US2979919A - Vapor cooling systems - Google Patents

Description

Aprll 18, 1961 c. R. JONES ET AL 2,979,919

VAPOR COOLING SYSTEMS Filed Nov. 13, 1957 5 Sheets-Sheet l j BY Mau..

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April 13, 1961 c. R. JONES ETAL 2,979,919

VAPOR COOLING SYSTEMS Filed Nov. 13, 1957 3 Sheets-Sheet 2 April 18, 1961 c. R. JONES ET AL VAPOR COOLING SYSTEMS :5 sheets-sheet s Filed Nov. 13, 1957 VAPOR COOLING SYSTEMS Clyde R. Jones, 350 Latch Drive; Henry J. Steckelmeyer, 239 Sequoia Drive; George E. Priest, Jr., 2155 Drexel Ave.; Melvin A. Schoening, 2442 Waverly Ave.; Norman Ohlenburger, 659 W. Theo; and Ted Gittinger, 222 Drake Ave., all of San Antonio, Tex.

Filed Nov. 13, 1957, Ser. No. 696,299

2 Claims. (Cl. 62--314) (Granted under Title 35, U.S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the United States Government for governmental purposes without payment to us of any royalty thereon.

The present invention relates generally to cooling systems for electric motors and generators and, as illustrated herein, relates more particularly to systems for cooling such machines by means of a vaporized liquid introduced into a cooling medium such as air.

The cooling of electric motors and generators has heretofore been accomplished by use of any one of three methods. The use of a stream of air passing through States Patent" the machine is most generally used but is objectionable spray lto the interior of the machine is used to some extent butthis method is diilicult to control since even a small excess of water may cause short circuits with consequent damage to the machine. The use of refrigerated passages of heat exchanging tubes within the machine effectively cools the` machine but involves considerable expense ininstallation and maintenance.

The present invention contemplates the use of air cooling in conjunction with vaporized water to provide an effective coolant which does not require immense volumes of air and which is simple to control and which effectively eliminates, nearly entirely, the danger of damage to the machine. To this end, the system provides means for supplying a column of air and means for introducing a predetermined quantity of water vapor into said column of air before it enters the machine.V As illustrated, the system is so designed and controlled, that an excess of free air is removed from the column before the air enters the machine, thus effectively preventing water from collecting on the interior of the machine.

Thc present invention presents many advantages overk prior cooling systems and methods of cooling electrical machines. The use of a column of air saturated with water vapor increases substantially the cooling effect of the column of cooling air due to the latent heat of vaporization of Water. Even though the water in the column is not entirely vaporized there will, under normal conditions, be no precipitation of moisture on the interior parts of the motor or generator. Danger from such a source is effectively eliminated by the moisture trap in the duct of the cooling system. Since a much smaller volume of air is necessary to provide adequate cooling, the pump or blower mechanism is reduced to a minimum size with a consequent drop in cost. Since the air is saturated with water vapor, dust which may be drawn into the system is removed to a large extent by the moisture trap.

Another object of the invention is to improve generally upon the construction and operation of cooling systems for electric motors and generators.

With the above and other objects and features in "lee ` embodiment of the present invention;

Fig. 2 is a view in side elevation of the construction shown in Fig. 1;

Fig. 3 is a view partly in section, of a shutter for controlling the ow of air toa fan or blower;

Y Fig. 4 is a view in section taken along the line IV-IV of Fig. 3;and

Fig. 5 is a view, partly in section, of a portion of the air duct having therein vaporizing means.

The present invention is illustrated as applied to a generator test stand to provide cool air for generators undergoing'test. It is clear, however, that the present invention is not limited to such use but may be used to cool electric motors or generators in actual use at locations where high ambient temperatures are found.

The generator test stand shown in the drawings comprises a test stand 10, only a fragmentary portion of which is shown in Fig. 1. The test stand 10 is provided with' suitable power means (not shown) for supplying power to a shaft 12 which may be coupled to the shaft of a generator 14 by suitable connecting means (not shown). The generator 14 is provided with an enclosing housing 16 in which the heat developing members are enclosed. These heat developing members include the rotor and, stator of the usual type of electric motor or generator. A power-driven blower 18 delivers cooling air to the housing 16 througfh a duct 2G. Preferably the air is filtered prior to entering the blower 18. As shown in Fig. 2, air is drawn through a conventional type of air lter 22 and through an intake duct 24 into the blower 18.

The ow of air into the blower 18 is controlled by a manually operated valve 26 having a cylindrical segment 28 pivotally mounted in the valve body 26 and having an external handle `30 for rotating the segment 28 into and `out of duct closing position. It is to be noted that the valve 26 is provided with an openingV 32 which may be closed as the intake opening 34 in the duct 24 is being opened by rotation of the segment 28 in 'a clockwise direction. Thus the flow of filtered Vair may be increased or diminished as required. During replacement,- removal of a generator or motor 14 or the ow of air to the exhaust end 36 of the valve body 26 may beV prevented by rotating the segment-28 in a clockwise direction. Thus, the flow of air into the housing 16 may be delayed until after the generator or motor 14 has vreadied normal operating temperature. This is important for reasons which will later become apparent.

