US1681574A - Rotary compressor - Google Patents

Description

Aug. 21, 1928. 1,681,574 c. c. FARMER I ROTARY COMPRES SOR Filed March 1, 1923 INVENTOR CLYDE C. FARMER ATTORNEY I Patented Aug. 21, 1928.

UNITED STATES PATENT OFFICE.

CLYDE C. FARMER, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOB TO THE WESTING- HOUSE AIR BRAKE COMPANY, OF WILLIERDING, PENNSYLVANIA, A CORPORA- TION OF PENNSYLVANIA.

ROTARY COMPRESSOR.

Application filed March 1, 1923. Serial No. 622,099.

This invention relates to rotary compressors and the principal object of my invention is to provide means for cooling and lubricating a rotary compressor.

In the accompanying drawing; Fig. 1 1s a diagrammatic view, partly in sectlon of a lubricating and cooling system applied to a rotary compressor in accordance with my invention; and Fig. 2 a plan view, partly in section, of the rotary compressor shown in Fig. 1.

The rotary compressor may comprise a casing 1 having a cylindrical chamber 2 within which is 'eccentrically mounted a rotor shaft 3. On the shaft 3 is mounted a rotor member 4 having radialslots 5 for receiving radially movable rotor blades 6.

The rotor rotates in the direction of the arrow. as shown in Fig. 1 and the air inlet 7 is connected by pipe 8 to a suitable suction inlet air strainer 9. The outlet 10 for compressed air is connected by pipe 11 to an oil reservoir 12 which is charged with a suitable quantity of lubricating oil 13.

From the oil reservoir 12, compressed air passes through a suitable oil separator 14, adapted to separate oil from the compressed air, to a pipe 15 which is connected to a compressed air storage reservoir 16.

' The rotary compressor is provided with an annular chamber 17 through which water circulates for the purpose of cooling the compressor and the circulating water is .cooled by means of a radiator 18, preferably of the Well known automotive type.

Immersed in the lubricating oil 13 in the reservoir 12 is a thermostat 19 which is operatively connected by'a lever 20 to a shaft 21 carrying a lever 22. Associated with the reservoir 12 is a'valve casing 23 containing a valve 24 for controlling the flow of cooled water from the radiator 18'through pipe 25 to a pipe 26 which is connected to chamber 17 of the rotary compressor. A valve stem 27 is connected to valve 24 and extends out of casing 23 in position to be engaged by the end of lever 22. Cooling water flowing through pipe 26 to chamber .17 flows back to the radiator 18 by way of pipe 28.

Lubricating oil from reservoir 12, under the pressure of the compressed air in said reservoir, flows through pipe 29 into the rotor bearing chamber 30 of the rotary compressor. A hole 31 is drilled through the axis of the rotor shaft 3 and from this hole, radial ports 32 lead to the" respective rotor blade slots 5.

In order to prevent possible leakage of oil at the rotor shaft bearing to thedriving electric motor 33, an annular chamber 34 is provided between the compressor and the motor and surrounding the shaft bearing. Said chamber is connected by a passage 35 to a pipe 36 leading to the compressor air inlet pipe 8, so that any oil leaking into the chamber 34 will be returned to the compressor by the suction or partial vacuum existing in the inlet pipe 8.

In operation, when the rotary compressor is started, the temperature of the oil 13 in the reservoir 12 will be relatively low and the thermostat rod 19 will therefore be retracted so that the lever 22 will be in the position shown in Fig. 1, permitting the valve-24 to seat. WVith the valve 24 seated there is no circulation of cooling water through the rotary compressor. As thecompressor operates air is compressed by the well known action of the blades 6 and the compressed air passes through pipe 11 to the oil reservoir 12. The pressure of air thus created in reservoir 12 causes a flow of lubricating oil from reservoir 12 through pipe 29 to the rotary compressor and the oil then flows through the hole 31 and the radialports 32, so as to lubricate the compressor and any oil flowing past the rotor shaft bearing will be trapped in chamber 34, whence it will be drawn through pipe36 by the suction in pipe 8 to the inlet opening 7 of the compressor.

The act of compressing air heats the same and tends to heat. the compressor and the heated compressed air flowing into the oil reservoir 12 heats the oil 13 therein.

When the temperature of the oil has risen to a predetermined degree, the thermostat will act by expansion to raise the lever 22 so as to lift the valve 24 fromits seat. Cooling water is then permitted to circulate through the compressor, as supplied from the radiator 18, and this tends to cool the compressor and also reduce the temperature of the compressed air. If the temperature of the compressed air should fall below a -predetermined degree, the thermostat will operate to permit the valve 24 to close or partially 'close so as o cut off or reduce the flow of able that this water should not condense and mingle with the oil supply in the reservoir 12 and therefore the thermostatic control mechanism is so adjusted that the temperature of the compressed air will be maintained high enough to maintain the water in a vaporized form, so that it will be held in suspension in the compressed air and will pass out of the oil reservoir 12 without condensation and be carried over into the air storage reservoir 16.

On the other hand, the temperature of the lubricating oil should not be allowed to rise to a point at which the oil will vaporize and thus pass out with the water vapor to the storage reservoir, or at which it is liable to burn, or at which its lubricating qualities are reduced, and consequently the thermostatic control mechanism is so adjusted that the temperature of the oil will not be increased above a predetermined degree. I

The thermostatic control is thus made to work between two range limits, the higher limit to prevent the oil from becoming heated to such an extent as to permit vaporization of the oil, and the lower limit to prevent the cooling of the compressed air to such anextent that water carried with the air will tend to condense in the oil reservoir The oil carried by the compressed air into the reservoir 12 being in the form of minute particles carried in suspension and not in a gaseous form, the oil separator readily operates in the well known manner to separate the oil from the air and allow same to flow back into the oil reservoir.

Having now described my invention, what I claim as new and desire to secure by Let-' ters Patent, is

1. The combination with a rotary fluid compressor, of a reservoir into which flows fluid compressed by the compressor and containing a quantity of oil, means for supplymg oil from said reservoir to lubricate the compressor, mechanism for regulating the temperature of the compressor, and a thermostat subject to the temperature of the oil in the reservoir for controlling the operation of said mechanism.

2. The combination with a rotary compressor, of a system for circulating oil to lubricatethe'compressor, a system for circulating a cooling medium throu h the compressor, and means subject to t e temperature of the oil for regulating the flow of cooling medium.

3. The combination with a rotary compressor, of a system for circulating oil to lubricate the compressor and means for maintaining the temperature of the compressor and thereby the fluid compressed by the compressor at a tempe:ature above the vaporizing point of water and below the vaporizing point of the oil supplied to lubricate the compressor.

4. The combination with a rotary compressor, of a reservoir containing oil, means a for supplying oil from said reservoir to lubricate the compressor, mechanism for effecting the clrculation of a coollng ll'qllld through the'compressor, a valve for controlling the flow of cooling liquid, and a thermostat device subject to the temperature of the oil in said reservoir for operating said valve.

5. The combination with a rotary compressor, of a reservoir containing oil and into which flows fluid compressed by the compressor, means for effecting the circulation of oil from the reservoirthrough the com-' pressor for lubricating said compressor, mechanism for effecting the circulation of a cooling liquid through the compressor, a

valve for controlling the flow of cooling liquid, and a thermostat device subject to the temperature of the oil in .said reservoir for operating said valve- In testimony. whereof I have hereunto set m hand. I

y CLYDE C. FARMER.

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