What is a pneumatic shut-off valve?
A pneumatic shut-off valve is an automated on/off valve that uses compressed air (typically 4–7 bar) to drive an actuator (rack & pinion or scotch yoke) to open or close the valve. It is used for remote isolation, emergency shutdown (ESD), and process automation. Unlike control valves, pneumatic shut-off valves are designed for full open or full close operation only, providing fast, reliable isolation.
What is the difference between double-acting and spring-return actuators?
Double-acting actuators use air pressure to drive the valve both open and closed — air is supplied to alternate ports. They require air pressure to hold position in both open and closed states. Spring-return actuators use air pressure to drive the valve in one direction (e.g., open) and a spring to return it to the fail-safe position (e.g., closed) when air pressure is lost. Spring-return provides fail-safe operation for ESD and safety applications.
Can pneumatic shut-off valves be used for emergency shutdown (ESD)?
Yes. Pneumatic shut-off valves with spring-return (fail-closed) or double-acting with air reservoir tanks are commonly used for ESD applications. They can be integrated with emergency shutdown systems per IEC 61508 SIL ratings. TANGGONG pneumatic shut-off valves are SIL-capable and can be configured for fast-acting ESD response (≤ 2 seconds for ball valves, ≤ 10 seconds for butterfly valves).
What positioners and accessories are available?
For on/off shut-off service, pneumatic actuators are equipped with: (1) Solenoid valves (24VDC / 220VAC / 110VAC), (2) Limit switches (mechanical or inductive proximity), (3) Position indicators (visual or NAMUR), (4) Speed control valves, (5) Air filter regulators, and (6) Manual override handles. For modulating service, smart positioners (HART, Foundation Fieldbus) are available.
Are TANGGONG pneumatic valves available in ATEX configuration?
Yes. TANGGONG pneumatic shut-off valves are available with ATEX/IECEx certified actuators, solenoid valves, limit switches, and positioners for Zone 1/2 hazardous areas. The ATEX-certified configuration includes flameproof enclosures, increased safety (Ex e), and intrinsic safety (Ex i) options to meet the requirements of refineries, chemical plants, and offshore platforms.
