CA1075171A - Dual path drift eliminator structure and method for crossflow cooling tower - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A dual path drift eliminator and method is provided which effectively removes entrained water particles from high velocity moist airstreams leaving a crossflow cooling tower fill structure by the use of spaced, cellular, individually draining, diversion path-defining structures strategically located and ar-ranged to facilitate maximum drift elimination. The drift elimi-nator has a plurality of elongated air passages therein disposed to first divide the moist air from the tower fill into a series of separate streams which are first diverted at an upward angle relative to the initial path thereof, and thereafter re-diverted laterally to one side of the first diversion path. Water particle removal is thus greatly enhanced by virtue of increased impinge-ment of the entrained particles against the cellular walls defin-ing the respective diversion paths. The eliminators hereof have special advantages in crossflow cooling towers because the spac-ing between the diversion path defining cellular structures per-mits separate draining of the water collected in each, so that air inlet blockage resulting from the accumulated drainage of large volumes of water from a single drainage area is avoided. The elimi-nator structure preferably includes a number of juxtaposed pairs of spaced, elongated, transversely corrugated, preformed sections sandwiched between elongated, preformed, transversely V-shaped panels to define a structurally distinct eliminator pack which can be manufactured using assembly line techniques; such packs are moreover of nestable configuration permitting complemental posi-tioning of a plurality of packs to present a substantially con-tinuous drift eliminator unit free of objectionable vertical gaps, notwithstanding the lack of conventional shiplap joints or other mechanical interconnection between individual eliminator packs.

Description

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DUAL PATH DRIFT ELIMINATOR STRUCTUR~
AND METHOD FOR CROSSFLOW COOLING TOWER

This invention relates to cross10w water cooling towers and especially improved drift eliminator constructions and methods for effectively removing entrained water particles from generally horizontally directed air currents leaving the tower fill structure. More particularly, it is concerned with such eliminators and methods wherein -the moist airstreams are di-verted at a first angle upwardly relative to the initial path thereof, and thereafter again diverted along a second diversion path situated laterally of the first path in order to greatly en-hance removal of entrained water particles; in addition, the con-struction of the eliminator allows individual water drainage from the respective div~rsion paths, so that troublesome water blockage of the eliminator is avoided.
In evaporative water cooling towers of the crossflow variety heat is removed from initially hot water by causing the latter to gravitate through a surface~increasing fill assembly in crossflowing intersecting relatîonship to currents of cool air directed through the fill. Drift eliminators are usually pro-vided to remove entrained droplets or particles from the air leav-ing the tower fill structure. I drif~ eliminator structures arenot employed in such tQWers, substantial quantities of water can be discharged into the atmosphere. This results in undesirable operating conditlons leading to e~cessive wetting of surrounding areas and corresponding coating thereof with mineral deposits.
In addition, icing of adjacent equipment and structures can readily occur during wintertime operations. Thus, adequate drift elimi-natlon is very necessary with evaporative type cooling towers, especially when large towers are ~sed in metropolitan areas or as part of a large industrial complex where cold weather occurs.
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One type of drift eliminator for water cooling towers which has been used successfully for a number of years is de-picted and described in U. S, Patent No. 2,892,509. The Herring-bone drift eliminator of this patent utilizes a number of wooden slats which are both transversely and longitudinally inclined for deflecting the air from the fill assembly upwardly at an angle to effect removal of water droplets therefrom as the particles of moisture impinge upon the double inclined surfaces of the elimi-nator slats. More effective removal of entrained water from the airstream is accomplished by providing a double pass of elirnina-tor slats with the first layer being disposed with the longitudi-nal axis thereof inclined in one direction, while the next layer is longitudinally inclined in the opposite direction. Although highly effective, the Herringbone eliminator structure declines in performance as higher air velocities are encountered. Inclina-tion and overlapping of the slats is correlated with the static air pressure drop to pxevent an undesirable decrease in perfor-mance of the tower and in an effort to more effectively remove water droplets from the moist airstream. With increasing concern about the potential dele~erious environmental effects of cooling tower drift, especially when brackish or saltwater is used as the cooling mPdium, a need has arisen for a more efficient drift eliminator than is inherent in the Herringbone, without signifi-cant cost increases or a decrease in thermal performance of the overall tower unit.
Another approach to drift elimination is found in U. S.
Patent No. 3,065,587 which dis~loses honeycomb eliminators asso-ciated with horizontal wooden slats somewhat similar to the first pass of the Herrirlgbone design. Further, in one specific embodi-ment disclosed în Fig. 9 of the drawings of this paten~, the useo~ a pair of adjacent, coplanar, angularly disposed cellular honeycomb sections is taught. Although honeycomb eliminators have ~O 7~

