Cashco 988-MB User Manual
INSTALLATION, OPERATION & MAIN TE NANCE MANUAL (IOM)
MODELS 988 and 989
GLOBE-STYLE PNEUMATIC CONTROL VALVE BODY
SECTION I
I. DESCRIPTION AND SCOPE
Model 988’s and 989’s are pneumatically actuated, globestyle control valves. Sizes are 3/4", 1", 1-1/2" and 2". Ma te ri als are available in cast carbon steel, Grade WCB (CS);
cast 316L SST, Grade CF3M (SST); and cast CW-12MW,
sim i lar to Hastelloy C (H-C).
Failure position is determined by actuator for:
"D" = Direct action; on increasing air loading pressure, the
actuator stem extends. Fail-safe position is with the stem
retracted.
"R" = Reverse action; on increasing air loading pressure, the
actuator stem retracts. Fail-safe position is with the stem
extended.
IOM-988/989
12-13
These valves are designed for chemical service and most
com mon liquid, gaseous, or steam services.
Models 988 and 989 differ only in the face-to-face di men sions of fl anged units; 988’s have a “regular” (“long”) body
pattern, and the 989’s have a “short” body pattern.
II. REFERENCE
Refer to Technical Bulletin 988-TB or 989-TB for complete
tech ni cal specifi cations coupled with either Cashco Actuator
Model C27 or C53.
www.cashco.com/techbulletins/988.pdf
www.cashco.com/techbulletins/989.pdf
Refer to following Installation, Operation & Main te nance
Manuals (IOM’s) for either actuator and/or devices that
maybe mounted to a Model 988 or 989:
Actuators: www.cashco.com/IOM/C27-C53.pdf
Positioners:
P/P: www.cashco.com/techbulletins/9540l.pdf
I/P: www.cashco.com/techbulletins/srd991.pdf
I/P: www.cashco.com/iom/PS2iom.pdf
Model 988
with ATC - FO Actuator
Shown with Internal Live-Loaded Packing
SECTION II
ABBREVIATIONS
ATO-FC ............. Air-to-Open, Fail Closed
ATC-FO ............. Air-to-Close, Fail Open
CCW .................. Counter Clockwise
CW ..................... Clockwise
D or DIR ............. Direct Acting
HC ..................... Cast CW-12MW or Wrought Hast C-22
IAS ..................... Instrument Air Supply
LOAD ................. Positioner Output Air Pressure
R or REV ........... Reverse Acting
SIG .................... Output Signal from Instrument
SST.................... Cast or Wrought 316L Stainless Steel
V ........................ Vent
SECTION III
III. INSTALLATION
A. Orientation:
1. Recommended orientation when installed in a hor i zon tal pipe line is with the stem vertical. Valves may
also be installed in vertical pipelines with stems
horizontal.
2. Outdoors, all installations may be oriented any
an gle from horizontal-to-vertical. (Orient actuator
vent cap, if supplied, to not collect rainwater that
might freeze.)
3. Model 988/989 valves with actuators are not rec om mend ed for installation with the actuator ori ent ed
down wards.
B. Piping System:
1. It is recommended that the control valve unit be in stalled with a double-block and bypass as in di cat ed
in Figure 1. This arrangement is rec om mend ed
especially where maintenance will be done on the
valve body while still installed in the pipe line.
4. For split-ring fl anged end connections, install fl ange
bolting to following torque values.
Recommended Maximum Flange Bolting Torque (ft-lbs.)
Body Size Body Material 150# Flange 300# Flange
3/4"
1" 29 36
1-1/2" 43 43
2" 66 33
3/4"
1" 24 30
1-1/2" 36 36
2" 54 27
3/4"
1" 32 40
1-1/2" 48 48
2" 72 36
CS
SST
HC
23 28
19 25
26 32
5. Clean piping of all foreign debris, including chips,
weld scale, weld spatter, oil, grease, sand or dirt
prior to in stall ing the control valve. This is an ab so lute re quire ment for valves supplied with com po si tion soft seats. System startup strain ers for re mov al
shortly after initial startup are rec om mend ed.
Figure 1: Typical Control Valve Station
2. Pipe unions are recommended for NPT screwed
or sock et welded installations to allow complete
re mov al from sys tem. If removal for maintenance
is by cutting torch for socket welded valves, leave
suffi cient pipe nipple space between the body and
the next piping component up or downstream to
allow socket weld couplings for re in stal la tion.
3. If pipe reducers are located before and/or after the
valve body, keep the reducers as close as prac ti cal
to the valve body; this is especially important where
the re duc ers are more than one line size larger than
the valve body size, which is common in gaseous
service.
