US2834428A

US2834428A - Eliminator screen for evaporative towers and the like

Info

Publication number: US2834428A
Application number: US532054A
Authority: US
Inventors: Madan L Ghai; Joseph A Koren
Original assignee: Dunham Bush Inc
Current assignee: Dunham Bush Inc
Priority date: 1955-09-01
Filing date: 1955-09-01
Publication date: 1958-05-13
Anticipated expiration: 1975-05-13

Description

May 13, 1958 M. L. GHAI ET AL' ELIMINATOR SCREEN FOR EVAPORATIVE TOWERS AND THE LIKE Filed Sept. l. 1955 2' Sheets-Sheet Mw ?ka Joseph .a. Karen BY m 77 g ATTOR G VENTO 72 L I I I I I .l v

May 13, 1958 M. L. GHAI ET AL 2,834428 ELIMINATOR SCREEN FOR EVAPORATIVE TOWERS AND THE LIKE Filed Sept. l, 1955 2 Sheets-Sheet 2 3 .Ji/[adam 9 gYoseph, A, Karen,

INVENTOR E Ga? United %States ELIIMINATOR SCREEN FOR EVAPORATIVE TOWERS AND THE LIKE Madan L. Ghai, Manchester, and Joseph A. Karen, Hartford, Conn., assignors, by mesne assignments, to Dunham-Bnsh, Inc., West Hartford, Conn., a corporation' of Connecticut Application September 1, 1955, Serial No. 532,()54 8 Claims, (CI. 183-75) ticles from an air stream. A further object-is to remove. particles from an air stream or the like with minimum' statc pressure drop and in an efiicient, dependable manner. A further object is to imp'ove the operation of cooling towers and the like 'by providing for the removal ot water particles from the air stream in an improved manner. A further object is to provide improved structures and methods for removing water particles from theair in such a way as to avoid the difficulties which have been encountered in the past. A still further object is to provide for the above with structure which is simple and sturdy, inexpensive to manufacture and install, readily se'viced, and dependable and efiicient in use. These and other objects Will be in part obvious and in part ponted out below.

In the drawings:

Figura 1 is a side elevation of a cooling tower incorporating one embodiment of the invention, with parts broken away; i

Figure 2 is a somewhat enlarged View on the line 2-2 of Figure 1;

Figure 3 is an enlarged fragmentary View showing the details of the structure of Figures 2, 4 and 5, and the mode of operation;

Figure 4 is an enlarged sectional view on the line 4-4 of Figure 3; and,

Figura 5 is a sectional view on the line 5-5 of Figure 3.

In refrigeration systems of a size greater than the order of three tons Capacity, it has been increasingly common practice to provide evaporative cooling towers. With such apparatus, water is sprayed into a fast movng stream k of air to evaporate water and dissipate heat. The water may be circulated from the tower to the condenser of the refrgeration system or the condenser of the refrigeration system may be located in the tower. are frequently positioned upon a roof or elsewhere high above the ground. Frequently, such towers have been considered objectionable because of the noise which they produce and also because of the tendency for such towers to expel water particles in the air stream which passes from them. The most serious object to such towers often comes from people who pass near the tower within range of the escapng water particles. In the past, attempts have been made to remove all the particles from the air stream,

but this has involved the provison of the air-escape louvers which passed the air in thin streams along zig; zag paths. Such arrangements are apt to increase materially the static pressure drop in the air stream so that Such towers zemres Patnted May 13, ?358 the air circulation is reduced unless fan equipment was enlarged. However, the enlargement of the fan equipment tends to increase the power requirements and the cost of operation; and, it also increases the noise produced by the unit. It is among the objects of the present invention to overcome these problems and to avoid the difiiculties which have been encountered with this type of apparatus in the past. This is accomplished by providing an improved eliminator screen structure for removing water particles from the air stream passing from the cooling tower.

Referring particularly to Figure l of the drawings, an evaporative cooling unit 2 has a finned condenser coil 4 positioned within a casing 6 and cooled by simultane-` ously passing water and a stream of air through it. The stream of air is drawn in at the right at 8, passes horizontally and somewhat upwardly through the coil 4, and is discharged at the left through an air dscharge opening 10 by a fan 12 driven by a motor 14. Water is supplied to` coil 4 from a distributor pan 16 which is rectangular and has bottom openings from which small streams of water pass. The water is intercepted and dispersed by a Water distributor screen 18 and -covers the entire "face of coil 4. The water fiows through coil 4 downwardly and the right; and, some of the water is evaporated, and the remainder is collected in a bottom sump and is recirculated 'by a pump not shown.

