What are the Problems faced with Control Valve Actuators?

Control Valves
1

Mention the different types of problems faced with control valve actuators used in industries.

Pneumatic actuators

BOTH PNEUMATIC ROTARY AND PNEUMATIC CYLINDER ACTUATORS

  1. The valve is binding.
  2. The motive pressure is incorrect.
  3. The solenoid voltage is incorrect.
  4. The solenoid ports are plugged.

PNEUMATIC ROTARY ACTUATORS

  1. The system leakage in front of the actuator is not allowing the minimum SCFM (standard cubic feet per minute) for operation.
  2. The system or actuator filter is blocked or clogged.
  3. The actuator ports are plugged with contaminants.
  4. The speed controls are closed.
  5. There is too much condensation.
  6. The spring return units have broken springs.
  7. There are problems with the seals.
  8. The actuators are undersized.

PNEUMATIC CYLINDER ACTUATORS

  1. Air is leaking at the piston guide bushings.
  2. There is increased thrust due to valve issues.
  3. There is excessive side loading in rotary applications.
  4. The piston seals are leaking.

Electric, or motor-operated-valve (MOV), actuators

ELECTRICAL ISSUES

  1. The power voltage isn’t correct.
  2. The control voltage isn’t correct.
  3. The fuse has blown.
  4. There is a power board failure.
  5. The wire has become fused or disconnected.
  6. The thermal overload is engaged.
  7. The power phasing is incorrect.
  8. The limit switch is not set correctly.
  9. The quick disconnect harness is loose.

MECHANICAL ISSUES

  1. There are problems with the valve binding or the stem.
  2. There are problems with the drive nut.
  3. The center column gear is stripped.
  4. The motor pinion / worm gear is stripped.
  5. The torque switch is engaged.
  6. The handwheel declutch has failed.

Gas-over-hydraulic, or gas-over-oil, actuators

  1. The valve and the actuator aren’t in the same orientation.
  2. The key is not installed.
  3. There are shipping plugs in the gas supply, exhaust ports, or tubing connected to the gas hydraulic tanks.
  4. The power gas pressure is too low.
  5. The speed controls are closed.
  6. The valve is stuck.
  7. The hydraulic fluid level is too low.
  8. The hand pump has failed.
  9. The actuator seals have failed.

Reference