US2312386A - Spray booth - Google Patents

Description

SPRAY BOOTH Filed April 7, 1939 ATTORNEY Patented Mar. 2, 1943 SPRAY BOOTH Eugene F. Brady, Maplewood, N. 3., assignoito .Western Electric Company, Incorporated, New

York, N. Y., a corporation of New York Application April I, 1939, Serial No. 266,520?

2 Claims.

This invention relates to spray booths, particularly the type employed in coating articles with paint or the like.

In spraying articles with coating material such as paint various problems arise certain of which are believed quite important, such as the exhausting of the air laden with the excess coating material, the cleansing of the air of such material and the elimination of particles of the excess material from becoming deposited upon the walls of the spray booth.

An object of this invention is to provide a spray booth which is simple in structure yet efilcient in exhausting excess coating material.

With this and other objects in view, the invention comprises a spray booth having a coating compartment wherein there is disposed a liquid screen in front of the walls of the compartment to prevent particles of excess coating material from depositing thereon, the said particles being drawn from the compartment by a current of air which is cleansed of the particles by first drawing them through the liquid screen, then moving them helically against a spray of cleansing fluid, and finally, should any particles remain in the air current, moving them in a zigzag path between bafde plates. 1

Other objects and advantages will be apparent from the following detailed description when taken in conjunction with the accompanying drawing, wherein Fig. l is a side elevational view of the spray booth, portions thereof being shown in section;

Fig. 2 is a top plan view of the spray booth, a portion thereof being broken away;

Fig. 3 is a fragmentary sectional view taken along the line 3-3 of Fig. l, and

Fig. 4 is a fragmentary sectional view taken along the line i% of Fig. 1.

Referring now to the drawing, particularly Figs. 1 and 2, it will be observed that the spray booth is of the type which may be mounted upon the floor, having a compartment i0, which might be termined a coating compartment, open at the front and with closed side walls ii, an inner or back wall 12 and top it. A bottom wall it oi A trough or fluid receiving member 20 extending the full width of the inner or back wall I2 is secured in place, as illustrated in Figs. 1 and i, this trough being of the cross sectional contour shown in Fig. l and having its lower portion positioned adjacent the back wall so that a fluid overflowing the trough will travel in the form of a curtain down the back wall and through the passageway iii. The upper edge of the trough 29 has a multiplicity of notches 2! formed there in to assist in even distribution of the fluid over the back wall as it overflows the trough. In the present instance a fluid for the trough 28 may be supplied from a pipe line 23 leading to a suitable supply (not shown). As illustrated in Fig. i, the pipe line 23 extends through the top wall it and into the trough 29, where it is connected to another pipe 25 extending longitudinally through the trough with both ends thereof closed yet provided with a plurality of passageways 25 to supply the fluid to the trough uniformly throughout its length.

By viewing Fig. 1 it will be observed that a wall 28 cooperates with the wall l2 together with an extension 2a of the wall i2 in addition to the side walls of the spray booth, in forming the passageway it. The passageway it, therefore, pro vides communication between the coating compartment it and the cleansing portion of the spray booth, which cleansing portion includes, in addition to the fluid curtain through which air, laden with particles of coating material, is drawn, means lying in the path of travel of the air to free the air to these particles of coating material. One of these means consists of a series of spiral compartments having walls 38 spiral in formation, as illustrated in Fig. 3, positioned between the extension 29 and a partition 32 providing inlet openings 33 for the entrance of the air. Outlet openings 3d are disposed in the par tition 32 in the location shown in Fig. 3, providing walls, indicated at 35, adjacent the inlet openings 33 for a purpose hereinafter described.

The partition 32 separates the lower portion of the cleansing compartment and extends downwardly into a fluid supply 39, as illustrated in Fig. 1, the partition being formed angularly to assist in directing the travel of the air from the passageway It to the inlet openings 33.

In the upper portion of cleansing compartment I is disposed a series of baiile plates 40 positioned, as illustrated in'Fig. 2, to cause a zigzag move ment of the air in travelling from a passageway 62 to an outlet 83, the latter communicating with means for creating an air current through the carried by the topo! the booth. 'lhelowerends oithebaileplatesextendintoatraylland rest upon a perforated shelf ll. The perforationsinthe shelf ll permitexcesscoatins materIaLshouIdanyrema-lnintheairhythetimeit reachesthebailleplatesandbecomelodgedon liquideurtainand'passintothemplr I8 theplates,topas into thetrayll. Adrainliextendsi'romthetrayltmtothefluidsupplya Asshowninl'igs. land 2,anoszleilisprovided for each spiral compartment, these nozzles being positioned axially with the center lines of their respective outlet openings 34 to cause a liquid spray to pass into the spiral compartments against the direction oi. movement or the currentoiaircausedbytheexhaustianfl. The nozzles areconnected topipelines I4 which extendrearwardlythroughthe backwallofthe cleansing compartment and are connected to a main supply line II. The liquid, which in the present instance is water, is withdrawn from the supply 38 through a suction pipe I! by a pump II which forces the liquid through. the main supply line 55, the pipe lines It, and through the nomlesil. Asillustratedinl'lgs. l and 2,the pipe line 23 is connected to the main supply line 55 and through theoperation o! the pump I liquid will be led from the supply II to the trough II as well as to the non-les i3. Afloat valve 82 connected in a main supply line II is controlled by the fluid supply 38 to maintain-the'fluid at a constant level, which level is above the suction pipe 5!. A drain I! adjacent the bottom of the cleansing compartment which, for the purpose of the claims, might be termed a liquid supply tank, provides means for draining the liquid from the tank and removingwithit the particles of coat- Buchparticleswouldtraveldownwardlyin particlesoicoatingmaterlalremainingintho currentoiairpassthroughthcpassagewayll,

