US2971750A - Evaporative cooling tower and the like - Google Patents

Description

Feb. 14, 1961 c. BOLING EVAPORATIVE COOLING TOWER AND THE LIKE 4 Sheets-Sheet 1 Filed Aug. 3. 1955 -lNVENTO R Cecil Boll/n MW/Mir a. 9

ATT =H- Feb. 14, 1961 c, BQLING 2,971,750

EVAPORATIVE COOLING TOWER AND THE LIKE Filed Aug. 3, 1955 v 4 Sheets-Sheet 2 Cecil 3011;,

BY m mf g ATTORN Feb. 14, 1961 C. BOLING EVAPORATIVE COOLING TOWER AND THE LIKE 4 Sheets-Sheet S Filed Aug. 3, 1955 INVENTOI? Cec L l 1301 Feb. 14, 1961 c. BOLING EVAPORATIVE COOLING TOWER 'AND THE LIKE Filed Aug. :5 1955 4 Sheets-Sheet 4 INVENTOR Cec ii ,3 01621 ATTJM United States Patent EVAPORATIVE COOLING TOWER AND THE LIKE Cecil Boling, West Hartford, Conn., assignor to Dunham- Bush, Inc., West Hartford, Conn., a corporation of Connecticut Filed Aug. 3, 1955, Ser. No. 526,105

6 Claims. (Cl. 261-111) This invention relates to evaporate cooling, and more in particular to cooling water in a refrigeration or air conditioning system.

An object of this invention is to provide an improved evaporative cooler construction. Another object is to provide an improved apparatus for cooling water. Another object is to provide improved refrigeration systems of the type having cooling water which is evaporated to dissipate the heat. A further object is to provide improved refrigeration systems having water-cooled condensers with provision for cooling the water and recirculating it. A further object is to provide for the above with a structure which is compact, light in weight, efficient and dependable in use, and which will withstand considerable abuse and extended usage without material damage thereto. A further object is to provide for the above with a cooling tower arrangement which operates with minimum power requirements for the circulation of air and without excessive noise.

A further object is to provide for the above in such a manner as to avoid the difiiculties which. have been encountered in the past. These objects will be in part obvious, and in part pointed out below.

In the drawings:

Figure 1 is a side elevation with the casing wall broken away of a cooling tower which constitutes one embodiment of the invention and is incorporated for purposes of illustration into a refrigeration system which is represented schematically;

Figure 2 is an elevation of the cooling tower from the left-hand side of Figure 1;

Figure 3 is an enlarged elevation of a unit of the towers of Figures 1 and 2;

Figure 4 is a further enlarged view of a portion of the structure of Figure 3;

Figure 5 is a sectional view on the line 5-5 of Figure 4;

Figure 6 is an enlarged perspective View of a portion of the structure of Figure 3; and

Figure 7 is a perspective view of another embodiment of the invention, with parts broken away.

Referring to Figure 1 of the drawings, the cooling tower 2 has a casing 4 with side walls 3 and a top wall 5, and it encloses an evaporative unit 6. At the left in Figure 1, there is a fan 8 which is supported and driven by a motor 10, and the motor is supported upon a pair of mounting brackets 11 removably attached to the casing. Mounted within the casing directly beneath the top wall 5, is a water distributor pan 12 into which water flows through a coupling 14. The bottom of pan 12 is provided with a large number of evenly-spaced water outlet openings through which the water flows at a constant rate, and with even distribution throughout the rectangular zone which is the width of the pan (Figure 1) and extends between the side walls 3 of the casing. The bottom of casing 4 is for'rnedby a sump tank or pan 16,

into which the water falls after being cooled and from' ,at an angle of the order of 6 from a right-angle or" vided, and (see Figure 2) a drain 90 is connected into the bottom of the pan so that the water may be drained from the unit during periods of non-use. A. float 26 in tank 16 controls a water inlet valve 24 and maintains a constant water level in the tank. As will be discussed more fully below, water is continually evaporated from the tower during operation so that water from the city mains or another source is supplied to the tank through valve 24.

