US2545672A - Spray booth - Google Patents

Description

March 20, 1951 F. E. PEARsoN SPRAY BOOTH 2 Sheets-Sheet 1 FiledApril e, 1948 March 20, 1951 F. E. PEARsoN SPRAY BOOTH 2 Sheets-Sheet 2 Filed April 6, 1948 Patented Mar. k20, 1951 SPRAY Boo'rH Frank 1E'. Pearson, Portland, Oreg., ass-ignor to Cascade Manufacturing Company, Portland, Oreg., a corporation of Oregon Application/April e, 194s, serial No. 19,342

This invention relates toY spray booths, and more particularly to those of the type used in spraying paint and the like, and which utilize a water curtain in addition to the controlled flow of air for confining and cleaning polluted air from the spray area. a Y

One of the objects of my invention is to provide a spray booth which utilizes a water curtain to cover the rear wall of the spraying space and embodies structural parts and arrangements such that the flow of the curtain water is controlled and metered to produce a continuous and solid water curtain below that rearvwall through which the llow of polluted air is directed from the spraying space for thorough washing by the water.

It is another object of the invention to provide a spray booth in which the air is suiciently washed and dried that it may b e recirculated into 4 Claims. (Cl. 18S-26) the room, rather than being exhausted outside of spray booth in which a cleaning liquid is used for washing a directed flow of air which is circulated therethrough and wherein the structure and arrangement is such that a quantity of cleaning liquid may be used for a considerable period of time by recirculation without being changed andv the pollution thus taken from the air will becollected in a reservoir for removal with the liquid and possible reclamation. l

Other objects and advantages of the inventio will be apparent from the following description and the accompanying drawings in which similarV characters of reference indicate similar parts through the several views. Y

Referring to the two sheets of drawings,

Fig. l is a front elevational view of a preferred embodiment of my spray booth with a portion at,

one side cut away to show the internal construction;

Fig`- 2l is a side sectional view of the spray booth shown in Fig. 1', drawn to a somewhat larger scale and wherein the section is taken substantially on a line 2 2 of Fig. 1 and in a direction indicated by the arrows; and

Fig. 3 is a fragmentary perspective view de-V picting a detail of kthe preferred structure of my spray booth.

Referring generally to the exemplary embodiment of my invention which is disclosed in the accompanying drawings for illustrative purposes, the spray booth has a base portion Iii which by preference is in the form of a rectangular tank f I2 from which side walls I3 and I4 and a back `the top, the side and back Walls I3, I4 and I5 are adjoined by a hood-type top having an air ow opening I9 therein which communicates withthe duct I'I and is adjoined by an air flow-` conduit 20. A partition wall 22 extends from side wall to side wall in spaced relationship to the back wall I5 to effect the division between the spray housing I6- and air flow duct I'I. At its lower end, the partition wall 22 terminates in a substantially straight edge 23 spaced" above a normal liquid level 2li in the tanl; I2 and determined byan overflow port 25.

A fan 26 is, by preference, supported bythe top I8 in the opening I9 to force air through the spray booth in the manner depicted by arrows in Figs. 1 and 2. Air is drawn into the booth through the spray housing and it passes'under the partition wall 22 into and upwardly within the air flow duct I'I. In order to prevent the adhesion of va sprayed substance, such as paint, to the surface vof the partition wall 22, toward which the spray lower end of the partition wall 22 and the liquid level in the tank I2. It may be noted that the ilow of air from the spray housing partition of the booth is through the continuous and substantially solid layer of liquid which forms thecurtain below the partition wall, so that the pol-,-

luted air from the spray space is washed by the liquid and the air passes into the duct I'I; the spray particles washed from the air being co1- lected in the liquid which is held by the tank I2. Considering the disclosed spray booth structurev in greater detail, the tank I2 is desirably made of sheet metal and has a bottom 32, front and rear walls 33 and 34 respectively and end walls 35.

As disclosed, the overow port 25 is in one of the;

' end walls 35. In addition to the overflow port, I

also provide a drain port 36 and a ow outlet port Y 31. Formed marginal portions 38 provide a rim for the upper edge of the tank. A

The side walls I3 andv I4 of the spray housing are secured and extend upwardly from the end walls 35 of the tank; the back wall I5 also being secured to and extending upwardly from the rear wall 34 of the tank. The top of the spray housing between the side walls I3 and IG and back to the partition wall 22 is closed by a cover plate 3S. The top I8 is constructed of formed sheet metal and shaped togprovide aconnection to the air flow conduit, as well as covering `the air low duct portion of the spray booth which acts as an air dryer.

