Fluid pump

1. A piston pump, comprising:

a housing;

a rotor assembly rotatably disposed in the housing,

the rotor assembly comprising:

a rotor;

a pumping chamber disposed in the rotor;

a piston slidably disposed within the pumping chamber and movable between a first position and a second position therein;

the housing comprising:

a first housing inlet and a second housing inlet selectively fluidly communicating with the pumping chamber;

a first housing outlet and a second housing outlet selectively fluidly communicating with the pumping chamber;

an inlet cam assembly fixedly disposed in the housing, the inlet cam assembly having first and second inlet cam lobes operative to move the piston to the first position; and

an outlet cam assembly fixedly disposed in the housing, the outlet cam assembly having first and second outlet cam lobes operative to move the piston to the second position;

the rotor being rotatable sequentially between first, second, third and fourth positions relative to the housing,

wherein when the rotor is in the first position,

the pumping chamber is in fluid communication with the first housing inlet and in fluid isolation from the second housing inlet and from the first and second housing outlets; and

the first inlet cam lobe urges the piston toward the first position to draw fluid into the pumping chamber via the first housing inlet;

wherein when the rotor is in the second position,

the pumping chamber is in fluid communication with the first housing outlet and in fluid isolation from the first and second housing inlets and from the second housing outlet; and

the first outlet cam lobe urges the piston to the second position to expel fluid out of the pumping chamber via the first housing outlet;

wherein when the rotor is in the third position,

the pumping chamber is in fluid communication with the second housing inlet and in fluid isolation from the first housing inlet and from the first and second housing outlets; and

the second inlet cam lobe urges the piston toward the first position to draw fluid into the pumping chamber via the second housing inlet; and

wherein when the rotor is in the fourth position,

the pumping chamber is in fluid communication with the second housing outlet and in fluid isolation from the first housing outlet and the first and second housing inlets; and

the second outlet cam lobe urges the piston to the second position to expel fluid out of the pumping chamber via the second housing outlet.

2. The piston pump of claim 1 , wherein the housing is generally symmetric about a central longitudinal axis of symmetry.

3. The piston pump of claim 2 , wherein the rotor is rotatable about the central longitudinal axis of symmetry.

4. The piston pump of claim 3 , wherein:

the inlet cam assembly is centered about the central longitudinal axis of symmetry.

5. The piston pump of claim 4 , wherein:

the outlet cam assembly is centered about the central longitudinal axis of symmetry.

6. The piston pump of claim 1 , wherein:

the housing further comprises a third housing inlet selectively fluidly communicating with the pumping chamber and a third housing outlet selectively fluidly communicating with the pumping chamber;

the inlet cam assembly further comprises a third inlet cam lobe;

the outlet cam assembly further comprises a third outlet cam lobe; and

when the rotor is in the first, second third and fourth positions, the pumping chamber is in fluid isolation from the third housing inlet and the third housing outlet;

the rotor being further rotatable between fifth and sixth positions relative to the housing,

wherein when the rotor is in the fifth position,

the pumping chamber is in fluid communication with the third housing inlet and in fluid isolation from the first and second housing inlets and from the first, second and third housing outlets; and

the third inlet cam lobe urges the piston toward the first position to draw fluid into the pumping chamber via the third housing inlet;

wherein when the rotor is in the sixth position,

the pumping chamber is in fluid communication with the third housing outlet and in fluid isolation from the first, second and third housing inlets and from the first and second housing outlets; and

the third outlet cam lobe urges the piston to the second position to expel fluid out of the pumping chamber via the third housing outlet.

7. The piston pump of claim 1 , wherein:

the pumping chamber is a first pumping chamber;

the piston is a first piston;

the chamber inlet is a first chamber inlet;

the chamber outlet is a first chamber outlet;

the rotor further comprising:

a second pumping chamber disposed in the rotor;

a second piston slidably disposed within the second pumping chamber and movable between a first position and a second position therein;

the housing further comprising:

a third housing inlet and a fourth housing inlet selectively fluidly communicating with the second pumping chamber;

a third housing outlet and a fourth housing outlet selectively fluidly communicating with the second pumping chamber;

the rotor being further rotatable between fifth, sixth, seventh and eighth positions relative to the housing;

wherein when the rotor is in the fifth position,

the second pumping chamber is in fluid communication with the third housing inlet and in fluid isolation from the fourth housing inlet and from the third and fourth housing outlets; and

the first inlet cam lobe urges the second piston toward the first position to draw fluid into the second pumping chamber via the third housing inlet;

wherein when the rotor is in the sixth position,

the second pumping chamber is in fluid communication with the third housing outlet and in fluid isolation from the third and fourth housing inlets and from the fourth housing outlet; and

the first outlet cam lobe urges the second piston to the second position to expel fluid out of the second pumping chamber via the third housing outlet;

wherein when the rotor is in the seventh position,

the second pumping chamber is in fluid communication with the fourth housing inlet and in fluid isolation from the third housing inlet and from the third and fourth housing outlets; and

the second inlet cam lobe urges the second piston toward the first position to draw fluid into the second pumping chamber via the fourth housing inlet; and

wherein when the rotor is in the eighth position,

the second pumping chamber is in fluid communication with the fourth housing outlet and in fluid isolation from the third housing outlet and the third and fourth housing inlets; and

the second outlet cam lobe urges the second piston to the second position to expel fluid out of the second pumping chamber via the fourth housing outlet.

