US2119338A - Apparatus for conditioning air - Google Patents

Description

May 31,1938. BEMILLS 2,119,338

APPARATUS FOR CONDITIONING AIR Filed Sept. 24, 1934 2 Sheets-Sheet l May 31, 1938. B. E. MILLS APPARATUS FOR CONDITIONING AIR Filed Sept. 24, 1934 2 Sheets-Sheet 2 2,119,33t PAATUS lFiHiR ECQNDIIEEUUG R a n. Mills, carries, llllL, assignor it li/iillis Novelty iloinpany, @hicago, iii, a corporation v of llilinois application September 24, 19341, Serial No. 'ii5,lii5

t illlaims.

This invention relates to an improved apparatus for conditioning air, and particularly to an apparatus for cooling, and regulating the moisture content of, the air to be treated, by the use of a solidified refrigerant such as carbon dioxide.

One of the important objects of the invention is to provide an apparatus for emciently utilizing a refrigerant, such as solidified carbon dioxide. for the cooling of air in ofiices and similar places where it would not be practical or feasible to use a costly compressor-condenser type of refrigerating equipment.

Another object of the invention is to provide an air conditioning apparatus wherein a mass of solidified refrigerant, such as carbon dioxide, is efficiently utilized to cool the air through the provision of a plurality of air flow tubes which are submerged in a body of liquid which is maintained in contact with the mass of refrigerant, the liquid, by reason of its complete contact with the exterior surfaces of said tubes, providing an almost perfect medium for transfer of heat between the walls of the tubes and the mass of refrigerant.

Another object, of the invention is to provide a cooling apparatus of the character set forth in which the cooling tubes through which the air is circulated are arranged to operate as condensers for removing moisture from the air during the course of its passage through the tubes, thereby reducing the humidity. of the air in the .room as well as cooling the same to a comfortable degree.

A further object of the invention is to arrange the cooling tubes in such position that the moisture forming therein will bedrained from the tubes and automatically removed from the path of air flow.

A still further object of the invention is to provide in an air conditioning apparatus of the type specified, means for regulating the exwnt to which the mass of refrigerant is immersed in the body of liquid, thereby adapting the apparatus to variations in the rate of 'cooling, depending upon the volume of air being treated.

Other objects and advantages of theinvention will be apparent from the following detailed description taken in connection with the accompanying drawings wherein I have shown the preferred form in which I have thus far contemplated applying the principles of the invention.

Referring to the drawings:

Fig. 1 is a front elevational view of a cabinet (ill. 62-915) embodying the improved air conditioning apparatus, portions of the front wall of the cabinet being broken away to show the construction of the cooling tubes and the liquid level adjusting mechanism;

Fig. 2 is a top plan view of the cabinet, the

j top wall of the cabinet being broken away to show the construction of the inner top wall;

' I Fig. 3 is a horizontal section through the cabinet taken on line 3-3 of Fig. l; and

Fig. 4 is a vertical section through the cabinet taken on lined-t of Fig. 1.

Referring to the drawings in detail, the apparatus in the embodiment shown is embodied in a double walled cabinet consisting of a rectangular base 5, a pair of spaced front walls 5 and I, a similar pair of spaced back walls t and t, side walls I i and i2 extending between the inner pair of walls i and 9, and outer side walls l3 and I4 extending between walls 6 and t and spaced from walls I I and I2, respectively. The

edge portions of the inner vertical walls are flanged outwardly as indicated at it, these.

flanged portions being either welded or riveted to the adjacent upper edge portions of the outer walls. The packing of insulating material is thus completely enclosed and serves to efiectively pre-' vent transmission of heat to the interior of the .cabinet.

In accordance with my invention I provide in the cooling cabinet a plurality of air flow tubes 2i which are preferably formed of sheet metal. As shown in Fig. 4, these tubes extend between walls I and 9, the ends of the tubes being welded as indicated at 22 to the circumferential edges of openings which are formed in walls I and 9 to receive the ends of the tubes. The portions of the outer vertical front wall 6 which register with the ends of tubes 2| are cut away to provide openings 23, and the lower por tion of back wall 8 opposite the bank of tubes 2| is cut away to receive a fan jacket 24 which is riveted at 20 to wall 8. Air is circulated through tubes 2| by a fan 25 which is driven by an electric motor 26, the latter being removably secured by a series of bolts 21 -to casing 24, said casing being provided with openings 28 through which air may pass to the tubes 2|. If preferred, the blower unit consisting of -fan 25 and motor 28 may be made entirely separate from the cabinet. In fact an ordinary electric fan may be used for this purpose by merely placing it opposite the tube openings in rear walls 8 and 3.

