Cooled screw vacuum pump

Abstract

The invention relates to a screw vacuum pump, comprising two shafts ( 7, 8 ), each bearing a rotor ( 3, 4 ) containing a hollow chamber ( 31 ). Said chamber ( 31 ) contains a second hollow chamber ( 32 ) which embodies a component of a coolant circuit. The shafts ( 7, 8 ) have open bores ( 41 ) on the delivery side, through which the coolant is supplied and evacuated to or from the additional hollow chambers ( 32 ). In order to improve the effectivity of the cooling of the rotors, guide components ( 44 ) are located in the open bores ( 41 ) of the shafts ( 7, 8 ). Said guide components separately guide the inflowing and outflowing coolant.

1 . A screw vacuum pump, comprising: 
 two shafts, each bearing a rotor containing a first hollow chamber;    said first chambers each containing a second hollow chamber which defines a coolant channel;    the shafts have open bores on a delivery side, through which inflowing coolant is supplied to and outflowing coolant is evacuated from the second hollow chambers;    guide components located in the open bores of the shafts, said guide components separately guiding the inflowing and outflowing coolant.    
   
   
       2 . The pump according to  claim 1 , wherein the open bores include: 
 lateral sections of longitudinal grooves or outer sections turned off on a lathe in the guide components.    
   
   
       3 . The pump according to  claim 1 , wherein the guide components include: 
 axial and radial line sections arranged to allow for separate crossing guidance of the inflowing coolant and the outflowing coolant.    
   
   
       4 . The pump according to  claim 3 , further including: 
 a first longitudinal groove or a pair of longitudinal grooves for supplying the inflowing coolant; and    a second longitudinal groove or pair of longitudinal grooves offset by 90 degrees for evacuating the outflowing coolant.    
   
   
       5 . The pump according to  claim 4 , further including: 
 cross bores which cross the inflowing and outflowing coolant flows.    
   
   
       6 . The pump according to  claim 1 , further including: 
 radial bores linking the open bores to the second hollow chamber.    
   
   
       7 . The pump according to  claim 1 , wherein the guide components comprise: 
 three sections which divide the open bore in each shaft into three partial chambers which are each located at a level of a radial cross bore, longitudinal bores in the three sections and line sections linking said longitudinal bores, separate inflowing and outflowing coolant.    
   
   
       8 . The pump according to  claim 1 , further including: 
 lines for evacuating the coolant out into a gear chamber.    
   
   
       9 . The pump according to  claim 1 , wherein 
 an end of each shaft on the suction side is linked to an end of the rotor on the delivery sides and    the guide component extend up to and into the first hollow chambers.    
   
   
       10 . The pump according to  claim 9 , wherein the guide components are made of a light plastic material.  
   
   
       11 . The pump according to  claim 1 , wherein the first hollow chambers fully penetrates the rotors and the guide components function as tie rods for affixing the rotors to the shafts.  
   
   
       12 . The pump according to  claim 1 , wherein an inside wall of each first hollow chamber limits the second hollow chamber and widens conically in a direction of the delivery side.  
   
   
       13 . The pump according to  claim 1 , wherein each second hollow chamber is a relatively narrow cylindrical section of an annular ring through which the coolant flows, the section of the annular ring extending between one of the shaft and the guide component and a corresponding inner wall of the first hollow chamber and between a suction side and the delivery side of the rotor.  
   
   
       14 . The pump according to  claim 13 , wherein: 
 the shaft is connected on the delivery side with the rotor and    the guide component extends into the first hollow chamber in the rotor and    the guide component and the inner wall of the rotor form the annular ring.    
   
   
       15 . The pump according to  claim 13 , wherein the annular ring is located directly between the shaft and the inner wall of the first hollow chamber.  
   
   
       16 . The pump according to  claim 13 , wherein the shaft is equipped with a sleeve, the outside of which limits the annular ring.  
   
   
       17 . The pump according to  claim 1 , wherein the rotor has delivery side and suction side sections and delivery side and suction side hollow chambers are defined through which the coolant flows, said delivery side and suction side chambers being supplied through channels in the guide component.  
   
   
       18 . The pump according to  claim 17 , wherein: 
 the shaft penetrates the rotor at the delivery side section;    the suction side section is connected to an end of the shaft on the delivery side;    the guide component extends up to and into the suction side hollow chamber of the suction side rotor section and limits the suction side hollow chamber.    
   
   
       19 . The pump according to  claim 1 , wherein a direction of the flowing coolant is so selected that the flow passes through the second hollow chamber from the delivery side in the direction of a suction side.  
   
   
       20 . The pump according to  claim 1 , further including: 
 coolant pumps located in an area of the shaft ends on the delivery side.