6. Field hydrostatic testing the completed piping
sys tem to 1-1/2 x CWP in psig indicated on the
name plate including the Mod el 988/989 is acceptable. If hydro test pressure exceeds the 1-1/2
x CWP limit, the 988/989 must be removed for
such testing. Be fore pressurization, the valve plug
should be lifted from the seat if of reverse, ATO-FC
action. Tighten packing as required.
7. In placing thread sealant on pipe ends prior to en gage ment, ensure that excess material is re moved
and not allowed to enter the valve upon startup.
8. Flow Direction: Install so the fl ow direction match es
the arrow on the valve body.
9. For best performance, install in well drained
hor i zon tal pipe, properly trapped if a steam service
ap pli ca tion.
10. Valves are not to be direct buried underground.
11. Insulation may be applied as indicated in Figure
2. Drain age away from the packing area must be
en sured when fully in stalled, sealed and lagged for
outdoors in stal la tion.
12. Undue piping stress/strain or bending torques may
not be transmitted through the control valve body.
One pipe (inlet or outlet) should be anchored rig id ly for piping that is “hot” or “cold” with respect to
ambient temperature; the re main ing pipe (inlet or
outlet) should be supported and guid
ed to ensure
unidirectional expansion/contraction.
2
IOM-988/989-BODY
IV. STARTUP
C. Removal From Piping System:
1. Care should be taken in removal of separable
fl anged units. Run wire in 180° crossing pattern
through bolt holes to prevent fl anges from coming
loose during handling.
CAUTION
Exhibit care in handling fl anged units to prevent sep a ra ble
fl ang es from coming loose, falling to fl oor and smashing
feet/toes.
Figure 2: Body Insulation
SECTION IV
A. General:
1. Ensure that the Model 988/989 unit has been
prop er ly ad just ed and calibrated, including the
positioner if in stalled.
2. Recommend startup to be in a “manual” mode.
This pro ce dure assumes double block (iso la tion)
and bypass valves for the “control valve sta tion”.
See Figure 1.
3. Start with either of the two block valves closed,
with the oth er open. The bypass valve should be
closed. Pressurize sys tem if possible/practical.
4. Back out the airset’s adjusting screw until loose.
5. Turn on air supply pressure.
6. Adjust the air supply airset (fi lter-regulator) to the
prop er lev el as indicated as follows:
Bench Setting Airset Output
psig (Barg) psig (Barg)
5–15 (.34–1.0) 20 (1.4)
7. Place loop controller into “manual” mode. Vary
8. Confi rm that action of controller and positioner
15–60 (1.0–4.1) 75 (5.2)
set ting from minimum – mid-range – max i mum
SIG out put. Observe re sponse of con trol valve unit
to these chang es of in put SIG. The valve should
fully stroke at the vari a tion from min i mum SIG to
max i mum SIG; the mid-range SIG should have the
valve stem travel at/near 1/2 open.
– direct or reverse – are pro duc ing the desired re sponse in the con trol unit. Confi rm that the control
valve “fail” po si tion is as required.
CAUTION
DO NOT WALK AWAY AND LEAVE A MANUALLY CON TROLLED CONTROL VALVE UNATTENDED!
9. Hereafter, the procedure assumes that actual fl u id
fl ow may be established. This may not be prac ti-
cal/pos si ble in all cas es; if so, vary procedure as
re quired. Always “heat” or “cool” down the system
piping SLOW LY by open ing the control valve sta tion by pass valve in small increments.
10. With one of the control valve station block valves
still closed, and the loop controller still in “manual”
mode, open by pass valve and vary fl ow rate man u-
al ly to observe the response of the con trol ler and
control valve unit to geth er.
11. Attempt to develop manual control of the loop by
open ing/closing the manual bypass as re quired,
or by manually con trol ling mainstream fl ow as
re quired.
12. When the control valve is partially open, slowly
crack open the closed block valve while si mul ta neous ly closing the bypass valve. Continue this
pro ce dure until the bypass is closed and the block
valves are both fully open. The system is still un der “man u al” mode control, but all fl ow is pass ing
through the control valve.
13. Vary controller “manual” SIG output until match ing
the “au to mat ic” SIG output, then change the mode
of the controller over to “automatic”. The loop will
ex pe ri ence a minimum of upset conditions, and will
be in au to matic control.