The air passing from the conclenser coil 4 has been and has 'become saturated with moisture, and it also contains considerable water in the form of small particles. The present invention is concerned primarily with the removal of these small particles of water from the air. Accordngly, an elininator screen 20 is positioned between theecondenser coil 4 and fan 12, and all of the air passing. to the fan fiows through this eliminator screen. This eliminator screen is constructed as shown best in Figure 2, and has a rectangular wooden frame 22 with side upright members, top and bottom members 26,` and a central upright member 28. Stapled to the two side faces of frame 22 are two

identical screens

30 and 32 which are formed of thin sheet metal which has been fabricated in a manner discussed below to provide water eliminatng louvers.

The louver Construction 'constitutes vertical rows 34 of louvers 38 having slots 39 therebetween, and between the rows 34 are vertical imperforate strips 36. louver construction is' shown best in Figures 3, 4, and 5, where a portion of a row 34 is shown, together with the adjacent imperforate strips 36. In this connection, the screen is considered from the face shown in Fignre 5, which is positioned toward the oncoming stream of air during operation. The individual louvers 38 are flat strips of the sheet metal integral at their ends with the imperforate strips 36. The louvers extend longitudinally at an angle of 45 to the horizontal, and they also are 'twisted from the original plane of the sheet metal to inwardly (see Figure 5), but the louver maintains its original fiat condition.

Also, the left-hand end of each louver (that is, the lower end) is positioned outwardly so that it extends somewhat above the original plane of the 'sheet metal, whereas at the opposite (i. e., upper right-hand) end the louver is somew-hat depressed. Hence, each louver extends from the top from somewhat below the original plane of the sheet metal downwardly and to the left, and through this plane. Each of the imperforate strips 36 between the two rows of louvers is provided with a vertical channel or trough 46 which (see Figure 4) is somewhat an open-V in cross section, and this is below The the level o'f the original plane of the sheet metal. As indicated above, there are 'two iden'ticl scree'ns "50 "ana 32, and the relationship between these two screens is distance apart.

The louver-forming operation involves lcuttin'g,paral le'l slits 'into .the sheet metal along the side edges of the louvers 'being formed, 'and the 'forming .tools simultaneously push the lower edge o'f each louver oitwardty, and the upper edge of each lonver inwardly. The operaton also includes the forming of the troughs 46. Illustrafively, these eliminator screens are fabricated from strips of brass .008 inch thick and substantially 8inc hes Wide. After the .louver Construction has been formed, the 'individual strips are s'tapled together a't ;their ed'ges to form the entire assembledtscreen.

'In this embodiment, the channels .are spaced ;if an 'inch apar't, center 'to center, and the width of the strip forming each of 'the vertical channels is substantially inch. Hence., the width of .each row of louvers is inch. Hence, each of the louvers is of alength of substantially one inch. i I

During operation, 'the stream of air .approaches the eliminator screen from the bottom o'f/Figure 4 toward the face o'f screen 30, shown in'Figure 3. The louvers'tend to divertthe air somewhat upwardly through the Slots 39 and these Slots are ofsufficent size to permit :Satisfactory flow of the air. However, particles of water entrained in the .air stream .are fimpacted'aganst athe louvers and they cling to the louvers. 'The inital water particles impihg'ing on the louver surfaces tend 'to -wet these sur'faces, but as additional water .is deposited, :it accumulatesand starts to flow downwardly along the louvers. This flow is represented in Figure 3, and at the lower end of each louver .the water ows into the adja'cent trough 4'6. Hence, 'each trough collects water from the adjacent row of louvers and wthn this trough the water is no longer subjected `to the entrainin'g forces of the airstream, so that it fiows downwardly along -the troug'h to the bottom of the eliminator screen. -Here the water fiows from the eliminator screen to the sump tank. As shown best in figure 1, the eliminator screen 2'0 is .at .a small angle to the vertical, so thatit-inc lines upwardly against the air stream. This positioning of the screen .and the form and ,position of the .louvers insure that .the net effect of the actions of .gravity and the air stream s for the Water to flow down the louvers into the troughs, and thence =down the troughs.

