Pumps – Processes
Reexamination Certificate
1998-09-02
2001-07-03
Walberg, Teresa (Department: 3742)
Pumps
Processes
Reexamination Certificate
active
06254354
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to hermetic refrigeration compressors and to the flow of suction gas into the shells thereof. With more particularity, the present invention relates to refrigeration compressors of the reciprocating type in which the flow of suction gas to the compression mechanism within the shell of the compressor is to and through a motor end cap and suction tube. With still more particularity, the present invention relates to an improved motor end cap/suction tube arrangement by which the flow of suction gas into and through the shell of a hermetic refrigeration compressor is managed so as to prevent the carrying of debris into the compression apparatus and to enhance the cooling of the motor by which the compression apparatus is driven.
Hermetic refrigeration compressors are compressors in which a motor-compressor combination is mounted internal of a hermetic shell. Such compressors are used in refrigeration systems such as air conditioners, heat pumps and the like for purposes of compressing refrigerant gas from a lower (suction) pressure to a higher (discharge) pressure.
Certain of such compressors are so-called low-side compressors meaning that the interior of the shell in which the motor-compressor is disposed contains refrigerant gas at suction pressure. Such gas surrounds the motor-compressor assembly and is drawn therefrom into the compression mechanism. The suction gas in a refrigeration compressor is a relatively low pressure gas which, even though relatively warm in terms of comparative refrigerant temperatures in other portions of the refrigeration system, is low enough to cool the still higher temperature motor portion of the motor-compressor by flow over, through and around it.
The use of motor end caps and suction tubes to channel the delivery of suction gas to the compression mechanism of a refrigeration compressor in a manner which cools the motor by which the compression apparatus is driven has long been known and there have been many improvements in such arrangements over the past decades. The use of motor end caps in such compressors, while advantageous, does bring certain disadvantages and difficulties that must be overcome in order to permit their use without adversely affecting suction gas flow or unnecessarily complicating compressor fabrication.
Among the disadvantages/difficulties that must be overcome when a motor end cap and suction tube arrangement is employed in a compressor is the need to minimize pressure drop in the suction gas flowing to the compression apparatus as a result of the use thereof. Further, the use of an end cap, which overlies the motor of the compressor, can potentially complicate the compressor assembly process which requires that a predetermined gap be set between the stator and rotor of the compressor drive motor once these components have been assembled into place during the compressor's manufacture. The setting of the rotor-stator gap requires access to the motor for that purpose and the use of a motor end cap, which is most often attached directly to and overlies the motor's stator, poses an obstacle to access to the rotor-stator gap. Difficulties in setting the rotor-stator gap can therefore be encountered to the extent that the end cap, in the process of its assembly to the motor-compressor, blocks access to and/or observation of the rotor-stator gap for gap setting purposes.
The need continues to exist for an improved motor end cap/suction tube arrangement in a refrigeration compressor which minimizes pressure drop in the flow of suction gas enroute to the compression mechanism, which prevents the entry of debris into or onto the compressor drive motor and compressor portions of the motor-compressor combination and which facilitates compressor manufacture and assembly by providing access to the rotor-stator gap so as to permit the setting of that gap conveniently and at minimal expense.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a motor end cap in a refrigeration compressor which minimizes pressure drop in the suction gas flowing into and through it.
It is another object of the invention to provide a motor end cap in a refrigeration compressor which prevents debris from entering into or onto both the motor and compression apparatus while permitting essentially unobstructed flow of suction gas over the motor, for motor cooling purposes, and into the compressor without significant pressure drop therein.
It is a still further object of the invention to provide a motor end cap in a refrigeration compressor which is conveniently and inexpensively assembled to the compressor drive motor yet which allows convenient access to the rotor-stator gap of the motor for purposes of setting that gap during the compressor assembly process.
These and other objects of the present invention, which will become apparent when the attached Drawing Figures and following Description of the Preferred Embodiment are considered, are accomplished by a motor end cap arrangement in a refrigeration compressor which, by its definition of a closeable aperture, provides convenient access to the rotor-stator gap of the compressor drive motor for purposes of setting that gap during compressor manufacture and which, by the use of a suction screen that stands off of the entry location for suction gas into the interior of the end cap, prevents the entry of debris into the motor end cap while permitting essentially unobstructed suction gas flow thereinto. Pressure drop in the gas flowing to the compression apparatus, to the extent it is caused by virtue of the use of the motor end cap is thereby minimized while the motor and compressor are, at the same time, protected from the adverse affects of debris that would otherwise carried onto or into them.
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Davenport Kendall D.
Sonnier, Jr. W. J.
American Standard Inc.
Beres William J.
Ferguson Peter D.
O'Driscoll William
Robinson Daniel
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