Leslie Controls CONTROL VALVES SINGLE PORTED DOS - Manual (Page 7)

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valve plug stem when lapping. Weight of
parts is sufficient to cause lapping action.
4.
Place lapping compound on valve plug face.
5.
As lapping progresses lift valve plug off seat
occasionally and rotate 45
°
to keep
compound evenly distributed.
6.
Remove all traces of compound after
lapping.
Control Valves Fitted with Cage
Type Trim
(see Fig. 7)
Assemble component parts as shown in figure 7.
Follow lapping procedure described or use
alternate method described below and shown in
figure 7.
Place seat ring/insert in a suitable holding device
(that will not distort seat ring/insert). Position
seat-retaining guide/cage on seat ring/insert. (In
the case of “O” trim – Classes DOS, etc. – be
sure to assemble the valve plug guide/cage in
their respective positions before lapping,
regardless of procedure followed). Very little
lapping is required with cage type trim. A few
turns should be sufficient.
Figure 7 - Alternate Method
Reassembly- Single Ported
Control Valves (DL Type)
(See Fig. 4)
1.
After all parts have been cleaned and
prepared for reassembly, place gasket (47)
on bottom cap (flange) (48).
2.
Assemble bottom cap (flange) (48) to valve
body and tighten.
3.
Place bonnet gasket (44) on valve body.
4.
Insert valve plug stem through bonnet (43).
5.
Position on valve body making sure that
valve plug engages seat ring/insert properly.
6.
In the case of heavy units, first insert valve
plug in seat carefully down over valve plug
stem.
7.
Tighten evenly and firmly.
8.
Install packing in packing box.
9.
Replace actuator on bonnet. Insert
capscrews (39) and tighten.
10.
Reassemble nut (34) and travel indicator
(31) to valve plug stem.
11.
Lift valve plug stem and engage its threads
with those in actuator stem (25).
12.
Screw valve plug stem at least one diameter
into actuator stem.
13.
Adjust actuator spring preload and rated
travel of valve. (See Adjusting Actuator
Spring Preload).
Cage Type Trim (DOS Type Ctrim
Parts)
(see Fig. 3)
1.
Install internal components in valve body
before assembling bonnet to body.
2.
Place rod in valve body and down through
body bridge to prevent seat ring/insert or
gasket from falling into body throat when
assembling.