In order to efiect the drying of the airas 4it moves upwardly through the duct I'I, which drying is particularly desirable'in installations Where the air is to be exhausted 'into 'the room from which it is taken, groups of baies are preferably provided to effect the ormationmfaisinuousrpath for the flow of the air through the duct. .In the preferred embodiment of my invention, baiiies l, 42 and 43 are secured within the lower portion offtheduct I?. These-baiilesaresecured to and extend -betweentheside lwalls i3 and I4. Also, theyarealternatelymounted to extend inwardly to the ipartition wall -22 and back wall t5 -so as to joverlap *one another in spaced relationship. To -eect and assist the -oW of moisture from the air tothe tank I2, ythefbales 40,42 and-3 slope ldownwardly and inwardly. The "baille ft2 has -a-n outer edge adjoining the back Wall I5, while the outer edges of the `baiiles di) and #t3 adjointhe partition -wall 22. In the flow-of air around the bafes 40, 42 and ifthe changes of direction ofthe air arefromand toward-the-back wall- IY and partitioni'wall IZ2.

Abovethebales 23S, "42and 43, itis my preference to provide vertically'displaced rows 45,45, 46 and fit-"i Iof Ysubstantially trough-like baffles 49, which loafes extend longitudinally vbetween -th'e back wall i5 and partition wall 22. Alsofandby preference, the trough-like-'bailes It-are laterally V-shaped in section with theirconcave surfaces disposed upwardly and the -bales of adjacent rows rare -in staggered and-overlapping relationship to oneanoth'er, as depicted Yin Fig. 1. At opposite-ends, the baies S-'are supported relative lto the 4partition Wall'22and back wall vt5 by formed rbracketplatesvil and 5S respectively. yAt spacedpositions along `the bracket plates '549 and 50, 4bracing straps such -`as '52 extend'between -the bracket plates and aresecuredthereto. yIt may be observed with respect-to theJb-aiiles 58 that vthe direction changes'oftheair iioW effected'by'those bafles are lateral Yto thetiuct-'and transverse vto thoseeiected bythe Jbaiiles toni-2 and e3.

Along the opposite `rsides the 'partition vwall 2-2 is lsecured to and supported -by Vangle straps 53 on -the side walls IS'and I For conservation of space andmaterial, as well'as to provide 4for eiective-and convenient construction, the reservoir 28 forms a part of the separating wall -between the -spray housing -I and air A-iiow duct H'and disposed to-extend Aacross the partition wall 22 at the -top of the spray housing. As shown in Fig. 2, the reservoir 2-8 is made of formeds'heet metalhaving toprandfbottoni walls 54 and l55 respectively and .a back Wall 5G 'integrally connected and with `flanged front -margins lfand -5'8 of vthe Ytop and bottom walls-'secured to 4a partition Wall extension plate 5S and the partition wall 22 respectively. Preferably -end iianges ii, '62 and 63 on the ltop, bottom and rear walls 15%, 55 fand 55 respectively are :secured to :the side-walls I3 and I'of the-air iiow duct. At the front of the reservoir, va -.\veir:plate 161% is secured-to fthe partition-'wall 22 and extendsup- "stantially oval Vand :circular shapes.

wardly to a position spaced somewhat below the top reservoir wall 54 to establish a normal flow level 65 for the liquid 2'I within the reservoir. At one end, the reservoir is provided with an inlet port 66.

For controlling and evening the ow of the liquid within the reservoir 218 from the inlet port B5 Aand-over the top of lthe .Weir plate G4, a series `ofbaillest, 68, 69, 'I0 and`12 is provided. These bailles, in my preferred structure, are each Vsmaller in area than the lateral area of the reservoir .128 and, as satisfactory sectional contours which may be readily manufactured, as well as producingthe-desiredresults, I have selected sub- In order to effect 'the desired `iiow control at different posi- .tionsin :thereservoir with respect to the inlet port, Ialso vary the size and angular disposition oithe loa'ifles relative to the normal direction of iluid ow at their location Iand the general plane of lthe Weir over which uidfflews from'thef-reservoir. I utilizetwo straps `-`I3 and 114 ondiametrically opposite sidesfoflthe bafes 61,68, 69,1111 and l2, to which those vbales -are secured, and which extend longitudinally-of the-reservoir I28, for -supporting the bales in spaced relationshipand l'at their pref-erred angular -positi'ons within -th'e -reser-voir. c