found substant~al application, their principal usage has been limited for the most part to smaller package-type counterflow towers because of the problems associated with providing a pack of sufficient structural integrity in order to minimize the ex-ternal supports needed to hold the eliminator in position across the moist air outlet face of the fill assem~ly without sagging, warping, or collapse of the cellular material.
U. S. Patent No. 3,500,615 to Meek, discloses the type of two ~ass drift eliminator wherein separate eliminator packs are respectively composed of interconnected, alternating corru-gated sheets, with the separate packs being located such that the corrugated sheets in each are at right angles relative to the sheets in the adjacent pack. Actual testing of this type of eliminator structure has demonstrated ~hat it does not give ade-quate drift elimination, and that the pressure drops attributable to the unit are e~cessive. It is believed that a prime reason for the deficiency of this type of eliminator stems from the fact that no means is provided for separately draining the respective corrugated packs, and that accordingly the air passages thereof can become partially or fully blocked with water. The accumulated water is then very susceptible to becoming reentrained in the cool~
ing air, thus further lessening the drift e].imination properties of this type of eliminator construction.
It is therefore a primary object of the invention to provide dual pass cellular drift eliminator structures and method for use in crossflow water cooling towers which overcomes many of the problems associated with drift eliminators used heretofore in commercial practice, and that are operable to remove a signifi-cantly higher portion of entrained water particles from hi~h ve-locity moist airstreams leaving the fill assembly of a coolingtower without substantial increase in the overall cost of the eliminator assembly, or significant increase in the static air ~s~

pressure drop associated with the use thereof.
A further important objeet of the invention is to pro-vide two-pass drift eliminator structure and methods especially adapted for use with crossflow water cooling towers, and which are effective to remove entrained water particles from generally horizontally directed airstreams leaving the tower fill in a man-ner essentially independent of stream velocity through utiliza-tion of dual path elimina~ors having spaced, cellular, diversion path-defining structures disposed to first divert the airstreams upwardly and preferably laterally at an angle relative to the nor-mal path thereof, and to thereafter divert the streams laterally to one side of the first diversion pakh~ In particular, a repre-sentative ~ector of the air approaching the eliminator, and a representative vector of the air during the first diversion there-of, establish a reference plane; and a representative vector of the air during the second diversion thereof is situated at an angle with respect to the established reference plane.
A still further important object of the invention is to provide a dual path drift eliminator of the type described wherein the first and second diversion path-defining cellular struetures thereof are spaced a sufficient distance to permit sepa-rate drainage of the volumes of water collected in each section -so that water blockage of the air inlet face of the drift elimina-tor structure is avoided to minimize accumulation and re-entrain-ment of water in the air leaving the eliminator.
Yet another aim of the invention is to provide multi-cell dual path drift eliminator constructions which are configured to present nestable packs permitting complemental positioning of a plurality of the packs without creation of objectionable vertical gaps between the sections which could allow substantial volumes of entrained water to escape to the atmosphere.
A still further object of the invention is to provide ,, .

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a ~ulticell dual path elimin~tor ~ebricated of rigidized pre-~orme~ sheets pre~erably eomposed o~ neopr~ne a~be3to~ and where in the deformed surfaces thereof are configured and arranged ~o th~t the drift eliminator pack3 can be produced by ~tacking and gluing the preformed ~ections util:izing desirable assembly line tech~iques.
In genexal ter~s, ~he presen~ invention pro~icles, in a crossflow cooling tower, a ho~: water distributor;

; a cold water collection ba~in beneath said dis~ributor;

~ill 0~ruc~ure locsted b~wae~ d basi~ ~nd ~i8tr~utor or dispers~g hot w4t~r ~rav~tllti~g fro~ th~ la~t~r; ~n~an~ ~or di-rectl~g amble~lt-derlYed al~ throu~ ~aid ~ill structu2~ c~o~-flowizlg ln~er~ec~g relatlo~ship to the flow o ~t~r ~her2-through ~os cooli~g o~ th~ ter; two-pa~s, c~llular drlf~ eliml-nator ~truc~ur~ po~ieio~d pro~i ~ 1 t~ the air ~xlt ~ce o~ ~a~d f~ll st~ucture for r~o~lng drople~s of w~ter e~trai~d ~hi~

the mol~ alr leav~ng th~ truc~ure, ~aid el~m~na~or ~ruc-tuse c~m~r~sing: ~ plural~y of horiæo~lly spaced, elo~ga~d, g~erally uprlgh~, ~ran~er~ly V-~haped memb~3 each hs~ing ~ir~t and 3econd g~ner~lly planar ~hees~ or~e~ed ~t a~ ~gl~
rQla~v~ to ea~h other; partitio~ m~an~ ~oin~d to ~d po~ltioned bPtw~en each oppo~ed p~ir of ad~acen~ fls~t ~d ~ec~d ~heet~ o~
pro~imal Y-shaped me~be~s di~idl~g ~he ~pace hereb~tween i~o l~dlvitual, ~lo~ga ~d d~cr~te cell~ located ~o~ pa~g~ o ~ deri~d mol~t air ~herethrough, ~he aix cell~ betwe~ ~he first ~d seco~d ~heets r~p~c~vely pre~en~l~g ~orse~po~dl~g Ride-by-8id~ f~ r9~. a~d ~eco~d el~ml~tor Bectlon~, ~ald ~lda-b~-s~de el~m~ator 8ectio~ ~etwe~ re~pect~ve pa~r~ of V~haped ~ ~ber~ belng located ~n ~paced relationshlp to o~ znother ~o def~n~ ther~betwee~ ge~rally uprlght w~ter drainage p~s~ag~
for ~ach cell re~pec~el~ ~d ~xte~din~ gen2rally rom ~h~ ~op ~ _ 5 _ ', ' .

