Offer: 2XZ series two stage rotary vane vacuum pumps

Working Principle
2XZ series rotary vane vacuum pump is double stage high speed oil sealed rotary vane vacuum pump (hereinafter referred it as "the pump" for short). Its pumping principle is same as that of 2X type pump. Rotors are eccentrically mounted within the cylindrical housing of the stators and vanes are fitted freely inside the respective slots of the rotor.
When the rotor rotates at high speed, vanes in the rotor slot are urged outwards by centrifugal force as well as by spring force so as to keep close contact at their tips with the stator wall throughout rotation. Thus the inlet port and outlet port on the stator are separated by them. The volume of the space leading to the inlet port expands progressively and periodically with gas filling the space through inlet pipe, meanwhile the volume of the space leading to the outlet port diminishes progressively and periodically to compress the gas previously sucked.
By means of gas pressure and oil pressure exhaust valve on the outlet port is opened to expel gas out of the pump through the valve, then vacuum is obtained at the intake side of the pump. Fig 1 shows the working principle of a single stage pump. Double stage pump is the arrangement of two single stage pumps in series. When the intake pressure is higher, both stages of the pump may exhaust simultaneously, while at lower suction pressure gas is first expelled out from first stage to second stage, then from second stage exhausts to the open air.
2XZ type pump is equipped with gas-ballast valve. Its function is to fill the exhaust space with certain amount of air, when the valve is open, so to reduce the proportion of the partial pressure of vapor in the total discharge pressure.