Cryogenic Ball Valve
The cryogenic ball valves is used to cut off or connect the media in various pipeline of Class 150~Class
The Forged Cryogenic Valves is used to cut off or connect the media in various pipeline of Class 150~Class 1500. The valves made of different materials are suitable for various media and different temperature. The lowest working temperature is -196℃. The driving modes include manual operation, worm and worm gear transmission, pneumatic operation and electric operation. The connection ends can be flange or welding.
The Cryogenic ball valves are classified into cryogenic floating ball valves and cryogenic trunnion ball valves. Refer to the data of floating ball valve and trunnion ball valve for the product range, face-to-face dimensions, connection flange dimensions and etc. For the ball valves with temperature high than -50℃，the long neck structure is not designed. For the ball valves with temperature lower than -50℃, the neck length is generally designed according to standard requirements or according to user requirements.
The cryogenic ball valve is used for low temperature service condition, especially the dangerous media service conditions such as natural gas. Our company has accumulated rich experience in designing, manufacturing, testing and inspecting the cryogenic ball valve.
Structural Design and Machining and Manufacturing FeaturesAccording to standard requirements, the ball valves with temperature low than -50℃ generally adopts the long neck structure design to improve the temperature at the packing and ensure reliable sealing of stem packing. The neck length is generally designed according to standard requirements or according to contract requirements if users have special requirements. For the valve used for low temperature media, when the valve is at the closed position, the low temperature liquid staying in the middle cavity of valve will be gasified with the rise of temperature, which causes the volume to expand rapidly and leads to abnormal pressure rise in the middle cavity, or even valve breakage if serious. The ball valve is provided with function of middle cavity automatic pressure relief. In case of abnormal pressure rise in the middle cavity, the medium in the middle cavity will overcome the spring pre-tightening effect through its own force and push the seat out of the ball to realizeautomatic pressure relief, so as to ensure valve safety.
According to contract requirements, cryogenic test can be carried out to test operating torque, sealing performance and other indexes under low temperature.
The parts of the valve have been subjected to cryogenic treatment to ensure stability of form and size ofparts under low temperature.
Material SelectionCommon Steel will show low temperature brittleness under low temperature. Therefore, it is a key for design and manufacturing to select suitable body materials according to the lowest working temperature of the cryogenic ball valve. Refer to the following table for the lowest working temperature of body
materials. The low temperature materials shall be subjected to low temperature impact test according to standard requirements. For valves with working temperature lower than -100℃, the body, bonnet and stem must be subjected to cryogenic treatment after tough machining. The ball and seat sealing face
should be subjected to cryogenic treatment hard alloy spray welding/overlay welding. Then grinding and assembly can be carried out, so as to ensure the adaptability of materials under low temperature. In addition, the pacing, gasket, bolt and nut shall be made of materials suitable for low temperature service