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to the bottom o~ 9aici dr~t ~llminator for at lea3t p~rtlal dral~-sge along respecti~re drai~age ps~age~, the psrtition mQan~ pre-ser~tin~ the ~r cells of ~aid firse eliD2ina~0r 8eCtioD, and che l~rst sheet~ beln~ loc ted to def ~ne lo~gitud~ n~lly parallel ai~
pa~age~ for r~cel~l~g alx from s,~id ou~le~ face a~d orie~ted for dit~ert~g ~uch alr upwardl7 r~lat~ to ~he l~ ial path o2 the ~lr leavl~g s~d e~it face ~uch tha~ a ~ec~or r~pr~e~tlng the tra~el o mol~t a~r alo~g aaid inlti~Ll pa~h, arld a v~ct~r repre~enting the tra~l. of mol~t alr ~lorlg th~ ~ir pa~g~ o 10 said ~r~t s~ctiorl, cooperati~rely es~cabl~s~ing ~ r~fere~c~ pl~
the partition m~ d~fining he sir cell~ of ~ald ~cond el~ml nator ~ect$on ~nd the seco~d sheet~ be ln~ loca~ed ~o de~ine longl-tudln~lly parallel alr passage~ ~or recei~i~g a~t aft:er flow thereo~ through said fir~ ol~ to~ ~ctlo~ snd orie~ted for dlvart~g such air lat~rall7 r~lati~e to th~ pa~h o~ ~ir lea~ing ~aid ~rst ~l~mlnator aectlo~, ~u h ~hs~ a ~eccor represerL~in~
thg t~aYel of air alon~ t~e air pa~ages of s~d ~econd ~ectlon is a1: an angl~ relat~e to ~aid re~er~ce pla~a.
In another aspect, the present invention provides a drift eliminator structure adapted to be positioned adjacent the air exit face of the fill structure of a cro~lo~ cool~n~ tow~r for remoYi~g e~tra~ed water droplet8 fr~m the moist a~.r, leavin~ a~id f~ll 8txu~ture, sa1d drl t el~m~
na~or at~ cturQ co~pri~ing: ~ plural~ of horizo~tally ~paced, elonga~ed, ge~rall~ upright, tran8~aræel~ V~ ped member~ each h~vln& firs~ and 8econd generally pla~ar she~tg oriented at a~
~ngle relatiYe ~o each other; par~lon nean~ ~oined to and po-~it~n~.d bet~ee~ each oppo~d pair of ad3~cent Rheets of proxi-mal Y-shaped me~bers dividing the space therebetween înto i~di-30 vidua~, elo~gated discrete cells loc~t~d for pa~sage of flll-d~rlved moist air ~chereehrough, ~he air cells ~etween th~ f~rst ~ - 5a -a~d ~econd ~heet~ re~pectively ~resenting corre~po~ding side-b7-~ide fir~e and ~econd eliminator ~ectlo~ id ~ide-b7-side elimi-nator ~ection~ between re~pecti~e pair~ of V-~haped me~bers be~ng located in ~paced relation~hip to one ano~her to deflne therebe-tween generally upright water draina~e passages for e~ch cell respectiv~ly and extendlng generally ro~ the ~op to the bott~m of ~aid drlft eliminator for at least part~al water drai~age along resyective dral~age p~age~, t~ p~rt~tion mean~ pre~enting th~
~lr cell~ of s~id fir~ elimlnator s~ction and the fir~t ~heet~
bei~ located to define long~tu~inally parallel air cells for receivi~g ~ir ~rom aaid outle~ ~ace ~nd ori~ted for divertlng such air upw~rdly relat~e t~ the initial p~th of the air lea~Lr~
~a~d exit ~Ace ~uch th~t a vector repre~enti~g the t~a~el of ; 3t air alo~g said initial path, ~nd a ~ector repre~nting the tra~el of moi~ air alo~g the air passa~e~ of sald ~irst ~cti~n, co-operstively establishin~ a referencP plane, the par~ition me~3 defining the ~ir cell~ of said ~econd elimi~ator section and the seco~d sheeta belng locat~d to define longitudinally parallel a~r pas~age~ for receivi~g ai~ ater 10w thereof through ~ald f~r~t oliminato~ ~c~o~ aad orlented ~or d~erel~g ~uch Rir laterally relat~e to th~ p~th of ~lr leav~ng said fir~t elimi~ox ~ec~lon, ~uch th8t ~ ~ector repEesent~Qg the t~avel of ~ir al~g ehe air paa~a~e~ of ~aid 8ec~d ~a~lo~ 4~ a~ ~ sngl~ r~l~tiv~ to ~aid r~f~ranc~ pla~e.
In a still further aspect of the present invention, a method is provided for removing entrained water particles from a moist sir~tream tra~eli~g a~o~g a ge~erally hor~o~tal in~ti~l path, eompr1sl~g ~:he 8tep8 of: ~ni~ally divertl~g ~aid moist air~tre~ upwardly relsti~e to sald ~ ia} path such ths~ a ~ector represe~ti~g ~ravel of ~he i~ a~r ~long ~aid l~ltlal pa~h, ~nd a vectox ~eprese~tlng txa~al of the molst al~ during ~a~d upward and lateral diverslo~, cooperati~l~ e~tablish a reference pla~e, ~ ~ 5~ ~

