US3378239A

US3378239A - Counterflow cooling tower

Info

Publication number: US3378239A
Application number: US622307A
Authority: US
Inventors: Jr John Engalitcheff; Thomas F Facius
Original assignee: Baltimore Aircoil Co Inc
Current assignee: Baltimore Aircoil Co Inc
Priority date: 1966-06-13
Filing date: 1967-03-10
Publication date: 1968-04-16
Anticipated expiration: 1985-04-16

Description

April 1968 J. ENGALITCHEFF, JR. ETAL 3,378,239

COUNTERFLOW COOLING TOWER Filed March 10, 1967 a Sheets-$heet 1 A/gOUT 3" 33 AIRTOUT L "ii;i wwaew was n COOL WATER m q I' T 32 INVENTOR John E ngal/fcheff, Jr: Thomas F. Fae/us ORNEYS April 1968 J. ENGALITCHEFF, JR.. ETAL 3,378,239

COUNTERFLOW COOLING TOWER Filed March 10, 1967 8 Sheets-Sheet 2 FIG.2.

mvsmoas John Enga/ifcheff, Jr. Thomas Fae/us Mm a % RNEYS April 16, 1968 J. ENGALITCHEFF, JR, ETAL 3,378,239

COUNTERFLOW COOLING TOWER Filed March 10, 1967 v a Sheets-Sheet 5 FIG. 3.

O 24 INVENTORS John E ngol/lcheff, Jr.

Thomas E Fam'us TTORNEYS April 16, 1968 J. ENGALITCHEFF, JR, ETAL 3,

Filed March 1o, 1967 FIG. 4.

v mvmrons John Enga/ifcheff, Jr. Thomas E Fae/us TTORNEYS April 16, 1968 J. ENGALITCHEFF, JR.. ETAL 3,378,239

COUNTEBFLOW COOLING TOWER 8 Sheets-Sheet 5 Filed March 10, 1967 20 I III:

INVENTORS Joha Enga/i/cheff, J. Thomas E Fae/us wm 19m TTORNEYS April 16, 1968 J- EN(.EALITCl-IEFF, JR, ETAL COUNTERFLOW COOLING TOWER Filed March 10, 1967 WATER 8 Sheets-Sheet 6 FE. K

"H H H a BB 5 a AAAAAAIQ A' ,AAA/\ AAA John E nga/ifcheff, Jr. T hamas F. Facl'us WAQ m zwv TTORNEYS April 1968 J. ENGALITCHEFF, JR., ETAL 3,378,239

COUNTERFLOW COOLING TOWER Filed March 10, 1967 8 Sheets-Sheet 7 j; Huff}, INVENTORS f jf' f dolm Enga/i/che ff, Jr.

" Thomas .E Fae/us a 6 ATTORNEYS April 16, 1968 J. ENGALITCHEFF, JR.. ETAL 3,373,239

COUNTERFLOW coomue TOWER Filed March 10, 1967 a Sheets-Sheet a FIG. l2.

FIG. l3.

x n x mvmons 68 John E ngol/Icheff, Jr.

Thomas F. Facl'us ATTORNEYS United States Patent 3,3783% COUNTERFLOW COOLING TOWER John Engalitcheif, Jr., Gibson Island, and Thomas F.

Facins, Baltimore, Md., assignors to Baltimore Aircoil Company, Inc, Baltimore, Md., a corporation of Maryland Continuation-impart of application Ser. No. 465,273, June 21, 1965. This application Mar. 10, 1967, Ser. No. 622,307 Claims priority, appiication Canada, June 13, 1966,

Claims. in. set-29 ABSTRACT OF THE DISCLOSURE This invention relates to a broadly new evaporative cooler, commonly known as a cooling tower. This application is a continuation-in-part of application Ser. No. 465,273 filed June 21, 1965, now abandoned.

In an evaporative cooler, the water to be cooled is usually gravitated through a predetermined path in direct contact with counter-flowing air. Some of the gravitating water is caused to evaporate and the heat of vaporization necessary to this change of state is taken from the remainder of the water which is thus cooled. The capacity of an evaporative cooler, that is, the amount of water which it can cool, is importantly related to the amount of air-water interface that can be maintained. The simplest form of a cooling tower is a so-called spray filled tower in which water is atomized by means of sprays into the air. However, this type of a tower has its limitations because the atomized water congeals very quickly into larger particles and this decreases the air-water interface and thereby reduces the efiiciency of the tower. Therefore, the effective height of a spray filled tower is limited to a point where the drops begin to congeal.

