cashco DA2 설치, 운영 및 유지보수 매뉴얼 - 페이지 11

{카테고리_이름} cashco DA2에 대한 설치, 운영 및 유지보수 매뉴얼을 온라인으로 검색하거나 PDF를 다운로드하세요. cashco DA2 16 페이지. Direct-acting, positive bias differential pressure reducing regulator

페이지 인쇄

of valve plug (20). Hold torque wrench

sta tion ary and rotate diaphragm lock nut

(7) to the following torque values:

Body Size

(DN)

1/2" - 1"

(15-25)

1 1/4" - 2" (32-50)

2 1/2" - 4" (65-100)

DO NOT allow valve plug (20) to rotate

against seat ring (21) during tightening.

This completes ITA reassembly.

8. Units with V-TFE & CTFE seat ring (21): Due

to the relative "hardness" of the V-TFE & CTFE

ma te ri al, to obtain the best possible shutoff it

is nec es sary to "coin" the V-TFE & CTFE with

a per ma nent in den ta tion.

a. Close-off the outlet connection.

b. The level of seat leakage can be quantified

at the internal sens ing drilled plug (32) for

internal sensing units. For external sensing

units, it will be nec es sary to re move the

in ter nal sensing plug (33).

c. Pressurize the valve's inlet with gas or air

to 50 - 150 psig (3.5 - 10 Barg).

d. Using a soft-headed mallet (rubber,

leath er), sharply rap the top end of the

plug (20) for composition di a phragm de-

signs, or the pis ton-guide bear ing (13) for

metal di a phragm designs. (NOTE: Gas

will escape as the plug (20) opens at the

seat ring (21). Allow sufficient time for

leak age pressure on out let to bleed-off.)

The hammer rap should be strong enough

to "bounce" the plug (20) into the seat

ring (21), leaving the "coined" in den ta tion.

Check for leakage at the internal sensing

port with a leak detection fluid. One bubble

per second is typical of Class IV shut off.

e. Repeat d. a minimum of 2 times until the

best possible seat leakage is ob tained.

After "coining" completed, remove gas

pressure source, remove outlet clo sure,

and re in stall plug (33) if removed.

9. Metal Diaphragm Designs:

a. Install new diaphragm gasket (37) onto

body (23) diaphragm flange.

b. Position diaphragm(s) (9) onto body's (23)

diaphragm flange.

c. Position upper diaphragm pressure plate

(8) onto center top of diaphragm(s)) (9)

with counterbore upwards.

IOM-DA2

Torque

ft-lbs

(N-m)

60-70

(81-95)

120-130

(163-176)

180-200

(244-271)

10. Lubricate and install o-rings (34) into grooves

on the adjusting screw (1).

11. Assembly of range spring and spring chamber:

a. Lubricate the threads of adjusting screw

(1) then thread into the spring follower (5).

The spring follower should be threaded

up adjusting the screw to within 3/8" of

the top threads (see sectional drawing,

figure 5.

b. Insert adjusting screw-spring follower into

spring chamber (4). NOTE: Milled slots in

spring follower must align with ribs in the

bore of the spring chamber. The top of

the adjusting screw must fit in the center

hole of spring chamber. A light rap with

a wooden handle of a hammer may be

needed to fully install the adjusting screw

into the spring chamber.

c. Aligning match marks and bolt holes,

place spring chamber (4) over range

spring (6.1).

flange reaches the body flange without

a gap, turn adjusting screw (1) CW 2-3

turns. Repeat this procedure until the

flanges are approximately 1/8" apart.

Be sure that range spring is properly

seated into counterbore on spring follower.

NOTE: For metal diaphragm con struc tion,

if flang es do not come to geth er equal ly,

the upper di a phragm pres sure plate (8)

may be off-center. Remove spring cham-

ber (4) and reposition upper di a phragm

pres sure plate (8) until the spring chamber

(4) comes down evenly on all sides.

12. Reinstall all flange bolts (11) and nuts (12)

with nameplate (99) located under one bolt

head. Hand-tighten nuts (12).

NOTE: If a three-ply diaphragm is being used,

it is important that the diaphragm (9) is "pre-

formed" – allow formation of a diaphragm (9)

convolution. Starting with the body bolts and

nuts (11,12) hand tight ened, "preforming" can

be accomplished by any one of the following

techniques:

a. Relax range spring fully by rotating

ad just ing screw CCW.

b. Apply 30 psig (2.1 Barg) pressure to the

valve outlet.

Block the valve outlet and apply 30 psig

(2.1 Barg) under the di a phragm through

the 1/4" NPT (plugged) external pres-

sure sens ing connection on the valve

diaphragm flange.

c. Leave pressure on through tightening

of bolt ing (11,12).

If the spring chamber