BY ACTUATION
Hydraulic Actuated Valves
Where the operating energy comes from — the line itself, a handwheel, or an external actuator.
Choosing Hydraulic Actuated Valves
Hydraulic valve actuation uses fluid power to produce movement; the hydraulic circuit is distinct from the process fluid passing through the valve. Hydraulic and electro-hydraulic packages can use different supply, stored-energy and return arrangements.
What to include in the RFQ
- Specify available hydraulic pressure, fluid and permitted temperature range.
- Provide valve torque/thrust, travel time and required failure position.
- Request the power-unit, accumulator or spring arrangement and manual-operation procedure.
Selection scenario
Where plant air is unavailable, compare an electro-hydraulic package with other actuator options using both normal operation and emergency movement requirements.
Common selection mismatch
Do not assume a hydraulic cylinder will move to a safe position after loss of its supply. The return mechanism and control circuit must be specified.