US2201099A - Refrigeration - Google Patents

Description

' R. c. ROE 2,201,099

REFRIGERATION May 14, :1940.

Filed June 8. 1933 2 Sheets-Sheet 1 Ffyure 2.

May 14, 1940. Q ROE 2,201,099

REFRIGERAT ION Filed June a, 1933 '2 Sheets-Sheet 2 Wffdwvmmg- I ATTORNEY Patented May. 14, 1940 UNITED STATES PATIENT OFFICE 3 Claims. (Cl. 82-115) My invention relates to improvements in refrigeration, particularly in water refrigeration under vacuum, and more particularly water refrigeration under vacuum for air conditioning. A further object of my invention is to provide air conditioning apparatus for the above purposes which does not contain obnoxious refrigeration fluids and which will operate without difliculty and trouble at high efliciencies. Other objects of my invention become apparent as the specifications appear and proceed.

In the present vacuum refrigeration practice, it is necessary to provide a source of high pressure steam for the actuation of steam actuated vacuum pumps and to have other cumbersome equipment which is not readily available for this purpose. In my invention, as hereinafter set forth, I have simplified this art. I have provided a piece of equipment which is hermetically sealed and which can be used in small or moderate sizes in the form of a self contained unit and that does not require a steam boiler or other steam producing apparatus of a similar character with its attendant complications and which will produce refrigeration with a lower expenditure of power, a high efficiency and in a manner believed to be heretofore unknown in the art without the use of obnoxious refrigerants, all as hereinafter set forth.

In this invention, it is proposed to use blade screws of a type somewhat similar to the last wheels of a reaction turbine but differing therefrom in the respect that they are compressing water vapor and not expanding water vapor. Many years ago the eminent turbine designer, Parsons, developed the theory of compressing gases with reaction blading driven by power. An

experimental machine was built at that time.

which was a failure. Later, work has been done on this in a mathematical way by Dr. George De Bothezat and others which has demonstrated the principles involved in elastic fluid compression in this type of blade screw. American practice on turbines using steam by expansion to produce power has been to have alternate rows of stationary and moving blades. Ljungstriim in Europe has developed a turbine in which the alternate rows of blades move in opposite directions, this turbine being used to produce power, improving the efficiency of expansion of the steam by this arrangement. In a similar manner, improvements in efficiency in the compression of steam can be accomplished, provided the blade types and structures are such as to function efliciently for compression purposes as distinguished from expansion purposes. The theory of this performance having been worked out'by others,

it is not the intention of thisapplication to claim the method or apparatus for compressing elastic fluids by blade screws, per se, but rather it is the c intention of this application to claim the combination of this apparatus with other apparatus for the purpose of producing a new type of elastic fluid refrigeration heretofore unknown and believed to be an improvement in the art.

In the drawings, Figure 1 is a diagrammatic representation of a vertical cross section of a refrigerating apparatus, Figure 2 is a plan view of a portion of Figure 1, along lines 82-82, with a part cut away to show heat exchange tubes, 15 Figure 3 is a partial cross section of a multistage screw compressor driven by external power, Figure 4 is a diagrammatic representation of a general blade arrangement for this apparatus.

In the figures, I is an evaporator, 2 is a fan, 3 is a condenser, 4 is ,a blade screw compressor, 5 is a, drip pan, 5 is a heat exchange surface in evaporator l, 1 is a water level in evaporator l, 8 is.a vapor space in evaporator I, 8 is a float valve controlling liquid supplied to evaporator I, I8 is a float controlling valve 9, H is a louver, i2 is a conduit, i3 is a conduit, i4 is a heat exchanger, IE is a vapor and air space in condenser 3, it are sprays, part of condenser 3, H is a conduit, I3 is a blower, i9 is a water circulating pump, 28 is a motor, M is a water level interior to condenser 3, 22 is a water level exterior to condenser 3, 23 is a city water supply line, 24 is a valve, 25 is a float actuating valve 24, 26 is a conduit between valve 24 and heat exchanger l4, 2'! are heat exchange tubes interior to con- 35 denser 3, 28 are fins to heat exchange tubes 21,

