This type of pump is a sliding - valve mechanical vacuum pump, and it is one of the vacuum pumping equipment for pumping general gases or gases containing a small amount of condensable vapor (a gas - ballast device should be used). The performance specifications of this type of pump: the geometric speed is 150L/s, and the ultimate pressure is 1 Pa. It is suitable for vacuum smelting, vacuum drying, vacuum coating, vacuum impregnation, and other vacuum operations. It can be used alone or as a fore - pump for other vacuum pumps, but it is not suitable for pumping from one container to another as a transfer pump. When pumping gases that are high in oxygen content, explosive, corrosive to ferrous metals, chemically reactive with vacuum oil, water - containing, dusty, etc., additional equipment should be installed.