US2347757A - Refrigeration - Google Patents

Description

A. R. THOMAS REFRIGERATION May 2; 1944.

Filed May 6, 1941 4 Sheets-Sheet 1 INVENTOR y 1944- A. R. THOMAS 2,347,757

REFRIGERATION Filed May 6, 1941 4 Sheets-Sheet 2 IN VENTOR MK/Vmu A TTORNE Y y 44- A. R. THOMAS 2,347,757

REFRIGERATION Filed May 6, 1941 4 Sheets-Sheet 3 7 a h 4 I 2 E 7 Z 47 v I INVENTOR A TTORNEYQ May 2, 1944.

A. R. THOMAS 2,347,757

REFRIGERATION Filed May 6, 1941 4 Sheets-Sheet 4 ATTORNEY Patented May 2, 1944 REFRIGERATION Albert R. Thomas, Evansville, Ind., assignor to Serve], Inc., New York, N. Y., a corporation of Delaware Application May 6, 19h, Serial No. 392,090

4 Claims (Cl. 261-112) My invention relates to cooling towers, and more particularly to cooling towers of the induced draft type in which liquid flowing downward by gravity is cooledby partial evaporation into air flowing countercurrent to the liquid.

It is an object of my invention to provide an improved cooling tower in which air passes countercurrent to downwardly flowing liquid at a relatively high velocity with substantially no entrainment of liquid in the air stream, so that the necessity of providing eliminators or similar devices to effect removal of liquid from the air stream is avoided.

Another object of the invention is to provide an improved cooling tower of the induced draft type in which counter-current flow of air and liquid is'efiected with air velocities as high as 1,000 feet per minute, so that a cooling tower of a given capacity will occupy a relatively small amountof space.

A further object of the invention is to provide an improved cooling tower in which the liquid to be cooled is distributed in a region or pocket not directly in the high velocity air stream to cause liquid films to be formed on suitable vertically extending surfaces contacted by the air stream.

A still further object of the invention is to provide an improved cooling tower utilizing countercurrent flow of air and liquid to effect cooling of the liquid, and to spray the liquid onto the top edges of paneling at a region in which the air is relatively stagnant to produce liquid films adapted to be contacted by air flowing at a high velocity.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the claims. The invention, both as to organization and method, together with the above and other objects and advantages thereof, will be better understood by reference to the following description taken in connection with the manner in which liquid films are formed on the paneling;

Fig. 5 is an enlarged fragmentary sectional view, taken on line 5-5 of Fig. 3; and

Figs. 6 and 7 are fragmentary perspective views illustrating in detail the paneling shown in Figs. 3 and 4.

Referring to Fig. l, the improved cooling tower l0 embodying my invention is shown in connection with an' absorption type refrigeration apparatus II. In apparatus of this type liquid refrigerant evaporates in a cooling unit with consequent absorption of heat from the surroundings to produce a refrigeratinng effect. The refrigerant vapor formed in the cooling unit is absorbed into a liquid absorbent in an absorber l2 and absorption liquid, enriched in refrigerant, is conducted to a generator. By heating the. generator, refrigerant is expelled from the absorption liquid, liquefied in a condenser l4, and then returned to the cooling unit to complete the refrigerating cycle. In order to simplify the drawings, the refrigeration apparatus illustrating a cooling tower embodying the invention shown in connection with an absorption type refrigeration system;

Fig. 2 is a perspective view of the cooling tower shown in Fig. 1;

Fig. 3 is an enlarged vertical sectional view, taken on line 3-3 of Fig. 2, to illustrate parts of the cooling tower more clearly;

Fig. 4 is an enlarged fragmentary sectional view, taken at line 4-4 of Fig. 3, to illustrate H has been illustrated very generally and in outline with the absorber l2 and condenser 14 constituting the only parts specifically shown,

the remaining parts of the apparatus not being illustrated since this is not believed to be necessary for an understanding of my invention.

The heat of absorption resulting from absorption of refrigerant vapor in absorber I2 is given up to a suitable cooling liquid, such as water, which enters the absorber through a conduit IS. The cooling water is conducted from absorber l2 through a conduit I6 to condenser M in which heat of condensation, resulting from condensation of refrigerant vapor, is given up to the cooling water. From the condenser l4 the cooling water is conducted through a conduit I! to cooling tower I0, and, after being cooled in the latter, the cooling water flows through conduit IE to absorber I2 to complete the cooling water cycle.