29 is an air duct from blower I8 to the lower portion of condenser 3, 30 is an air space in the bottom portion of condenser 3, 3| are openings from duct 29 to space 38 of condenser 3, 32 is a discharge connection to a flue, 33 is a motor driving blade screw compressor 4, 34 is a coupling between motor 33 and blade screw compressor 4. In blade screw compressor 4, 35 is an external case or shell supported by stream line spiders 36 and spider 31 and interconnecting evaporator I and condenser 3, 38 is a shaft connected to coupling 34; 39, 48, 4| and 42 are bearings, 43 is a spider connected to shaft 38 and rigidly keyed 5 thereon; 44, 45, 46, and 41 are blade rows connected to spider 43 and directly driven from shaft 38, 48 is a rotating gear fastened to shaft 38, 49 is a stationary gear fastened to housing 5| and connected to stationary spider 36, 58 is a drain connection, BI is a housing as previously mentioned, 82 is a cover over bearing 48 and enclosing the end nut 53 on shaft 38, 84 and 55 are gears in mesh with gears 48 and 48 supported on shafts 53 and 51 and rotating thereon,- 58 is a housing supporting shafts and El and enclosing gears 54 and 55 and gears 48 and 48 and running on bearings H and 42, this housing rotating as will hereinafterbe explained in an opposite direction to shaft 38, 53 are blades from housing 58 to drum 60, these blades being fastened rigidly both to housing 58 and to drum 60, therefore rotating in an opposite direction to spider 43 as will hereinafter be explained, GI, 82, 63 and 64 are blades rigidly fastened to drum 68 and rotating with said drum, 65 is a spider connected by blade 64 to drum 30 and supporting said drum by means of bearing 38 and drum shaft 38, 86 and 61 illustrate general blade shapes and positions and may be in pairs of succeeding blades in blade screw compressor 4, 68 is an atmospheric water space in condenser 3, 69 is an internal water space in condenser 3, I is a conduit, II and I2 are lead and exit blocks, I3, i4, I5, I6, ll, 18,19,811 and 8| are close clearance end tightening shrouds, 82-82 represents extremities of section line showing section as illustrated in Figure 2.

In operation, evaporator I, condenser 3 and interconnecting piece 35 with their interconnections hereinbefore enumerated are made absolutely tight against leakage and are vacuumized and preferably hermetically sealed. These parts have enclosed in them blade screw compressor t with its driving motor, said motor being connected through vacuum tight connections electrically with connections on the exterior of the device (not illustrated). These devices also contain suitable refrigerating fluid, preferably water, in a pure state, and therefore the pressure when standing is proportional to the temperature corresponding to the device, the whole device being highly vacuumized in general and voided of all vapors except vapor of the refrigerant (water).

When operation is started, air is circulated over heat exchange surface 21 in condenser 3 by means of blower I8, driven by motor 20 and at the same time water is taken from external water space 68 in condenser 3by means of pump I9 via conduit II, through sprays I 6 and thence over heat exchange surface 21 and fins 28, back to water space 88, the air passing upward through heat exchange tubes 21 and around fin surface 28. Any excess heat in the apparatus is carried out in the air either by direct contact with the air passing through tubes 21 or by vaporization of the water which vapor is carried out with the air. To replenish water vaporized in this manner, fresh water is supplied by conduit 23, float valve 24 under control of float 25, via conduit 26, heat exchanger I4, conduit I8.

Upon the starting of motor 33 by means of blade screw compressor 4 a differential pressure is established between evaporator I and condenser 3 and the temperature of evaporator I is lowered by evaporation of water therein and the water therein cooled, this vapor being condensed in condenser 3 as will be hereinafter explained. Upon starting fan 2, air from the room is circulated over cool heat exchange surface 6 of evaporator I which has been cooled by the evaporation of water caused by differential pressure as heretofore explained and heat from this air is absorbed through said heat exchange surface 6 of evaporator Ito the water interior to said evaporator. This water being evaporated by the addi:

- 68 as evidenced by water level 2i and thence,

when and as needed in evaporator I to replace water evaporated in the manner heretofore described, it passes through conduit I3 to heat exchanger It where it is cooled by the interchange of heat to the incoming water through conduit 26 as heretofore explained and thence through conduit I2, valve 9 under control of float it, replenishing water which has been evaporated from evaporator I.