The apparatus is designed to cool the air during its passage through tubes 2| under the action of fan 25. In the embodiment shown I employ a mass of solidified carbon dioxide 28 which is supported in the cabinet above tubes 2| on a screen 3|, the latter being supported in the cabinet on a pair of angle bars 32 and 33 which are secured to walls 1 and 9, respectively. In accordance with one of the important features of the invention, the mass of solidified carbon dioxideor dry ice 29, instead of being placed in direct contact with tubes 2|, is supported in the upper portion of the cabinet, as shown in Figs. 1 and 4, and a path for flow of heat from the walls of tubes 2| to the mass of refrigerant is provided by a body of liquid 34 which extends from the bottom of the cabinet to level slightly above screen 3|. The purpose of this liquid is to provide for a more perfect path for flow of heat through the walls of tubes 2| to the mass of refrigerant than would be obtainable if the refrigerant were simply placed in direct contact with the exterior-walls of said, tubes. In the case where dry ice is employed as' the refrigerant,

I find that denatured alcohol is a suitable liquid.

to use for this purpose. In general it may be said that the liquidused must be one which has a freezing point below the melting point of the particular refrigerant employed. Also the liquid should be one in which the refrigerant will readily dissolve.

An apparatus of this type, which uses an expendable refrigerant, must necessarily be designed to operate for a period of several hours, or possibly a day, without requiring replenishment of the refrigerant. In the embodiment shown, in which the apparatus is especially designed for the use of dry ice, I find that most eillcientuse of the refrigerant is obtained by adjusting the level of liquid 34 so'that it has but very slight contact with the mass of refrigerant, it being noted from Figs. 1 and 4 that the surface of the liquid 34 is but slightly above screen 3|. As previously explained, the bodyof liquid serves as a cooling bath for extracting heat from the walls of tubes 2| and it is usually unnecessary to have any substantial portion of the mass of refrigerant immersed in the liquid.

At ordinary pressures solidified carbon dioxide vaporizes without passing through the intennediate liquid stage. The carbon dioxide gas is re moved from the cabinet through a vent pipe 35 which is positioned in the upper portion of the rear wall of the cabinet. The top of the cabinet is closed by a sheet metal cover plate 36, and an inner cover plate 31, formed of suitable insulating material, is provided for sealing the refrigerant compartment, this cover being provided at its rear edge with a pair of cleats 39 which are received in sockets formed in the rear wall of the cabinet. The. front edge of cover 31 is provided with sliding latch members 41 which are secured in position by channel strips 42. The cover 31 is locked in position by inserting cleats 39 in the rear cabinet wall after which the sliding latch members 4| are moved outwardly into locking position against the front wall as shown in Fig. 2.

By locating the vent tube 35 at the top of the refrigerant chamber (the space defined by walls 9, top 36, and screen 3|) and keeping the latter covered, a blanket of vaporized carbon dioxide is constantly maintained around the entire body of unmelted refrigerant, insulating the same from such heat as may find its way to the inner walls 9. At the same time, the excess (and least cold) carbon dioxide is allowed to flow ofl, while the colder portion of the carbon-dioxide blanket, remains in the chamber.

By maintaining the body of solid refrigerant completely above and spaced from, the air tubes 2| it is possible to use solid cakes of the refrig-q erant of large enough size to fill the refrigerant chamber, and the conduction of heat thereto from all of the tubes 2|, will be uniform. This is of particular importance in connection with the use of carbon-dioxide ice, because of the great difference between the vaporizing temperature of the latter and the temperature to which the air is to be cooled. It is undesirable to have direct contact between the, air-flow tubes and the solid refrigerant. Maximum cooling efliciency can be obtained by cooling all of the tubes to uniform'temperature, keeping the body of solid refrigerant insulated from heat absorption by the enveloping blanket of carbon-dioxide gas above it and on 'allsides, and limiting its heat absorption to the contact'of its bottom with the liquid which carries the heat uniformly 'from all of the tubes.

Means for varying the extent of immersion of the mass of dry ice 23 in the liquid 34 is provided-whereby to regulate the container, to the cooling of a greater or less volume of air as may be desired. In the embodiment shown I provide jects from the side wall of thecabinet. By turning crank 48, panel 43 may be raised or lowered in the body of liquid 34, thereby changing the liquid level to regulate the extent of immersion of the mass of dry ice 29. If air is being circulated through tubes 2| at a comparatively rapid rate, it may be desired to have the mass of refrigerant 29 immersed'to a considerable extent in liquid 34. On the other hand, if the cooling demand is comparatively light, panel 43 may be raised to produce a correspondingly lower liquid level and a consequent lessening in the rate at which" the refrigerant is expended.

