Vacuum pump

Abstract

A method for controlling the temperature of a rotor of a vacuum pump comprising said rotor and a stator comprises the steps of flowing a rotor cooling fluid through a rotor cooling circuit to cool the rotor, flowing a stator cooling fluid through a stator cooling circuit to cool the stator, conveying the stator cooling fluid from the stator cooling circuit to a heat exchanger of the rotor cooling circuit to cool the rotor cooling fluid, returning the stator cooling fluid from the heat exchanger of the rotor cooling circuit to the stator cooling circuit, supplying a further coolant to a heat exchanger of the stator cooling circuit to cool the stator cooling fluid, and controlling the supply of further coolant to the heat exchanger of the stator cooling circuit to control the temperature of the stator cooling fluid.

1 . A method of controlling the temperature of a rotor of a vacuum pump comprising said rotor and a stator, the method comprising the steps of flowing a rotor cooling fluid through a rotor cooling circuit to cool the rotor proximate a first end, flowing a stator cooling fluid through a stator cooling circuit to cool the stator, conveying the stator cooling fluid from the stator cooling circuit to a heat exchanger of the rotor cooling circuit to cool the rotor cooling fluid, returning the stator cooling fluid from the heat exchanger of the rotor cooling circuit to the stator cooling circuit, supplying a further coolant to a heat exchanger of the stator cooling circuit to cool the stator cooling fluid, and controlling the supply of further coolant to the heat exchanger of the stator cooling circuit to control the temperature of the stator cooling fluid.  
     
     
         2 . The method according to  claim 1 , wherein the supply of further coolant to the heat exchanger of the stator cooling circuit is controlled as a function of the temperature of the stator.  
     
     
         3 . The method according to  claim 1 , wherein the supply of further coolant to the heat exchanger of the stator cooling circuit is controlled using a variable flow control device.  
     
     
         4 . The method according to  claim 3 , wherein the variable flow control device has a conductance which is varied as a function of the temperature of the stator to control the rate of supply of the further coolant to the heat exchanger of the stator cooling circuit.  
     
     
         5 . The method according to  claim 4 , wherein the conductance of the variable flow control device is controlled as a function of a signal output from a sensor for monitoring the temperature of the stator.  
     
     
         6 . The method according to  claim 3 , wherein the variable flow control device has a setting that is variable to control the respective temperatures of both the stator and the rotor.  
     
     
         7 . The method according to  claim 3 , wherein the variable flow control device is a manually controlled valve.  
     
     
         8 . The method according to  claim 1 , wherein the first cooling fluid comprises an oil.  
     
     
         9 . The method according to  claim 1 , wherein the second cooling fluid comprises water.  
     
     
         10 . The method according to  claim 1 , wherein the further coolant is supplied to the heat exchanger of the stator cooling circuit from a mains water supply.  
     
     
         11 . The method according to  claim 1 , wherein the stator cooling circuit extends about the stator.  
     
     
         12 . The method according to  claim 1 , wherein the rotor cooling circuit is configured to supply the rotor cooling fluid to one end of the rotor.  
     
     
         13 . The method according to  claim 12 , wherein a second rotor cooling circuit is provided for cooling the rotor proximate a second end, the method further comprising the steps of flowing a rotor cooling fluid through the second rotor cooling circuit, conveying the stator cooling fluid from the stator cooling circuit to a heat exchanger of the second rotor cooling circuit to cool the rotor cooling fluid therein, and returning the stator cooling fluid from the heat exchanger of the second rotor cooling circuit to the stator cooling circuit.  
     
     
         14 . The method according to  claim 1 , wherein the vacuum pump is a dry vacuum pump.  
     
     
         15 . The method according to  claim 1 , wherein the vacuum pump is a screw vacuum pump.