CA1058396A - Spray booth - Google Patents

Spray booth

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Publication number
CA1058396A
CA1058396A CA238,073A CA238073A CA1058396A CA 1058396 A CA1058396 A CA 1058396A CA 238073 A CA238073 A CA 238073A CA 1058396 A CA1058396 A CA 1058396A
Authority
CA
Canada
Prior art keywords
baffle plates
oil
air
plates
chamber
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA238,073A
Other languages
French (fr)
Inventor
George W. Lau
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Binks Sames Corp
Original Assignee
Binks Sames Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Binks Sames Corp filed Critical Binks Sames Corp
Priority to CA238,073A priority Critical patent/CA1058396A/en
Application granted granted Critical
Publication of CA1058396A publication Critical patent/CA1058396A/en
Expired legal-status Critical Current

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Abstract

Abstract of the Disclosure A paint spray booth for removing excess atomized paint from the air in the vicinity of a spray painting operation comprises a spray booth structure having a work-ing or spray painting area, an exhaust chamber and an exhaust stack, which together define an air passage having an inlet at the spray painting area and an outlet at the stack, within which a fan is mounted for drawing air through the inlet and out the outlet at high velocity. A
plurality or generally vertical baffles are disposed in the passage between the spray painting area and the exhaust chamber for the purpose of removing overspray or excess atomized paint from the air before it is exhausted out of the stack. Mineral oil is continuously flowed over the front surface of the baffles so as to entrain therein paint solids in the air stream, and the oil is received in a reservoir or holding tank wherein the paint solids are allowed to settle, and from which the oil is recirculated for downward flow over the baffles.

Description

~058396 ' This invention xelate to a method &nd apparatu~
for c~ecting exces~ paint spray particles in a paint spraying operation.
The term nspray booth" is a term of art generally denoting a large 3heet metal structure or hou~i~g having so-called working area or ~pace within which ~pray painting operations are carried out, an exhaust chamber ~ith an a~ociated stack communicating with the working area, a fan in the stack for dra~in~ fresh air into and through the working area to maintain it well ventllated, and means be-; . ...
t~een the working area and the exhau~t chamber for removingpaint particles from the air before the air is exhausted up the ~tack. In es~ence then, the booth structure defines an ~, air rlow pas~a~e through which air i~ moved at high veloc-ity to eliminate mists created by a spray paint operation.
Remo~al of alr laden with spray mist and overspray is necessary, among other reason~, to prevent excessive or explosively high concentration of Yolatile solvents and ;~ other rlammable materials, to protect per~onnel in the vicinity from exposure to toxic ~aterials, and to maintain a clean environment ~or proper finishing Or the ware.
~ Current standards require a minimum air Mow rate at the ; ~;
; faee of the booth of 60 cubic reet per minute per square foot, or at least 60 linear ~eet per mlnute at each point at the face o~ the booth for unattended booths, and 100 c~m 1 per square foot or 100 linear feet per mi~ute for attended ¦ booths. In order to collect the paint particles and ~i minimize pollution of the at~osphere, especially at the high rates of air flow, the exhaust air laden with spray residue i8 circulated throu~h an eliminating de~ice or medium, which serves to remove the paint particles be~ore the air is exhausted into the atmosphere.

