Pumps – Motor driven – Axial thrust balancing means for rotary pump and motor
Reexamination Certificate
2001-01-23
2003-06-17
Walberg, Teresa (Department: 3742)
Pumps
Motor driven
Axial thrust balancing means for rotary pump and motor
C418S055500
Reexamination Certificate
active
06579076
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a system for balancing loads on a shaft and, more particularly, to a system for balancing pressure-induced, axial shaft loads.
2. Description of the Related Art
Most motor-driven devices utilize a rotating shaft to distribute power from the motor to carry out various operations. In such devices, it is common for unequal loads to develop on opposite ends of the shaft. Load imbalances of this type are particularly common in devices where the ends of the shaft are located in separate compartments having different operating pressures.
One such device is a “split-shell” compressor system having a housing divided into a low pressure compartment containing a motor, and a high pressure compartment containing an oil sump. A shaft extending between the compartments transfers power from the motor to a compressor unit, which compresses a working fluid. In this system, the low pressure compartment is maintained at the suction pressure of the compressor unit, and the high pressure compartment is maintained at the discharge pressure of the compressor unit. This pressure differential between the shaft ends causes an axial load on the shaft.
Loading of this type can cause excessive wear on the shaft's bearings and thrust a surfaces and can cause the compressor to stall under high pressure conditions. These problems result in inefficient operation and shorter operational life of the equipment, thereby increasing operating costs.
SUMMARY OF THE INVENTION
To overcome the drawbacks of the prior art and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a load balancing system for use with a housing divided by a partition into a first chamber at a first pressure and a second chamber at a second pressure lower than the first pressure, the system including a fluid reservoir in the housing, a shaft passing from the first chamber into the second chamber, a channel extending substantially axially through the shaft between a first shaft end and a second shaft end, wherein the first shaft end is in fluid communication with the fluid reservoir, and a reaction member engaging the second shaft end, such that fluid passing through the channel interacts with the reaction member to create a force on the second shaft end approximately equal to a force acting on the first shaft end.
The invention further provides a shaft load balancing system, including a housing, a partition within the housing defining a first chamber at a first pressure and a second chamber at a second pressure, wherein the first pressure is greater than the second pressure, a fluid reservoir disposed in the housing, a shaft extending from the first chamber into the second chamber, the shaft having a first end in fluid communication with the fluid reservoir, and a second end. The invention further provides a substantially axial channel disposed in the shaft between the first end and the second end, and a reaction member disposed in the second chamber engaging the second end, wherein fluid from the fluid reservoir forced through the channel contacts the reaction member and generates a force on the second end approximately equal to a pressure-induced force on the first end.
The invention further provides a system for balancing axial shaft loads, the system including a housing, a partition within the housing defining a low pressure chamber and a high pressure chamber, a fluid reservoir disposed in the high pressure chamber, a rotatable shaft extending from the low pressure chamber into the high pressure chamber through the partition, the shaft including a first end disposed in the high pressure chamber in fluid communication with the fluid reservoir, a second end disposed in the low pressure chamber, and a channel extending substantially axially through the shaft between the first end and the second end. The invention further provides a reaction member sealed with respect to the shaft, the reaction member including a compression volume engaging the second end, such that fluid entering the compression volume from the channel creates an axial force on the second end approximately equal to a pressure-induced force on the first end.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
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Monk David Turner
Narney, II John Kenneth
Bristol Compressors, Inc.
Fastovsky Leonid M
Finnegan Henderson Farabow Garrett & Dunner LLP
Walberg Teresa
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