Unit 6 is formed by four decking surface assemblies 28, 30, 32 and 34 (shown in broken lines) which are rigidly mounted between a pair of end plates 36. The two decking surface assemblies 28 and 30 are identical, and assemblies 32 and 34 are identical; and, all of these assemblies are of similar construction and the same width, but assemblies 32 and 34 are substantially longer; that is, of greater height than the other two. Each of these assemblies has a rectangular wooden frame formed by a pair of side frame members 17 and 19, and top and bottom frame members 21 and 23, all of redwood. The wood frame has sheet metal reinforcing at its edges, and mounted within the wooden frame there is a sheet metal decking surface assembly 25.

The sheet metal decking surface assembly is formed by a plurality of corrugated strips 15 (see Figures 3, 4 and 5). In this embodiment, each strip is made from sheet copper, illustratively, one inch wide and .004 inch thick, and the strip is fabricated into corrugations which are one-half inch deep and inch wide so that there are vertical portions 92 and horizontal portions 27.

Each of these strips extends lengthwise horizontally the full width of the frame, and two strips are positioned side-by-side to form a horizontal layer in the frame, as shown in Figure 5. These horizontal layers, each formed by two strips are stacked one above another to fill the entire frame. The assembly of strips presents two rectangular faces 31 and 33 (see Fifure 5) and the strips may be considered as comprising one vertical layer adjacent'each of these faces. The corrugations in strips 15 are in the form of alternate upright and inverted channels. Each of the channels forming the corrugations in a strip is substantially in alignment with a channel in the horizontally aligned strip so that the two strips in each horizontal layer form a row of straight channels extending between faces 31 and 33.

The corrugations ineachof the strips are offset at, a small angle from lines normal to the'edges of the strip so that (see the left-hand portion of Figure 5) each of the channels forming the corrugations in the strip is offset the width of the channel. A the two strips forming a horizontal layer,;eachlchannel is offset the width of two channels. corrugations of the two strips of each layer is opposite to that offset of the strips in the two adjacent horizontal layers. In other words, in stacking the layers of strips in the frame, the alternate layers are reversed so that the corrugations in one layer slant ,to the left as shown at the left in Figure 5, whereas the corrugations in the next layers above and below slant to the right as shown at the right in Figure 5. In this way, the strips in each of the successive layers are supported by the strips directly below them because the angular relationship between the contacting corrugations prevents the corrugations from nesting. In other words, the angular relationship of the corrugations with respect to the faces 31 and .3 permits the supporting of each strip by the strip beneath it. As will be further pointed out below, this angular relationship also has important operative advantages. In this embodiment of the invention, the corrugations are Hence, in the full width of The oifset in the transverse relationship so 7 the three pronged strips 35 along. this surface.

that the corrugations in each layer extend substantially at an angle of 12 with respect to the corrugations in the next layers.

For some conditions of operation/the two strips forming each horizontal layer are reversed so that the corrugations of one stripslant to the left, and'thecorrugations of the other strip] of that layer slant to the right. With this. arrangement, the mating channelso-fthe. two strips are. at an angle to each other, ,and the straight channel releationship of Figure is not provided;

At the ends and at the centervof strips 15 three pairs of pronged metal strips 35" which extend, respectively,

along the faces 31 and 33 (see Figures 4 and 5) hold.

the strips in alignment (see Figure 3) and provide support for each of them atthese points. Strips 35 are attached at their top and" bottom ends to the wooden frame and are heavy, gauge sheet metal so. that they have substantial rigidity, These strips have integral prongs 37 punched from them which extend horizontally from the strips; that is, transversely of the faces 31 and 33. These prongs are spaced thevertical dimension of the corrugated strips 15, and each prong extends into the top of one of the inverted channels of a corrugated strip. Each of the strips 35 on face 31 has a prong 37 which extends below the horizontal portion of one of the inverted channels of each of the adjacent strips 15, and the strips 15 along surface 33 are similarly supported by Hence, each of the corrugated strips has three prongswhich extend into it to provide support.