IOM-988/989-BODY
3
SECTION V
B. Actuator Assembly Removal:
WARNING
SYSTEM UNDER PRESSURE. Prior to performing any
main te nance, isolate the valve/actuator from the system
and re lieve all pressure. Failure to do so could result in
personal in ju ry.
V. MAINTENANCE
A. General:
1. Maintenance procedures hereinafter are based
upon re mov al of the valve/actuator unit from the
pipeline where in stalled.
2. Owner should refer to Owner’s procedures for
re mov al, han dling and cleaning of non-reusable
parts, i.e. gaskets, suit able solvents, etc.
3. Valves supplied from the factory do not use any
aid to assist in gasket sealing such as oil, sealant
or pipe dope. Owner may use such aids provided
the aids are com pat i ble with the Owner’s fl uid.(See
below for “oxygen cleaned” valves.)
4. Valves originally supplied per Option-55 require
special clean ing procedures. Refer to Cashco
Spec i fi ca tion No. S-1134 for details. When in
com pli ance with/to Spec. No. S-1134, the valve
is suit able for oxygen service. This procedure is
limited to bodies of SST or HC only.
5. All indicated Item Numbers that are with respect to
the actuator assembly (AA) will be in parenthesis
and un der scored; i.e. (20); All Item Numbers that
are with respect to the body assembly (BA) are not
underscored; i.e. (32).
6. Special care must be exhibited when rotating
the plug/stem (3) of the valve to not mar that portion of the surface of the stem where it contacts
with the packing (6). To rotate the plug/stem use
the jam nuts (52) or a soft jawed pliers. NOTE:
When using the jam nuts to rotate the plug/stem,
use the upper jam nut to rotate the stem CW, and
the lower jam nut to rotate the stem CCW, when
viewed from above valve plug/stem.
7. Hereafter, whenever text has the following notation,
"
(Note PA.)", the following text is to be applied:
1. Refer to the correct actuator IOM for this pro ce dure.
2. Secure the (BA) in a vise with the (AA) oriented
vertically.
3. Rig (AA) to be supported above the (BA). Place
matchmarks between the bonnet/yoke and yoke/
ac ces so ry plate.
4. This procedure assumes that the (BA) is fully
assembled through the bonnet (2), in clud ing the
pack ing fl ange (4), fol low er (5), and packing (6).
5. (Note PA.)
stem (6) by wrench, loos en stem jam nuts (52) by
rotating CW (viewed from above) one-at-a-time.
6. Fully loosen any accessory devices that are con nect ed to/with the stems (6), (3), such as ac ces so ry
plate ((AP)) for limit switch or positioner. If actuator
has handwheel - see Actuator IOM for removal
instructions.
7. Using a blunt end tool, hammer rap the tool to
loos en yoke nut (25), turning CCW (viewed from
above) approximately 1/2 revolution.
8. If the actuator is to be reinstalled, put paint or dye
mark er between the plug/stem (3) and the ac tu a tor
stem (6), to serve as matchmarks.
9. Loosen packing (6) by rotating nuts (15) CCW 2-3
revolutions. (Note RP).
NOTE: To fully disengage the actuator stem (6)
from the plug/stem (3) is a two-step procedure. Be
aware of the valve’s stroke length as indicated on
the name plate (40) before beginning dis en gage ment. During the dis en gage ment, measure the
distance ex tend ed and attempt to make each step
about half of full stroke. Keep track of the num ber
of rev o lu tions for each step in the box below.
For Steps 10A and 10B: Count the Number
of revolutions to disengage plug/stem from actuator stem:
Step A. __________ Step B. _________
TOTAL ________
Securing the “fl ats” of the actuator
"For ATO-FC units ONLY, connect a tempo-
10A. For ATO-FC Reverse Action Actuators:
rary air source with gauge to the actuator
and pressurize to a level suffi cient to initi-
ate travel to approximately mid-stroke."
8. Hereafter, whenever text has the following
notation, "(Note RP.)", the following text is to
be applied:
"For ATO-FC units ONLY, release all tem-
a. (NOTE PA).
b. Step A. Rotate plug/stem (3) CW (viewed from
above the valve) to disengage the actuator
stem from the plug/stem. Record number of
plug/stem revolutions for Step A in box above.
When dis en gage ment reaches ap prox i mate ly
50% of full stroke travel, Step A is complete.
porary air pressure."
4
IOM-988/989-BODY
c. Step B. Support the (AA) from above. Fully
loosen yoke nut (25) to re mov al. Lift the (AA)
up wards approximately 1/4"–3/8" (6–8 mm).
