/8-inch

12-11
Table II:
Extended Plug to Bonnet Dimensions
(refer to Figure 5)
Valve Size Stroke Distance Between
(inches) (inches) Extended Plug
and Bonnet
1/2, 3/4, 1 1.00 1.03
11/2, 2 1.50 1.56
3, 4, 6 2.50 2.56
(class 150)
19. Install the entire actuator/bellows seal subassem-
bly into the valve body. Tighten the bonnet flange
bolting finger-tight.
20. Applyairpressureoverthepistonwhileexhausting
the other side to seat the valve. Tighten two
opposing bonnet flange bolts or nuts 1/6-turn (one
flat). Tighten each bonnet bolt in this manner until
the bonnet bottoms metal-to-metal in the body.
This can easily be felt through the wrench.
21. Release the air in the cylinder. Firmly tighten the
upper and lower housing clamps or flanges by
tightening two opposing bolts, so that even pres-
sure on the gasket and proper alignment of the
housing and body bonnet are maintained.
22. Adjust the stem clamp to the correct position ac-
cording to the air action (air-to-open valves should
be adjusted so that the stem clamp points to
“closed” on the stroke indicator plate; air-to-close
valves should point to “open”).
23. Attach the packing box bolting and tighten the
packing box nuts to slightly over finger-tight.
CAUTION: Do not overtighten packing. This
can cause excessive packing wear and stem
friction which may impede stem movement.
24. Stroke the valve and check for smooth operation.
Troubleshooting Formed Metal Bellows Seals
Failure Probable Cause Corrective Action
Leakage through 1. Insufficient compression of housing 1. Tighten flanges or clamps until leakage
lower housing gasket stops
clamps or flanges 2. Worn or defective lower housing 2. Disassemble and replace lower housing
gasket gasket
Leakage through 1. Insufficient compression of seal ring 1. Tighten flanges or clamps until leakage
upper housing gaskets stops
clamps or flanges 2. Worn or defective upper seal ring 2. Disassemble and replace upper seal
gaskets ring gaskets
Leakage through 1. Insufficient compression of bonnet 1. Tighten bonnet flange bolting until
bonnet gasket gasket leakage stops
2. Worn or defective bonnet gasket 2. Disassemble and replace bonnet gasket
Leakage through 1. Failure of metal bellows seal 1. Disassemble and replace metal bellows
packing box or assembly seal assembly and all gaskets
“tell-tale” tap
Valve does not 1. Loose stem locknut on plug stem 1. Disassemble, tighten stem locknut
seat or seats 2. Improper actuator stem 2. Correct stem engagement (refer to steps
too early engagement 15 and 16 in the “Reassembly” section)
16. Forcorrectstemengagementonair-to-closevalves,
a check valve must be used to lock air into the top
of the actuator. This puts the actuator stem in the
extendedposition. Turntheactuatorstemontothe
bellows seal stem until about 1/16-inch of space is
left between the bottom of the yoke and the shoul-
der of the bellows seal bonnet. Carefully exhaust
thecheckvalveandtheyokewillcomeintocontact
withthebonnet. Thiswill provide the proper clear-
ance between the piston and the top of the yoke.
17. Attach the yoke clamps.
18. Using new seat and bonnet gaskets, replace the
seat ring and seat retainer in the body.

12-12 © 1992, Valtek Incorporated, a subsidiary of The Duriron Company, Inc.
Valtek will continue to provide its customers with the best possible products and service available. Should you have any questions about
these provisions or about Valtek's products in general, contact your localValtek representative or the factory directly for assistance.
Valtek International is represented by factory-trained manufacturer representatives throughout the world.
Valtek International Headquarters – Springville, UT
Phone [phone] Fax [phone]
Web www.valtek.com
Valtek Baton Rouge – Baton Rouge, LA
Phone [phone] Fax [phone]
Valtek Beaumont – Beaumont, TX
Phone [phone] Fax [phone]
Valtek Corpus Christi – Corpus Christi, TX
Phone [phone] Fax [phone]
Valtek Houston – Deer Park, TX
Phone [phone] Fax [phone]
Valtek Business Development Group – Houston, TX
Phone [phone] Fax [phone]
Valtek Philadelphia – Boothwyn, PA
Phone [phone] Fax [phone]
Valtek Controls Ltd. – Edmonton, Alberta
Phone [phone] Fax [phone]
Valtek Australia Pty. Ltd. – Scoresby, Victoria
Phone [phone] Fax [phone]
Valtek Engineering Ltd. – Pershore, England
Phone [phone] Fax [phone]
Kämmer Valves Inc. – Pittsburgh, PA
Phone [phone] Fax [phone]
Kämmer Ventile GmbH – Essen, Germany
Phone [phone] Fax [phone]
Valtek-Sereg Vannes S.A. – Paris, France
Phone [phone] Fax [phone]
Valtek Sulamericana Ltda. – Sao Paulo, Brazil
Phone [phone] Fax [phone]
Valtek India Ltd. – Ahmedabad, India
Phone [phone] Fax [phone]
Durco Valtek Pte. Ltd. – Singapore
Phone [phone] Fax [phone]
Yokogawa•Kitz•Valtek – Tokyo, Japan
Phone [phone] Fax [phone]
Valtek Nederland BV – Capelle A/D IJssel, Holland
Phone [phone] Fax [phone]