Fuel pump

Abstract

Fuel pump ( 10 ) may comprise a casing ( 18 ) and a substantially disc-shaped impeller ( 20 ) rotating within the casing. A plurality of groups of concavities ( 20 a , 20 b ), arranged in concentric circles with respect to the rotational axis of the impeller, may be formed in at least one surface of the impeller. A plurality of grooves ( 24 a , 24 b , 24 c ) may be formed in the inner surface of the casing that faces the surface in which the groups of concavities are formed. Each groove extends from an upstream end to a downstream end. Fuel is drawn in from the outside of the casing to the upstream ends of each of the grooves ( 24 a , 24 b , 24 c ), and the fuel drawn into the casing is discharged to the outside of the casing from the downstream ends of each of the grooves ( 24 a , 24 b , 24 c ). Each of the plurality of grooves ( 24 a , 24 b , 24 c ) may face at least two or more of the plurality of groups of concavities ( 20 a , 20 b ) formed in the impeller.

1 . A fuel pump comprising a casing and a substantially disc-shaped impeller rotating within the casing, wherein 
 a plurality of groups of concavities arranged in concentric circles with respect to the rotational axis of the impeller are formed in at least one surface of the impeller,    a plurality of grooves are formed in the inner surface of the casing that faces the surface in which the groups of concavities are formed, each groove extending from an upstream end to a downstream end,    a intake hole and discharge hole are formed in the casing, the intake hole passing from the exterior of the casing to the upstream end of each groove, and the discharge hole passing from the exterior of the casing to the downstream end of each groove, and    each of the plurality of grooves comprises at least a first groove portion that faces one of the plurality of groups of concavities, a second groove portion that faces a group of concavities that is different from the group of concavities facing the first groove portion, and a third groove portion that links the first groove portion and the second groove portion.    
   
   
       2 . A fuel pump according to  claim 1 , wherein the length from the upstream end to the downstream end of each groove is substantially equal.  
   
   
       3 . A fuel pump according to  claim 2 , wherein the upstream end of each groove is arranged in a symmetrical position with respect to the rotational axis of the impeller, and the downstream end of each groove is arranged in a symmetrical position with respect to the rotational axis of the impeller.  
   
   
       4 . A fuel pump comprising a casing and a substantially disc-shaped impeller rotating within the casing, wherein 
 a plurality of groups of concavities arranged in concentric circles with respect to the rotational axis of the impeller are formed in at least one surface of the impeller,    a plurality of grooves are formed in the inner surface of the casing that faces the surface in which the groups of concavities are formed, each groove extending from an upstream end to a downstream end, and    each of the plurality of grooves formed in the inner surface of the casing face at least two or more of the plurality of groups of concavities formed in the impeller.