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- Eliminating media in current use include the dry -~; baf~le system, the dry filter syste~, and the water wAsh -; system. In the dry bafrle syste~, the air i8 circulated in a tortuous path over solid baf~le sur~aces disposed bet~een ;' the working area and the exhaust cha~ber, ~hich causes the 'd~ paint resldue to be depo~ited thereon~ The dry filter ~ystem employs rilters Or a varlety of types through whlch the alr 18 clrculated. Both Or these dry systems involve requent cleaning and maintenance problems due to paint accu~ulatlon, and also the problem Or ~lsposal of waste matter and spent rilters as well as presènting a fire hazard.
In the water wash booth, such as that descrlbed in Pearson ~nlted States patent No. 2,545,672, wate~ i8 caU8ed to ~low do~nward over an imperforate wall at the back oi the working area and acro~s an open gap between the bottom or $ said ~all and the liquid level in an underlying water .~ . . .
reservolr in the form ~ore or less Or a water~ ~ll, thereby to ror~ a curtaln Or descending water against and through which paint laden air is drawn at high velocity, and whereby ~; 20 the!paint mist is entrained in the water and collected in the reser~oir. Principal drawbacks Or the water system are that the water ~ust be treated wlth chemlcals to prevent .
growth of`algae and to control the paint collected ln the reser~oir, and that the waste water is a pollutant. A180, since thè area ior passage Or air into the exhaust chamber ~8 relatlvely ~mall in co~parison with the booth size, and located solely at the bottom regions o~ the booth, the air ~lo~ rate i~ not uniform within the booth, and a high horsepower fan must be used to maintain the mini~um pre-. .
;~ 30 scribed air flow rate in all areas at the face Or the boothO
Moreover, the accumulated paint solids cannot be reclaimed and reused and tend to clog the system. Rusting of the 105~3396 booth interior is al80 a problem, and a severe loss ofefriciency in paint remo~al is experienced if the water curtain is interrupted. ~-In a development entirely separate from the paint spray booth art, proposals were made during the 1930's to remove dust particles from air by drawing the air a~ low velocity in a tortuous path through an oil coated baffle syætem, Representative United States patents relating to this development include Hines patent No. 1,751,999;
Adams et al, patent No. 1,807,950, Ga4en patent No.
1,895,61~3 Dauphinee patent No. 1,899~017; and WeiQgerber patent No. 1,083,764. Hines patent No.
1,751,999, for example, discloses a low velocity air filter having a plurality of closely spaced, angularly disposed baffles, together wlth means to circulate oil over the baf-fles and through a filter.
Notwithstanding general similarities between the arts of dust air filters and spray booths, a~d a high degree of further development in the art of spray boothæ since the above devel~pment, the use of oll or other viscous liquid as an eliminating medium in a spray booth of the structure hereinafter described has not been de~eloped in the prior art, and the arb o~ alr filters has developed separately and independently from the art of spray booths. Qne fair sup-position for this divergence is that the use of oil in a conventional water wash booth would cause conta~ination of the external atmosphere with oil, due to the high velocity air flow. Conversely, the requirement of a high velocity air flow in ~ spray booth would be incompatible with the a~oresaid air filter devices becauæe large amounts of oil would be stripped off the baffle surfaces, causing such devices to become inoperable.

~058396 In accordance with the present invention, a sup-ported moving film Or oil is ~ ed as the paint collecting medium in a speeially designed paint spray booth. The booth comprises an enclosure having an i~let opening there-in through which air is drawn at a high velocity, or in excess of 60 cfm per square foot of opening. Spaced in~ard from said opening are a plurality of rows o~ baffles ar-; ranged substantially perpendicular to the air flow. The rront row of baffles are substantially planar with wide frontal faces, and are closely spaced to define naxrowvertical spaces therebetween through which air may pass.
A film of oil iB continuously flowed over the front sur-faces of the baffles in order to entrain therein paint mist càrried by the air stream, and the oil is circulated through a reser~oir wherein the paint settles and may be removed and reclaimed. Means downstream of the baffles are al90 pro-vided to remove oil droplets from the high velocity air before it is exha~sted into the atmosphere.
The use of mineral oil as a permanent paint eol-lecting or eliminating medium provides unexpected and uniquebenefit~ not attainable by prior art methods. The paint is ;~ not chemically modified by the oil and may be easily separ-ated and reclaimed. The oil is continuously rec$rculated through the system, which allows for self-cleaning of the booth interior and prevents adherence of paint on any ex-posed surface, and the ~el~-contained oil circulation system eliminates pollution problems. The baffle arrange-~en~ provides for a uniform high ~elocity flow of air through the working area of the booth without stripping the oil from the ba~les.
The benefits herein recited are unexpected because both oil and paint mist are combustible materials, and it . . .

lOS8396 ~ould be expected that the combination of the two would be unacceptable becau~e of the possible fire hazard.
Unexpectedly, for reasons explained in detail herein, the combination of mineral oil and paint mist in a spray booth does not result in a flammable mixture at normal or above normal operating temperatures. The high rate of air flow through the booth prevents absorption of the volatile and highly flammable paint components into the thin film of oil, whereas the paint solids are entrained in the oil in a highly ~;
efficient manner. The entrained paint solids are thus coated with non-flammable mineral oil and tend to collect in a harmless manner at the bottom of the oil reservoir.
In one particular aspect the present invention provides a paint spray booth comprising, in combination, an enclosure having side and top walls defining therein a spray painting chamber, an air inlet in one side of said chamber and an air outlet in the other side of said chamber, means for trawing air through said inlet and said chamber and discharging lt through said outlet, substantially vertical wall means in said enclosure between said chamber and said outlet extending ~from side wall to side wall and from top to bottom thereof, said vertical wall means including a plurality of longitudinally spaced sets of vertically extending laterally spaced baffle plates, the baffle plates of the first set having broad front faces exposed to said chamber and forming a rear wall for said chamber against which spray painting operations may be performed, the baffles of said first set being mounted closely ad~acent to define narrow vertical slits between said plates for escape of air from said chamber, the baffle plates of each -30 succeeding set being staggered relative to the plates of the preceding set with each plate of each succeeding set being aligned wlth and laterally broader than a respective one of the spaces .

