Vacuum Pump

Abstract

A vacuum pump for producing a vacuum in a space which is to be evacuated comprises a housing ( 10 ) having a cylindrical inner space ( 22 ). An expeller ( 26 ) is arranged eccentrically in the inner space ( 22 ). A helical sealing element ( 34 ) is provided between the expeller ( 26 ) and an inner wall ( 38 ) of the housing ( 10 ) for forming at least one crescent-shaped conveying space. The housing ( 10 ) or the expeller ( 26 ) are connected to a drive device ( 44 ) for producing a relative rotary movement between the housing ( 10 ) and the expeller ( 26 ). The vacuum pump is configured as a dry-running vacuum pump.

1 . A vacuum pump for producing a vacuum in a space, comprising
 a housing having a cylindrical inner space,   an expeller arranged eccentrically in the inner space,   a helical sealing element arranged between the expeller and an inner wall of the housing for forming at least one crescent-shaped conveying space, and   a drive device, connected to the housing or the expeller for producing a relative rotary movement between the housing and the expeller, the vacuum pump being configured as a dry-running vacuum pump.   
   
   
       2 . The vacuum pump according to  claim 1 , wherein the expeller is supported concentrically. 
   
   
       3 . The vacuum pump according to  claim 1 , wherein the dry-running operation is realized by suitable material pairings between the sealing element and a sliding surface with good sliding properties, particularly by use of material pairings of PTFE and/or PEEK and/or smoothed anodized aluminum. 
   
   
       4 . The vacuum pump according to  claim 1 , wherein an inner wall of the inner space has a roughness Rz of 0.1 to 5, preferably of 0.5 to 2. 
   
   
       5 . The vacuum pump according to  claim 1 , wherein the sealing element is held in a groove for radial displacement therein, said groove being arranged in the housing or in the expeller. 
   
   
       6 . The vacuum pump according to  claim 5 , wherein said groove is coated. 
   
   
       7 . The vacuum pump according to  claim 1 , characterized by a cooling element, connected to the housing, for cooling the housing inner wall. 
   
   
       8 . The vacuum pump according to  claim 1 , wherein said cooling element comprises cooling ribs arranged on an outer side of the housing. 
   
   
       9 . The vacuum pump according to  claim 1 , wherein bearings are arranged for rotatable support of the housing or the expeller. 
   
   
       10 . The vacuum pump according to  claim 1 , wherein the expeller is supported in an overhung manner. 
   
   
       11 . The vacuum pump according to  claim 1 , wherein the expeller is provided with inner bearings. 
   
   
       12 . The vacuum pump according to  claim 11 , wherein the expeller comprises a hollow space having arranged therein a drive shaft connected to the expeller. 
   
   
       13 . The vacuum pump according to  claim 12 , wherein said hollow space has provided therein a hollow axis surrounding the drive shaft and serving to accommodate the bearings. 
   
   
       14 . The vacuum pump according to  claim 1 , wherein the rotational number of the housing or of the expeller is delimited to 500 l/min, preferably to 200 l/min. 
   
   
       15 . A vacuum pump comprising:
 a cylindrical rotor having a rotor central axis, the cylindrical rotor defining a helical channel along an outer surface thereof;   a sealing element received in the helical channel;   a housing defining a cylindrical chamber having housing central axis;   a bearing assembly which mounts the cylindrical rotor and the housing for relative rotational movement around an axis of rotation, the axis of rotation being aligned with the rotor axis and radially offset from the housing axis.