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said diverslon lncludl~g ths~ 8t:ep5 of moving ~aid moist air into i~dlvidual elongated fir~t ~lr eell~ located in parallel relatton-ship and orie~ted :or cau~l~g ~aid upward d~version ~d de1ned by;
walls pre~e~ting said flr~ air cells th~rebetwe~; thereaf~er seco~darll~ diYerting the i8'C Air 1at~rRlly relQtl~7e to the pa~h of the alr from the firs~ air cellB ~ch that ~ v~ctor repre~
sentl~g travel of the mol~t 8ir du~.i~g the ~econd lateral diverslon ~hereof i8 ~t a~ le relat~ve . o said reiEerence pla~e, said ~econdEIr~ divar310~ clud~r~g the ~Iteps o~ virlg ~aid molst air from said f~ r~t alr cella into ind~vidual elo~ga~ed seco~d a~r cell~ spaced fro~ the flr~t a:Lr.~cells di~oaed i~ parallel rela-tioDLship ~d or~ ented ~or cau~ a~ d ~e~ond lateral divez~lon and defined by wall~ pre~e~ting said second air cell~ therebetweer~;
permitting the entr~ined ~ater p~ticles irl said nlr~tream to lm-pin~e agaiwt ~he wall~ d~firLi~g said fir~ d ~eco~d alr cPlls durl~g ~ald ~ltial aDd ~econdar~ dlv~r~ior~ of the ai~tream; and draini~g th~ water collected by Ylrtue of ~aid implngeme~t by al-low~g ~t lPast a p~t of ~a~d w~t~r to gra~itate be~ee~ ~ld first s~d ~econd alr c~l~. 8 along th~ spac~ therebe~eeII .
2C In th~ drawingn:
Figure 1 is a fr~mentary end elevational view o a dual pat~ ~lticell eliminator pack and ~howing a pair of ~qpaced, angulaxly corrugated neoprene asbesto~ 5ection5 secured to a tra~sver3ely V-shaped support panel therefor;
Fig. 2 is a fxagmentary, side elevational view OIC t}~e eliminator pack illustrated in Fig. l;
~ig. 3 is a ~ragmentary top plan view o the drift eliminator pack depicted in Fig. 2;
Fig. 4 is anotner 3idP elev~tional view of the drift eliminator paek depicted in Fig~. 2 and 3 and taken along line 4-4 o~ Fig. 3;

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Fig. j is an essentially schematic, frag~en~ar~f ~D
plan view of a pair o~ nes~able drlft eliminator pack~, shown in complemental nested relationship.
Fig. 6 is an essentially schematic, fragmentary Pnd elevational view of a drift eliminator pack illustrating the water droplet removal operation thereof in a cros~low-~ype cooling tower;
Fi~. 7 i3 aIl essentially schematic top plan vie-~ of a pair of nested elimina~or pack~ and further ~how~ng the wa~er droplet removal ~unction thereo;
Fig. ~ is a graphic~l repre~entation ~howing th~ en-hanced drift elimin~tion capabil~es of the eliminator ~tructures of the pre~ent invention, compared with a coplanar-~ype two pa~s honeycom~ dri~t eliminator depicted in U. S. Patent No. 3,065,587;
~ig. 9 is an ess n~ially 3chema~ic, fragmentary, ve~-~ - 5d -?~ ~.7 ~, t:ical sectional view of a hyperbolic crossflow cooling tower shown with a plurality of multi-pack, vertically stacked elimi-nator sections positioned adjacent the exit face of the fill structure thereof;
Fig. 10 is an essentially schematic, fragmentary, ver-tical sectional view of a mechanical draft crossflow cooling tower with a plurality of multi-pack, vertically stacked elimi~-nator sections positioned adjacent the exit face of the ~ill structure thereof;
Fig. 11 is an essentially schematic, fragmentary, ver-tical sectional view of a mechanical draft crossflow cooling tower, illustrating a plurality of vertically stacked eliminator sections in an inclined, complemental orientation relative to the exit face of the structure ~hereof; and Fig, 12 is a view identical with that shown in Fig. 11 excépt that the eIiminator sections are in horizontally offset relationship with one another.
Drift eliminator pack 20 incorporating the preferred concepts hereof is illustrated in Figs. 1-4. In general, elimi-nator pack 20 comprises a plurality of side-by-side pairs o~ air passage-defining partition means pre~erably in the fo~m of elon-gated, angularly corrugated sPgments 22 7 with the opposed seg-ments of each pair being sandwiched between a pair of identical, preformed7 imperforate, transversely V-shaped support panels 24.
The latter present first and second generally planar sheets which are angularly oriented with respect to one another.
The segment pairs and panels are positioned in alternating, ad-hesively secured, stacked relationship as best seen in Fig. 2 in order to define an elongated, multicell dual path eliminator pack.
Each segment 22 is an elongated? preformed member preferably composed of neoprene asbestos and having a plurality of aligned, side-by-side, generally sinusoidal, angularly disposed .

