Centrifugal Pump

Abstract

A centrifugal pump includes an impeller rotated about a rotational axis in a rotational direction by a motor and a housing defining a pump chamber therein. The impeller is housed in the pump chamber. The impeller includes a main plate having substantially circular shape and a first surface extending perpendicular to the rotational axis. The main plate is provided with a plurality of blades projecting axially from the first surface and extending radially along the first surface. Each of the blades has a radially inner blade part and a radially outer blade part extending radially outward from the radially inner blade part. Each of the outer blade parts has a front surface that extends from the main plate obliquely either frontward or rearward relative to the rotational direction.

What is claimed is: 
     
         1 . A centrifugal pump, comprising:
 an impeller configured to be rotated in a rotational direction about a rotational axis by a motor, wherein the impeller includes a main plate and a plurality of blades, wherein the main plate has a substantially circular shape and a first surface, wherein each of the blades extends axially from the first surface of the main plate and radially along the first surface of the main plate; and   a housing defining a pump chamber that houses the impeller therein, wherein the housing includes an inlet port configured to supply a fluid into the pump chamber axially toward a center of the first surface of the main plate and an outlet port configured to discharge the fluid in a tangential direction from the pump chamber, wherein:   each of the blades has a radially inner blade part and a radially outer blade part extending radially outward from the radially inner blade part, and   each of the radially outer blade parts has a front surface that extends from the main plate obliquely rearward relative to the rotational direction.   
     
     
         2 . The centrifugal pump of  claim 1 , wherein:
 an angle of the front surface of one of the radially outer blade parts relative to a straight line extending in parallel with the rotational axis is acute and continuously increases moving radially outward.   
     
     
         3 . The centrifugal pump of  claim 1 , wherein:
 one of the radially outer blade parts includes a radially outer end that is divided into a main plate side part adjacent to the main plate and an opposite side part positioned away from the main plate,   a reference line passes radially through both the rotational axis of the impeller and a radially inner end of the one of the radially outer blade parts,   the main plate side part is positioned in front of the reference line relative to the rotational direction, and   the opposite side part is positioned rearward of the reference line relative to the rotational direction.   
     
     
         4 . The centrifugal pump of  claim 1 , wherein:
 a thickness in the rotational direction of each of the radially outer blade parts continuously increases moving axially toward the first surface.   
     
     
         5 . The centrifugal pump of  claim 4 , wherein:
 each of the radially outer blade parts has a rear surface extending perpendicular to the main plate or extends obliquely rearward relative to the rotational direction.   
     
     
         6 . A centrifugal pump, comprising:
 an impeller configured to be rotated about a rotational axis in a rotational direction by a motor, wherein the impeller includes a main plate and a plurality of blades, wherein the main plate has a substantially circular shape and a first surface, wherein each of the blades projects axially from the first surface of the main plate and extends radially along the first surface of the main plate; and   a housing defining a pump chamber that houses the impeller therein, wherein the housing includes an inlet port configured to supply a fluid into the pump chamber axially toward a center of the first surface of the main plate and an outlet port configured to discharge the fluid from the pump chamber in a tangential direction, wherein:   each of the blades has a radially inner blade part and a radially outer blade part that extends radially outward from the radially inner blade part, and   each of the radially outer blade parts has a front surface that extends from the main plate obliquely frontward relative to the rotational direction.   
     
     
         7 . The centrifugal pump of  claim 6 , wherein:
 an angle of the front surface of one of the radially outer blade parts relative to a straight line extending in parallel with the rotational axis is acute and continuously increases moving radially outward.   
     
     
         8 . The centrifugal pump of  claim 6 , wherein:
 one of the radially outer blade parts includes a radially outer end having a main plate side part adjacent to the main plate and an opposite side part positioned away from the main plate,   a reference line passes radially through both the rotational axis of the impeller and a radially inner end of the one of the radially outer blade parts,   the main plate side part is positioned rearward of the reference line relative to the rotational direction, and   the opposite side part is positioned in front of the reference line relative to the rotational direction.   
     
     
         9 . The centrifugal pump of  claim 6 , wherein:
 a thickness in the rotational direction of each of the radially outer blade parts continuously increases moving axially toward the first surface.   
     
     
         10 . The centrifugal pump of  claim 9 , wherein:
 an outer periphery of the main plate is curved radially inward between a pair of circumferentially adjacent blades to define an opening along the outer periphery of the main plate, and   the front surface of the radially outer blade part of a rear one of the pair of circumferentially adjacent blades relative to the rotational direction faces the opening.