Vacuum pump

Abstract

Vacuum pump having a housing which defines a pump chamber and a drive chamber. A rotor is arranged in the housing, wherein the rotor has at least one rotor element arranged in the pump chamber for conveying a gaseous medium from an inlet to an outlet. Therein, the rotor extends from the pump chamber through a shaft feedthrough into the drive chamber. The shaft feedthrough has a connection, wherein the connection is connected to an underpressure, so that a barrier gas flows from the drive chamber at least partially through the shaft feedthrough to the connection.

1 . A vacuum pump having:
 a housing which defines a pump chamber and a drive chamber,   a rotor arranged in the housing, wherein the rotor has at least one rotor element arranged in the pump chamber for conveying a gaseous medium from an inlet to an outlet, wherein the rotor extends from the pump chamber through a shaft feedthrough into the drive chamber,   wherein the shaft feedthrough has a connection, wherein the connection is connected to an underpressure, so that a barrier gas flows from the drive chamber at least partially through the shaft feedthrough to the connection.   
     
     
         2 . The vacuum pump according to  claim 1 , characterized in that a pressure P 1  prevails in the drive chamber and the underpressure has a pressure P 2 , wherein P 2 <P 1 , wherein in particular P 1  corresponds to atmospheric pressure. 
     
     
         3 . The vacuum pump according to  claim 1 , characterized in that a pressure P 3  prevails in the pump chamber at the shaft feedthrough and the underpressure has a pressure P 2 , wherein P 2 <P 3 , and in particular P 3 ≥P 1 >P 2  applies. 
     
     
         4 . The vacuum pump according to  claim 1 , characterized in that the connection is connected to a further vacuum pump for generating the underpressure. 
     
     
         5 . The vacuum pump according to  claim 1 , characterized in that the connection is connected to a vacuum portion of the pump chamber. 
     
     
         6 . The vacuum pump according to  claim 5 , characterized in that the vacuum portion of the pump chamber corresponds to the inlet of the vacuum pump. 
     
     
         7 . The vacuum pump according to  claim 1 , characterized in that a first throttle is arranged between the drive chamber and the connection. 
     
     
         8 . The vacuum pump according to  claim 7 , wherein the first throttle is formed by a first portion of the shaft feedthrough, in particular designed as a contact-free shaft seal. 
     
     
         9 . The vacuum pump according to  claim 1 , characterized in that a second throttle is arranged between the pump chamber and the connection. 
     
     
         10 . The vacuum pump according to  claim 9 , wherein the second throttle is formed by a second portion of the shaft feedthrough, in particular designed as a contact-free shaft seal. 
     
     
         11 . A vacuum pump system having a first vacuum pump and at least one second vacuum pump, wherein each vacuum pump has the following:
 a housing which defines a pump chamber and a drive chamber,   a rotor arranged in the housing, wherein the rotor has at least one rotor element arranged in the pump chamber for conveying a gaseous medium from an inlet to an outlet, wherein the rotor extends from the pump chamber through a shaft feedthrough into the drive chamber,   wherein the shaft feedthrough has a connection, wherein the connection is connected to a common inlet of the first vacuum pump and the at least second vacuum pump or to a common further vacuum pump, so that one barrier gas each flows from the respective drive chamber through the respective shaft feedthrough.   
     
     
         12 . The vacuum pump system according to  claim 11 , characterized in that the outlet of the first vacuum pump is connected to the inlet of the second vacuum pump for the serial arrangement of the vacuum pumps. 
     
     
         13 . The vacuum pump system according to  claim 11 , characterized in that the inlet of the first vacuum pump is connected to the inlet of the at least one second vacuum pump and the outlet of the first vacuum pump is also connected to the outlet of the at least one second vacuum pump for the parallel arrangement of the vacuum pumps. 
     
     
         14 . The vacuum pump system according to  claim 13 , characterized in that a check valve, which closes when the pressure in the respective vacuum pump is higher than at the common inlet, is arranged between each vacuum pump and the common inlet.