Azbil VDC - Page 46

Parts Replacement Azbil Corporation
6-10 VDC, VAC, VST, VAA - Diaphragm Control Valve
Procedure
Step 1) Pull out AUTO/MANUAL switchover pin out of holder and disengage chain,
which binds the handwheel to the wheel
Step 2) Verify the label on handwheel and turn the handle to the direction of SHUT
and lower slide screw.
Step 3) Match the round holes of slide screw and actuator's rod, and insert pin.
Push it all the way in and x it there.
Step 4) Verify OPEN, SHUT arrows on label, and turn the handwheel to either
direction to open or close the valve. The turning torque should be under
127N (13kgf)
Step 5) When the handwheel does not turn any further, check valve opening and
stop operation.
CAUTION
Do not apply undue force on valve when it reaches mechanical stop. Otherwise valve
stem may be damaged. Refer to Chapter 10, Trouble shooting for remedial action.
Step 6) To resume automatic operation, remove the switchover pin, turn
handwheel until the slide screw stop reaches AUTO position (refer to
Figure 6-10 below). Run the chain on the pin through in order to restrict
handwheel movement and x the pin on holder. Resume automatic
operation after verifying this condition.
Figure 6-10 Disassembly and Assembly of Actuator
6-6-3 : Disassembly of Actuator <Disassembly Procedure>
Disassembly procedure of actuator is described herein. Refer to Figures 6-11 for
information.
1. Marking and protection
Step 1) Match mark on spring retainer on the top of actuator, lift stopper, cylinder
and cylinder assembling yoke boss.
Step 2) Wrap PVC tape on rod bushing to protect sealing parts, guide bushing.