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A fluid pump may include an electric motor having an output shaft driven for rotation about an axis and a pump assembly coupled to the output shaft. The pump assembly has a first cap and a second cap with at least one pumping channel defined between the first and second caps, and an impeller between

A fluid pump may include an electric motor having an output shaft driven for rotation about an axis and a pump assembly coupled to the output shaft. The pump assembly has a first cap and a second cap with at least one pumping channel defined between the first and second caps, and an impeller between the first and second caps. The impeller is driven for rotation by the output shaft of the motor and includes a plurality of vanes in communication with the at least one pumping channel. Each vane has a root segment and a tip segment and a line from a base of the root segment to an outer edge of the tip segment trails a line extending from the axis of rotation to the base of the root segment by an angle of between 0° and 30° relative to the direction of rotation of the impeller.

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1. A fluid pump, comprising: an electric motor having an output shaft driven for rotation about an axis;a pump assembly coupled to the output shaft of the motor and having: a first cap and a second cap with at least one pumping channel defined between the first cap and the second cap, andan impeller

1. A fluid pump, comprising: an electric motor having an output shaft driven for rotation about an axis;a pump assembly coupled to the output shaft of the motor and having: a first cap and a second cap with at least one pumping channel defined between the first cap and the second cap, andan impeller received between the first cap and the second cap, wherein the impeller has a hub and a hoop, is driven for rotation by the output shaft of the motor and the impeller includes a plurality of vanes disposed between the hub and the hoop and in communication with said at least one pumping channel, each vane has a leading face with a root segment and a curved tip segment and the root segment extends between 10% and 50% of the radial length of each vane;the leading face of each vane is configured so that a line from a base of the root segment to an outer edge of the tip segment trails a line extending from the axis of rotation to the base of the root segment by a first angle of between 0° and −30° relative to the direction of rotation of the impeller;the leading face of each vane is also configured so that a line extending from the base of the root segment to the outer end of the root segment is inclined relative to a line extending from the axis of rotation to the base of the root segment by between −20° and 10° relative to the direction of rotation of the impeller;the leading face of each vane is also configured so that a line extending from a radial mid-point of the vane to a radially outer edge of the vane is inclined relative to a line extending from the axis of rotation to the radial mid-point of the vane by between −5° and −45° relative to the direction of rotation of the impeller;the leading face of each vane is curved from at least the radial mid-point to the tip of such leading face; andthe leading face of each vane is also configured so that the tip segment is inclined rearwardly to a greater extent than the root segment relative to the direction of rotation of the impeller. 2. The fluid pump of claim 1 wherein each vane has an upper portion extending from an upper face of the impeller to an axial mid-point of the vane and a lower portion extending from the axial mid-point of the vane to a lower face of the impeller, and the transition from the upper portion to the lower portion along the leading face of the vane is radiused providing a generally u-shaped leading face of the vane in cross section. 3. The fluid pump of claim 2 wherein each vane also has a trailing face and the radius is between 90% less than to 50% greater than the minimum spacing between the trailing face of a vane and the leading face of an immediately circumferentially adjacent trailing vane, along the axial length of these faces of these adjacent vanes. 4. The fluid pump of claim 1 wherein the first cap includes an inlet passage through which fuel is admitted to the pumping channel and an entrance portion of the pumping channel, and the entrance portion of the pumping channel is disposed at an angle of between 0 and 30 degrees relative to an internal surface of the first cap and facing the impeller. 5. The fluid pump of claim 4 wherein the entrance portion is disposed at angle of between 13 and 14 degrees. 6. The fluid pump of claim 4 wherein the inlet passage is formed in both the first and second caps, and an upstream edge of the inlet passage at a face of the first cap confronting the impeller is aligned with an upstream edge of the inlet passage at a face of the second cap confronting the impeller so that a line through these upstream edges is parallel to the axis of rotation of the impeller. 7. The fluid pump of claim 4 which also includes an outlet passage from which fuel is discharged from the pumping channel, a downstream edge of the outlet passage at a face of the first cap confronting the impeller and a downstream edge of the outlet passage at a face of the second cap confronting the impeller and these downstream edges of the outlet passage are circumferentially offset by an angle between 0 degrees to 20 degrees, where the angle is measured between two lines each extending radially from the axis of rotation of the impeller and through a respective one of these downstream edges. 8. The fluid pump of claim 7 wherein the angle of the circumferential offset is between 3 to 5 degrees. 9. The fluid pump of claim 4 wherein an upstream edge of the inlet passage at a face of the first cap confronting the impeller and an upstream edge of the inlet passage at a face of the second cap confronting the impeller are circumferentially offset from a downstream edge of the outlet passage at a face of the second cap confronting the impeller by an angle with its vertex on the axis of rotation of the impeller by between 10 and 25 degrees. 10. The fluid pump of claim 9 wherein the circumferential offset is between 22 and 24 degrees. 11. The fluid pump of claim 1 wherein the first cap includes an inlet passage through which fuel is admitted to the pumping channel and the inlet passage has an entrance portion directly adjacent to the pumping channel, and an angle greater than 109 degrees is formed between the entrance portion of a pumping channel and a lower half of a vane disposed in the pumping channel. 12. The fluid pump of claim 11 which includes an inner pumping channel and an outer pumping channel, and the impeller includes an inner array of vanes located in the inner pumping channel and an outer array of vanes located in the outer pumping channel, and the angle between the entrance portion of the inner pumping channel and a lower half of a vane in the inner array of vanes is between 110 and 120 degrees. 