It has been indicated above. that the corrugated strips 15 are supported by each other and also by the pronged strips 35, and that the pronged strips hold the corrugated strips inalignment. In addition, there is along each of the faces 31 and 33 a supporting grid. assembly (see Figure 3 formed by taut verticalwires 39 and horizontal wires 41. These wires aresecurely anchored to' the frames at their ends by staples 43. -Furthermore, at each intersection of a wire 39 with a wire 41, there is an angle bar 45 (see also Figure 6) which extends through the corrugated strip assembly from face 31 to face 33 and has in each end an opening 47 and two openings 49. The vertical.wires.39 extend through openings 47, and the horizontalwires. 41- extend throughopenings 49. Bars 45 are of sheet metal and are sufficiently small to extend between two adjacent horizontal layers-of corrugated strips 15 without. any substantial displacement of the strips. However, the corrugated strips are sufficiently flexible to permit this smalldisplacementr These bars are rigidly held by wires 39 and-41, and they cooperate with the prongs 37 to providereinforcing support for the strips. .Wires.39-and 41 also cooperate with strips- 35 to confine the corrugated strips substantially between theplanes- 31 and 33. In Figure 3, eight vertical wires 39 and four horizontal wires. 41 are shown, andthey; are.

spaced substantially four. inchesapart.

Unit 6 restsQupon a parrot angle members 38 (Fig the left, and thence downwardly along the front face'of. unit 6 substantially one-half inch from the surface of.

the unit.. At the bottom edge of assembly 28, screen 44 extends at an angle downwardly, and thence along the surface of assembly 32 to the bottom thereof. Screen 44 is expanded sheet metal formed with diamond-shaped openings which are relatively small. Screen 44'has sub stantial rigidity, and it is supported at itsv top-end edges. by brackets fixed to unit 6. This screen extends the width;of. unit.6, and. its top and bottom: edges extend:

. 4 beyond the edges of the zone into which water falls from pan 12. Hence, during operation, the small streams and drops of water from the pan are intercepted by the screen, and the impact disperses the water and breaks it into small particles and droplets.

At the left of unit 6 there is an eliminator screen 50 which is mounted at an angle of substantially 10 from the vertical. Screen 50 is rigidly clamped at the top between a pair of strips 52 which are held together by a plurality of bolts and are supported at their ends by a pair of brackets mounted upon the end walls 3- of the casing. The bottom edge of screen 50 is clamped to a baffie plate 54, mounted on the casing, by a removable angle bar 56 which is held in place by a plurality of screws. At the leftof eliminator screen 5!} there is a fan cowl plate 58 which surrounds the fan and forms the adjacent casing wall, and a cage-like fan guard 69 is removably clamped to the cowl plate. The right-hand side of the casing is closedat' the top by a panel 62, and beneath this panel there is an air inlet opening 64 in horizontal alignment with unit 6.

During operation, fan 8 draws air in through opening 64, and thence through unit 6, and the air is discharged through the fan at the left. Simultaneously, water from pan 12 falls in small streams and drops onto screen 44, and the-streams andv drops are dispersed so that the water falls in fine particles which are somewhat spattered onto the exposed surface of unit 6. Hence, the water thoroughly wets the surfaces of. the corrugated strips, and the water moves to the right and downwardly along the corrugations, andemerges from the right of the unit 6, and a certain amount of water drops into the pan 16. However, during this time, air. which is drawn into the right-hand side of casing 4 at opening 64, flows through the corrugations toward the left and upwardly countercurrent to the water flow, and the'air flow is sufficient to cause considerable turbulence in the flowing water.

Hence, the water isblown back and up, and is spattered.

so that the corrugated -strips are thoroughly and c0nstantly wetted. Some water which emerges at the right of unit 6 and drops from the unit iscarried back into the unit by the air stream. Therefore, while the water tends to fall, as indicated in Figure 1', onto the entire left-hand surfaceof unit 6, and having passed through unit 6 countercurrent to the air flow, some of the water starts to drop, but is thrown back into the unit.

The assemblies 28, 3t), 32 and 34 are identical'in construction although, as indicated, the. latter two are larger than the former two. Hence, the unit 6 is honeycomb like in construction, with the channels formed by the passageways or. channels in the strips extending atslight angles to lines transverse of the faces of the assemblies.

and of the unit. These channels slant in their general horizontal planes alternately to the left and right, so that.

air passingv through the channels atone layer. tends to move at the left, whereas air passing throughthe channels above and below tendsto move to the right, and water'tends to move oppositely. water counter-current to the air flow results from the positioning of unit 6 at anv angle to thevertical so. that the channels are slanted from the horizontal..'