YIt is my preference, for e'iecting airelativly even now-of Vliquid over therweir -p'lateldgtha't thebaiil'esfE andfSS which are near theinlet port end Lof the Yreservoir shall be obliquely-dispose'd within the reservoir and wtih respectito the-general plane fof the Weir "plate, Ywith `that roblique angular -disposition selected to effect a reverse component -of *flow -direction :toward -the weir plate and with -frespectito rthe-normal direction-of flow through the Preservoirfrom the'inlet port. The remaining -bafes 11 0 Land -'I"2 are disposed substantially in right angulal` relationshipftothe general vplanefof fthe'weir plate. Also, since -the required --diversion 'of flow `diminishes somewhat with the distance ffrom :the -in'let sport, the baiiies of `'mydisclosell structurelare successfully smaller in areaas their successive -distancesof disposition from the inlet portinci-'ease In VAaddition fto the -use 4of the reservoir '128, ntogether with its (Jo-acting Weir --and baie --plates for eiecting the flow-oa continuous levenwand completely 'solid layer -of "liquid yover =the lfront surfaceof the partiticn'fpla'te and a substantiallyv continuous and complete curtainofiliquid below the Ypartition plate, Ifalso utilize famovable ow control valve l'element 'I5. yIn fthe present instance, the =Va1ve `L`element L15 lis in the nature/oi? a formed cover plate I6 havingafconcave interior facing and covering fthe weir rplate |64 -and hingedlysupported along its'upper `edge soasfto'have its Anormal position kkdetermined '-by gravity. The hinge support is inexpensively provided vin the present instance by a Vreturned 'bent 2marginal portion 'H along the upper edge of lthe -eover plate-Which over-'hangs andlmovably-rides upon an upwardly disposed vedge '18 of -a channel T9 securedto the partition wallal'ongftheupper-edge of the reservoir. Having a concave surface facingfthe weirfplate 64, a substantially straight bottom edge 8'0 -of the Acover vIplate normally rests against the front 'surface #of fthe partition fwall Z2 `below thebottom edge loi lweir plate "621. Elin operation, the cover plate I5 tends=to 'accumulate liquid within its :concave interior which accumulated lli-quid fforc'es the lower Aedge 80 of the cover plate away from the front surfacef'ofzthe partition wall 1'22 :to a @distance `dependent Iupon the rate of flow, and as illustrated in dot and dash lines at 'ISalin Fig. 2, so that the liquid flows downwardly over the surface of the partition wall. It may be understood that the action of the movable cover plate valve is to effect. an even iiow over the surface and to tend to eliminate any undesirable turbulance.

For additional improvement of the flow and liquid coverage over the front surface of the partition wall 22, I have also found it desirable that a considerable lower portion of that partition wall shall slope forwardly, toward the bottom of the spray housing. Additionally, the bottom end portion of the partition`v wall 22, adjacent the lower edge 23 has a gentle, smooth and rearward curvature, as depicted at 82 in Fig. 2. The aforementioned forward slope and rearward cur- Vature have a tendency to maintain the completeness of the liquid coverage over the surface vof the partition wall and in the curtain below the partition wall, and thereby to prevent the forced air flow along that partition wall surface and through the curtain from effecting appreciable breaks in the liquid continuity.

The disclosed spray booth structure is adapted to the recirculation of a predetermined quantity of air cleaning liquid for a considerable period of time without the replacement of the liquid or the cleaning of the interior of the structure. For the purpose, and as shown in Fig. l, a pump 83 is connected by a pipe 84 to the outlet port 3'! of the tank l2. The output side of the pump 83 is connected through a pipe 85 to the inlet port 56 of the reservoir 28. The capacity of the pump 83 and its associated pipes 34 and 85 are such that a quantity of liquid is pumped from the tank i2 and into the reservoir 2S which is sucient to maintain the desired continuous and complete liquid layer over the surface of the partition wall 22 and in the curtain below the partition'wall. The liquid returns to the tank l2, carrying with it the spray particles4 collected along the surface of the partition wall and in the washing of the air by the liquid curtain during the passage of that air under the partition wall and along the surface of the liquid in the tank.

From the foregoing description and structure of the operation of my spray booth, it may be readily understood that in addition to confining the spray particles to the interior of the booth, the air which flows through the spray housing is so completely washed by the liquid curtain and dried in the air flow duct that it can be recirculated, if desired, into the room in whichA `the booth is located. In addition to adapting the booth for use in restricted and conned areas, the complete cleaning and drying of the air, so that the air is i'lt for recirculation, is important for the conservation of heat in the spray room. The maintenance of the continuous and substann tially solid curtain for washing the air in a restricted area below the partition wall and immediately above the liquid in the tank at the bottom of the booth provides a thorough air cleaning action which is effective before the air enters the drying space within the iiow duct at the rear of the booth. Additional washing of the air in that iiow duct is entirely unnecessary. This eliminates the necessity for adding moisture in the .drying space and also eliminates the necessity of frequent cleaning of the now duct portion of the str-ucture. Recirculation of the same washing liquid for considerable periods while the pollution from the spray is collected in the tank at the base 'of the booth eiects'anv important saving in operating cost. It is also of importance that the parts such as the tank l2 which are subject tothe necessity of periodic cleaning are readily accessible for the purpose.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing Vfrom the spirit of the invention, and I do notl wish to be limited to the precise details of construction set forth, but desire to avail myself of all changes within Y the scope of the appended claims. Y