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between the plate~ of the preceding set and spnced sligh~ly rearwaldl.y there-from as to ca~lse alr passing through said sets of plates to bc divertcd into tortuous paths around the plateæ of each set, the sets of baffle plates succeeding said first set belng shorter than the first set and suspended :

therebehind by an imperforate web coextensive with the upper portions of the ., ~ ,-, baffle plates of the first set, said web equalizing the greater air flow over ~ -! and through said first eet of baffle plates and thus throughout said chamber, an oil reservoir in said enclosure beneath said baffle plates, oil in said reservoir the level of which is spaced below the l.ower ends of said baffle :.
plates, means between the lower ends of said baffle plates and the oil in said i. -~; .reservoir for preve~ting passage of air below said baffle plates and for con-straining the air to pass through said sets of baffle plates, means for con-tinuously pumping oil from said reservoir to the upper ends of the baffle plates of at least the first and second sets and for gravitationally flowing a film ~
of oil uniformly over the front faces of the baffle plates of the first and : :
second sets, whereby particles of paint sprayed against the baffle plates of the first set and carried in the air passing through the slits between the baffle plates of the first set are entrained in the oil and flushed thereby into the reservoir, the oil flowing over said baffle plates belng returned to said reservoir and having a free fall from the lower edges of said baffle : .
plates to the level of the oil in the reservoir whereby to cause the entrained.
paint particles to penetrate the surface of the oil and become immersed therein and to sink to the bottom on the reservoir, the baffle plates of the first set .
having the side edges thereof bent rearwardly toward the baffle plates of said ; second set and the baffle plates of said second set having a central concave ., ':
portion for catching and retaining oil and paint particles passing thereto from the preceding set of plates, the baffle plates of the last set each having the slde edges thereof bent forwardly into spaced generally parallel relation with the side edges of the respective plates of the preceding set for catching and retaining oil and paint particles passing thereto from the preceding set, whereby the paint particles are entrained in the oil and .~ .