corrugations 26 along the length thereof. Similarly, each panel 24 is an integral member preferably formed of neoprene asbestos and presenting an included obtuse angle "X" (see Fig. 3). Al-though other materials such as vinyl can be used to ~orm seg-ments 22 and panels 24, neoprene asbestos is preferred from the standpoint o~ cost and ease of fabrication.
Referring specifically to Fig. 3, it will thus be seen that eliminator pack 20 presents a first cellular section 28 with a secondary, identically configured cellular section 30, laterally disposed with respect to section 28 and separated therefrom by a distance referred to by the numeral 32. The individual elongated cells within each cellular section 28 and 30 are defined by the individual corrugations 26 in the respective segments 22, as well as the adjacent support panels 24, as will be readily seen.
The angular, generally V-shaped disposition of the sup-port panels 24 permits complemental positioning o~ a number of eliminator pac-ks 20 in aligned, end-to-end relationship as de-picted in Figs. 5 and 7. For example J a pair of ~liminator packs 20a and 20b can be complementally and nestably positioned in an abutting manner without any objectionable vertical gaps along the joint therebetween. This permits rapid positioning of a plu-rality of adjacent eliminator packs 20 in complemental, juxtaposed, covering relationship to the air outlet face of cooling tower fill structure without the need of shiplap joints or other mechani-cal interconnection between the respective eliminator packs, as has been conventionally required.
Most important however, the configuration of the elimi- --nator packs 20 is designed to present a dual path, individually draining, multicell unit that has proven to be extremely efective in removing entrained water particles from moist airstreams leav-ing the exit face of cooling tower fill structures. Referring to schematic Figs. 6 and 7 wherein the water droplet removal opera-.
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tion of the present eliminator in a crossflow type tower is de-picted, it will be seen that the moist air is initially directed against the air inlet face of ~irst cellular section 28. By vir-tue of the fact that the individual cells thereof are inclined upwardly relative to the initial path of air, the air is first diverted along the inclined path thereof in passage therethrough.
Upon lea~ing the cellis of first cellular section 28, the moist airstream next passes through the laterally oriented, upwardly inclined cells o~ secondary cellular section 20. It is important that the secondary air diversion path defined by cellu-lar section 30 is æituated to one side of the first diverslon path presented by section 28 in order to enhance the water removal capabilities of the overall eliminator. Actual test results have proven that this relative disposition of the respective cellular sections has the effect of dramatically increasing ~he e~fective-ness of the eliminator.
In order to more precisely describe the relative orien-tation of diversion path defining sections 28 and 30 relative to the initial path of molst air, the following is helpful. For ease of discussion, the initial path and magnitude of such moist air can be thought o~ as a representative single vec~or 38. Upon entering section 28) the air represented by vector 38 is diverted along a first diversion path represented by vector 40 which is situated at an angle relative to vector 38. Vectors 38 and 40 also establish a reference plane which may be essentially ver~
cal or at any one of a number of angles with respect to the verti-cal. The moist air next enters section 30 and is redîverted along a second diversion path represented by vector 42, As best seen in Fig. 7, vector 42 is situated at an angle with respect to the reference plane established by vectors 38 and 40.
It will t:hus be seen that the preferred eliminator struc-ture hereof is operable to divert the initial moist air path first ~ 7 ~7~
upwardly and laterally and then laterally again so that the moist air is varied in a number of directions duri.ng travel thereof through the eliminator. In any event, such a dual path structure defined by the relative dlsposition of the cellular sections mak-ing up the eliminator has been proven to dramatically increase drift elimination.
As discussed, the indivua.l cells defining ~irst cellu-lar section 28 should be oriented at an upwardly inclined angle relative to the initial path of moist air in order to initially 10 direct the moist airstreams therethrough. In more de~initive terms, thls angle should broadly vary between about 10 to 60 relative to the horizontal in a crossflow tower application, more preferably from about 15 to 50 , and most preferably at an angle of about 30 .
It is also extremely desirable from the drit elimina-tion standpoint to angularly orient the cells of secondary cellu-lar section 30 with respect to the initial path of moist air, in addition to the lateral disposition thereof relative to the cells of cellular section 28. In this regard, the same inclination angles listed above in connection with the cells of section 28 can be used to good advantage in orienting the cells of section 30. This has the effect of directing the streams upwardly through the entire eliminator to facilitate discharge thereof from the tower. Moreover, this orientation minimizes the objectiQnable pressure drop across the eliminator.
During travel of moist air along the first and second air diversion paths deined by cellular sections 28 and 30, the inertia of the entrained water particles causes the latter to impinge against the defining cellular sidewalls of the sections.
This in turn causes collection of the impinged water particles on such sidewalls and permits removal o~ water droplets by gravi-tational drainage, illustrated by arrows 44 and 46 in Fig. 7.

