Pneumatic Diaphragm Single Seat Control Valve — Cryogenic & High Temperature Service
Specifications
- Valve Type: Pneumatic Diaphragm Single Seat Globe Control Valve
- Applicable Media: LNG, liquid nitrogen, liquid oxygen, steam, water, oil, gas, and general process fluids
- Temperature Range: -250°C to +550°C (-418°F to +1,022°F) depending on bonnet configuration
- Size Range: DN15 – DN250 (½” – 10″)
- Pressure Classes: ANSI Class 150, 300, 600 / PN16, 25, 40, 64
- End Connections: Flanged per ASME B16.5 — FF, RF, RTJ; Butt Weld; Socket Weld; Threaded
- Flow Characteristics: Linear or equal percentage
- Leakage Class: ANSI/FCI 70-2 Class IV (metal seat) / Class VI (soft seat)
- Actuator Signal: 20–100 kPa / 40–200 kPa / 80–240 kPa pneumatic; I/P converter for 4–20 mA
- Fail Action: Air-to-close (fail open) or air-to-open (fail closed)
- Body Materials: A216 WCB, A217 WC6, A352 LCB, A351 CF8, CF8M, CF3M
- Seat Seal Materials: PTFE/RPTFE (soft seat), Stellite 6 (metal seat)
- Bonnet Options: Plain (-17°C to +230°C) / Extension Type 1 (-45°C to +566°C) / Cryogenic Type 2 (-196°C to -45°C) / Welded Cryogenic (to -250°C)
A pneumatic diaphragm-actuated, single seat globe control valve engineered for precise flow regulation across an exceptionally wide temperature range, covering cryogenic service in LNG, liquid nitrogen, and liquid oxygen applications through to elevated temperature process service. Compressed air acts on the diaphragm to drive the valve stem and plug, modulating the valve opening in response to a 4–20 mA or pneumatic control signal from the plant automation system. The single seat, top-guided design delivers high shutoff performance, low flow resistance, and accurate flow characteristics with minimal pressure drop.
Bonnet configurations are selectable to match the operating temperature — plain bonnet for standard service, extension bonnet for intermediate low and high temperature ranges, and a cryogenic welded or integral cast bonnet for deep-cold service down to -250°C. Flow characteristics are available in linear or equal percentage to suit specific process control requirements. Compatible with a full range of accessories including valve positioners, I/P converters, solenoid valves, limit switches, and handwheels for manual override.
- Pneumatic diaphragm actuation with spring return — fail-open or fail-closed configuration selectable
- Top-guided single seat design for high shutoff integrity and precise, stable flow control
- Selectable bonnet type to cover standard, extended temperature, and deep-cryogenic service
- Linear or equal percentage flow characteristics available to suit process control requirements
- Soft seat (PTFE/RPTFE) for bubble-tight Class VI shutoff; metal seat (Stellite) for Class IV in high-temperature and abrasive service
- S-shaped flow port for low pressure drop and large flow capacity relative to valve size
- Compatible with P/P or I/P positioner, solenoid valve, limit switch, booster relay, and handwheel accessories
- NACE MR0175 compliant configurations available for sour service