Question

What are the disadvantages and advantages of meter-out and meter-in flow control valves?

Answer 1

Advantages of meter-in flow control valve :-

• Finer speed control is possible.
• Suitable for high pressure applications.
• Low level of friction – longer service life of components.

Disadvantages of meter-in flow control valve :-

• Cannot be used for hydromotor.
• Pressure drops across due to throtlle and hence the pressure of the fluid fed into the actuator will be less than required.
• Inefficent because excess flow goes to tank.
• Cannot prevent the load from running away as in the case of drilling machine.
• Heat generated due to throttling is fed to the actuator.

Advantages of meter-out flow control valve :-

• No loss of pressure of the oil at the head end of the cylinder.
• The actuator movement is more stable.
• Suitable for controlling the speed of both cylinder and motor.
• Heat generated during throttling goes to the tank.
• Provide positve speed control of cylinder.
• Pump works against the maximum pressure.
• Positive speed control and stable.

Disadvantages of meter-out flow control valve :-

• Even at no load the cylinder is subjected to maximum pressure.
• Piston rod side is subjeted to counter pressure which increases as area ratio increases.
• The friction is higher.
• If the flow control is installed after the DCV, leakage in DCV will affect the accuracy.