Baker Hughes Masoneilan 4700P, Инструкция по эксплуатации

Страница: 38 / 66

© 2021 Baker Hughes Company. All rights reserved. 38 | Baker Hughes
Cam Lobe Change
If it is necessary to change the cam lobe only (without changing actuator action or positioner
action) then proceed as follows:
CAUTION
If cam is not at low signal line on lobe (low end of
range), do not attempt to remove cam. The cam must
be at low signal line. Select correct actuator and
positioner action and proceed as follows.
NOTE
Do not disturb cam holder (36) setting on rotary
actuators. [i.e. do not touch set screws (35)].
Air to Open / Direct Acting Positioner
See Figure 18 (page 56) and Figure 19 (page 58).
1. Shut off supply pressure and signal to positioner. Valve is now closed and cam (26) is at
low signal line on lobe.
2. With cam at low signal line remove screw (28), lockwasher (51) and washer (27). Note the
relative position of the cam lobe being changed and then remove the cam (26).
3. Select the desired cam lobe and replace cam (26) on cam shaft with low signal line of
desired lobe against cam follower. Ensure the newly selected cam lobe is in the same
relative position as the lobe noted in Step 2.
4. Replace washer (27), lockwasher (51) and screw (28). Turn on supply pressure and signal
to positioner. Check zero and span adjustment. Refer to “Zero Adjustment” and Span
Adjustment37.
Air to Open / Reverse Acting Positioner
See Figure 18 .
1. Shut off supply pressure and signal to positioner. Valve is now closed and cam (26) is at
high signal line on lobe. Do not remove.
2. Run an independent regulated air line to the valve actuator in place of positioner output
line. Slowly apply proper air pressure through the regulator to open the valve. Do not
exceed designated supply pressure. (Handwheel may be used to open the valve in place
of regulated air line). Align the travel indicator with the open end of travel scale. Do not
over travel. Cam is now at low signal line on lobe.
3. With cam at low signal line remove screw (28), lockwasher (51) and washer (27). Note the
relative position of the cam lobe being changed and then remove the cam (26).