Cryogenic liquid pumps (cryogenic pumps) are special pumps used to transport cryogenic liquids (such as liquid oxygen, liquid nitrogen, liquid argon, liquid hydrocarbons, liquefied natural gas, etc.) in petroleum, air separation and chemical plants, Cryogenic liquid is delivered from places with low pressure to places with high pressure. With the development of air separation technology, cryogenic liquid has been widely used and developed. Its role in the air separation plant as long as: for liquid circulation; or from the tank to extract liquid and pressure into the carburetor, vaporized and sent to the user. As the cryogenic liquid pump medium for the transport of low-temperature liquid in the process of transporting medium should be kept low, if once absorbed from the pump around the more heat, the pump will be a lot of low-temperature liquid vapor, resulting in gas, thus affecting the pump work . Therefore, cryogenic pump in the structure, materials, installation and operation has its special requirements, in order to achieve cryogenic liquid delivery requirements. In accordance with the different working principle, cryogenic pump is divided into two types of reciprocating and centrifugal.