In the past large air-water interface in evaporative coolers has been maintained by putting materials having large surface area in the evaporative cooler below the sprays. These materials are known in the industry as fill, and they present large surface areas which are kept wet as air is passed across them and, thus, the necessary vaporization is effected. Such a system, known to the trade as a wet deck system, has good cooling efficiency but is expensive to build, ship, install and maintain for, whatever material is used to provide the fill, it must be i ed in large quantity to afford the necessary surface area. This material must be purchased, fashioned into the desired shape and size and installed in the cooling tower, all items of cost. Of course, the fill adds to the weight of the tower and its presence makes necessary a tower of sufficient strength to support them. These requirements cause added weight which, in turn, increases shipping costs and costs of installation.

It is an object of the present invention to provide a highly efficient cooling tower far less costly to build and much lighter in weight than a conventional evaporative cooler of equal cooling capacity.

According to the present invention the fill of an evap- 3,378,239 Patented Apr. 16, 1968 orative cooler is largely eliminated and the air-water interface is maintained by a series of vertically spaced regenerative structures which cause the air to undergo a momentary increase in velocity. The resulting high velocity air breaks the water into small droplets and carries them into a region above the regenerative structure. As these droplets are agitated in this upper region or chamher they merge together creating larger droplets and fall into the next lower regeneration chamber. Here they encounter the next series of regenerative structures and the process is repeated. This results in a high efficiency spray filled cooling tower in which high water-air interface is maintained throughout the chamber without the use of large quantities of fill.

Other objects and advantages of the present invention will be apparent from the following detailed description of several embodiments thereof in conjunction with the annexed diagrammatic drawings wherein:

FIG. 1 is a view in vertical section of a cooling tower incorporating a preferred form of regenerative structure constructed and arranged in accordance with the teachings of the present invention;

FIG. 2 is a fragmentary view in horizontal section taken on the line 22 of FIG. 1, an enlarged scale being used for convenience of illustration;

FIG. 3 is a view in section taken on line 3-3 of FIG. 1;

FIG. 4 is a fragmentary perspective view of a course of a preferred form of regenerative structure;

FIG. 5 is another fragmentary perspective view to an enlarged scale of the preferred regenerative structures of FIG. 1 showing the details of the margin structure;

FIG. 6 is a fragmentary view in vertical section and to an enlarged scale of a portion of the apparatus illustrated in FIG. 1 showing the spray regeneration which results from the operation of the present invention;

FIG. 7 is a view in vertical section of a cooling tower incorporating a modified form of the present invention, crescent shaped regenerative structure elements being shown in section;

FIG. 8 is a fragmentary view to an enlarged scale of a portion of one of the crescent shaped regenerative structure elements illustrating the corrugation thereof;

FIG. 9 is a fragmentary view to an enlarged scale of the inner side wall of the cooling tower of FIG. 7, illustrating one of the corrugated water distribution members attached to the chamber wall and used to distribute water to the regenerative structure below it;

FIG. 10 is a fragmentary view to an enlarged scale of a portion of the apparatus illustrated in FIG. 7 showing the regeneration of the spray which takes place when the apparatus is in operation;

FIG. 11 is a view similar to FIG. 8 but showing a modified type of crescent shaped element characterized by notched edges;

FIG. 12 is a view similar to FIG. 9 but showing a side wall type water distribution member having a notched edge; and

FIG. 13 is a view in plan of a modified regenerative structure in the form of a double grid of crisscrossed pipes.

Before discussing the structural details of the cooling tower illustrated in FIGS. 1 to 6, inclusive, it is well to review the functions which the illustrated apparatus performs. The cooling tower 10 essentially comprises a means 11 near its top to supply streams of water across the cross section of the tower, a sump 12 at the bottom to collect water, a fan 13 having an outlet 14 above the sump to blow air countercurrent to gravitating water, and regenerative structures 15 above the fan and below the water supply which, with the flowing air, function to maintain throughout the tower a fine spray-like condition produce-d by myriads of water droplets. These droplets present to the counter-flowing air an enormous surface so that the air-water interface is conducive to efficient evaporation. The heat necessary to support the evaporation of some of this water is extracted from the rest of it so that the water which finally reaches the sump 12 has had substantial amounts of heat extracted from it.

