Hermetically sealed pump for a refrigeration system

A constant volume, balanced rotor, hermetically sealed vane pump comprising:

• an hermetic enclosure comprising a hollow pump housing and a motor housing with an outlet opening therethrough, the motor housing and pump housing being joined in axial alignment;
• the pump housing having a circumferential wall defining a generally elliptical rotor chamber having opposed circular portions, opposed cam portions angularly spaced from the circular portions, and an inlet port connected to each cam portion at a leading edge thereof;
• an end wall at each axial end of the rotor chamber further defining the rotor chamber, the circumferential wall and end walls defining a chamber housing;
• an outlet port extending from each cam portion at a trailing edge thereof to a discharge port in the hermetic enclosure;
• a cylindrical pump rotor rotatably supported wholly within the pump housing for rotation in the rotor chamber and having a plurality of radially extending, slidably mounted vanes adapted to form a constant volume pumping chamber defined between each pair of adjacent vanes, the rotor, and the circumferential and end walls at the cam portions between each inlet port and each outlet port;
• each of the cam portions, inlet ports and outlet ports being located 180 degrees apart from the other of the respective cam portions, inlet ports and outlet ports whereby radial forces on the pump rotor are balanced;
• a motor with an output shaft coupled to the pump rotor for driving the pump rotor;
• the motor comprises a stator mounted within the motor housing, a motor rotor disposed within the stator for rotation and a motor shaft mounted to the motor rotor and extending axially from a first and second axial end of the rotor, and further comprising:
• bearing supports, wholly within the motor housing, mounting motor bearings at the first and second ends of the motor rotor, the bearings supporting the motor shaft, at least one of said bearing supports has an opening for liquid to pass therethrough;
• a slidable drive coupling between the motor shaft and the pump rotor for slight axial and radial movement between the two;
• and
• the outlet ports include passages which extend through one of the end walls into the motor housing wherein the fluid to be pumped can cool the bearings.

A constant volume, balanced rotor, hermetically sealed vane pump comprising:

• an hermetic enclosure comprising a hollow pump housing;
• the pump housing having a circumferential wall defining a generally elliptical rotor chamber having opposed circular portions, opposed cam portions angularly spaced from the circular portions, and an inlet port connected to each cam portion at a leading edge thereof;
• an end wall at each axial end of the rotor chamber further defining the rotor chamber, the circumferential wall and end walls defining a chamber housing;
• an outlet port extending from each cam portion at a trailing edge thereof to a discharge port in the hermetic enclosure, the outlet ports extend through both of end walls, the outlet ports are triangular in shape, having one side along the rotor chamber and an apex radially spaced from the rotor chamber and aligned with an axially oriented passage through the pump housing, the axially oriented passage being radially displaced from the rotor chamber;
• a cylindrical pump rotor rotatably supported wholly within the pump housing for rotation in the rotor chamber and having a plurality of radially extending, slidably mounted vanes adapted to form a constant volume pumping chamber defined between each pair of adjacent vanes, the rotor, and the circumferential and end walls at the cam portions between each inlet port and each outlet port;
• each of the cam portions, inlet ports and outlet ports being located 180 degrees apart from the other of the respective cam portions, inlet ports and outlet ports whereby radial forces on the pump rotor are balanced;
• and
• a motor with an output shaft coupled to the pump rotor for driving the pump rotor.