Multi Stage Diffuser Pump

Abstract

The object of the present invention is to provide a pump structure that can reduce a hydraulic force applied to a casing of a multi stage diffuser pump, which includes multiple stages of impellers fixed to a rotary shaft rotatably supported in the casing and multiple stages of guide vane diffusers and return blade passages fixed on the casing in correspondence with the multiple stages of impellers, thereby reducing the vibrations and noises of the pump. In a multi stage diffuser pump of the type which includes multiple stages of impellers fixed to the rotary shaft and multiple stages of guide vane diffusers and return blade passages fixed on circular disks in the casing in correspondence with the multiple stages of impellers, in the impellers of the two stages of front and rear stages, which are equivalent in the form and number of blades, the phases of positions in the peripheral direction of the blades of the impellers of at least one pair of front and rear stages are deviated from each other by 0.47 pitch or more and 0.53 pitch or less. With this, a hydraulic force in the axial direction applied to the casing can be reduced and hence the vibrations and noises of the pump can be reduced.

1 . In a multi stage diffuser pump of the type which includes a rotary shaft rotatably supported in a casing, multiple stages of impellers fixed to the rotary shaft, and multiple stages of guide vanes and return blades fixed to circular disks in the casing in correspondence with the multiple stages of impellers,
 wherein: the impellers are combinations of two stages of front and rear stages, which are equivalent in form and number of blades; and   phases of positions in a peripheral direction of the blades of the impellers of at least one pair of front and rear stages are deviated from each other by 0.5 pitch.   
   
   
       2 . The multi stage diffuser pump according to  claim 1 ,
 wherein the phases of positions in the peripheral direction of blades of the impellers of at least the one pair of front and rear stages are deviated from each other by 0.47 pitch or more and 0.53 pitch or less.   
   
   
       3 . The multi stage diffuser pump according to  claim 1 ,
 wherein the number of blades of the impeller is an even number.   
   
   
       4 . The multi stage diffuser pump according to  claim 1 ,
 wherein the number of blades of the impeller is an odd number.   
   
   
       5 . The multi stage diffuser pump according to  claim 1 ,
 wherein phases of positions in the peripheral direction of the guide vanes and the return blades fixed to the circular disks are made to be equivalent to each other for all of the stages.