Referring again to Figure 4, the discussion immediately above concerns the eliminator action at screen 30. After the air passes through screen 30, itpasses on and approaches the face of screen 32. Here the watenelimi nating action is repeated, with the air being diverted somewhat upwardly and With any .remaining zp'articles of water impinging upon-and being deposited .upon the louvers of screen 32. Under some circunstance's,-i-t may be desirable to provide additional screens, .butsit :has-.been found that two screens are very adequate .for thepartio ular embodiment .here being discussed.

The Suspended water particles 'are `sparated *from the air stream With the structure heren 'disclosed, -w'ith minimum static pressure drop, and 'the water removed is not re-entrained into the air stream. The :louvers present sufficient impingement .area to collect tthe water, and the free openings between them ,permit `the :air to pass. The inclination of the .louvers lengthwise, with the appropriatelyspaced Channels or troughs, nsure the removing of the moisture which is collected.

Under some circumstances, the faces, relative ,proportions and positionings of the "louver 'may be varie'd, while not losing certain-or all of'the *advantages of 'the 'invention. The open-V trough or channel provides a water 'stream w'hih 'tl'ows downward without 'being distur'bed by the air stream. Under 'some circumstances the form of the trough may be varied and a single trough may be provided for two rows of louvers. Also the louvers may be slanted downwardly so that they tend to deflect the air in a downward direction instead of upwardly in which case the louvers may be more nearly vertical to insure that the wa't'er will flow down 'them *b'y 'surface flow. Under some circumstances 't'h'e louvers o"f 'screen 30 may be slanted as heren shown, whereas :the louvers .in screen 32 may be slanted oppositely, "either `'downwardly or upwai-.dly :and to the ig ht in Figur 49 I As many possible embodiments may b'e "made in the above invention and asmany changesmight Joe :made in the embodiment above set "forth, 'it is to be understood that all matter her'einb'eore ;set for th or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

We claim:

;1. In -apparatus of the 'oharater described, 'an "eliminator !screen 'com'prisin'g a frame Construction, 'and an eliminator screen 'supported by 'said frame Construction formed by sheet metal 'and c'omprising a 'pluralty of vertically extending rows of louvers having passageways therebetween and 'trough means -'adjacent eaeh of 'said rows, 'said louvers be-ing poitioned at an angle 'to the horizontal and extending downwardly toward 'said trough means whereby liqn'id 'collecting on said louvers fio'ws downwardly therealong tosad "trough means and 'thence in :a protected .stream 'downwardly "toward the 'bottom of said :sot-een.

2. Apparatus as described =i'ncla'im '1, where'in each of said 'louvers is turned about its axis to an angle *dt sbstaiitially '45 from the general plane 'of the 'screen and extends longituinally at *an an'g'le -of sdbstantially 45'? :from the horizontal.

3-. Appa'r'tis as described *in claim *1, wherein 'each df said louvers h`a`s it's lower 'end extendng outwardly from :general p'l'ane of the screen -wh'erby 'the liquid passes by surface flow to said trough means.

4. Apparatus as described in claim *3, 'w'herein said trough means is 'in the form 'of -an open-V 'trough 5. Apparatu's as 'described in 'claim 1, wherein said louvers are of the order of one inch in width and 'said trough means is formed'in a 'strip 'of imperforate sheet metal having a width of the order of inch.

An'eliminatorscreen Construction'which is adapted to remove lquid particles from 'a fast-'ilow'ing''airfstream comprising, a sheet metal screen formed 'of'p'arallel vertical 'rows o'f louvers 'with a vertical 'channel p'ositio'ned between each row and the next, said louvers 'being positioned'at an 'anglebPthe'order of TS 'from 'the horizontal and with the planes slanting generally upwardly a't an ang'l'e -'from the 'horizontal 'where'by "each louver resents an impacting surface to interce'pt *liquil 'particles and li'quid accumulatinjg -"thereon flows downwardly to the 'ajacen't vertical channel.

a wo'oden 'franre 'providing support for said 'sheet metal I screen. I

'ke'ferences tiitea in 'the'file *Df'th'is patent 'UNITED STATES PATENTS