Y Theair passes from the blower 18 and into one end of the duct 20 which is provided with a control valve 38 of conventional design which controls the flow of air into the duct 20. The filtered air from the blower 18 is relatively dry and hence must be provided with sufficient moisture to provide a substantially saturated stream of air. To this end, a vaporizer 40 is provided which supplies vaporized water to the moving air column in the duct 20. The vaporizer 40 is generally of conventional construction and comprises a water conducting tube 42 which is supplied with water from a suitable tank 44 through a flexible tube 46. For convenience, the tank 44 is secured to an upright portion of the air blast duct or conduit 20. Water may be supplied to the tank 44 through a tube 48 from a suitable source l of supply and the flow of water to the tank 44 may be ,shown in Fig. 5, the water tube 42 and the air tube 50 are assembled so that a stream of air from the tube 50 passes across the end of thetube 42 and sets up a partial vacuum therein. Water flows from'the endY offthe-tu'be ',42'and is vaporized by th'e air blast from'lthe'tubefSO.

The 'stream of air passing through the duct-20-froml-the blower 18 mixes with the vaporized 'water so that'the blast of air in the duct- 20 issubstantially saturated with ymoisture to produce the Vmaximum air cooling-effect.

The ow of compressed air through the tube S-'may be controlled by a conventional valve 52. By controlling Ilthe iiow of air through the tube 50, the flow of water through the tube 42 is also controlled. Thus, an amount the plate 56 and moisture is trapped and collects in drops thereon. Moisture leaves the lower portion of the plate 56 into the lower portion of the trap 54 where it is passed through tubes 58 to a suitable lwaste line 60. By this means liquid is not permitted to lreach the interior of the housing 16, thus serving to prevent corrosion and also short circuits.

In order to insure efficient operation, pressure of the stream of air flowing through the duct 20 is measured by readings in a manometer 62 which is fixed in a c onvenient location on a vertical portion of the `duct 20. Pressure is measured at a point just in front of the Yentrance to the housing 16 in the duct 68. A'suitable tube 64 extends into the passage and isconnected to the manometer 62 by a flexible tube 66. I A

Inoperation, air from the blower 18, 'enters theduct 20 and air pressure within the duct 20 is controlled by the valve 38 according to readings vrecorded on the manometer 62. The compressed air valve 52 is opened to about three-fourths of its maximum whichpermits the desired blast of air to pass across the end of the tube 42 which causes water'to be siphoned from the ytank 44 and to be atomized as the water leaves the-endA of the tube 42. The atomized water mixes with theb1ast of air in theduct 20 coming from blower 18: this'increases the humidity of the air and also ,decreases its temperature to the dry bulb temperature in proportion to its relative humidity. The humid air continues through the duct 20 and impinges Vagainst the plate dish l56-in the water trap 54. The plate dish 56 traps any condensed vapor which is drained o through the tubes 58. The humidied air then passes into the enclosing -casing 16 throughtube 64 on which a suitable thermometer 70 is mounted. At this point, the air blast will have reached its lowest temperature, as indicated by the thermometer 70. The air valve 52 is gradually closed until the temperature as indicated by the thermometer begins to rise: this will be the temperature of the cooling air entering the generator housing 16.

The above described apparatus and method of controlling both the amount of water vapor and the temperature of the `humidiiied air provides an eiective apparatus and method for cooling electrical apparatus of the type described above. The air blast as it enters the interior of the generator 14is free from condensed moisture and since the temperature within the generator is relatively high there can be no accumulation ,of condensed moisture which might cause short circuits. Furthermore, the ow of humidiied air to the interior ofthe generator 14 is so controlled by the valve 38 -that flow of air intovthe duct 20 is effectively prevented until the temperature of the generator 14 on the test stand 1t) has had an opportunity vto reach'operating temperature.

While'the present invention has been described with particular reference to one preferred embodiment thereof, it is to be understood that the invention is not limited thereto but may be varied within the scope and spirit of the appended claims.

'Having thus described our invention, what we claim as new and desire to secure by Letters PatentV of the United States is:

'1."In combination an electrical apparatus having a casing and an electrical current carrying, heat developing member and a cooling means therefor, saidfcooling means comprising'an air filter, a blower having its inlet connected with 'said filter, conduit means from the outlet of said blowerto said casing, valve means at the outlet of said blower, means within vsaid conduit yand downstream of said valve means for supplying water vapor to the air traveling through said conduit from said blower,

and means within said conduit and downstream of said `means for supplying water vapor for trapping and removing water condensed from the air prior 4to the-entrance of the air nto'said casing.

2. The combination of claim 1 wherein said electrical 'apparatus comprises a rotor and a stator and wherein said valve means controls the pressure and velocity of "said air.

References Cited in the lile of this patent Y UNITED rSTATES PATENTS

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