Again, ro tate plug/stem (3) CW (viewed from
above) until dis en gage ment from actuator
stem (6). Record num ber of plug/ stem revolutions for Step B in box on previous page.
NOTE: Take notice of the parts “dangling loosely”
about the stem, the order of their location and their
proper orientation.
d. Fully raise (AA) above (BA). Remove carefully
to prevent "dangling parts" (position indicating
washer (51), accessory plate ((AP)), yoke nut
(25)) from falling.
(Note RP).
6. Lower (AA) until the opening of the ac tu a tor yoke
(3) is at the level of upper jam nut (52).
7. Place yoke nut (25) over the plug/stem (3) and
lower the nut to rest upon the yoke.
8. Place travel indicator washer (51) and accessory
plate ((AP)) over stem (3) and allow to rest upon
upper stem jam nut (52).
9. Align matchmarks between body/bonnet, bonnet/
yoke and yoke/accessory plate. Continue to lower
(AA) until two stems are approximately 3/8" (8mm)
apart.
10. Ensure that plug/stem (3) is resting on seat ring.
10B. For ATC-FO Direct Action Actuators:
a. Step A. Rotate plug/stem (3) CW (viewed
from above the valve) to disengage the actuator stem from the plug/stem. Record number
of plug/stem revolutions for Step A in box on
previous page When dis en gage ment reach es
ap prox i mate ly 50% of full stroke travel, Step
A is completed.
.
b. Step B. Support the (AA) from above. Fully
loosen yoke nut (25) to re mov al. Lift the (AA)
up wards approximately 1/4"–3/8" (6–8 mm).
Again ro tate plug/stem (3) CW (viewed from
above valve) until dis en gage ment from ac tu a-
tor stem (6). Record the num ber of valve stem
rev o lu tions for Step B in box on pre vi ous page.
NOTE: Take notice of the parts “dangling loose ly”
about the stem, the order of their location and their
proper orientation.
c. Fully raise (AA) above (BA). Remove care-
fully to prevent “dan gling parts” (position indicating
washer (51), ac ces so ry plate ((AP)), yoke nut (25)
from falling.
C. Mounting Actuator Assembly to Body As sem bly:
1. Refer to the correct actuator IOM for completion of
this pro ce dure.
2. Secure the (BA) in a vise with the plug/stem (3)
oriented vertically. Push stem down until plug
touches the seating surface in the body.
3. Rig (AA) to be supported above the (BA).
4. This procedure assumes that the packing assembly
and bonnet (2) have been bolt ed to the body (1).
5. Engage stem jam nuts (52) one-at-a-time to the
plug/stem (3) by rotating CW (viewed from above
stem end). Rotate jam nuts all the way down to the
root of the stem threads.
11A. For ATC-FO: Hook up a temporary air supply
hose that has an ad just able airset connected at
the actuator inlet to allow pres sur iza tion. Slowly
pres sur ize ac tu a tor to bring the actuator stem to
within 1/8" (3mm) of touching the plug/stem.
11B. For ATO-FC: Continue lowering (AA) un til ac tu a-
tor’s stem (6) and valve’s stem (3) almost touch.
12. Rotate yoke nut (25) onto bonnet (2) threads as far
as able to help stabilize topworks. Wrench-tighten
one-half (1/2) extra rev o lu tion.
13. Use hand to lift plug/stem (3) upwards to engage
with actuator stem (6). Ro tat ing plug/stem CW
(viewed from plug end) the same number of rev o lu tions recorded to dis en gage the stem per B Step
10A.
14. For ATC-FO: Release air pressure from (AA).
For ATO-FC: (NOTE PA).
15. Fully lower the (AA) down wards un til the yoke (3) is
properly positioned on the valve bon net (2). Handtighten yoke nut (25).
16. Complete the engagement of plug/stem into the
ac tu a tor stem the same number of revolutions
re cord ed to disengage the stems per B Step 10B.
(NOTE RP)
17. Connect “dangling parts” – accessory plate (AP)
and travel indicator disc (51) – to actuator stem (6)
with stem jam nuts (52).
18. Retighten packing fl ange nuts (15).
19. Hammer rap yoke nut (25) with a blunt end tool
until tight.
20. Check valve stem stoke by alternately pressurizing and then de pres sur iz ing the actuator. Repeat
several times. DO NOT OVER PRES SUR IZE.
21. Release all air pressure from (AA) and re move
temporary air supply hook up.
IOM-988/989-BODY
5
D. Trim and Packing Removal and Replacement for
Units with Internal Live-Loaded Packing; Opt-STD
or Opt-KRI: (See pg. 19 for Item # identifi cation.)
