Centrifugal pump

Abstract

A centrifugal pump has at least one impeller, a pump housing and an electrical motor. The pump has a Q-H pump curve having a head H 0 at zero flow and a head H ref corresponding to the highest hydraulic power, and that H ref is greater than H 0 . The pump has low energy consumption rate, especially at low flow corresponding to the conditions in which the pump is operated most of the time. Thus, the pump according to the invention is less energy consuming than the prior art centrifugal pumps.

1 .- 12 . (canceled) 
     
     
         13 . A centrifugal type circulator pump comprising at least one impeller ( 32 ), a pump housing and an electrical motor, where the pump has a Q-H pump curve ( 4 ) having a head n 0  ( 28 ) at zero flow and a head, H ref  ( 30 ), corresponding to the highest hydraulic power, wherein H ref  ( 30 ) is greater than H 0  ( 28 ). 
     
     
         14 . The centrifugal pump according to  claim 13 , wherein the at least one impeller ( 32 ) comprises impeller blades ( 34 ) that are shaped in a manner so that that H ref  ( 30 ) is greater than H 0  ( 28 ). 
     
     
         15 . The centrifugal pump according to  claim 13 , wherein a first part ( 8 ) of the Q-H curve ( 4 ) is an increasing function of a flow ( 6 ). 
     
     
         16 . The centrifugal pump according to  claim 13  wherein a last part ( 10 ) of the Q-H curve ( 4 ) is a decreasing function of a flow ( 6 ). 
     
     
         17 . The centrifugal pump according to  claim 13  wherein the pump housing and/or the impeller ( 32 ) is configured to introduce a flow restriction that causes an end part ( 10 ) of the Q-H curve ( 4  ) to be a decreasing function of a flow ( 6 ). 
     
     
         18 . The centrifugal pump according to  claim 13 , wherein the impeller ( 32 ) has forward swept blades ( 34 ). 
     
     
         19 . The centrifugal pump according to  claim 13 , wherein the motor is a synchronous motor. 
     
     
         20 . The centrifugal pump according to  claim 13 , wherein the centrifugal pump is a wet-runner type pump. 
     
     
         21 . The centrifugal pump according to  claim 13 , wherein the motor is a line start permanent magnet motor. 
     
     
         22 . The centrifugal pump according to  claim 14 , wherein the impeller blades ( 34 ) are arced and distributed symmetrically along a periphery of an impeller plate ( 48 ). 
     
     
         23 . The centrifugal pump according to  claim 13 , wherein the impeller ( 32 ) comprises a first set of impeller blades ( 34 ) and a second set of impeller blades ( 35 ), where the first set of impeller blades ( 34 ) are longer than the second set of impeller blades ( 35 ) and where the first set of impeller blades ( 34 ) and the second set of impeller blades ( 35 ) are distributed alternately along a periphery of an impeller plate ( 48 ). 
     
     
         24 . The centrifugal pump according to  claim 13  wherein (⅔)·H ref ≧H 0 . 
     
     
         25 . The centrifugal pump according to  claim 13 , wherein (⅗) H ref ≧H 0 .