Valve for medium with temperature of -40℃ to -196℃ is called cryogenic valve. Cryogenic valve includes cryogenic ball valve, cryogenic gate valve, cryogenic globe valve, cryogenic check valve and cryogenic throttle valve. It's mainly for ethylene, liquefied natural gas device, natural gas LPG LNG storage tank, air separation equipment, petroleum and chemical end gas separation equipment, liquid oxygen, liquid nitrogen, liquid argon, carbon dioxide cryogenic storage tank and tanker and other device. The output low temperature liquid medium is not only flammable and explosive, it's gasified when heating-up, and the volume expands hundreds times after gasification.
Cryogenic Ball Valve
1. Cryogenic ball valve is a kind of valve that is mainly for ethylene, liquefied natural gas and other chemical device. It's mainly divided into cryogenic floating ball valve and cryogenic standing ball valve. 2. Long-necked structure is not usually applied for temperature above -50℃, and applied for temperature below -50℃. It aims to protect the stuffing box. Locate stuffing box far away from low temperature.To guarantee sealing effect of the stuffing, cold insulation material also can be wound to prevent loss of cold energy. it's a kind of valve that mainly for ethylene, liquefied natural gas and other chemical device.
Cryogenic Globe Valve
Cryogenic globe valve uses valve stem pressure to make the sealing face of valve clack and sealing face of valve seat fit tightly to cut off medium. It's a forced seal valve. 1. Flow direction of medium in globe valve includes "low in and high out" and "high in and low out". The medium is allowed to flow in only one direction. The valve shall be installed in right direction. 2. Cryogenic globe valve has structure of straight-through type, direct flow type and right angle type. 3. When globe valve is open, and the opening height of valve clack is up to 25% ~ 30% of nominal diameter of the globe valve, the flow reaches the maximum which show that the valve reaches the fully open position.
Cryogenic Gate Valve
Cryogenic gate valve is straight-through valve. It's closed when rotate hand wheel clockwise, and the flashboard drops and cuts off the channel. It's opened when rotate hand wheel counter-clockwise, and the flashboard rises. 1. The flashboard has two sealing faces. The most commonly used flashboard has a wedge forming by two sealing faces. The wedge angle varies with valve parameters, usually 5°. 2. The sealing principle of wedge gate valve is seal through close connection of wedging of two sealing faces of wedge flashboard and two sealing faces of valve body. 3. Cryogenic gate valve is suitable for methane, liquefied natural gas, methane, carbon dioxide, liquid ammonia, liquid oxygen, liquid nitrogen, liquid hydrogen and other low temperature mediums.