With this arrangement, the air entering the tower 2 at 64 (Figure 1) moves horizontally toward unit 6 and.

heighth of" assemblies 32 and 34. That is, with the arrangement shown, the lower portion of unit'6 provides The movement of the.

The air is distributedso thatit flows through the an air flow path through only two of the decking surface assemblies, whereas the air flow path in the upper twothirds of the unit is through all four of the decking surface assemblies. It has been found that this arrangement gives improved results for some conditions of operation because the distribution of air is better than when all of the assemblies are of the same size.

With this unit, a very largeamount of effective decking surface is provided Within a very small volume; that is, unit 6 contains several times the amount of wetted surface as an equal volume of standard decking. Also, the corrugated strips are constantly wetted upon both sides and the sheet metal corrugations are shaped so as to provide maximum heat transfer with low air pressure drop. This is accomplished by providing the rectangular air channels or passageways through which the air flows from one side of unit 6 to the other, and which extend vertically 'and are relatively thin so that the air throws the water up along the strip surface. During operation, each metal strip conducts heat from one surface to the other so that both surfaces are eifective evaporating surfaces, and the heat passes to the cooler surface.

As the air moves from the left-hand side of unit 6, it tends to carry some water with it, and this water tends to fall down onto the unit. However, water held in the stream of air is intercepted by the eliminator screen 50, and passes down this screen, and flows along baffle 54 and drops onto the bottom of unit 6. All of the unevaporated water from unit 6 has been cooled and is collected in the drip pan 16. The air is discharged through the fan free of water.

In the embodiment of Figure 1, the. cooling tower 2 is shown, for purposes of illustration, as incorporated into an air conditioning system as part of the air-cooling refrigeration system. Accordingly, water is withdrawn from sump tank 16 through a line 68, and flows through the water circuit of a water-cooled condenser 69. Condenser 69 is part of the refrigeration system which also has a receiver 71, a motor-compressor 73, an evaporator 75, and a fan 77. Fan 77 directs the stream of air to be cooled through the evaporator, and the system includes standard controls and auxiliaries.

The cooling water is withdrawn from condenser 69 by a pump 79 which delivers the water through line 81 back to coupling 14 and to the water distributor pan 12. Hence, the water is re-circulated and water is added automatically at all times to maintain the desired level in the sump tank or pan 16. When the operation of the system is discontinued, the water drains from pan 12 and unit 6, and this tends to raise the level above the top of the overflow pipe 22. Hence, during normal operation there is some water discharged to the drain at the end of each operating cycle, and this may provide desired purging.

In accordance with the present invention, the water is maintained in rapid flowing condition through the zone of unit 6. The thin strips forming the decking surface insure maximum water evaporation and heat transfer in the space which is occupied. The water flows from pan 12 through relatively large openings which in this embodiment are three-sixteenth inch in diameter. How ever, the individual streams fall by gravity and, as discussed above, are broken up when they hit the distributor screen 44. The entire path of circulation of the water does not include any nozzles or other restrictions of the type which are apt to clog during normal usage.

With the arrangement herein disclosed, the water is cooled very efficiently and rapidly. This cooling action is insured by the very great amount of decking surface, the turbulence in the water flow which materially promotes evaporation, and the uniform counter-current flow of the air and the water, which insures that all of the air is thoroughly saturated. In spite of the very rapid and turbulent counter-current flow within unit 6, the construction and mode of operation are such that the operation is quiet and the power consumption is low. It has been indicated above that the reduced vertical heighth of units 28 and 30 insures an even distribution of air because the lower portion of unit 6 has water'and air paths of reduced length. It should be noted also that the longer flow paths of the upper portion of unit 6 permit a greater cooling period for the water, and a greater period of time for the air to take on water vapor and heat; this appears to insure improved operation for some conditions of operation because the warm water from the distributor pan 12 reaches this upper portion of unit 6 before being cooled materially.

