Regenerative pump

Abstract

A regenerative pump includes a casing having a fluid passage connecting an inlet with an outlet. An impeller has vanes faced to the fluid passage that includes an arc passage. An outlet passage communicates with the outlet. The outlet passage is substantially constant in cross sectional area. A communication passage connects the arc passage with the outlet passage. The casing has an inner wall that defines the communication passage. The inner wall is in a curved shape in an axial section that includes a center axis of the communication passage and extends along a center axis of the casing. The center axis of the communication passage and the outer circular profile of the impeller define an intersection therebetween. The communication passage has a vertical section, which includes the intersection, being perpendicular to the center axis of the communication passage. The inner wall reduces a crosssectional area of the communication passage in the vertical section.

1 . A regenerative pump comprising: 
 a casing that has an inlet and an outlet, the casing defining a fluid passage that is in a substantially arc shape connecting the inlet with the outlet; and    an impeller that is rotatable in the casing, the impeller having a plurality of vanes each having a radial end defining an outer circular profile of the impeller, the plurality of vanes being faced to the fluid passage,    wherein the fluid passage includes an arc passage, an outlet passage, and a communication passage,    the arc passage is in a substantially arc shape along a circumferential direction of the casing through a predetermined angular range,    the outlet passage communicates with the outlet, and has a cross sectional area that is substantially constant with respect to a flow direction of fluid,    the communication passage connects the arc passage with the outlet passage, the casing has an inner wall that defines the communication passage,    the inner wall is in a substantially curved shape in an axial section that includes a center axis of the communication passage and extends along a center axis of the casing,    the center axis of the communication passage and the outer circular profile of the impeller define an intersection therebetween,    the communication passage has a vertical section, which includes the intersection, being perpendicular to the center axis of the communication passage, and    the inner wall reduces a cross-sectional area of the communication passage by extending through the vertical section.    
   
   
       2 . The regenerative pump according to  claim 1 , wherein the inner wall defining the communication passage is in an arc shape.  
   
   
       3 . The regenerative pump according to  claim 1 , wherein the inner wall defining the communication passage is in a cycloid curved shape.  
   
   
       4 . The regenerative pump according to  claim 1 , wherein the inner wall defining the communication passage is in a parabolic curved shape.  
   
   
       5 . A regenerative pump comprising: 
 a casing that has an inlet and an outlet, the casing defining a fluid passage that is in a substantially arc shape connecting the inlet with the outlet; and    an impeller that is rotatable in the casing, the impeller having a plurality of vanes each having a radial end defining an outer circular profile of the impeller, the plurality of vanes being faced to the fluid passage,    wherein the fluid passage includes an arc passage, an outlet passage, and a communication passage,    the arc passage is in a substantially arc shape along a circumferential direction of the casing through a predetermined angular range,    the outlet passage communicates with the outlet, and has a cross sectional area that is substantially constant with respect to a flow direction of fluid,    the communication passage connects the arc passage with the outlet passage, the casing has an inner wall that defines the communication passage,    the inner wall is in a substantially curved shape on a radially outer side in an axial section that includes a center axis of the communication passage and extends perpendicularly to a center axis of the casing,    the center axis of the communication passage and the outer circular profile of the impeller define an intersection therebetween,    the communication passage has a vertical section, which includes the intersection, being perpendicular to the center axis of the communication passage, and    the inner wall reduces a crosssectional area of the communication passage by extending through the vertical section.    
   
   
       6 . The regenerative pump according to  claim 5 , wherein the inner wall defining the communication passage is in an arc shape.  
   
   
       7 . The regenerative pump according to  claim 5 , wherein the inner wall defining the communication passage is in a cycloid curved shape.  
   
   
       8 . The regenerative pump according to  claim 5 , wherein the inner wall defining the communication passage is in a parabolic curved shape.  
   
   
       9 . A regenerative pump comprising: 
 a casing that has an inlet communicating with an outlet through an arc passage, a communication passage, and an outlet passage, the arc passage extending from the inlet circumferentially in the casing, the communication passage connecting the arc passage with the outlet passage, the outlet passage communicating with the outlet, and having a cross sectional area that is substantially constant with respect to a flow direction of fluid; and    an impeller that is rotatable in the casing, the impeller having a plurality of vanes each having a radial end defining an outer circular profile of the impeller, the plurality of vanes being faced to the fluid passage,    wherein the communication passage has a center axis extending substantially along the flow direction,    the center axis of the communication passage and the outer circular profile of the impeller define an intersection therebetween,    the communication passage has a vertical section, which includes the intersection, being perpendicular to the center axis of the communication passage,    the casing has an inner wall that defines the communication passage,    the communication passage has a height when being viewed from an axial section that includes the center axis of the communication passage and extends along a center axis of the casing, and    the inner wall is curved to reduce the height of the communication passage by extending through the vertical section.    
   
   
       10 . A regenerative pump comprising: 
 a casing that has an inlet communicating with an outlet through an arc passage, a communication passage, and an outlet passage, the arc passage extending from the inlet circumferentially in the casing, the communication passage connecting the arc passage with the outlet passage, the outlet passage communicating with the outlet, and having a cross sectional area that is substantially constant with respect to a flow direction of fluid; and    an impeller that is rotatable in the casing, the impeller having a plurality of vanes each having a radial end defining an outer circular profile of the impeller, the plurality of vanes being faced to the fluid passage,    wherein the communication passage has a center axis extending substantially along the flow direction,    the center axis of the communication passage and the outer circular profile of the impeller define an intersection therebetween,    the communication passage has a vertical section, which includes the intersection, being perpendicular to the center axis of the communication passage,    the casing has an inner wall that defines the communication passage,    the inner wall is in a substantially curved shape on a radially outer side when being viewed from an axial section that includes a center axis of the communication passage and extends perpendicularly to a center axis of the casing, and    the inner wall is curved to reduce the cross sectional area of the communication passage by extending through the vertical section.