8. The piston pump of claim 7 , wherein:

the third housing inlet is the first housing inlet; and

the fourth housing inlet is the second housing inlet.

9. The piston pump of claim 7 , wherein:

the fifth position is the first position;

the sixth position is the second position;

the seventh position is the third position; and

the eighth position is the fourth position.

10. A method of distributing fluid via a pump having:

a housing;

a rotor rotatably disposed within the housing;

the rotor having:

a pumping chamber disposed therein; and

a piston slidably disposed within the pumping chamber;

the housing having:

a first housing inlet and a second housing inlet selectively fluidly communicating with the pumping chamber, and

a first housing outlet and a second housing outlet selectively fluidly communicating with the pumping chamber;

an inlet cam assembly fixedly disposed in the housing, the inlet cam assembly having first and second inlet cam lobes; and

an outlet cam assembly fixedly disposed in the housing, the outlet cam assembly having first and second outlet cam lobes;

the method comprising:

rotating the rotor to a first position providing:

fluid communication between the pumping chamber and the first housing inlet;

fluid isolation between the pumping chamber and the second housing inlet;

fluid isolation between the pumping chamber and the first and second housing outlets; and

actuation of the piston by the first inlet cam lobe to draw fluid into the pumping chamber via the first housing inlet;

rotating the rotor to a second position providing:

fluid communication between the pumping chamber and the first housing outlet;

fluid isolation between the pumping chamber and the second housing outlet;

fluid isolation between the pumping chamber and the first and second housing inlets; and

actuation of the piston by the first outlet cam lobe to expel fluid out of the pumping chamber via the first housing outlet;

rotating the rotor to a third position providing:

fluid communication between the pumping chamber and the second housing inlet;

fluid isolation between the pumping chamber and the first housing inlet;

fluid isolation between the pumping chamber and the first and second housing outlets; and

actuation of the piston by the second inlet cam lobe to draw fluid into the pumping chamber via the second housing inlet; and

rotating the rotor to a fourth position providing:

fluid communication between the pumping chamber and the second housing outlet;

fluid isolation between the pumping chamber and the first housing outlet;

fluid isolation between the pumping chamber and the first and second housing inlets; and

actuation of the piston by the second outlet cam lobe to expel fluid out of the pumping chamber via the first housing outlet.

11. The method of claim 10 , wherein:

the housing is generally symmetric about a central longitudinal axis of symmetry; and

rotating the rotor comprises rotating the rotor about an axis coaxial with the central longitudinal axis of symmetry.

12. The method of claim 10 , wherein

the housing further comprises a third housing inlet selectively fluidly communicating with the pumping chamber and a third housing outlet selectively fluidly communicating with the pumping chamber;

the inlet cam assembly further comprises a third inlet cam lobe; and

the outlet cam assembly further comprises a third outlet cam lobe;

rotating the rotor to any of the first, second, third and fourth positions further providing fluid isolation from the third housing inlet and the third housing outlet;

the method further comprising:

rotating the rotor to a fifth position providing:

fluid communication between the pumping chamber and the third housing inlet;

fluid isolation between the pumping chamber and the first and second housing inlets;

fluid isolation between the pumping chamber and the first, second and third housing outlets; and

actuation of the piston by the third inlet cam lobe to draw fluid into the pumping chamber via the third housing inlet; and

rotating the rotor to a sixth position providing:

fluid communication between the pumping chamber and the third housing outlet;

fluid isolation between the pumping chamber and the first and second housing outlet;

fluid isolation between the pumping chamber and the first, second and third housing inlets; and

actuation of the piston by the third outlet cam lobe to expel fluid out of the pumping chamber via the third housing outlet.

13. The method of claim 10 , wherein:

the pumping chamber is a first pumping chamber;

the piston is a first piston;

the chamber inlet is a first chamber inlet;

the chamber outlet is a first chamber outlet;

the rotor further comprising:

a second pumping chamber disposed therein;

a second piston slidably disposed within the second pumping chamber;

the housing further comprising:

a third housing inlet and a fourth housing inlet selectively fluidly communicating with the second pumping chamber;

a third housing outlet and a fourth housing outlet selectively fluidly communicating with the second pumping chamber;

the method further comprising:

rotating the rotor to a fifth position providing:

fluid communication between the second pumping chamber and the third housing inlet;

fluid isolation between the second pumping chamber and the fourth housing inlet;

fluid isolation between the second pumping chamber and the third and fourth housing outlets; and

actuation of the second piston to draw fluid into the second pumping chamber via the third housing inlet;

rotating the rotor to a sixth position providing:

fluid communication between the second pumping chamber and the third housing outlet;

fluid isolation between the second pumping chamber and the third and fourth housing inlets;

fluid isolation between the second pumping chamber and the fourth housing outlet; and

actuation of the second piston to expel fluid out of the second pumping chamber via the third housing outlet;

rotating the rotor to a seventh position providing:

fluid communication between the second pumping chamber and the fourth housing inlet;

fluid isolation between the second pumping chamber and the third housing inlet;

fluid isolation between the second pumping chamber and the third and fourth housing outlets; and

actuation of the second piston to draw fluid into the second pumping chamber via the fourth housing inlet; and

rotating the rotor to an eighth position providing:

fluid communication between the second pumping chamber and the fourth housing outlet;

fluid isolation between the second pumping chamber and the third housing outlet;

fluid isolation between the second pumping chamber and the third and fourth housing inlets; and

actuation of the second piston to expel fluid out of the second pumping chamber via the fourth housing outlet.