Pneumatic cryogenic ball valves are used to output liquid cryogenic media such as ethylene, liquid oxygen, liquid hydrogen, liquefied natural gas, liquefied petroleum products, etc. Not only are they flammable and explosive, but they must be gasified when the temperature rises. When gasified, the volume expands hundreds of times. The material of the LNG valve is very important. If the material is unqualified, it will cause external leakage or internal leakage of the shell and the sealing surface.The comprehensive mechanical properties, strength and rigidity of the parts cannot meet the requirements of use or even break. Causes explosion of LNG medium leakage. Therefore, in the process of developing, designing and developing LNG valves, the material is the most important issue. The valve body and valve cover are made of special materials such as low temperature resistant stainless steel and low temperature resistant cast steel. Pneumatic cryogenic valve is one of the indispensable important equipments in petrochemical industry, air separation, natural gas and other industries. Its quality determines whether it can be produced safely, economically and continuously. Low-temperature ball valves are divided into low-temperature floating ball valves and low-temperature fixed ball valves. For temperatures above -50℃, long-neck structures are generally not used. For ball valves with temperatures below -50℃, the neck length T is generally 250mm.
1. Cryogenic treatment of all valve parts with a service temperature of less than -100°C in accordance with relevant regulations to prevent low-temperature brittleness of the material and volume change due to material phase change at low temperature
2. The pneumatic ultra-low temperature ball valve adopts a long neck structure, which makes the working temperature of the packing above 0 ℃, which effectively prevents the packing from reducing the sealing performance or even sealing failure due to the working temperature being too low. At the same time, it is convenient to wrap the valve with insulation material to prevent the loss of cold energy
3. For the floating ball valve, the inlet pressure relief outlet seal design is used to effectively prevent the abnormal pressure increase in the middle cavity due to temperature changes and ensure the safe operation of the valve and pipeline.
4. Pneumatic actuators with double-layer stem packing and counter-pressure disc shrapnel device adopt new GTD series or ATD series pneumatic actuators, which have double-acting type and single-acting type (spring return), gear transmission, safe and reliable; large-diameter valve AW series pneumatic actuator fork drive is adopted, with reasonable structure and large output torque, with double-acting type and single-acting type.
Post time: Nov-25-2021