Positive-displacement rotary pump having a positive-displacement auxiliary pumping system
Positive-displacement auxiliary pumping systems for use in pump apparatus of different configurations are disclosed. The positive-displacement auxiliary pumping systems are included in positive-displacement rotary pumps having a casing defining a pumping cavity, an inlet port connected to the pumping cavity, a discharge port connected to the pumping cavity, and a positive-displacement auxiliary pumping port connected to the pumping cavity. Pumping elements move within the pumping cavity of the casing and define a collapsing pocket that maintains fluid communication with the positive-displacement auxiliary pumping port after the collapsing pocket is no longer in fluid communication with the discharge port.
1. A positive-displacement rotary pump comprising:
a casing defining a pumping cavity;
an inlet port connected to the pumping cavity; a discharge port connected to the pumping cavity;
a positive-displacement auxiliary pumping port connected to the pumping cavity and being smaller in comparison to the discharge port,
pumping elements that move within the pumping cavity of the casing and define a collapsing pocket that maintains fluid communication with the positive-displacement auxiliary pumping port after the collapsing pocket is no longer in fluid communication with the discharge port;
wherein the casing configuration includes having the positive-displacement auxiliary pumping port positioned sufficiently proximate the discharge port to permit the positive-displacement auxiliary pumping port to remain in fluid communication with the collapsing pocket immediately following discontinuation of fluid communication between the discharge port and the collapsing pocket;
wherein fluid is positively-displaced through the positive-displacement auxiliary pumping port at a flowrate that is substantially independent of the differential pressure of the pump and/or fluid viscosity; and
further comprising a passage that is in fluid communication with the positive-displacement auxiliary pumping port, wherein the passage is configured to direct positively displaced fluid to at least one dynamic seal positioned within the casing, to bearings positioned within the casing and/or to an interior of an annular separation canister positioned within the casing.
2. A positive-displacement rotary pump in accordance with claim 1 , wherein the pumping elements further comprise a rotatable rotor having a plurality of movable vanes.
3. A positive-displacement rotary pump in accordance with claim 1 , wherein the pumping elements further comprise rotatable gears.
4. A positive-displacement rotary pump in accordance with claim 1 , wherein the pumping elements further comprise rotatable lobes.
5. A positive-displacement rotary pump in accordance with claim 1 , wherein the inlet port, the discharge port and the positive-displacement auxiliary pumping port all are positioned radially relative to the pumping cavity in the casing.
6. A positive-displacement rotary pump in accordance with claim 1 , wherein at least one of the inlet port, the discharge port and the positive-displacement auxiliary pumping port is positioned radially relative to the pumping cavity in the casing.
7. A positive-displacement rotary pump in accordance with claim 1 , wherein at least one of the inlet port, the discharge port and the positive-displacement auxiliary pumping port is positioned axially relative to the pumping cavity in the casing.
8. A positive-displacement rotary pump in accordance with claim 1 , further comprising:
a rotatable annular magnetic drive assembly having a recess with an opening at one end;
an annular separation canister having a recess with an opening at one end, and at least a portion of the annular separation canister being disposed within the recess of the rotatable annular magnetic drive assembly,
an annular magnetic driven assembly having a magnetic portion disposed substantially within the recess of the annular separation canister, and the magnetic portion being substantially in magnetic alignment with the rotatable annular magnetic drive assembly; and
wherein the annular magnetic driven assembly is connected to a rotor gear that drives an idler gear.
9. A positive-displacement rotary pump in accordance with claim 8 , wherein the pumping elements are the rotor gear and the idler gear.
10. A positive-displacement rotary pump in accordance with claim 1 , wherein the positive-displacement auxiliary pumping port is connected to a conduit that runs external to the casing.
11. A positive-displacement rotary pump in accordance with claim 10 , wherein the conduit is connected at a first end to the positive-displacement auxiliary pumping port and is connected at a second end to a further port on the casing.
12. A positive-displacement rotary pump in accordance with claim 1 , wherein the casing further comprises a casing body that is connected to a casing front portion and a casing rear portion.