1. Remove (AA) as described in Sub-Sec tion V.B.
Leave (BA) in vise with plug/stem (3) upwards.
14. Examine plug/stem (3) in critical fi nish zone where
con tact is made with the packing (6). It is desirable
to re store the surface of the stem (3) to a #4 Ra μ-in
surface fi nish; metal removal should not exceed
0.001 inch material. A deeply scratched or pitted
stem should be replaced.
2. Continue to loosen stem packing (6) by rotating
pack ing nuts (15) CCW to just short of disengagement from packing studs (14). DO NOT REMOVE
PACKING NUTS (15).
3. Remove all bonnet stud nuts (17).
4. Lift bonnet (2), plug/stem assembly (3), cage (10)
and all packing zone parts up and out of the body
- grasp stem (3) to prevent from falling. Lay these
parts down horizontally on a workbench. NOTE:
Seat ring (11) (and seat retainer (23) and soft seat
insert (24) for com po si tion/soft seated de signs)
may also pull out with the above parts assembly.
5. Remove both stem nuts (52).
6. Withdraw plug/stem (3) out through bottom of the
bon net (2) and packing (6). Hold cage (10) to
pre vent from dropping. Set parts (3, 10) aside.
7. Place bonnet (2) into a second vise with the pack ing
zone on top.
8. Remove the packing nuts (15).
9. Remove packing fl ange (4) and fol low er (5).
CAUTION
Take extreme care to not mar internal wall surface of the
bonnet (2).
10. Using a sharp, hooked-end, pick-type tool, hook and
pull the packing rings (6) up and out of the bon net’s
(2) stuffi ng box in di vid u al ly. Examine for excessive
wear. Discard old pack ing.
11. Remove bonnet (2) from vise and invert to al low
pack ing washer (7), packing spacer (9) and pack ing
spring (21) to slide out of the bonnet’s stuffi ng box.
12. Solvent clean all parts to be reused, including bon net (2). Examine any parts for wear and cor ro sion.
Replace any corroded or warn parts.
15. Examine plug/stem (3) for wear around the seating
area. Ex am ine seat ring (11).
a. Plug head of stem assembly (3) for metal
seat ed design may be hand lapped using
suit able lap ping compound. If hand lapping will
not re store sur fac es to an acceptable de gree,
then re place ment of plug/stem assembly is
rec om mend ed.
b. For composition seated design, if plug/stem
as sem bly is wear damaged, the stem should
be re placed.
16. Examine the inner surface of the bonnet’s (2)
stuffi ng box. It is desirable to restore the surface
of stuffi ng box to a #8 Ra μ-in surface fi nish; metal
re mov al should not exceed 0.001 inch material. A
deep ly scratched or pit ted bon net (2) should be
replaced.
17. Examine packing follower (5) for corrosion. Re place if corroded:
a. Replace follower bushing (26) with new bush-
ing.
b. Replace wiper ring (22) with new wiper ring.
18. Turn attention to the body (1) and remaining parts
yet there in. Remove seat ring (11) (and seat re tain er (23) and soft seat in sert (24) for com po si tion/
soft seated de sign) if not already removed. Discard
used soft seat in sert (24); always use a new soft
seat insert upon re as sem bly. If seat ring (11) or
seat retainer (23) are damaged, replace.
19. Examine gaskets (12,13) to see if leakage oc curred. Re move and discard both the seat ring
gasket and bonnet gas ket. Always use new gaskets
upon reassembly.
20. Remove body (1) from vise. Solvent clean all loose
parts with suitable solvent. Determine parts to be
re placed due to wear and/or corrosion. Clean seat
ring (11), cage (10), and seat re tain er (23).
21. Place body (1) into vise with body/bonnet fl ange
face up.
22. Place a new seat ring gasket (13) into position.
13. Examine plug/stem (3) at lower guide bushing (8)
area for wear. If there are signs of ex cess wear,
guide bushing (8) should be replaced:
a. Place the bonnet (2) on a bench press. Press
the guide bush ing (8) out of the bonnet and
discard.
b. Rotate bonnet (2) end-for-end. Place a new
guide bush ing (8) into position and press fully
into the bonnet.
c. Reclean bonnet with suitable solvent.
6
23. Note correct orientation of seat ring (11) and place
inside the body (1).
24. For composition/soft seat design, position a new
soft seat insert (24) and the seat retainer (23) into
position on top of seat ring (11).
25. Place new bonnet gasket (12) on the body’s bonnet
fl ange face.
IOM-988/989-BODY
Loading...