Referring more particularly to Figs. 1,2 and 3, the cooling tower It! includes a base l8, an upright shell l9 mounted on and extending upward from the base l8, and a hood or cover 20; The base [8 is formed with inclined side walls 2| having air inlet openings 22 which are covered by screens 23. One of the side walls of shell I9 is provided with an opening at the upper part of electrical energy." The motor 29 is disposed in a casing 30 supported at the bottom of the horiz ontal portion of duct 24, and, in order to dampen the vibrations of the motor 29, the latter is preferably mounted on rubber blocks, as indicated at 3| in Fig. 3.

When fan 21 is operating, air is drawn into the base. l8 through the inlets 22 and flows upward through shell l9. The side wall of shell l9 to which duct 24 is connected is provided with a deflector or baflie 32 to increase the vertical distance through which air flows upwardly in shell I9, and also to causethe air to pass into the top part of the horizontal portionof duct 24. From duct 24 the air is discharged at the outlet 25 to the atmosphere. The screens 23 at the inlets 22 remove foreign matter from air drawn into the base i8, and the screen 26 at the outlet 25 protects the fan 21 disposed in the duct 2d.

The cooling water conducted through conduit ll to the top part of cooling tower ii] is distributed within the hood or cover 20 and flows downward by gravity in shell E9 in a manner to be described presently. During downward flow in shell it, the water is cooled by partial evaporation into the air stream flowing countercurrent thereto. The cooled water collects in the bottom part of base it which serves as a sump. To the base i8 is connected a conduit 33 through which water is conducted from a suitable source of supply. The water is maintained at a predetermined level in the bottom of base it by a float 34 operatively connected by an arm 35 to a valve 35 which is connected in the part of conduit 33 within the base it.

During circulation of water in the cooling water circuit described above, a small amount of water is lost due to evaporation in the cooling tower iii. The water conducted to base l9 through conduit 33 keeps the water at a predatermined level in the sump and is referred to as additional or make-up water which takes the,

place of water lost by evaporation. An overflow conduit 31 is located in the bottom part of base l8 so that water can flow to waste when the liquid level in the sump rises above the upper end of this conduit.

The water is drawn from the bottom of base l8 through suitable screening 38 connected to the end of conduit i5, so that foreign matter will be removed from the water prior to entering the absorber l2 and condenser M. A pump 39, which is connected in conduit i and arranged to be driven in any suitable manner, as

ago

by an electric motor, for example, is provided to circulate the cooling water through absorber l2 and condenser it of the refrigeration apparatus ll.

Within the upright shell l9 are disposed a plurality of closely spaced vertical panels ill. The panels fill are held in position by suitable supporting structure including a plurality of horizontal angle members ii having the ends thereof secured to the end walls of base i8, as indicated at 42 in Fig. 3. The horizontal angle members 4| are located at the same height and are parallel to each other with each member being disposed adjacent to and substantially midway between the top and bottom edges of the inlets 22. To the horizontal angle members ii are secured the lower ends of a plurality of U-shaped channels or guides 53, as shown most clearly in Figs.

3 and 5. The channels .23 are spaced close together at opposite sidewalls of shell it with the open ends' facing each other. The rear sides of the closed ends of channels 43 are secured to horizontal angle members 44 having the ends thereof connected to the end walls of shell H9. The horizontal angle members 45 are positioned at the extreme upper ends and also at a central or intermediate region of the vertical channels 43 to provide a rigid supporting structure for the panels so now to be described more fully. A suitable reinforcing member 45 extends from. one slopin sidewall 2i to the opposite sidewall of base it and is connected at its ends to intermediate regions of the horizontal angle members 5! as best shown in Fig. 3.

The panels dd are preferably formed from a number of separate plates 56 disposed one agove the other. The plates :55 may be formed of wood or metal, and plates formed from red cypress have been satisfactorily employed. The vertical channels 33 at opposite sides of shell it are directly opposite each other and receive the plates so. The bottom plates dd of each panel ill rest directly against the bottom horizontal angle members 4!. From the base it to the region of shell 09 just below the top edge of deflector 32, the plates 46 in each'panel db preferably do not abut each other but are spaced apart by approximately one-half inch by spacer rods t? which are parallel to the-sidewalls and extend from one end wall to the opposite end wall of shell 59. The spacer rods at rest against the open ends of vertical channels 33 with each rod being held in position by the weight of the plates lii and rods it above it. In'the top part of shell 99, at the region extending upward from the extreme top edge of deflector 32, the plates at rest directly against each other to form solid panel portions, as best shown in Figs. 3 and 4.