I find that by cooling the air through the use of tubes 2| in the manner described I am able to likewise control the relative humidity of the air, thereby preventing an oppressive increase in the moisture content of the air upon a lowering in the temperature. Figs. 1 and 4 that the use of a plurality of tubes 2| arranged as shown, provides a very large surface which the air may contact during its passage through the cabinet. As the temperature of the air falls, the saturation point for the lower temperature is reached, with resultant condensation of moisture on the walls of tubes 2|. I find that this condensation is suflicient to prevent the It will be apparent from.

aliases air from becoming excessively humid even where the temperature drop is as much as 40 F. In order to remove the condensed moisture from tubes 2| I arrange the latter in inclined position as shown in Fig. 4. With the tubes in this position the moisture will drain toward the forward ends of the tubes, and will then flow downwardly along wall I into a drip pan 49, which is placed below the cabinet. The condensed moisture is months. Under such conditions the outlay requiredl for a mechanical refrigerating unit would be prohibitive.

The foregoing detailed description has been given for clearness' of understanding only, and no unnecessary limitations should be understood therefrom, but the appended claims should be construed as broadly as permissible in view of the prior art.

What I regard as new and desire to secure by Letters Patent is: r

1. Air conditioning apparatus comprising, in combination, a cabinet, a plurality of air flow tubes extending transversely through said cabi-. net near the bottom thereof, the lower'portion of the cabinet enclosing said tubes being adapted to hold a body of liquid extending to a level above the uppermost of the tubes, means for supporting a mass of a solidified refrigerant in the cabinet above said tubes and in position to be partially submerged by the liquid contained in the lower portion of the cabinet, and means for regulatlng'the extent of immersion of the mass of refrigerant in said liquid.

2. Air conditioning apparatus comprising, in

combination, a cabinet, a plurality of air flow tubes extending transversely through said cabinet near the bottom thereof, the lower portion of the cabinet enclosing said tubes being adapted to hold a. body of liquid extending to a level above the uppermost of the tubes, means for support ing a. mass of a solidified refrigerant in the cabi- 1 net above said tubes and in position to be partially submerged by the liquid contained in the lower portion of the cabinet, and means comprising a vertically movable fluid displacing memher for varying the level of liquid in the cabinet whereby to regulate the extent of immersion of said mass of refrigerant in the liquid.

3. Air' conditioning apparatus comprising a receptacle having a plurality of air flow tubes extending transversely therethrough; means for supporting a mass of a solidified refrigerant in said receptacle above said tubes, a body of liquid disposed in said receptacle around the tubes and in contact with a portion of the mass of refrigerant, the freezing point of said liquid being below the melting point 'of the refrigerant, and

means for regulating the extent of ersicn oi the refrigerant in said liquid.

4. Air conditioning apparatus comprising, in combination, a cabinet, a. plurality of air flow tubes extending transversely through said cabinet near the bottom thereof, the lower portion of the cabinet enclosing said tubes being adapted to hold a body of liquid extending to a level above the uppermost of the tubes, and means for supporting a mass of solid carbon dioxide in the cabinet spaced above the uppermost of said tubes and in position to be partially submerged by the liquid contained in the lower portion of the cabinet.

5. Air conditioning apparatus comprising, in combination, a cabinet,. plurality of air flow tubes extending transversely through said cabinet near the bottom thereof, the lower portion of the cabinet enclosing said tubes being adapted to hold a body of liquid extending to a level above the uppermost of the tubes, means for supporting a mass of solid carbon dioxide in the cabinet spaced above the uppermost of said tubes and in position to be partially submerged by the liquid contained in the lower portion of the cabinet, and

means for circulating the air to be treated through said tubes.

. a body of liquid disposed in said receptacle around the tubes and in contact with a portion of the vmass of refrigerant, the freezing point of said liquid being below the melting point of the refrigerant, and means for circulating the air to be treated through said tubes.

7. Air-conditioning apparatus comprising: a cabinet, a plurality of air-flow tubes extending transversely through the lower region of said cabinet, a refrigerant chamber being formed above said tubes, said chamber being closed on all sides and at the top, and of such dimensions as to receive a. mass of carbon-dioxide ice and provide a closed space around all sides of and above said mass, means'to support said mass above and out of contact with said tubes, and means for withdrawing the vapor, resulting from vaporization of said mass, from the upper region of said chamber, the region of said cabinet below said chamber being adapted to hold a body of liquid extending to a level in contact with the bottom of said mass, forming the bottom of said closed space in which said vapor is confined in the form of an insulating blanket enveloping all sides or said mass except its bottom.

8. Air conditioning apparatus comprising, in combination, a cabinet, a plurality. of air flow tubes extending transversely through said cabinet near the bottom thereof, the lower portion or the cabinet enclosing said tubes being adapted to hold a body of liquid extending to a level above the uppermost of the tubes, and means for supporting a mass of solid carbon dioxide in the cabinet spaced out of contact with said tubes and in position to be partially submerged by the liquid contained in the lower portion or the cabinet.

BERT E. MILLS.

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