IM-P006-07
CTLS Issue 12
21
5.7 How to renew the pilot valve diaphragms
1.
Isolate the reducing valve and zero the pressure.
2.
Release the lock-nut (
2
) and turn the adjustment screw (
1
) anticlockwise until the spring is slack.
3.
Slide the 'C' washer (
3
) from underneath the lock-nut and remove the cover (
12
).
4.
Remove the spring (
6
) and the top spring plate (
5
).
5.
Undo the 4 x M10 nuts (
8
) and remove the spring housing (
4
), bottom spring plate (
7
)and the old
diaphragms (
9
).
6.
Refit 2 new diaphragms (
9
) making sure that all contact faces are clean.
7.
Place the bottom spring plate (
7
) in position and secure the spring housing with the 4 x M10 nuts (
8
)
tightening to a torque of 50 N m.
8.
Replace the spring (
6
) and top spring plate (
5
), turn the adjustment screw (
1
) until it just locates on the
top spring plate. Replace cover (
12
) and 'C' washer (
3
).
9.
Bring the valve back into commission by following as many steps as are necessary in Section 4.1, 'Start-
up'.
5.8 How to renew the main diaphragms
1.
Isolate the reducing valve and zero the pressure.
2.
Undo the long union nut (
32
) and pull it away.
3.
Undo the M12 nuts and bolts (
23
) and drop away the lower diaphragm chamber (
22
), the two stainless
steel diaphragms (
24
) and the main diaphragm plate and pushrod assembly (
25, 26, 30
).
4.
Thoroughly clean off the lower diaphragm chamber and make sure that the contact surfaces are clean.
5.
Replace the main diaphragm plate and pushrod assembly and loosely refit the lower diaphragm chamber
on the two bolts either side of the union connection, see Figure 10 so that the spigot is located into the
recess. Also ensure that the connecting stainless steel pipework is located into its fitting.
6.
Bring the two main diaphragms together and slide into position, first easing the diaphragm plate upwards
to clear, see Figure 10.
7.
With the main diaphragms in position, push the lower diaphragm chamber home to locate in the recess
and refit the M12 nuts and bolts. Tighten to a torque of 75 N m.
8.
Retighten the long union nut to ensure a steam tight seal on the stainless steel pipework.
9.
Bring the valve back into commission by following as many steps as are necessary in Section 4.1,
'Start-up'.
5.9 How to service or renew the main valve and seat
1.
Isolate the pressure reducing valve and zero the pressure.
2.
Undo the union nuts and release the 6 mm stainless steel pipework.
3.
Undo the nuts (
21
) and remove the pilot valve block (
10
) complete with the spring housing assembly.
4.
Remove the main valve spring (
16
) and the main valve head (
17
).
5.
Using a socket remove the main seat (
18
), as shown in Table 2 (page 22).
Note:
A special tool is required for the DN80 valve.
Содержание DP143
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