Pneumatic low temperature ball valve is used to output liquid low temperature medium such as ethylene, liquid oxygen, liquid hydrogen, liquefied natural gas, liquefied petroleum products, etc. It is not only flammable and explosive, but also vaporizes when it is heated. When it is vaporized, the volume expands hundreds of times. The material of the LNG valve is very important. If the material is unqualified, it will cause leakage or leakage of the casing and sealing surface. The comprehensive mechanical properties, strength and rigidity of the parts can not meet the requirements of use or even break. Causes leakage of LNG media to cause an explosion. Therefore, in the process of developing, designing and developing LNG valves, material is the primary key issue. The valve body and bonnet are made of special materials such as low temperature resistant stainless steel and low temperature resistant cast steel. Pneumatic low temperature is one of the most important equipments in the petrochemical, air separation, natural gas and other industries. The quality of the products determines whether it can be safely, economically and continuously produced. Low temperature ball valves are classified into low temperature floating ball valves and low temperature fixed ball valves. For temperatures above -50 °C, long neck structures are generally not used. For ball valves with temperatures below -50 °C, neck length T is generally 250 mm, or according to me. The company's design and calculations are determined.
1. For all valve parts with a temperature less than -100 °C, cryogenic treatment according to relevant regulations to prevent low-temperature brittleness of materials and volume change caused by material phase transformation at low temperature
2, pneumatic ultra-low temperature ball valve uses a long neck structure, so that the packing working temperature is above 0 °C, effectively prevent the packing due to low working temperature, resulting in reduced sealing performance or even seal failure, and at the same time convenient to wrap the insulation material to prevent cold energy loss
3. For the floating ball valve, the inlet pressure relief outlet seal design is adopted to effectively prevent the abnormal rise of the middle cavity due to temperature changes, ensuring the safe operation of the valve and pipeline.
4, double valve stem packing and pneumatic disc type shrapnel device pneumatic actuator adopts new GTD series or ATD series pneumatic actuator, double acting and single acting (spring return), gear transmission, safe and reliable; large diameter valve It adopts AW series pneumatic actuator forklift transmission with reasonable structure, large output torque, double acting and single acting.