The illustrated cooling tower is square in cross section and is defined by

side walls

16, 17, 18 and 19. Near the top of the cooling tower there are arranged parallel, horizontally spaced, generally U-section troughs 20 having V-notches in their side walls. These troughs form a distribution system such as is described and claimed in copending applications Ser. No. 425,783 and 425,785, now abandoned, both applications were filed Jan. 15, 1965. It will sufiice for purposes of this application to point out that the V-notches 21 of these troughs are offset in opposite side walls so that a stream originating from a V-notch on one side of a trough flows down the side wall of that trough and leaves from the other side of the vertical center line of that trough. The adjacent stream from the opposite side of the trough does not interfere because of the offset. A head of water is maintained in header 22 so that there will be a steady spill from the notches 21 throughout the length of each trough 20. The streams issuing from the notches 21 are distributed over the cross section of the tower but, when the apparatus is in operation, these streams do not remain as such very long after they lose contact with the surface of the trough. This is brought about by the fact that air flowing countercurrent to the water accelerates as it passes between the troughs due to the fact that the troughs 21 reduce the crosssectional space for air flow in the plane in which they are located. This reduction in air flow space brings about a localized acceleration of the air flowing between them. This accelerated air attacks the streams just leaving the bottom of the troughs and fragments them into droplets in a manner that can best be appreciated by referring to FIG. 6. The droplets formed by the action of the troughs and the air flowing between them would, in the absence of any further structure, gradually merge and form undesired large drops before reaching the sump 12. In the present invention, however, this eventuality is avoided by the use of the regenerative structures 15 illustrated in each of FIGS. 1 to 4, inclusive. Above the outlet 14 of the air fan there are located on the front wall 19 and rear wall 17 L-section brackets 23 which support the lowermost of many superimposed courses of regenerative structures. The lowermost course of regenerative structures is comprised of a number of inverted channel section members 24 arranged in parallel spaced relation with their opposite ends resting on the brackets 23. These channel section members 24 are provided with peripheral corrugations 25 along each lower edge; see FIG. 5. At spaced intervals along the bight of the channel sections 24 there are stamped out tabs 26 which engage and support inverted channel section members 27 which run at right angles to the channel section members 24 between the

side walls

16 and 17 of the tower. The channel members 27 also have corrugated margins at 28; see again FIG. 5.

The channel section members 24 have a greater vertical dimension than the channel section members 27 which they support. The channel section members 24 of any course are less numerous than the vertically shorter channel section members 27 by a ratio of about 3 to I. In FIG. 1 the bottom course shows three channel section members 24 supported from the walls of the tower through brackets 23. Only one of the shallow inverted channel section members 27 shows in the first course of regenerative structures. In the second course, however, the ratio of three channel members 27 per channel member 24 is evident. The several courses of channel members are so arranged that looking down upon them one sees defined a grid the square holes of which have dimensions of something less than half of the dimension of the spacing between the shallow channel members 27 of one course. This is accomplished by offsetting respective courses of regenerative structures, as can best be appreciated by reference to FIG. 2.

In FIG. 2 there are shown four courses of regenerative structures 15. The lowermost course is supported from channel section members 24 which, in turn, support shallow channel section members 27 held in position by tabs 26. The next course of regenerative structures is supported on high channel section members 24 only one of which shows in FIG. 2. Attached across the top of this channel section member are a number of channel section members 27 which make up the second course of regenerative structures. The third course of regenerative structures illustrated in FIG. 2 is supported from a high channel section member 24 which lies in a position resting on the tops of the low channel section members 27 but horizontally offset to register midway between the pairs of low height cross-sectional members 27 The fourth course of regenerative structures 15 shown in FIG. 2 is supported from a high channel section member 24 resting on the tops of the low channel section members 27 and having fastened to it channel section members 27.; several of which show in FIG. 3.

By horizontally offsetting the succeeding courses of regenerative structures, the structures are caused to define as viewed in plan above the fourth course a series of square holes. The pattern is reepated in each group of four courses. A fifth course of regenerative structures, if applied to FIG. 2, would therefore lie directly vertically above the course 24 -27 If now reference is again made to FIGS. 3, 4 and 5, it can be seen that each channel section member 24, by reason of having a greater vertical dimension than the channel member 27 which it supports, creates a certain amount of vertical space between successive courses. It is in this space that the regeneration of the spray occurs; see FIG. 6. As the water gravitates through the tower, some of it is always striking the inverted regenerative structures and by reason of their corrugated edges is fed back into the air stream along the corrugated edges of the inverted

channel section members

24 and 27. Because the channel section members reduce the free crosssectional area of the tower in each plane in which they exist, the air flowing upwardly through the tower is subjected to repeated accelerations as it passes through the spaces defined by the regenerative elements. This maintains the spray in a manner which can best be appreciated by reference to FIG. 6.