inietllwheretheeurrentisdivldell into smaller currents caused to travel helically in the various spiral ts, The wallslioieachcopreventthesmaller currentsoi'airiromescapingtotheoutletopenp ingsuimmediatelyuponenteringtheinletopm, ings. Therefore, these currents must travel hel 'ically for some distancebei'orethey are allowed topassthroughtheoutlet openings. Duringthe travel orthe smallercurrentsoiairiromthe inlets-fltotheoutletsfltheyareopposedby their individual sprays entering .the compartmentsi'romtheirrespectivenonlesiltheae 'spraysotliquidremovlngtheparticlesoi'exceing material which have been removed from the air. A door it in one wall of the cleansing compartment enables the operator to determine whether or not the noasles are operating eiieetively.

To condition the spray booth for use the exhaustingianllandthe p\1mplIaresetinop-.

eration, the fan creating a current of. air which travels in the path indicated by the arrows in Fig. 1, while the pump 80 starts circulation of the liquid irom the fluid supply ll through the various nozzles, and also supplying a suflicient amount of the liquid to the trough 2. so that coatingmaterialwhichhaveremainedintheallf currents during the travel thus far.

The smaller aircurrents leaving the outlet openings throughthespraysoiliquidmerge again-into acommonaircurrentwhich includu asmallerquantityottheliquidinvaporiorm. Theflnalstepistakenaiterthecurrentotair passesthroughtheewayflandiscaused Inthe presenttthetroughll onlyshownadjacentthebackwall "but shouldbeimderstoodthatthis extend acrosstheendwalls ll, Ilalsoextended'tosupplya frontotthethreemainwallsoi cleansingtheairoitheparticlesofcoaflngma coating material which would not be stopped by the article would continue toward the back wall "of the t. However, the current of air will intercept the major portion of these particles of excess coating material and carry them through the passageway II. If certain of the particles should be travelling at a rate of speed greater than would be possible for them to be controlled by and included in the current of air, such particles wouldbe sufliciently interrupted in their travel with the air current that they could be stopped by the liquid curtain terialconsistsintheeflectotthespiralcanparh mentsontheaircurrent. Thesecompartmm ts dividethemainaircurrentmtoa'plurllltyol smallercurrentstocausethesmallercurrmtsto m rt rwshspmrsoi iqlfldandtruei inadirectionagainstthetorceortheliquidin ordertocontinuetheirtravel. Thehelicalmovementoftheaircurrentsthrough-theomttmentsisathighvelocity" ,thecurvahireoithe ts a s sthealrcurrentstotnvel throughandagainsttheiorceoitheliquidsprm andasaresultthereoithepamtparticleswillbe n up' ytheliquidwmleme mroreeu outwardly by centrifugal force, by th travel of the air,-againstthe wallsoi the compartments.

' lheliquid,withthepaintparticlesther.ein,willr flow down the walls of the compartments, out

theoutletopeningandbackintothesupplyll.-

'lheflnalstep,thatis,theorth ealr current'betweenthebailie plates,removesany and prevented from engaging the back wall ll. to liquid which may have been picked up m n current and causes the liquid to return to its original source.

The embodiment of the invention herein disclosed is illustrative only and may be widely modified and departed from in many ways without departing from the spirit and scope of the invention as pointed out in and limited only by the appended claims.

What is claimed is:

1. In an apparatus for treating a gas to remove impurities therefrom, a chamber having an axially horizontal and spirally cylindrical side wall with the spaced edges forming a slot in the wall and the chamber having an end wall with an aperture therein part of whose rim is tangent to an arc of the side wall at the bottom thereof, and means to cause gas to be cleaned to move into the chamber between the spaced edges of the side wall and substantially tangentially thereto so that the gas entering the chamber tangentially must move helically around the chamber to the aperture and axially out thereby, in combination with means to cause a spray of washing liquid to pass transversely through the helically advancing gas'substantially in the direction of the axis of the helical motion of the gas.

2. In an apparatus for treating a gas to remove impurities therefrom, a chamber having an axially horizontal and spirally cylindrical side wall with the spaced edges forming a slot in the wall and the chamber having an end wall with an aperture therein part of whose rim is tangent to an arc of the side wall at the bottom thereof, and means to cause gas to be cleaned to move into the chamber between the spaced edges of the side wall and substantially tangentially thereto so that the gas entering the chamber tangentially must move helically around the chamber to the aperture and axially out thereby, in combination with means to cause a spray of washing liquid to pass transversely through the helically advancing gas substantially in the direction of the axis of the helical motion of the gas and contrary to the advancing axial direction thereof.

EUGENE F. BRADY.

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