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is: n

1. Astructure for removing foreign material from an air stream and comprising, in combination, a base in the form of arectangular tank open at the top and having fluid outlet, drain and overflow ports therein, a housing including back and side walls extending upwardly from the base and having an open front, a hood-type top forY said housing, an air flow opening inthe top, a partition wall extending from side wall to side wall in the housing in spaced relationship to the back wall, said partition wall adjoining the top in front of said air flow opening and terminating at the bottom in an edge extending across said tank at a level above the level of said overflow port, the lower portion of said partition wall being sloped to extend somewhat away from the back wall toward the bottom, said partition wall, back wall and side walls together forming an air ilow duct communicating with said opening, a series of baffles in staggered and overlapping relationship in said air now duct between the back and partition walls, an elongated reservoir secured to the top portion of the partition wall between the latter and back walls and extending substantially from one side of said partion wall to the other, means defining a weir extending laterally of the partition wall at the front of said reservoir and over which Weir fluid from the reservoir may flow downwardly over the surface of the partition wall, said reservoir having an inlet port at one end, a series of bafes in spaced relationship along the Weir within the reservoir for evening the flow along the length of the Weir, movable flow control means comprising a cover overlying said weir on the side thereof opposite the reservoir, said cover being hingedly supported at the top and having an interior space terminating in an edge extending across the partition wall below the base, said cover normally gravitating to a position such that said edge thereof rests against the partition wall, and a flow pipe including a pump connecting the outlet port of the tank to the inlet port of said reservoir, said flow pipe and pump having a fluid flow capacity for effecting the low of a continuous and solid screen of fluid over the front surface of said partition wall and across the space below said edge of the partition wall.

2. A structure for removing foreign material from an air stream as dened in claim l, and wherein said baiiles in the air flow duct comprise a series of staggered plates sloping downwardly in spaced relationship from the partition and 2, megeve wherein; said; loailie's:` in. the; reservoir: comprise.v a

seriesz of'A substantially flat plate' elements: disposed.; in spaced;rel'a-i'f'onshipz` along` the reservoir with"` their planes' substantiallyr perpendicular: to the Weir, said plate" elements being. smaller. in size'. than. the internal reservoir. sertion andi Varying-l in'.` size; Withy their distance' from; the inlet part to.y theV4 rese'izvoir;-

41;. In al structure for removing foreign materiali from an air stream,V the. combination. comprising a. wall. having substantially flat and?. con--A tiguous front surface'. portions; one` above: the other', andiA thel'ower of. whichslopes forwardly toward the bottom, the lower.` end. portion of the lower one of said surface. portions being smoothly curved rearwardly and' terminating in a substantially"straightbottom edge; andz means :forV electingf tlie flow ofa continuous and substantially eonipleteflayero? liquid downthe front surfacevv of said wallwhchresults in'A the formation of-'a substantially solidcu1t'ain=ofliquid ow from the bottomy of! thev wall surface, said means comprising :ai-'reservoir at the top of said wall and 8 including. a wein over whishz liquid flows. from the" reservoir'. to theA fronti wall' surfac. said; res'- ervoir having azli'quid inl'etzport at onerencl'l thereof: for. the flow.v of: liquidlthereto.; and a. series. of baffles; in the. reservoiry anni: disposed: in` angular relationshipf to: theA Weir anda toi7 the'l direction. of iluid flow from theT inlet. port.4 for. evening.- the flow over the weirf` PEERSGN'.

REFERENCES; GI'I'ED' The'foilo'wing" references are of record inthe ille of this' patent:lv

UNITED STATES'. PATENTS Number Name. Date.

701,074 MoCreery May 2.75.1902 230543124 Forbes,.Jr.., etlal.v Sept. 15,1936 2,180,586 Gustafsson. Nov.. 2.1i, 11939 2,243,839 Dalton Junel 3', 19411 2,266,335Y Roche etlal Deo..11i., 1941i 2,353,548 Dalton July 11'-, 1944 2,382,026- Roche Aug; 14.3.1945

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