It is thus seen that air in a room or from any other point which may be handled by fan 2 is lowered in temperature by transferring heat to water on the interior of evaporator I, such water being vaporized. The vapor is compressed to a higher pressure by blade screw compressor 3, is condensed in condenser 3 exchanging the heat which originated from the air being cooled together with the heat from mechanical losses with the cooling air or water circulating over the exterior of said condenser. The condensed vapor in the form of water is then returned by way of screw compressor 1 will have a compression duty of only 2 H.g. total pressure.

The volume of water vapor leaving evaporator I will be approximately 1702 cu. ft. per pound which is a very large volume on account of the low pressure. Blade screw compressors as d are a very desirable type to handle large volumes at low pressures with high efflciencies. With the present types of centrifugal compressors, it is possible to handle these volumes and small pressures at efficiencies not to exceed, with present day practice and knowledge, about 65%, whereas with a properly designed, multi stage blade screw compressor adapted for the particular work involved in this application, it is expected that efficiencies in excess of 80% may be readily obtained. With the differences in emciences which can be obtained, it is very obvious that a combination of a blade screw compressor with a sealed water refrigerating system is a desirable and efficient method of producing the differential pressure between the evaporator and the condenser. In order that the efiiciency of blade screw compressor 4 may be maintained at its maximum, lead and exit blocks II and I2 are installed and close clearance end tightening shrouds I3, I4, I5, I6, 11, I8, I9, 80 and 8I are provided, reducing the leakage of the steam around the ends of blade screws in a similar manner as is done in turbine practice in this country.

To explain the operation of blade screw compressor 4 in which the blades driven by shaft 38 revolve in one direction whereas the blades driven by drum 68 rotate in the opposite direction, it should be borne in mind that gear 48 is fastened fastened to housing 5|, and is stationary. Gears 54 and 55 are in mesh with gears 48 and 49. Gears 54 and 55, however, are in reality a two part gear, one part having a larger number of teeth and pitch diameter than the other. A suitable arrangement to drive the drum and its attendant blades at the same speed in a reverse direction to the shaft would be to have gear 48 of 30 teeth and that portion of gears 53 and 54 in mesh with gear 48 of 30 teeth and gear 49 of teeth and that portion of gears 54 and 55 in mesh with gear 49 of 20 teeth. Other arrangements may be provided which will accomplish the same result or if desired, arrangements may be made which will provide different speeds. In operation, gear 48 rotates by means of rotation of shaft 38, rotating gears 54 and 55 in mesh therewith and gears 54 and 55 rotate themselves around gear 49. Gears 54 and 55 being supported by housing 58 which is connected with drum 60 by blades 59 cause the housing and the drum and all interconnecting parts to rotate in the opposite direction than those parts firmly driven directly by shaft 38. This method of obtaining opposite rotation of blade screws in blade screw compressors is believed to be new and novel.

Having described one embodiment of my invention according to patent statutes, it is understood that my invention is capable of embodiment in a variety of 'forms of apparatus and that I am not limited to the specific form of arrangement or structural parts shown and described but that the scope of my invention is to be gauged by the accompanying claims taken in connection with prior art.

I claim:

1. A refrigeration system including: an evaporator and condenser having connections with one another, the whole arranged to constitute a cyclic passage and maintained under relatively high vacuum; and a reaction-type power-drivable axial-blade-screw compressor in said cyclic pas sage and in compressive relation from said evaporator to said condenser, the portion of said cyclic passage containing said compressor being substantially straight from said evaporator to said condenser and the axis of said compressor extending in the same general direction as the axis of said portion of said cyclic passage.

2. A refrigeration system including: an evaporator and condenser having connections with one another, the whole arranged to constitute a cyclic passage and maintained under relatively high vacuum; and a reaction-typevmulti-stage power-drivable axial-blade-screw compressor in said cyclic passage and in compressive relation from said evaporator to said condenser, the portion of said cyclic passage containing said compressor being substantially straight from said evaporator to said condenser and the axis of said compressor extending in the same general direction as the axis of said portion of said cyclic passage.

3. A refrigeration system including: an evaporator and condenser having connections with one another, the whole arranged to constitute a cyclic passage and maintained under relatively high vacuum; and a reaction-type multi-andreversed-rotation-stage power-drivable axialblade-screw compressor in said cyclic passage and in compressive relation from said evaporator to said condenser, the portion of said cyclic passage containing said compressor being substantially straight from said evaporator to said condenser and the axis of said compressor extending in the same general direction as the axis of said portion of said cyclic passage.

RALPH C. ROE.

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