GE mn-28000_series Service Manual download pdf (Page 15)

Masoneilan VariPak Adjustable Cv Control Valves Instruction Manual | 15

5.3 DISASSEMBLY (Figures 5, 24, 25, 26, 27, 28 and 29)

In some cases, it may be necessary to disassemble the

VariPak valve, for example, to replace the plug/seat ring

assembly (ﬁtting new parts or changing the maximum

value) or to change the packing rings when the

maximum C

is less than 0.6.

Note: If the maximum C

≥ 0.6, a quick change method

can be used to avoid disassembling the valve (see page

18).

Caution: The valve must be isolated and

pressure vented before disassembly.

A. Loosen cover screws (109) and remove cover (110). If

the valve is equipped with a handwheel, loosen cover

screws (109) and handwheel lock (121), then turn

handwheel (120) counterclockwise to release cover

(110).

Disassembly procedure for the VariPak 28001 single-

lever valve:

B. Unlock nut (117) and completely loosen screw (116).

Remove spring clamp (115) from lever (113) and

remove spring (114) from the positioner.

C. Remove the two retainer clips (112c) from pin (124)

and disengage the pin to uncouple piston clevis

(104b) from lever (113).

Note: To simplify this operation, admit air pressure to the

actuator to drive the piston clevis (104b) upwards, then

release the air pressure.

D. Remove retainer clips (112b) from pin (18) and

disengage the pin from lever (113) and plug clevis

(104a).

E. Remove two retainer clips (112a) from pin (105)

and disengage the pin to uncouple lever (113) from

actuator bracket (108). Now proceed in the same way

as for the VariPak 28002 adjustable- C

valve, as from

step I.

Disassembly procedure for the VariPak 28002

adjustable-C

valve:

B. Adjust the signal to close the valve. Change the signal

slightly so that the plug just moves off the seat ring.

Set adjustment knob (24) to the minimum C

position.

C. Loosen locknut (103) and, using a screwdriver, turn

the plug stem one and three-quarter turns counter-

clockwise. Shut off signal and supply pressure.

Slightly tighten locknut (103) against the clevis.

D. Completely loosen locknut (117) and screw (116).

Remove spring clamp (115) from lever No. 2 and

remove balance spring (114) from the positioner.

E. Remove the retainer clip (112b) from each of the two

pins (184) and disengage the pins from lever No. 1

and clevis (104a).

Note: This operation will be simpliﬁed by relieving

the load exerted on the plug clevis by the conical

compression spring (106). To do this push against the

plug stem end with a screwdriver while driving out the

pins.

F. Remove the two retainer clips (112c) from pivot pin

No. 4 (124) and disengage the pin to uncouple piston

clevis (104b) from lever No. 2 (22).

G. Remove the two retainer clips (112a) from pivot pin

No. 1 (105) and disengage the pin to uncouple lever

No. 1 from the actuator bracket (108). Disengage the

smooth end of adjustment pin (23) from the groove

in lever No. 2 and remove adjustment knob (24) and

adjustment pin (23) from lever No. 1.

H. Drive out pivot pin No. 3 (18) and remove lever No. 2

(22).

I. Hold the plug stem in place using a screwdriver and

unlock nut (103). Loosen clevis (104a) and locknut (103).

Remove spring button (102), spring (106), and grommet

plate (101).

J. Remove the two packing ﬂange nuts (8b), packing

ﬂange (10) and packing follower (9). Remove the two

bracket mounting nuts (8a) as well as the bracket

(108).

K. Using a packing hook, remove as many packing rings

(6) as possible from the packing box. Remove safety

pin (11) and pull the plug stem to remove the packing

spacer (5), the plug and its stem and, if necessary, the

rest of the packing.

L. Using a 9/16" or 14 mm piece of hex stock and a

wrench, unlock and pull out the seat-ring retainer (4).

M. Remove seat ring (3) and gasket (2) using a hook

made from steel wire, approx. diameter 3 mm.

Carefully fettle the hook end.

Note:

- The seat-ring of VariPak valves with C

max.< 0.10

consists of two parts: the seat ring proper (3e), and

a spacer (3f). These parts have a small oriﬁce and

so cannot be removed using a hook. It is therefore

necessary to remove the body from the pipe and turn

it over and, if necessary, hit the bottom with a wooden

mallet. If the seat ring (3a) is jammed in its housing, it

can be removed by inserting a screwdriver through the

outlet oriﬁce.

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GE mn-28000_series Service Manual Page 15

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