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Such water drainage is greatly facilitated in the present eliminator hy provision of the spacing 32 between cellu-lar sections 28 and 30. By virtue of this spacing, the water collected in each individual section 28 and 30 can he separately drained to the cooling tower basin therebelow. This is advan-tageous because of the fact that la:rge volumes of water, if drained only from the alr entrance face of the eliminator, could cause water blockage of the inlet face wh:ich in turn increases the static air pressure drop across the eliminator and deleteriously effects the overall per~ormance thereof. Thus, the spacing 32 between the cell sections is particularly preferred, especially when the elimi- -nator 20 is to be utilized in the crossflow type of cooling tower where the ellminator packs are positioned in a generally upright orientation.
The eliminator packs of the present invention are usable in virtually all types of evaporative crossflow cooling towers.
Figures 9-12 illustrate the use of the present eliminators in the context o~ annular crossElow cooling towers, which include circum-scribing upright fill structure 48, an annular hot water delivery basin 50 thereabove, and a cold water collection basin 57 under-lying the fill. Fill 48 defines a central plenum chamber 54 with-in the confines thereof, the latter being in communication with the air currant-inducing apparatus associated with the overall tower.
For example, in Fig~ 9, an upright, natural draft-inducing hyper-bolic stack 56 is fragmen~arily depicted, and in Fig. 10, a mechani-cal draft-inducing fan assembly 58 is shown. Either of these ex-pedients can be ut:ilized for inducing crossflowing currents of air through ~ill structure 48 for evaporative cooling of hot water descending through the latter.
It will be seen that the annular eliminator structures utilized for drift el.imination with relatively tall, annular cross-flow fill structures are comprised of a series of vertically stacked -,: .

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and juxtaposed eliminator sections which are defined by a number of side-by-side, nested ce].lular eliminator packs 20. For example, our sections 60, 62, 64 and 66 are shown in Figs. 9 and 10, and the latter cooperatively extend substantially the entire height of the respective fill stru~tures 48 in proximal, complemental relationship with the air outlet faces thereof.
A mechanical draft crossflow cooling tower is also il-lustrated in Fig. 11 wherein conventional fill structure 68 is employed which is configured and arranged to compensate for water pull-back at the base of the fill. Eliminator structure 70 is inclined at substantially the same angle as the exit face of the fill and i8 comprised of a series of three inclined eliminator sections 72, 74 and 76. Thus, the overall eliminator structure 70 is complementally arranged with respect to the air outlet face of fill structure 68.
In other instances, it has proven to be beneficial to utilize an eliminator structure 78 as shown in Fig. 12 having horizontally offset, multi-pack eli~inator sections positioned with the lowermost section situated at the innermost position, and all higher sections being horizontally offset outwardly there-from. In this embodiment lowermost eliminator section 80 is situated at the innermost position with higher eliminator section 82 and 84 being horizontally offset with respect thereto.
Actual testing in practice has proven that the dual path dri~t eliminators hereof give dramatically enhanced water particle removal from moist airstreams, as compared with conven~ional units.
It is beIie~ed that this stems from the use of first and second cellular structures operable to first divert the mois~ fill air-stream into a first di~ersion path disposed at an angle relative to the normal path of the air, followed by a diversion along a second diversion path dîsposed to one side of the first diversion path. Such an irr~egular diversion of air through the eliminator , , . .
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maximizes the probability tha~ the erltrained water par~icles will impinge against the defining sidewalls of the elimina~or cells and thus collect for drainage therefrom. Also, provision of sepa-rately draining first and second cellular sections as explained is belie~ed to materially assist in drift elimination because water accumulation and blockage of the air passages, and resul-tant re-entrainment of water droplets, is e~fectively avoided.
These enhanced operationa:L characteristics will be readily apparent from a study of the graphical representation of Fig. ~. The latter represents a test conducted to determine the respective water removal capabilities of a 5-inch width, two-pass honeycomb drift eliminator similar to the type depicted in Fig. 9 o~ the drawings of U. S. Patent No. 3,065,587, compared with a 5-inch width dual path dri~t eliminator in accordance with the present invention. The prior art eliminator uses coplanar, angu-larly disposed cellular sections, The drit elimination capa-bilities of the two~pass honeycomb were recorded as a function of the velocity of air leaving a crossflow cooling tower ~ill structure, and these results were arbitrarily taken to represent a 100% drift rate. The same test was also performed with the present dual path eliminator, and the results likewise plotted as a function of airstream ~elocity from the fill structure. As clearly shown in the graph, the drift elimination capabilities o~
the present eliminator structure are at least five times that of the two-pass honey~omb eliminator at substantially all airstream velocities. Thus, the bene~icial results obtainable with the present eli~inator structure are conclusi~ely demonstrated.
In another series of tests the drift eliminator of the present invention was compared to two~pass structure of the type disclosed in U. S. Patent No. 3,5~0,615. In particular, two sepa-rate packs of 3 and 1/4 inches thickness were used, with the packs being oriented at 90 relati~e to each other and placed in stacked, ~, . , .:

