Rotary vane vacuum pump

Abstract

A rotary vane vacuum pump includes a pump casing having a gas inlet port and a gas outlet port, a stator provided within the pump casing and defining a cylindrical stator chamber and a cylindrical rotor eccentrically arranged in the stator chamber and equipped with radially movable radial vanes, the vanes cooperating with the inner wall of the stator chamber for pumping a gas from the gas inlet port to the gas outlet port, the pump casing being filled with such an amount of oil that the stator is immersed in an oil bath acting as cooling and lubricating fluid, wherein a motor for driving the pump is further provided, the motor being arranged in a motor casing that is in fluid communication with the pump casing, whereby the motor is immersed in the oil bath.

What is claimed is: 
     
         1 . A rotary vane vacuum pump, comprising:
 a pump casing in which a gas inlet port and a gas outlet port are defined;   a stator arranged inside the pump casing and defining a stator chamber of cylindrical shape;   a cylindrical rotor housed inside the stator chamber and having an axis parallel to the axis of the stator chamber, but eccentrically arranged relative to the chamber axis, which rotor is rotatable about a pump rotor shaft and is equipped with one or more radially movable radial vanes that cooperate with the inner wall of the stator chamber for pumping a gas from the gas inlet port to the gas outlet port;   wherein the pump casing is filled with such an amount of oil that the stator is immersed in an oil bath; and   wherein the pump is equipped with a motor for driving in rotation the pump rotor, the motor being arranged inside a motor casing that is in fluid communication with the pump casing.   
     
     
         2 . The rotary vane vacuum pump as claimed in  claim 1 , wherein the pump casing and the motor casing are made as a single, common casing housing both the vacuum pump and the motor. 
     
     
         3 . The rotary vane vacuum pump as claimed in  claim 1 , wherein the motor is an electric motor. 
     
     
         4 . The rotary vane vacuum pump as claimed in  claim 3 , wherein the motor is an asynchronous electric motor. 
     
     
         5 . The rotary vacuum pump as claimed in  claim 1 , wherein the oil of the oil bath acts as coolant fluid both for the vacuum pump and for the motor. 
     
     
         6 . The rotary vane vacuum pump as claimed in  claim 1 , wherein the motor includes a stator and a rotor rotatable about a motor rotor shaft and wherein the pump rotor shaft and the motor rotor shaft are made as a single, monolithic pump shaft. 
     
     
         7 . The rotary vane vacuum pump as claimed in  claim 6 , wherein the pump shaft is supported by supports arranged at both its opposite ends. 
     
     
         8 . The rotary vane vacuum pump as claimed in  claim 6 , wherein the pump rotor and the motor rotor are made as a single, monolithic piece together with the pump shaft. 
     
     
         9 . The rotary vane vacuum pump as claimed in  claim 6 , wherein the pump is further equipped with a cooling fan. 
     
     
         10 . The rotary vane vacuum pump as claimed in  claim 9 , wherein the cooling fan is rotatable about a fan shaft that is arranged coaxially with the pump shaft. 
     
     
         11 . The rotary vane vacuum pump as claimed in  claim 10 , wherein a pair of cooperating magnets are provided for driving in rotation the cooling fan, a first magnet of the pair of magnets being arranged in the pump shaft and the second magnet of the pair of magnets being arranged on the fan. 
     
     
         12 . The rotary vane vacuum pump as claimed in  claim 1 , wherein the rotor comprises a first rotor stage at lower pressure and a second rotor stage at higher pressure, each of the rotor stages being rotatable about the pump rotor shaft and being equipped with one or more radially movable radial vanes that cooperate with the inner wall of the stator chamber for pumping a gas.