Installation, Operation and Maintenance Manual
Butterfly Valves Type 75, 75D Pneumatic Actuated Type TW 21
(19) Inspection items
- Perform periodic maintenance. (Leakage may develop due to temperature changes or over periods of
prolonged storage, rest or operation.)
Portion to be inspected Inspection item
- Existence of rust, peeling of paint, and corrosion around the actuator.
- Tightening condition of respective threaded portions. (Loose or not)
- Existence of abnormality in opening and closing operating sounds.
- Smooth operation of manual handle.
※This actuator can be used without oiling. However, if lubricating oil is used, use
addition turbine oil specified follow:
JIS K 2213 Addition Turbine oil (ISO VG 32, 46)
Va l v e
- Existence of scratches, cracks, deformation, and discoloring.
- Existence of leakage from the valve to the outside.
- Existence of leakage when the valve is closed fully.
Problem Cause Treatment
The handle is not (can’t be)
turned when the valve is
The valve has already been opened fully. Turn the handle in the reverse
direction. (Refer to page 16.)
The air is supplied to actuator. Shut the main air valve, and open the
Foreign matter is in the valve. Disassemble the valve to remove
foreign matter. (Refer to page 8.)
The torque of the valve is increased by the
Remove the piping stress.
(Refer to page 8.)
The torque is increased by the influence
(temperature, components, pressure) of fluid
on the valve.
Check service condition.
(Refer to page 5)
The valve does not operate by
The power source of the solenoid valve is
turned off. Turn on the power source.
The solenoid valve is disconnected. Check the connection again.
(Refer to page 6)
The air is not supplied to actuator. Supply the air.
The supply voltage to the solenoid valve is
wrong. Check the voltage with a tester and set
The voltage to the solenoid valve is low.
The bypass valve is opened. Turn the knob of the bypass valve
right to close. (Refer to page 16)