External gear pump for a waste heat recovery system

Abstract

The invention relates to an external gear pump ( 1 ) having a pump housing ( 2 ). An inlet ( 2 a ), an outlet ( 2 b ), and a working chamber ( 6 ) are formed in the pump housing ( 2 ). A first gear ( 11 ), which is arranged on a first shaft ( 21 ), and a second gear ( 12 ), which is arranged on a second shaft ( 22 ), are arranged in the working chamber ( 6 ) in such a way that said first and second gears mesh with each other. Both gears ( 11, 12 ) have teeth having a tooth width (b). The first shaft ( 21 ) is radially supported in at least one plain bearing ( 61 ), and the second shaft ( 22 ) is radially supported in at least one further plain bearing ( 63 ). The plain bearing ( 61 ) has a bearing diameter (D 63 ), and the further plain bearing ( 63 ) has a further bearing diameter (D 63 ). During operation of the external gear pump ( 1 ), a delivery volume (V) of a working medium can be conveyed from the inlet ( 2 a ) to the outlet ( 2 b ). The two bearing diameters (D 61 , D 63 ) are selected in such a way that the ratio V/(D 61 2 *b) is less than 1.1 and the ratio V/(D 63 2 *b) is less than 1.1.

1 . An external gear pump ( 1 ) having a pump housing ( 2 ), wherein an inlet ( 2   a ), an outlet ( 2   b ), and a working chamber ( 6 ) are formed in the pump housing ( 2 ), wherein a first gear ( 11 ), which is arranged on a first shaft ( 21 ), and a second gear ( 12 ), which is arranged on a second shaft ( 22 ), are arranged in the working chamber ( 6 ) in such a way that said first and second gears mesh with each other, wherein both of the first and second gears ( 11 ,  12 ) have teeth having a tooth width (b), wherein the first shaft ( 21 ) is radially supported in at least one plain bearing ( 61 ), and wherein the second shaft ( 22 ) is radially supported in at least one further plain bearing ( 63 ), wherein the one plain bearing ( 61 ) has a first bearing diameter (D 61 ), and wherein the further plain bearing ( 63 ) has a further bearing diameter (D 63 ), wherein, during operation of the external gear pump ( 1 ), a delivery volume (V) of a working medium can be conveyed from the inlet ( 2   a ) to the outlet ( 2   b ),
 characterized in that the ratio V/(D 61   2 *b) is <1.1 and the ratio V/(D 63   2 *b) is <1.1.   
     
     
         2 . The external gear pump ( 1 ) as claimed in  claim 1 ,
 characterized in that   the ratio V/(D 61   2 *b) is >0.5 and the ratio V/(D 63   2 *b) is >0.5.   
     
     
         3 . The external gear pump ( 1 ) as claimed in  claim 1 ,
 characterized in that   the first bearing diameter D 61  and the further bearing diameter D 63  are equal.   
     
     
         4 . The external gear pump ( 1 ) as claimed in  claim 1 ,
 characterized in that   the first and second shafts ( 21 ,  22 ) are each radially supported in two plain bearings ( 61 ,  62 ,  63 ,  64 ), wherein, for each bearing diameter (D 61 , D 62 , D 63 , D 64 ): V/(D 2 *b)<1.1, where D={D 61 ; D 62 ; D 63 ; D 64 }.   
     
     
         5 . The external gear pump ( 1 ) as claimed in  claim 4 ,
 characterized in that   furthermore: D 61 =D 62 =D 63 =D 64 .   
     
     
         6 . An external gear pump ( 1 ) having a pump housing ( 2 ), wherein an inlet ( 2   a ), an outlet ( 2   b ), and a working chamber ( 6 ) are formed in the pump housing ( 2 ), wherein a first gear ( 11 ), which is arranged on a first shaft ( 21 ), and a second gear ( 12 ), which is arranged on a second shaft ( 22 ), are arranged in the working chamber ( 6 ) in such a way that said first and second gears mesh with each other, wherein the first gear ( 11 ) has a first tip diameter (DK 11 ) and the second gear ( 12 ) has a second tip diameter (DK 12 ), wherein the first shaft ( 21 ) is radially supported in at least one plain bearing ( 61 ) and wherein the second shaft ( 22 ) is radially supported in at least one further plain bearing ( 63 ), wherein the first and second shafts ( 21 ,  22 ) are arranged parallel with a center distance (a) with respect to each other, wherein the one plain bearing ( 61 ) has a first bearing diameter (D 61 ) and wherein the further plain bearing ( 63 ) has a further bearing diameter (D 63 ),
 characterized in that   the ratio (DK 11 *a)/D 61   2  is <2.5 and the ratio (DK 12 *a)/D 63   2  is <2.5.   
     
     
         7 . The external gear pump ( 1 ) as claimed in  claim 6 ,
 characterized in that   the ratio (DK 11 *a)/D 61   2  is >1.5 and in that the ratio (DK 12 *a)/D 63   2  is >1.5.   
     
     
         8 . The external gear pump ( 1 ) as claimed in  claim 6 ,
 characterized in that   the first bearing diameter D 61  and the further bearing diameter D 63  are equal.   
     
     
         9 . The external gear pump ( 1 ) as claimed in  claim 6 ,
 characterized in that   the first and second shafts ( 21 ,  22 ) are each radially supported in two plain bearings ( 61 ,  62 ,  63 ,  64 ), wherein, for each bearing diameter (D 61 , D 62 , D 63 , D 64 ): (DK*a)/D 2  is <2.5 where DK={DK 11 ; DK 12 } and where D={D 61 ; D 62 ; D 63 ; D 64 }.   
     
     
         10 . The external gear pump ( 1 ) as claimed in  claim 9 ,
 characterized in that   furthermore: D 61 =D 62 =D 63 =D 64 .   
     
     
         11 . A heat recovery system having a circuit that carries a working medium, wherein the circuit comprises a feed fluid pump, an evaporator, an expansion machine ( 104 ) and a condenser in the flow direction of the working medium,
 characterized in that   the feed fluid pump is embodied as an external gear pump ( 1 ) as claimed in  claim 1 .   
     
     
         12 . The external gear pump ( 1 ) as claimed in  claim 1 ,
 characterized in that   the ratio V/(D 61   2 *b) is >1.0 and the ratio V/(D 63   2 *b) is >1.0.   
     
     
         13 . The external gear pump ( 1 ) as claimed in  claim 6 ,
 characterized in that   the ratio (DK 11 *a)/D 61   2  is >2.0 and the ratio (DK 12 *a)/D 63   2  is >2.0.