The hood or cover 29 is removably fastened to the top part of shell W, as indicated at at in Figs. 2 and 3. Within hood 2b is secured a pipe db which serves as a manifold for distributing water and to which is connected a plurality of spray heads or nozzles 5t. One end of the pipe at is closed and the other end thereof is open and passes through a wall in the hood 20, as shown in Fig. 4. To the part of pipe d9 extending outside the hood 2b is connected the lower end of conduit H. In order that the hood 28 can be readily removed during operation of the cooling tower, the lower portion of conduit ii is pref=- erably flexible.

The water conducted through conduit ill to the nozzles 5E5 is sprayed in the pocket or chamber 59 formed by the hood 26. In order to form water films on the panels to the top plates as of each panel are provided with water distributing slats 52. The slats 52 are of the shape shown in Figs. 4 and 6 and are formed with tapered top portions to provide sloping surfaces for conducting spray water toward the surfaces of the highest plates 66'. The slats 52' are secured to the 'top plates co in any suitable manner, as indicated at 53 in Fig; 6. The slats 52 are formed with slots 52 to provide narrow passages at the surfaces of plates 26 to facilitate the formation of the liquid films on the surfaces of the panels ti.

During operation of the cooling tower it, the water returning from the refrigeration apparatus ii is sprayed into the chamber at by the nozzles so, as described above. It is only necessary to deliver water to the nozzles 5d at a relatively oration into the upwardly flowing air.

low pressure which is just sufilcient to cause distribution of the water over the entire top edges of the panels 40. In practice it has been found that delivering the water to the nozzles 50 at a pressure as low as two or three pounds per square inch is adequate to produce satisfactory distribution of the water in chamber 5|.

The tapered sides of the slats 52 and adjacent surfaces of the uppermost plates 46 form troughs 55, as best shown in Fig. 4, in which water collects. .The water collecting in the troughs 55 is formed by the drops of spray. water falling onto the top edges of the uppermost plates 46 and sloping sides of the slats 52. The water in troughs 55 passes between the contacting surfaces of the slats and portions of plates 46 covered by the slats, and also around the ends of the slats and through the passages formed by the slots 54, to produce liquid films on all of the surfaces of the uppermost plates 46. The water films first flow continuously on the solid upper portions of the panels 40.

At the region just below the top edge of the deflector 32, the first gaps 56 are formed in the panels by the uppermost spacer rods 41, as shown most clearly in Fig. 3. The gaps 56 are provided in the panels 40 to cause the water to drip from the bottom edge of each plate 46 onto the top edge of the succeeding lower plate to facilitate and promote the spreading of the water on the plates 46, so that the surfaces of the panels 40 are completely wetted and the tendency for water films to'form distinct streams will be avoided.

From the bottom edge of the lowermost plates 46 the water falls onto a splash plate 51 disposed in the base l8. The plate 51 is provided with inclined surfaces which are in the paths of the falling drops of liquid and extend below the water level in the base l8. With this arrangement the water flows on the inclined surfaces of the plate 51 and eliminates the noise in splashing that is usually encountered when drops of water fall onto the flat surface of a body of water.

The air drawn into the cooling tower I through the inlets 22 flows into the passages between the panels 40 not only at the bottom edges of the panels but also along the portions of the end edges thereof which project downward into the base l8 from the bottom of shell IS. The air flowing upward in shell H3 in the narrow passages between the panels 40 acquires a high velocity and comes in contact with the films of water formed on the surfaces of the plates 46. The Water flowing downward by gravity on the surfaces of the plates 46 is cooled by partial evap- The air stream changes direction very abruptly at the top part of shell IS with the air stream making practically a 90 or right angle turn from shell I! into duct 24.

It will be seen that the distribution of water onto the top edges of panels 40 is effected n chamber 5| which forms a dead-end pocket in the top part of the cooling tower with respect to the upwardly flowing air stream. The uppermost plates 46 and slats 52 associated therewith constitute a barrier to flow of air into dead-end p cker, 5| in which the air is relatively stagnant. In this way the distribution of water onto the panels 40 is effected in a region not directly in the high velocity air stream flowing upward in shell l9 and passing into duct 24, as indicated by the arrows in Fig. 3. In the part of shell IS in which the high velocity air stream is passing. the air comes in contact with the films of water which flow downward on and cling to the surfaces of the panels 40. The slats 52 insure the formation of the water films on the panels 40, so that drops of water from chamber 5| will not fall between the panels 40 into the air passages.