In addition to the structures already described, the evaporative cooler of FIG. 1 has the usual water makeup supply valve 29 controlled by a float 30, an inlet at 31 for water to be cooled, an outlet at 32 for withdrawing cool water from the sump 12. Mist eliminators 33 are provided above the water supply 11 and these serve to keep the air from carrying water drops out of the system. The fan 13 is provided with a duct 34 which extends for a sufficient length downstream of the cutoff to prevent the fan from sucking water, this feature being described and claimed in Patent No. 3,132,190.

In operation, water to be cooled is supplied through conduit 31. The troughs 20 are filled with water and are maintained filled by the header structures 22. The Water spills through the notches of the trough and the creation and regeneration of spray continues throughout the fall of the water to the sump; see FIG. 6. Of course, the cooling of the water is brought about by the evaporation of some of it, and the system is maintained stable by the makeup valve 29 which opens when the water in the sump falls below the design level.

Referring now in greater detail to FIG. 7, the numeral 40 represents the chamber of a cooling tower. The chamber 40 is defined by

side walls

41 and 42, two end walls, one of which, bearing reference character 43, shows in the drawing and a bottom wall 44. Water to be cooled is supplied near the top of the chamber 40 through a conduit 45 which leads to a trough type water distribution system 46 such as is described in conjunction with FIGS. 1 to 6, inclusive. These streams issuing from trough system 46 are distributed over the cross section of the tower 40 and the water gravitates to a sump 47.

Air is caused to flow countercurrent to the gravitating water in the chamber 40. To this end a centrifugal fan 48 is provided, similar in structure and function to fan 13 of FIG. 1. Air is discharged into the bottom of the chamber 49 above the sump 47 as indicated by the arrows and a pressure drop is thus maintained between the bottom of the chamber 40 and the top. Air flows upwardly through the chamber and exhausts through mist eliminators 49 to atmosphere as indicated by the vertical arrows. The water collected in sump 47 has been cooled by reason of evaporation taking place in the tower chamber 40. This cool water is withdrawn by a pipe 50 connected to the sump. Make-up water is added to the sump 47 by the opening of a valve 51 controlled by a float 52, the valve 51 being connected to a water supply pipe 53.

The troughs of the system 46 occupy a substantial portion of the cross-sectional area of the chamber 40 in the planes in which they are located. Thus, the air passing between them undergoes local acceleration or increase in velocity. Accordingly, the water leaving the troughs is fed into these high velocity air streams which break the water into small droplets which are carried to a region above the troughs but below the eliminators 49. In this region there is a turbulent atmosphere of atomized water and air characterized by large air-water interface; see FIG. 10.

As the water is agitated by the air in the region above the troughs 46, some droplets merge to produce droplets of larger size. Some of these larger droplets gravitate to a first regenerative structure 54 which is a grid made up of elongated, inverted, crescent shaped, corrugated members 55, each having an appearance best understood by reference to FIG. 8. The members 55 are arranged in mutually parallel, spaced relation and occupy a substantial portion of the cross-sectional area of the tower. Because of this, the regenerative structure 54 causes a local increase in air velocity. The corrugated, inverted, crescent shaped members 55 direct the water into this accelerated air in streams of the smallest possible size. The result is that the air breaks up the small streams into minute droplets and carries them to a first zone or regenerated spray. This zone occupies the chamber space above the regenerative structure 54. The spray zone is occupied by finely atomized water presenting a very large total airwater interface with resulting increased evaporation.

As the agitation continues some of the droplets merge, become larger, and eventually reach the second regenerative structure 56. Here the whole process is repeated and the spray is again regenerated, this time in a spray chamber above the regenerative structure 56. This happens again at regenerative structure 57 and again at structure 58.

It will be observed that the

regenerative structures

54, 56, 57 and 58 are vertically spaced so that a spray chamber is defined above each structure. The elements 55 which make up the regenerative structure 54 lie above, but in horizontally offset, staggered relation to, those elements which make up the structure 56. The relationship between

structures

54 and 56 is repeated between

structures

57 and 58 as can be clearly seen in FIG. 1. This staggering of the elements of adjacent regenerative structures has been found to contribute to better water distribution within the tower chamber 40.

As the water proceeds through the chamber 40, a portion of it contacts the

walls

41 and 42 and has a tendency to follow the respective wall to the sump without contributing to the cooling. To overcome this, special angular baffles 59 are used to redirect the water to the air stream at each regenerative stage. These baflles 59 may be of corrugated material like the members 55; see FIG. 9. In FIG. 7 their location on the

side walls

41 and 42 is shown and, from FIG. 9, it can be seen that they are attached to the chamber side wall by an integral flange portion. See in this regard the exemplification in FIG. 9 in which the flange 60 of a baffle 59 is attached to the inner face of the wall 42 of the tower chamber 40.