Illustratively, the corrugated strips forming the decking surface are of copper, but for some conditions of use these strips and other metal parts contacted by the water are made of stainless steel. Certain aspects of the invention are applicable to other evaporative cooling apparatus. For example, an evaporative condenser may be provided, having the condenser coil positioned in place of unit 6 in the illustrative embodiment. This coil will have an external fin assembly. The illustrative embodiment of the invention, therefore, might be considered as a refrigeration system having secondary evaporative cooling for its condenser, whereas the cooling could be direct with the evaporative condenser just discussed.

The illustrative embodiment of the invention of Figure 7 is a unit 70 similar in construction to the embodiment of Figures 1 to 6, but of large' capacity. Unit 70 has a casing 72, a decking unit 74 and other elements as in Figures 1 and 2, including a fan (which has been omitted from the drawing in order to show the water distribution system). This water distribution system includes two water distribution pans '76 and 78 having closed tops and positioned respectively at the top and central portion of unit 74. The incoming water is received at the center of pan 76 through a pipe 80 and flows toward the ends of this pan. At the extreme ends of this pan are two water chutes or conduits 82 which extend from the bottom of pan 76 down to pan 78. Hence, the water flows from the water inlet pipe 80 toward the ends of pan 76, and it is discharged through openings in the bottom of this pan in the manner described above in connection with Figures 1 to 6. Simultaneously, streams of water are carried through conduits 82 to pan 78 from which the water is discharged onto the lower portion of unit 74.

In Figure 7, the decking structure is identical with that of Figures 1 to 6, and the fan and the other elements are constructed, and they function in the same manner.

As many possible embodiments may be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinabove set forth, or shown in the accompanying rawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In evaporative cooling apparatus, a unit comprising a plurality of rectangular assemblies each of which is formed by a rectangular frame and a fin assembly mounted in said frame, each of said rectangular assemblies having two opposite faces, said fin assemblies comprising a plurality of corrugated strips mounted within said frame with the corrugations extending generally between said opposite faces but at a small angle from lines transverse to said faces whereby passageways are provided which are slightly offset, said corrugated strips being positioned so that the passageways formed by one strip are offset oppositely from the passageways of the next adjacent strip.

2. In an assembly of the character described, the combination of, a rectangular frame construction formed by four interconnected frame members, a fin assembly positioned within and substantially occupying a space within said frame and comprising a plurality of individual corrugated strips, a pair of grid assemblies each formed by an arrangement ofrintersecting: wires extending along the: op

3. Apparatus as'described in claim 2, wherein said wires extend substantially parallel with said frame members and 'whereinsaid interconnecting members are in the form of channels having holes in their ends through which said wires extend.

4. Apparatus as describedin claim 2 which includes a plurality of pronged strips extending generally trans versely ofsaidtcorrugated strips along'a face of said frame and having prongs which project into the respective corrugations of said corrugated'strips thereby to provide support.

5. Apparatus as .described in'claim 2, wherein said fin assembly forms a plurality of transverse passageways, andmeans supporting said frame construction at an angle of theorder of 60 to the horizontal.

6; In evaporative cooling apparatus of the character upii'ghtzchannelis positioned substantially.- above'an' invertedchannel, said channels are ofiset at an angle-of the order of 6 from a right angle relationship'with respect to: the edges of the strip from whichtthe corrugated strip is formed, and wherein the adjacent strips are inverted With respect'to each other whereby theofiset of the channels of one strip is offset oppositely to that of the channels of the next adjacent strips. 1

References Cited in the file of thispatent UNITED STATES PATENTS 836,702 Ostendorf Nov. 27, 1906 1,926,970 Cline Sept. 12, 1933 2,097,425 Wandell Oct.26, 1937 2,194,711 Mayer etal Mar. 26, 1940 2,360,669 Goethel Oct; 17, 1944' 2,490,079 Melvill Dec. 6,- 1949 2,630,305 Scofield et a1; Mar. 3, 1953 2,631,022 Baird et al. Mar. 10, 1953 2,644,322 Preble e July 7, 1953 2,650,082 Mart Aug; 25, 1953 FOREIGN PATENTS 60,262 Norway Jan; 9, 1939' 130,661' Australia Dec. 15, 1948 490,324 Great Britain Aug. 12, 1938 571,510 Great Britain Aug. 28, 1945

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