Sliding vane pump or turbine having track followers

1 . A positive-displacement pump or turbine comprising:

a rotor casing defining a rotor chamber having a contoured wall forming a plurality of lobes around a central axis, and a pair of sidewalls defining respective curved tracks spaced radially inwardly from said contoured wall, said curved tracks each comprising a groove formed in a respective one of said sidewalls;

a rotor positioned in said rotor chamber and having a rotational axis at said central axis, said rotor having a cylindrical outer rotor surface spaced inwardly from said contoured wall at said lobes, said rotor defining a plurality of blind slots open at said outer rotor surface and each having a continuous slot width extending from proximate said outer rotor surface to proximate a blind inboard end;

a plurality of vanes mounted at said rotor and spaced circumferentially around said outer rotor surface, said vanes comprising (i) distal ends configured to slidably engage said contoured wall along the width of said contoured wall including said plurality of lobes, (ii) proximal ends received in respective ones of said blind slots in said rotor, and (iii) recessed dimples formed in opposite side edges of said vanes, said recessed dimples spaced between said distal and proximal ends of said vanes; and

track followers engaging said curved tracks, said track followers comprising balls captured between said grooves and respective ones of said recessed dimples;

wherein each of said balls has a diameter not exceeding a thickness of a respective one of said vanes at said recessed dimple;

wherein said vanes are forced radially inwardly and outwardly relative to said rotor by engagement of said track followers with said curved tracks during rotation of said rotor and said vanes; and

wherein said curved tracks are spaced a uniform distance from said contoured wall including said plurality of lobes around said rotor chamber.

2 . The pump or turbine of claim 1 , wherein said grooves each comprise a semi-circular cross-sectional shape and said recessed dimples comprise semi-spherical shapes.

3 . The pump or turbine of claim 2 , wherein said balls are spherical and slide or roll along said groove so that said recessed dimples maintain alignment with said groove during rotation of said rotor and said vanes.

4 . The pump or turbine of claim 3 , wherein about one-half of each of said balls is contained within one of said dimples and the other half is contained in said groove.

5 . The pump or turbine of claim 1 , wherein said rotor casing comprises an opposite sidewall defining an opposite track, and each of said vanes comprises a pair of said track followers arranged at respective opposite sides of said vanes, wherein said track followers engage respective ones of said tracks.

6 . The pump or turbine of claim 5 , wherein said tracks are identically-shaped and aligned with one another at opposite sides of said rotor chamber.

7 . A pump or turbine comprising:

a rotor casing comprising a contoured wall including a lobe, and spaced-apart side surfaces defining respective continuous grooves that are spaced inwardly from said contoured wall, said contoured wall cooperating with said side surfaces to define a non-circular rotor chamber having a central axis;

a rotor positioned in said rotor chamber and having a rotational axis at said central axis, said rotor defining a plurality of blind slots open at a cylindrical outer rotor surface, each of said blind slots having a continuous slot width extending from proximate said outer rotor surface to proximate a blind inboard end; and

a plurality of vanes at respective ones of said blind slots of said rotor, each of said vanes comprising a radial locator, opposite edges, and a distal end configured to slidably engage said contoured wall along the width of said contoured wall including said plurality of lobes;

wherein said radial locator comprises a pair of balls configured to follow respective ones of said grooves to drive said vane radially inwardly and outwardly in response to rotation of said rotor;

wherein each of said balls has a diameter not exceeding a thickness of a respective one of said vanes at each of said balls; and

wherein said side surfaces of said rotor casing cooperate with said opposite edges of said vane to form fluid-tight barriers, and said distal end of said vane forms a fluid-tight barrier with said contoured wall including said lobe.

8 . The pump or turbine of claim 7 , wherein said radial locator comprises a dimple formed in each of two opposite edges of said vane, wherein one of said balls is captured between each of said dimples and a respective one of said grooves.

9 . The pump or turbine of claim 7 , wherein said radial locator maintains said distal end in continuous sliding contact with said contoured wall including said lobe when said rotor is rotating.

10 . The pump or turbine of claim 7 , wherein said contoured wall includes exactly four of said lobes, said contoured wall defining an inlet port and an outlet port at each of said lobes, and wherein said pump or turbine comprises exactly thirteen of said vanes spaced evenly along said outer rotor surface.

11 . A method of operating a positive-displacement pump or turbine, said method comprising:

rotatably driving a pump or turbine rotor located within a rotor chamber, the rotor having a rotational axis at a central axis of the rotor chamber, the rotor having a plurality of vanes mounted at respective blind slots formed in cylindrical outer rotor surface thereof, the blind slots each having a continuous slot width extending from proximate the outer rotor surface to proximate a blind inboard end, the vanes having track followers, the track followers having a thickness not exceeding a thickness of the vanes at the track followers; and

urging the vanes radially inwardly and outwardly via engagement of the track followers with a curved track formed in a sidewall of the rotor chamber to maintain distal ends of the vanes in sliding engagement with a contoured wall of the rotor chamber along the width of the contoured wall, the contoured wall including a lobe;

wherein the curved track is spaced a fixed distance from the contoured wall including the lobe.

12 . The method of claim 11 , wherein said urging the vanes radially inwardly and outwardly comprises driving the track followers in the form of balls associated with each of the vanes along a groove that forms the curved track.

13 . The method of claim 12 , wherein each of the vanes defines a recessed dimple, and wherein each of the balls are captured between the groove and respective ones of the recessed dimples.

14 . The method of claim 13 , wherein the groove has a semi-circular cross-sectional shape and the recessed dimples each have a semi-spherical shape.

15 . The method of claim 14 , wherein the balls are spherical and slide or roll along the groove so that the recessed dimples maintain alignment with the groove during rotation of the rotor and the vanes.

16 . The method of claim 15 , wherein about one-half of each of the balls is contained within one of the recessed dimples and the other half is contained in the groove.