It is possible to use instead of corrugated structures, such as are shown in FIGS. 8 and 9, structures having notched edges. In FIG. 11 there is shown a fragment of an inverted crescent shaped element 61 used to perform the function of part 55 previously described. This structure is made of flat rather than corrugated material and the teeth 62 along its opposite long edges serve to feed many very small streams of Water into the air. The regenerative structure made using elements 61 will look just about the same as the regenerative structures in FIG. 7. The elements 61 are arranged in spaced relation partially to obstruct air flow and so to cause localized increase in air velocity.

It is also possible to use the toothed structure as a side wall bafile. See in this regard FIG. 12, wherein a baflle 63 is shown having an integral flange 64 mounted on a tower wall 42. The edge of the baflle 63 which extends into the casing space is provided with a row of teeth 65. The teeth 65 function to feed small streams of Water into the air flowing upwardly in the chamber and, by so doing, present any appreciable amount of water from bypassing the system by gravitating to the sump along the chamber side walls.

In FIG. 13 there is shown an elementary form of double grid regenerative structure 66.. This structure 66 is made up of two

grids

67 and 68,. each made up of spaced tubes. While these tubes do a less good job of feeding water to the upflowing air than the inverted crescents, they do function to increase air velocity in a local region and hence the regenerated spray.

Whatever type of element is used to make up the regenerative structures, they must be arranged in vertically spaced relation to provide a spray chamber therebetween. The number of regenerative structures is dependent upon the capacity desired.

While in FIGS. 1 and 7 there is illustrated a blow through type cooling tower, it is to be understood that this invention is equally applicable to induce air flow type cooling towers and the fans can be either centrifugal or propeller.

What is claimed is:

1. In an evaporative cooler having means defining a chamber, means in an upper region of said chamber to distribute water for subdivided gravity flow throughout the cross section of said chamber, sump meansto collect cooled water at the bottom of said chamber, fan means to flow air through said chamber countercurrent to the water; wherein the improvement comprises mutually spaced regenerative means presenting a plurality of water distribution surfaces in the region of countereurrent flow, said regenerative means including a plurality of stacked groups of inverted channel members having outwardly sloping lower Wall portions, at least some groups each including a plurality of large and small channel members parallel to each other with the channel members of one group being supported upon the large channel members of the immediately adjacent underlying group, the channel members of a given group being disposed transversely to the channel members of an adjacent group, and at least some of said channel members having at the outer surface of their lower wall portions means to distribute water into the counterflowing air at a large number of horizontally spaced points, said channel members functioning to cause localized increases in the velocity of the air passing through said chamber.

2. In an evaporative cooler having means defining a chamber, means in an upper region of said chamber to distribute water for subdivided gravity flow throughout the cross-section of said chamber, means to flow air through said chamber countercurrent to the water; wherein the improvement comprises regenerative means presenting a plurality of water distribution surfaces in the region of countercurrent fiow and causing localized increases in the velocity of the air passing therethrough, said regenerative means including a plurality of stacked groups of inverted generally V-shaped channel members having outwardly sloping lower wall portions, at least some groups each including a plurality of large and small channel members parallel to each other with the channel members of one group being supported upon the large channel members of the adjacent underlying group, the channel members of a given group being disposed generally at right angles to the channel members of an adjacent group, and the channel members of alternate groups being horizontally olfset with respect to each other.

3. Apparatus according to claim 2, wherein the large channel members are provided with integral means to secure and engage the channel members supported there- 4. Apparatus according to claim 3. wherein said integral means are upwardly extending tabs.

5. Apparatus according to claim 2, further comprising corrugations povided in the lower wall portions of at least some of said channel members to improve the water distribution.

References Cited UNITED STATES PATENTS 736,087 8/1903 Graham. 1,005,809 10/1911 Hawkins et al. 261l11 2,064,808 12/1936 Beran. 2,497,389 2/1950 Ahrens 261-111 2,612,359 9/ 1952 Simpson. 2,872,168 2/1959 Mart. 2,890,870 6/ 1959 Spiselman. 2,990,031 6/ 1961 Michael. 3,290,025 12/1966 Engalitcheff. 3,290,867 12/1966 Jacir.

FOREIGN PATENTS 414,720 6/1910 France.

HARRY B. THORNTON, Primary Examiner.

TIM R. MILES, Examiner.