According to the provisions of the People's Republic of China Machinery Industry Standard JB / T7673-95, made a variety of domestic vacuum pumps from the basic model and the auxiliary two parts, the middle of a horizontal line. Its expression pattern is 123-456. The number 123 in the grid represents the base model and 456 the auxiliary model. Domestic vacuum pump models are usually shown in Table 3-2 Chinese pinyin letters. If in front of pinyin letters with 2 words, it means that the pump in the structure for the two-stage pump. In some vacuum pump series, the pumping speed is divided by geometric series. Its unit is L / S. Divided into 18 levels, respectively, 0.2,0.5,1,2,4,8,15,30,70,150,300,600,1200,2500,5000,10000,20000,40000. Vacuum pump series can sometimes be used to indicate the size of the pump inlet, the unit is mm. Due to the type of pump more, the selection should refer to different manufacturers of product brochures sample is very important. Table 3-2 Chinese Pinyin Code and Name of Common Vacuum Pump Code Name Name Code Name Reciprocating Vacuum Pump Z Oil Diffusion Jet Pump D Slicing Vacuum Pump S Sublimation Pump X Rotary Vane Pump LF Compound Ion Pump H Slide Valve Vacuum Pump GL zirconium-aluminum getter pump ZJ Roots vacuum pump (mechanical booster pump) DZ refrigerator cryogenic pump YZ trochoidal vacuum pump DG perfusion cryogenic pump L sputtering ion pump IF molecular sieve adsorption pump XD single-stage multi-rotary vane vacuum pump SZ Water ring pump F molecular pump PS water jet pump K oil diffusion pump P water vapor injection