~ ~ 7 ~ 7 ~
abutting relationship across the air exit ~ace of a counterflow-type test cell (at 0 relative to the horizontal) speci~ically designed for measuring counterflow drift elimination. The alter-nating corrugated sheets in each pack had a corrugation pitch of 1.83 inches (measured in a plane perpendicular to the corrugation valleys~, and a two-thirds inch peak-to~peak thickness. The ef-ficiency in parts per million o~ entrained water to e~it air was measured at air velocities of 400 and 550 ft./min., with a re-circulating water load of lQ gallons per minute per square foot (based upon the area of the cell exit face).
As a corollary test, a drift eliminator in accordan~e with the present invention was measured in a similar crossflow-type test cell. Tlle eliminator had a total width of 5 inches and was placed adjacent the air exit face of the test cell at an angle o 12 1/2 degrees relative to the ~ertical. The distance between the V-shaped members of the eliminator was two-thirds inches, and the e~fective drainage distance between the adjacent cellular sec-tions was approxi~ately 3/8 inch. The corrugations o~ the sheets between the V-shaped members was upwardly inclined at 60 relative to the eliminator ~ace. This eliminator was tested at 400 and 550 ft./min. air velocities with a recirculating water load of 10 gallons per minute per square foot.
In ~oth cases drift and pressure drop were separately measured to determine relati~e drift removal ef~iciencies. The ~-following table su~marizes these test results, wherein Test I is the eliminator o~ ~he type disclosed in Patent No. 3,500,615, and Test II is the eliminator o~ the present invention. For ease of comparison, the drlft and pressure drop results of Test I are taken as 100%, and those of Test II are expressed as percentages of this standard.

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TABLE

Test I Test II
Air Pressure Air Pressure Velocit~ Drift Drop Veloci~y Dri~t Drop .
400 (ft. min) -- 100% 400 (ft/min) -- 75~8v/o 550 --100% 550 -- 74 3%
400 100% -- ~00 26~3~/o --500 100% -- 500 23.~% --600 100% - 600 26.3% -- --~

The above data demonstrates that the eliminator hereof gives significantly greater drift elimination (by a factor of about four times) at all air velocities tested; moreover, this is accomplished with a lesser pressure drop than that e~perienced with the two-pass eliminator of Patent No. 3,500,615. Further-more, since the latter eliminator was tested in a counterflo~ cell, the comparative results would be expected to be even more dramatic if this eliminator were used on a crossflow test cell. This stems from the known fact that counterflow eliminators have inheren~ly better drainage by virtue o the orientation thereof, and that poor test results on a counterflow cell indicate that even worse results would be found in a crossflow test.
Although the reasons for the dramatic improvement of the eli~inator of the present invention over the eliminator of Patent ~o. 3,500,615 are not completely understood, it is hypo-thesized that lack of individual pack drainage in the latter unit is a primary cause. Also, the construction of this eliminator inherently provides a ~ertain percen~age of relatively unrestricted airflow channels for the moist air, as opposed to the posi~ive up~
~; ward and lateral air diversion~ provided by the eliminator hereof.
The eliminator constructions o~ the invention are also ~. :

,, ~
' ' ~ ' . ' ~' ' `' . ~ . ' . ' , ~ ~ 7 S~ ~
advantageous in that fahrication is a simple matter and amenable to production line techniques. In practice, an elongated, hollow form is provided ~or the production o~ the eliminator packs 20.
An initially transversely V-shaped support panel 24 is ~irst placed at the bottom of the ~orm, and the upraised apex portions o~ a pair of currugated segments 22 are coated with conventional heat-setting glue. The coated segments 22 are then positioned on the panel 24 in spaced, side-by-side relationship ~ith one another. Alternately, a single, elongated corrugated member can be longitudinally cut and spread over the ape~ o~ the support panel after glui~g. In this case the segments are comlected by a thin strip o~ material but are identical in every other way with the separate pairs of segments. A second panel section 24 is then placed over the corrugated segments 22 and the glue coat-ing and placement procedure repeated. This is continued until an eliminator pack havîng the desired number of cell-de~ining layers is built up in the ~orm. At this point, the ~orm is trans-~erred to a heating oven whereupon the heat-setting glue serves to bond the respective segments and panel sections into a com-pleted eliminator pack. In this manner, ~abrication costs aregreatly reduced and unskilled workers can be employed in the pro-duction procedure.

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Claims (19)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a crossflow cooling tower: a hot water dis-tributor; a cold water collection basin beneath said distributor;
fill structure located between said basin and distributor for dispersing hot water gravitating from the latter; means for di-recting ambient-derived air through said fill structure in cross-flowing intersecting relationship to the flow of water there-through for cooling of the latter; two-pass, cellular drift elimi-nator structure positioned proximal to the air exit face of said fill structure for removing droplets of water entrained within the moist air leaving the fill structure, said eliminator struc-ture comprising: a plurality of horizontally spaced, elongated, generally upright, transversely V-shaped members each having first and second generally planar sheets oriented at an angle relative to each other; partition means joined to and positioned between each opposed pair of adjacent first and second sheets of proximal V-shaped members dividing the space therebetween into individual, elongated discrete cells located for passage of fill derived moist air therethrough, the air cells between the first and second sheets respectively presenting corresponding side-by-side first and second eliminator sections, said side-by-side eliminator sections between respective pairs of V-shaped members being located in spaced relationship to one another to define therebetween generally upright water drainage passages for each cell respectively and extending generally from the top to the bottom of said drift eliminator for at least partial drain-age along respective drainage passages, the partition means pre-senting the air cells of said first eliminator section and the first sheets being located to define longitudinally parallel air passages for receiving air from said outlet face and oriented for diverting such air upwardly relative to the initial path of the air leaving said exit face such that a vector representing the travel of moist air along said initial path, and a vector representing the travel of moist air along the air passages of said first section, cooperatively establishing a reference plane, the partition means defining the air cells of said second elimi-nator section and the second sheets being located to define longi-tudinally parallel air passages for receiving air after flow thereof through said first eliminator section and oriented for diverting such air laterally relative to the path of air leaving said first eliminator section, such that a vector representing the travel of air along the air passages of said second section is at an angle relative to said reference plane.

