cashco 987 Installation, Operation And Maintenance Manual - Page 8

Browse online or download pdf Installation, Operation And Maintenance Manual for Control Unit cashco 987. cashco 987 15 pages. Globe-style pneumatic control valve body iom

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Use the total number of revs en gage ment

recorded in Step V.B.4. as the guide to control

engagement of the stems (6) (4).

en gag ing the stems, rotate yoke nut (15) as

able to help stabilize top works, continue to

pres sur ize the ac tu a tor in 2-3 psi (.15-.20 Bar)

in cre ments in an al ter nat ing se quence with

the distance en gaged until the total num ber

of revs engaged is reached.

30. Hand-tighten yoke nut (15) until fully po si tioned

with the yoke (3) sitting on the bonnet (2).

VI. CALIBRATION

A. General:

1. This section only covers cal i bra tion of the

control valve with Actuator Models C27/C53.

2. Positioner, if in stalled, requires ref er ence to

the spe cif ic positioner mod el IOM for prop er

cal i bra tion pro ce dure.

3. All indicated items numbers that are with

re spect to IOM-C27-C53 will be in pa ren the sis

and un der scored; i.e. (20); those that

reference the po si tion er IOM will be in double

parentheses; i.e. ((AP)). All item numbers

that are with respect to this IOM-987 are not

un der scored; i.e. (3).

B. Procedure - Reverse Action, ATO-FC:

1. Reference the name plate (40) at tached to

the ac tu a tor yoke (3). De ter mine the bench

set ting of the in stalled range springs (10) from

the name plate (40); i.e. 5-15 psig (.34 -1.0

Barg), or 15-60 psig (1-4.1 Barg).

2. Connect a temporary air supply with an in-

line ad just able airset regulator and gauge to

the lower actuator con nec tion. See Section

IV.A.6 for appropriate supply pressure. DO

NOT LOAD with any air pressure at this point.

3. To determine when stem/plug (4) begins to lift

out of the seat, touch the stem below the jam

nuts with one finger. (Stem will move when

actuator pressure exceeds the spring load.)

4. Slowly pressurize the ac tu a tor to a pres sure

equal to the lower pres sure lev el of the bench

setting; i.e. for a 5-15 psig (.34 -1.0 Barg)

range, set pressure at 5 psig (.34 Barg). Take

note of the pressure reading when the stem

first begins to move.

31. Secure "dangling parts" - ac ces so ry plate ((AP))

and indicator washer (16) - to ac tu a tor stem (6)

While

with stem jam nuts (17).

32. Ham mer rap yoke nut (15) until tight. (Release

tem po rary air source.)

33. Install nuts (21) on studs (20). Use torque wrench

to tighten to 25-30 in-lbs.

SECTION VI

5. If the loading pressure for the start of stem

movement is below the lower end of the

desired bench setting, then the com bined stem

(4, 6) length is too short.

a. Rotate both jam nuts (17) down to base of

b. Increase pressure in the actuator to

c. Rotate upper jam nut CW to increase the

d. Rotate upper jam nut CCW to hold

e. Release all pressure from the actuator and

6. If the loading pressure for the start of stem

movement is above the lower end of the

desired bench setting, then the com bined stem

(4, 6) length is too long.

a. Rotate both jam nuts (17) down to base of

b. Increase pressure in the actuator to

c. Rotate lower jam nut CCW to shorten the

d. Rotate upper jam nut CCW to hold

e. Release all pressure from the actuator and

7. After the opening set point pressure has been

established, rotate lower jam nut (17) CCW up

tight under the upper jam nut.

8. Release all pressure from the actuator.

9. Observe the location of the in di ca ting washer

threads on stem (4) and tighten together.

approximately mid range of the bench

setting.

combined stem length. DO NOT allow

actuator stem (6) to rotate in the actuator.

indicating washer (16) up against stem

(6).

repeat Step 4 previous.