13. The fluid pump of claim 11 which includes an inner pumping channel and an outer pumping channel, and the impeller includes an inner array of vanes located in the inner pumping channel and an outer array of vanes located in the outer pumping channel, and the angle between the entrance portion of the outer pumping channel and a lower half of a vane in the outer array of vanes is between 110 and 125 degrees. 14. The fluid pump of claim 1 which includes an inner pumping channel and an outer pumping channel, and the impeller includes an inner array of vanes located in the inner pumping channel and an outer array of vanes located in the outer pumping channel, and the ratio of the axial extent of each inner vane to the axial extent of the inner pumping channel is less than 0.6. 15. The fluid pump of claim 1 which includes an inner pumping channel and an outer pumping channel, and the impeller includes an inner array of vanes located in the inner pumping channel and an outer array of vanes located in the outer pumping channel, and the ratio of the axial extent of each outer vane to the axial extent of the outer pumping channel is greater than 0.76. 16. An impeller for a fluid pump, comprising: a hub having an opening adapted to receive a shaft that drives the impeller for rotation, a mid-hoop spaced radially from the hub and an outer hoop spaced radially from the mid-hoop;an inner array of vanes located radially outwardly of the hub and inwardly of the mid-hoop; andan outer array of vanes located between the mid-hoop and the outer hoop, both the inner array of vanes and the outer array of vanes configured to communicate with a single common fluid inlet and a single common fluid outlet,each vane in the inner array and the outer array has a leading face and a trailing face spaced circumferentially behind the leading face relative to the intended direction of rotation of the impeller, each vane has a root segment and a curved tip segment extending generally radially outwardly from the root segment, and the root segment extends between 10% and 50% of the radial length of each vane;the leading face of each vane is configured so that a line from a base of the root segment to an outer edge of the tip segment trails a line extending from the axis of rotation to the base of the root segment by a first angle of between 0° and −30°, relative to the direction of rotation of the impeller;the leading face of each vane is also configured so that a line extending from a radial mid-point of the vane to a radially outer edge of the vane is inclined relative to a line extending from the axis of rotation to the radial mid-point of the vane by a second angle of between −5° and −45° relative to the direction of rotation of the impeller; andthe leading face of each vane is also configured so that a line extending from the base of the root segment to the outer end of the root segment is inclined relative to a line extending from the axis of rotation to the base of the root segment by a third angle of between −20° and 10° relative to the direction of rotation of the impeller;the leading face of each vane is curved from at least the radial mid-point to the tip of such leading face; andthe leading face of each vane is also configured so that the tip segment is inclined rearwardly to a greater extent than the root segment relative to the direction of intended rotation of the impeller. 17. The impeller of claim 16 wherein each vane has an upper portion extending from an upper face of the impeller to an axial mid-point of the vane and a lower portion extending from the axial mid-point of the vane to a lower face of the impeller, and the transition from the upper portion to the lower portion along the leading face of the vane is radiused providing a generally u-shaped leading face of the vane in cross section. 18. The impeller of claim 17 wherein the leading face of each vane has a radius between the upper portion and the lower portion and the radius is between 90% less than to 50% greater than the minimum spacing between the trailing face of a vane and the leading face of an immediately circumferentially adjacent trailing vane, along the axial length of these faces of these adjacent vanes. 19. The impeller of claim 16 wherein each vane is generally v-shaped in cross-section with ends adjacent to each axial face of the impeller leading an axial mid-point of each vane relative to the direction of rotation of the impeller. 20. The impeller of claim 16 wherein each vane has an axial midpoint between axially spaced faces of the impeller, an upper half of each vane defined from an upper face of the impeller to the midpoint and a lower half of each vane defined between the lower face of the impeller to the midpoint, and the upper and lower halves of each vane are configured to define an angle between them of 60 to 30 degrees. 21. The impeller of claim 16 wherein the first angle is between −12 and −30 degrees relative to the intended direction of rotation of the impeller. 22. The method of making a fluid pump impeller, comprising: forming an impeller having a plurality of vanes in axially opposed faces and adapted to be rotated about an axis,forming a body that defines a radially outer sidewall of an impeller cavity in which the impeller rotates, the body having at least one generally axial face;positioning the impeller and the body so that one axial face of each may be machined at substantially the same time; andmachining one axial face of the impeller and the body while so positioned and at substantially the same time to provide a similar axial thickness of the outer sidewall of the body and of the impeller. 23. The method of claim 22 wherein the resulting difference in the axial thickness between the impeller and the sidewall is 10 microns or less. 24. The method of claim 22 wherein the impeller is received between first and second caps in use and the body is an annular ring that is formed separately from the first and second caps. 25. The method of claim 22 wherein the impeller is received between first and second caps in use and the body is an annular flange that is formed in one piece with one of the first or second caps. 26. The method of claim 22 further comprising positioning the impeller radially inwardly of the outer sidewall at least while machining the one axial face of the impeller and the outer sidewall of the body to provide the similar axial thickness of both the outer sidewall and the impeller. 27. The method of claim 26 wherein the resulting difference in the axial thickness between the impeller and the sidewall is 10 microns or less. 28. The method of claim 26 wherein the impeller is received between first and second caps in use and the body is an annular ring that is formed separately from the first and second caps. 29. The method of claim 26 wherein the impeller is received between first and second caps in use and the body is an annular flange that is formed in one piece with one of the first or second caps.