2. The cooling tower as set forth in Claim 1 wherein the orientation of the air passages of said second section serves to divert air received from said first section upwardly.

3. The cooling tower as set forth in Claim 2 wherein the air passages of said first and second sections are disposed at substantially equal angles relative to the initial path of moist air from said outlet face.

4. The cooling tower as set forth in Claim 1 wherein the disposition of the air passages in said first section serves to divert said air from said outlet face both upwardly and later-ally relative to the initial path of the air.

5. The cooling tower as set forth in Claim 1 wherein said partition means is in the form of an elongated, preformed, generally sinusoidally corrugated sheet.

6. The cooling tower as set forth in Claim 1 wherein said V-shaped members are substantially imperforate.

7. The cooling tower as set forth in Claim 1 wherein said V-shaped members are configured to present an included obtuse angle.

8. The cooling tower as set forth in Claim 1 wherein said V-shaped members and corrugated sections are formed of neoprene asbestos, and said segments are adhesively secured to said sheets.

9. The cooling tower as set forth in Claim 1 wherein said air current-directing means comprises a hyperbolic, natural draft-inducing stack.

10. The cooling tower as set forth in Claim 1 wherein said air current-directing means comprises a current-inducing powered fan.

11. The cooling tower as set forth in Claim 1 wherein the air passages in said first and second cellular structures are oriented at an angle of from about 10° to 60° relative to the horizontal.

12. The cooling tower as set forth in Claim 11 wherein said angle is from about 15° to 50°.

13. The cooling tower as set forth in Claim 12 wherein said angle is about 30°.

14. The cooling tower as set forth in Claim 1 wherein said drift eliminator is composed of a series of elongated, ver-tically stacked eliminator elements positioned adjacent the moist air outlet face of said fill structure, said stacked eliminator elements cooperatively extending substantially the entire height of said fill structure.

15. The combination of Claim 14 wherein said verti-cally stacked eliminator sections are positioned in offset rela-tionship to one another, with the lowermost eliminator section situated at the innermost position and all higher eliminator sec-tions being offset outwardly therefrom.

16. Drift eliminator structure adapted to be posi-tioned adjacent the air exit face of the fill structure of a crossflow cooling tower for removing entrained water droplets from the moist air, leaving said fill structure, said drift elimi-nator structure comprising: a plurality of horizontally spaced, elongated, generally upright, transversely V-shaped members each having first and second generally planar sheets oriented at an angle relative to each other; partition means joined to and po-sitioned between each opposed pair of adjacent sheets of proxi-mal V-shaped members dividing the space therebetween into indi-vidual, elongated discrete cells located for passage of fill-derived moist air therethrough, the air cells between the first and second sheets respectively presenting corresponding side-by-side first and second eliminator sections, said side-by-side elimi-nator sections between respective pairs of V-shaped members being located in spaced relationship to one another to define therebe-tween generally upright water drainage passages for each cell respectively and extending generally from the top to the bottom of said drift eliminator for at least partial water drainage along respective drainage passages, the partition means presenting the air cells of said first eliminator section and the first sheets being located to define longitudinally parallel air cells for receiving air from said outlet face and oriented for diverting such air upwardly relative to the initial path of the air leaving said exit face such that a vector representing the travel of moist air along said initial path, and a vector representing the travel of moist air along the air passages of said first section, co-operatively establishing a reference plane, the partition means defining the air cells of said second eliminator section and the second sheets being located to define longitudinally parallel air passages for receiving air after flow thereof through said first eliminator section and oriented for diverting such air laterally relative to the path of air leaving said first eliminator section, such that a vector representing the travel of air along the air passages of said second section is at an angle relative to said reference plane.

17. A method of removing entrained water particles from a moist airstream traveling along a generally horizontal initial path, comprising the steps of: initially diverting said moist airstream upwardly relative to said initial path such that a vector representing travel of the moist air along said initial path, and a vector representing travel of the moist air during said upward and lateral diversion, cooperatively establish a reference plane, said diversion including the steps of moving said moist air into individual elongated first air cells located in parallel relation-ship and oriented for causing said upward diversion and defined by walls presenting said first air cells therebetween; thereafter secondarily diverting the moist air laterally relative to the path of the air from the first air cells such that a vector repre-senting travel of the moist air during the second lateral diversion thereof is at an angle relative to said reference plane, said secondary diversion including the steps of moving said moist air from said first air cells into individual elongated second air cells spaced from the first air cells disposed in parallel rela-tionship and oriented for causing said second lateral diversion and defined by walls presenting said second air cells therebetween;
permitting the entrained water particles in said airstream to im-pinge against the walls defining said first and second air cells during said initial and secondary diversions of the airstream; and draining the water collected by virtue of said impingement by al-lowing at least a part of said water to gravitate between said first and second air cells along the space therebetween.

18. The method as set forth in Claim 17 including the steps of initially directing said moist airstream both up-wardly and laterally relative to said initial path.

19. The method as set forth in Claim 17 including the step of separately draining the water collected in said first and second air passages respectively.