Method and device for reducing axial thrust in rotary machines and a centrifugal pump using same
First Claim
1. A method for reducing axial thrust in a rotary machine, said machine comprising a housing with a center and a periphery, said housing containing a fluid inlet, a fluid outlet, a shaft rotatably mounted in said center, a rotor mounted on said shaft, said rotor having at least one radial surface, said housing having at least one interior wall surface proximate said radial surface of said rotor and defining a cavity therebetween, said cavity having a central area proximal the center of said housing and a peripheral area proximal the periphery of said housing, said method comprising the steps of:
- subdividing a fluid flow in said cavity into a first fluid flow and a second fluid flow; and
channeling said first fluid flow between said peripheral area and said central area while shielding it from said second fluid flow,whereby the fluid pressure of said second fluid flow in said cavity being altered in order to reduce the axial thrust on said rotor.
1 Assignment
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Accused Products
Abstract
A method and device for reducing or eliminating axial thrust in a rotary machine such as a centrifugal pump or compressor by altering the fluid pressure in a cavity formed between a rotor and a housing. The device contains a disk placed along the rotor for subdividing the fluid in the cavity in such a way that all annular gap leakage flow is channeled and pumped through the space between that disk and the rotor from the center of the pump towards the periphery. As a result, the pressure in the cavity is altered to reduce and control the axial thrust on the rotor which becomes independent of the wear state of the shaft seals. In another embodiment, the step of flow subdividing is achieved by providing a set of braking vanes along the periphery of the cavity for reducing the rotational speed of the fluid coming from the cavity as well as from the annular gap and a stationary disk placed along the interior wall of the housing for directing the radial flow of that fluid towards the center of the pump.
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Citations
26 Claims
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1. A method for reducing axial thrust in a rotary machine, said machine comprising a housing with a center and a periphery, said housing containing a fluid inlet, a fluid outlet, a shaft rotatably mounted in said center, a rotor mounted on said shaft, said rotor having at least one radial surface, said housing having at least one interior wall surface proximate said radial surface of said rotor and defining a cavity therebetween, said cavity having a central area proximal the center of said housing and a peripheral area proximal the periphery of said housing, said method comprising the steps of:
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subdividing a fluid flow in said cavity into a first fluid flow and a second fluid flow; and channeling said first fluid flow between said peripheral area and said central area while shielding it from said second fluid flow, whereby the fluid pressure of said second fluid flow in said cavity being altered in order to reduce the axial thrust on said rotor. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A device for reducing axial thrust in a rotary machine, said machine comprising a housing with a center and a periphery, said housing containing a fluid inlet, a fluid outlet, a shaft rotatably mounted in said center, a rotor mounted on said shaft, said rotor having at least one radial surface, said housing having at least one interior wall surface proximate said radial surface of said rotor and defining a cavity therebetween, said cavity having a central area proximate to the center of said housing and a peripheral area proximate to the periphery of said housing, said device comprising:
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a means for subdividing a fluid flow in said cavity into a first fluid flow and a second fluid flow; and a means for channeling said first fluid flow between said peripheral area and said central area of said cavity while shielding it from said second fluid flow, whereby the fluid pressure of said second fluid flow in said cavity being altered in order to reduce the axial thrust on said rotor. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A centrifugal pump with reduced axial thrust comprising:
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a housing with a center and a periphery, said housing containing a fluid inlet and a fluid outlet, said housing having at least one interior wall surface, a shaft rotatably mounted in said center, a rotor mounted on said shaft, said rotor having at least one radial surface proximate said interior wall surface of said housing, a cavity formed between said radial surface of said rotor and said interior wall surface of said housing, said cavity having a central area proximate to the center of said housing and a peripheral area proximate to the periphery of said housing, a means for subdividing a fluid flow in said cavity into a first fluid flow and a second fluid flow; and a means for channeling said first fluid flow between said peripheral area and said central area of said cavity while shielding it from said second fluid flow, whereby the fluid pressure of said second fluid flow in said cavity being altered in order to reduce the axial thrust on said rotor. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification