Masoneilan 31000 Series Control Valve Instruction Manual | 8
Copyright 2020 Baker Hughes Company. All rights reserved.
B. Valve open on air failure (Air to close) (Figure 8)
a. When the lever has reached the position corresponding
to the required tightness, measure the “D” distance
from the contact surface of the spring barrel on the yoke
to the beginning of the hole for the clevis pin in the lever
(135).
b. Supply air to the actuator so that the actuator stem
moves out fully. Set the clevis (100) so that the distance
from the beginning of the hole for the clevis pin to the
contact surface for the yoke is 1 to 2 mm greater than
the previously measured “D” distance.
c. Remove the handwheel or setting tool and secure the
spring barrel with screws (101) and washers (102).
2. Move the actuator to an intermediate position, align the lever
and the clevis holes, insert the clevis pin (124) and fit the
clevis pin clips (122).
3. Tighten the locknut (111A).
4. Press the lever (135) against the shaft bearing (125) and
tighten the lever cap screw (137).
5. Secure the indicator (154), screw in the handwheel (141) if
necessary and install the washer (139) and truarc ring (138).
Lock handwheel in neutral position. Install the remaining
covers (118, 121, 130 and 133).
7.4 Eliminating Seat Leakage During
Operation
If leakage between seat and plug is found during operation, it can
be eliminated in most cases by adjusting the actuator. Supply air
to put the valve at mid travel, remove the clevis pin (124) and
slide the lever (135) out of the clevis (100).
A. If the valve is closed on air failure (Air to open)
After loosening the locknut (111A), screw the clevis (100) in
by one full revolution.
B. If the valve is open on air failure (Air to close)
After loosening the locknut (111A), screw the clevis (100)
out by one full revolution.
After refitting the clevis pin, check the tightness between
seat and plug. If the necessary tightness has not been
reached, repeat Step A or B as required.
If adequate tightness cannot be achieved by adjusting the
actuator, the seat and plug should be checked for wear.
Tightness between seat and body must also be checked.
8. Seat Ring Replacement
To check the seat and plug for wear or to replace the seat ring,
perform the following steps:
1. Bring the plug into its fully open position (if the valve is
closed on air failure, supply air to the actuator to fully open
the plug).
2. Remove the bonnet bolting (14, 15, 16), turn the bonnet
(2) clockwise up to the stop on the body flange, and in this
position, carefully remove it from the body.
The seat ring (4) and plug (3) can now be checked for wear
and the seat ring replaced if necessary. The procedures for
disassembly and reassembly were described in detail in
Sections 6 & 7.
The plug can be replaced only after the complete
valve body S/A has been disassembled. Refer to Sec-
tion 6.2.
9. Assembly Tools
The operation of fitting the packing and adjusting the actuator
require the use of special tools. In addition these tools reduce
the risk of sealing elements being damaged during assembly.
The tools can be obtained as a complete set from Baker Hughes
parts department and are suitable for all valve sizes (refer to
Figure 2).
Fitting tools for the seat rings are available in accordance with
the valve size (refer to Figure 3).
