cashco 964 설치 운영 및 유지보수 - 페이지 3

{카테고리_이름} cashco 964에 대한 설치 운영 및 유지보수을 온라인으로 검색하거나 PDF를 다운로드하세요. cashco 964 16 페이지. Globe-style pneumatic control valve unit body iom

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11. Undue piping stress/strain or bend ing

torques may not be trans mit ted through the

valve body. One pipe (inlet or outlet) should

be an chored rig id ly for pip ing that is "hot" or

"cold" with respect to ambient tem per a ture;

the re main ing pipe (in let or out let) should

be sup port ed and guid ed to ensure

uni di rec tion al ex pan sion/con trac tion.

C. Air Supply:

1. Use a desiccant dried, instrument quality

air supply. Such a supply is recommended

for outdoor installations, and is required in

areas of freezing weather conditions.

IV. START-UP

A. General:

1. Ensure that the Model 964 unit has been

prop er ly adjusted and cal i brat ed, in clud ing

the po si tion er, if in stalled.

2. Recommend startup to be in a "man u al"

mode. This pro ce dure assumes dou ble

block (iso la tion) and bypass valves for the

"control valve station". See Fig ure 1.

3. Start with either of the two block valves

closed, with the other open. The bypass

valve should be closed. Pres sur ize sys tem,

if pos si ble/prac ti cal.

4. Back out the airset's adjusting screw until

loose.

5. Turn on air supply pressure.

6. Adjust the air supply airset (fil ter-reg u la tor)

to the proper lev el as in di cat ed as follows:

Bench Setting

psig

(Barg)

5–15

(.34–1.0)

15–60

(1.0–4.1)

7. Place loop controller into "man u al" mode.

Vary setting from minimum - mid-range -

max i mum SIG output. Ob serve re sponse of

con trol valve unit to these chang es of input

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.

IOM-964

SECTION IV

Airset Output

psig

(Barg)

(1.4)

(5.2)

2. If air supply contains moisture and /or

lubricating oil, the air should be filtered

with a coalescing type of filter prior to use

in stroking the actuator.

3. Failure to remove moisture will cause

corrosion to the internals of the actuator

casings.

4. Connections for the air supply are 1/4" female

NPT. Use a suitable pipe thread sealant

when installing the pipe or tube fitting. DO

NOT allow sealant to enter the tube/pipe.

DO NOT WALK AWAY AND LEAVE A MANUALLY

CONTROLLED CONTROL VALVE UNATTENDED!

8. Confirm that action of con trol ler and

po si tion er - direct or reverse - are producing

the de sired re sponse in the con trol unit.

Con firm that the con trol valve "fail" po si tion

is as re quired.

9. Hereafter, the procedure as sumes that ac tu al

fluid flow may be established. This may not

be practical / pos si ble in all cas es; if so, vary

procedure as re quired.

Always "heat" or "cool" down the system

pip ing SLOW LY by open ing the control valve

sta tion by pass valve in small in cre ments.

10. With one of the control valve station block

valves still closed, and the loop con trol ler

still in "man u al" mode, open by pass valve

and vary flow rate man u al ly to ob serve the

re sponse of the con trol ler and control valve

unit to geth er.

11. Attempt to develop manual con trol of the

loop by opening/clos ing the man u al by pass

as re quired, or by manually con trol ling

main stream flow as re quired.

12. When the control valve is partially open, crack

open slowly the closed block valve while

si mul ta neous ly clos ing the by pass valve.

Con tin ue this pro ce dure until the bypass is

closed and the block valves are both fully

open. The system is still under "man u al"

CAUTION