Below the top edge of th deflector 32 drops of water fall in the gaps 56 from the bottom edges of the plates 46 onto the top edges of the succeeding lower plates. These drops of water fall in regions at one side of streams of air passing upwardly at a relatively high velocity between the panels 46. The water dripping in the gaps 56 is protected to a great extent from the air flowing past the gaps from each plate 46 to the succeeding higher plate. At the gaps 56 there is a tendency for the pressure at these regions to be reduced slightly due to the action of the high velocity air passing these regions, whereby a pulling effect is exerted on the drops of falling water. Since the pulling effect on the water drops at one side of the gaps 56 is counteracted by a similar pulling effect on these drops at the opposite sides of the aps, the drops of water in the gaps 56 tend to remain in these regions and fall onto the top edges of the plates 46. Hence, entrainment of the drops of water in gaps 56 by upwardly moving air is not readily effected.

At the upper region of shell I9 at which the air stream makes an abrupt or right angle turn, the panels 40 are solid with no gaps provided between the individual plates 46. The solid portions of the panels 40 provide continuous surfaces to which the water effectively clings, so that entrainment of such water into the air stream is effectively prevented. Moreover, any tendency for water to be entrained in the upward- 1y air flowing in shell I9 is effectively counteracted by the abrupt change in direction of air flowing from the shell into the duct 24.

The water dripping from the bottom edges of panels 40 onto the splashplate 51 does not come into contact with high velocity air, because the air velocity does not build up until the air flows into the narrow passages formed between the panels 40. Hence, there is substantially no entrainment of water by the air While the latter is passing through the upper part of base l8. Any tendency for water to be entrained in the air in base it is effectively counteracted by causing the air stream to make an abrupt 90 or right angle turn upwardly into shell I!) after entering the base 8 more or less horizontally through the the cooling tower at relatively high velocities is due primarily to spraying the water in the pocket or chamber 5| in which the air is relatively stagnant, and flowing the water directly onto the surfaces of the panels 40 in the dead end pocket. With this arrangement, as pointed out above, when the water comes into contact with the upwardly flowing air stream, films of water are produced on the surfaces of the panels 40 to which the water readily clings. By flowing air countercurrent to fllmsof water in the manner described, it is possible to effect cooling of water with their velocities as high as. 1,000 feet per minute, whereby a cooling tower of a given capacity will occupy a relatively small amount of space.

While a single embodiment of the invention has been shown and described, it will be apparent to those skilled in the art that modifications and changes may be made without departing from the spirit and scope of the invention,

as pointed out in the following claims.

What is claimed is:

1. A cooling tower comprising a casing providing an upright shaft having an inlet for air in the lower part thereof and an outlet for air at the upper part thereof, members in said passage providing liquid bearing surfaces projecting above said air outlet, liquid distribution structure for depositing liquid on said surfaces and forming a liquid film thereon in a zone above said air outlet, said structure including a barrier to flow of air between the zone in which liquid is I deposited on said surfaces and said air outlet.

said liquid bearing surfaces being substantially continuous in vertical extent in the region of said air outlet so that all the liquid descendin by gravity through this region is adherent to said members so as not to be entrained by air flowing from the passage at high velocity, and said surfaces having small gaps at places below said air outlet so that liquid is redistributed on said surfaces by dripping across said gaps, the I spacing between said members being proportioned so that the velocity of air is substantially the same on all sides of said gaps so that the dripping liquid is not displaced into the air streams.

2. A cooling tower as set forth in claim 1 in which said liquid distributing structure includes a spray device within a hood or cover removably attached to said casing over the upper end of said shaft.

3. A cooling tower as in claim 1 in which said members are formed of spaced apart vertically extending slats, and said liquid distributin structure includes a sprayer over the upper ends of said slats, and said barrier is formed of closure members between adjacent slats, said closure members having drain openings adjacent the surfaces of the slats.

4. A cooling tower having a liquid inlet at the top, a filler comprising spaced apart vertically extending slats, connections for flow of air upward through said tower, and a partition at the upper end of said slats below said liquid inlet formed by a plurality of closure members secured between adjacent slats'at their upper ends to fill the gaps between said slats, said closure members having grooves in their edges next to the surfaces of said slats so that water deposited upon the top of said partition is divided by said closure members and flows downward through said grooves at the opposite edges of said closure members on to the opposing surfaces of each pair of adjacent slats.

ALBERT R. THOMAS.

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