Thrust bearing for multistage centrifugal pumps

A pump assembly comprising:

• a casing;
• an axially movable shaft having a longitudinal axis, said shaft having a movable axial position;
• an impeller mounted to said shaft;
• an inlet port mounted to said casing;
• a discharge port mounted to said casing;
• a discharge chamber within said casing and fluidically coupled to said discharge port;
• a bearing cavity fluidically coupled to said discharge chamber;
• an annular seal coupled within said casing;
• a disc coupled to said shaft positioned adjacent said seal, said seal and said disc having a gap therebetween, said annular seal and said disc at least partially defining said bearing cavity, said bearing cavity being fluidically coupled to said bearing cavity through said gap;
• and
• a feedback path coupling said bearing cavity to said inlet port,
• wherein a pressure within said bearing cavity controls said axial position of said disc and shaft.

A pump assembly comprising:

• a casing;
• an axial discharge piece coupled to said casing;
• an axially movable shaft having a longitudinal axis, said shaft having a movable axial position, said shaft rotatably coupled within said casing;
• an impeller mounted to said shaft;
• an inlet port through said casing;
• a discharge chamber;
• a bearing carrier coupled within said casing, said bearing carrier having a discharge port fluidically coupling said discharge chamber to said discharge piece;
• a balance disc coupled to said shaft;
• a cover coupled to said bearing carrier;
• a seal coupled to said bearing carrier;
• said balance disc, said seal, said bearing carrier and said cover defining a bearing cavity therebetween;
• a feedback path coupling said bearing cavity to said inlet port;
• wherein a pressure within said bearing cavity controls said axial position of said disc and shaft.