Cryogenic Pneumatic Emergency Shut-off Valves: Overview, Principle, Features & Technical Parameters

Cryogenic Pneumatic Emergency Shut-off Valves are suitable for cutting off circulating media on cryogenic storage tanks, especially capable of timely cutting off media in case of fire faults. They are widely used in LNG, liquid ethylene and other cryogenic media, featuring small volume, light weight, reliable sealing, rapid and reliable emergency shut-off, and anti-static properties.

Working Principle

The Cryogenic Pneumatic Emergency Shut-off Valve uses the pressure of the spring above the piston to push the piston downward, which in turn drives the piston rod and valve stem downward, making the sealing surface of the valve top closely fit with the sealing surface of the valve seat to realize the closing of the valve; when the cylinder is pressurized, the piston compresses the spring and moves upward, driving the piston rod and valve stem upward, lifting the valve top, and the valve opens;

When the valve is in the open position and working normally, if the ambient temperature rises to 70℃±5℃, the fusible plug installed at the cylinder melts, the cylinder relieves pressure, the spring pushes the piston downward, driving the valve stem and valve top downward, and the valve closes quickly to prevent the medium from continuing to flow and avoid the occurrence or expansion of dangers.

Structural Features

• It consists of a cryogenic globe valve and a pneumatic actuator with spring return, and safety accessories (fusible plugs) are added at the cylinder part;

• The valve body part adopts the structure of a manual cryogenic globe valve, and necessary improvements are made on the sealing surface to make it more suitable for the use requirements of emergency shut-off;

• The actuator part is a single-cylinder piston mechanism with stable and reliable action;

• The reset force of the valve comes from a high-quality compression spring;

• If the driving air source cannot be normally supplied to the valve, the manual device of the valve can be used to open and close the valve, so as not to affect the normal operation of the entire system.

Technical Parameters

• Product Name: Cryogenic Pneumatic Emergency Shut-off Valve

• Nominal Diameter: DN20~DN200

• Cylinder Material: Cast Aluminum

• Manufacturing Standards: National Standard GB / Ministry of Machinery Industry Standard JB / Ministry of Chemical Industry Standard HG / American Standard ANSI/API / Japanese Standard JIS / German Standard DIN / Customization according to other standards

• Applicable Temperature: -196℃~70℃

• Nominal Pressure: 4.0MPa

• Strength Test Pressure: 6.4MPa

• Gas Tightness Test Pressure: 4.0MPa

• Reverse Seal Test Pressure: 0.4MPa

• Cylinder Air Supply Pressure: 0.4~0.6MPa

• Applicable Media: LO2, LN2, LAr, LNG, LC2H4, etc.

• Emergency Shut-off Temperature: +70℃±5℃

• Emergency Shut-off Time: ≤2s

• Connection Form: Socket Weld