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~058396 deposited in the reservoir and air substantial].y free of paint and oil particles ls delivered to said outlet, and a second baffle system in said enclosure between the last set o~ said baffle plates and said outlet, said second baffle system comprising a vertical chamber rearwardly of said last set of baffle plates extending from sidewall to sidewall of said .
enclosure and including a vertical wall spaced rearwardly from said last set of baffle plates and terminating at its lower edge in upwardly spaced relation to the lower ends of said baffle plates to define an entrance into the lower end of said vertical chamber, a pair of laterally spaced baffles converging upwardly from the walls of said vertical chamber above said entrance, and a horizontal deflecting baffle mounted centrally in said vertical chamber above the upper ends of said converging baffles, said horizontal baffle being wider than the space between the upper ends of said converging baffles and having edges bent downwardly into spaced generally parallel overlying relation with an adjacent one of said converging baffles, said baffles in said vertical chamber causing the air passing there-through.to strike several baffle surfaces and to travel in atortuous path having several sharp turns therein for removing substantially all traces of paint and oil from the air, said vertical chamber having a bottom wall sloping toward said reservoir for returning to the reservoir all oil removed from the air.
In another particular aspect the present invention provides a paint spray booth comprising, in combination, an -anclosure having side and top walls defining therein a spray ~ainting chamber, an air inlet in one side of said chamber and :~
an air outlet in the other side of said chamber, means for =drawing air -through sald inlet and said chamber and discharging -lt through said outlet, substantially vertical wall means in -.said enclosure between sald chamber and said outlet extending ~A $ .~:
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: from side wall to side wall and from top to bottom thereof, sald vertical wall means including a plurality of longitudinally spaced sets of vertically extending laterally spaced baffle plates, the baffle p].ates of the first set having broad front faces exposed to said chamber and forming a rear wall for said chamber against which spray painting operations may be performed, the baffle plates of said first set being mounted closely adjacent to define narrow vertical slits between said plates for escape of air from said chamber, the baffle plates of each succeeding set being staggered relative to the plates of the preceding set with each plate of each succeeding set being aligned with and laterally broader than the respective one of the spaces between the plates of the preceding set and spaced slightly rearwardly therefrom so as to cause air passing through said sets of plates to be diverted into tortuous paths around the plates of each set, an oil reservoir in said enclosure beneath said baffle plates, oil in said reservoir the level of which is spaced below the lower ends of said baffle plates, means between the lower ends of said baffle plates and the oil -in said reservoir for preventing passage of air below said ~ baffle plates- and for constraining the air to pass through said i` sets of baffle plates, means for pumping oil from said reservoir to the upper ends of the baffle plates of at least the first and second sets for gravitationally flowing a film of oil uniformly over the front faces of the baffle plates of the first and second sets, whereby particles of paint sprayed against the baffle plates of the first set and carried in the air passing -. through the slits between the baffle plates of the first set '~ are-entrained in the oll and flushed thereby into the reservoir, the baffle plates on the first set having the broad front faces -thereof in substantially a common plane and having the side -etges thereof bent rea-rwardly toward the baffle plates of said ~second set, the baffle plates of said second set havlng a central A` ~ 5c- i / . ~05~396 concave portlon aligned with the s].lts between the baffl.e plates of the first set for receiving the flowing film of oll and catching ; and retainlng oil and paint particles passing thereto from said first set of plates, and a third set of baffle plates rearwardly of said second set to which oil is not supplied, the baffle plates of said third set having ~he side edges thereof bent . forwardly into spaced generally parallel relation with the side edges of the respective plates of the second set for catching and retaining oil and paint particles passing theret~ from said second set, the longitudinal spacing between the successive sets . of baffle plates being progressively smaller so as t-o cause a progressive increase in the volocity of the air passing through the successive rows of the baffle plates to increase the air scouring action thereof, the spacing of said baffle plates above the oil level causing the oil flowing over said baffle plates to be returned to said reservoir with a free fall from the lower edges of said baffle plates to the level of the oil in the reservoir whereby to cause the entrained paint particles to penetrate the surface of the oil and become immersed therein to sink to the bottom of the reservoir.
s In yet another particular aspect the present invention .
provides a paint spray booth comprising, in combination, an . enclosure having side and top walls defining therein a spray -:.
painting chamber, an air inlet in one side of said chamber and an air outlet in the other side of said chamber, means for drawing air through said inlet and said chamber and discharging it through said outlet, substantially vertical wall means in : said enclosure between said chamber and said outlet extending , .
from sidewall to sidewall and from top to bottom thereof, said ; 30 ~ertical wall means including a plurality of longitudinally .. 8paced sets of vertically extending laterally spaced baffle .~

plates, the baffle plates of the.first set having broad front :~
5d- :

~' ~OS8396 faces exposed to said chamber and forming a rear wall for 8a:Ld chamber against whlch spray pa~nting operations may be performed, ~.
the baffle plates of Eaid first set being mounted closely -ad~acent to define narrow vertical slits between said plates for :
escape of air from said chamber, the baffle plates of each ~.
succeeding set being staggered relatlve to the plates of the ::
preceding set with each plate of each succeeding set being aligned ~: with and alterally broader than a respective one of the spaces between the plates of the preceding set and spaced slightly rearwardly therefrom so as to cause air passing through said sets of plates to be diverted into tortuous paths around the plates of each set, the sets of baffle plates succeeding said first set being shorter than the first set and suspended therebehind by an imperforate web coextensive with the upper portions of the baffle plates of the first set, an oil reservoir in said enclosure beneath said baffle plates, oil in said reservoir, means for pumping oil from said reservoir to the upper ends of the baffle . plates of at least the first and second sets for gravitationally flowing a film of oil uniformly over the front faces of the baffle plates of the first and second sets, whereby particles of paint sprayed against the baffle plates of the first set and carried in the air passing through the slits between the baffle ; plates of the first set are entrained in the oil and flushed -:-thereby into ehe reservoir, the oil flowing over said baffle . plates being returned to said reservoir for recirculation over -~aid plates.
In a further aspect the present invention provides a paint spray booth comprising, in combination, an enclosure baving side and top walls defining therein a spray painting ~0 -chamber, an air inlet in one side of said chamber and an air outlet in the other side of said chamber, means for drawing air -through said inlet and said chamber and discharging it through ~ 5e-~ A

~aid outlet, means i.n said enclosure between ~aid chRmber and said outlet for removing from the air passing through sald chamber the majority of the paint partlcles resultlng from the spray palnting operations, and a baffle system between said particle removing means and said outlet for further cleaning - the air and removing therefrom substantially all traces of paint, said baffle system comprising a vertical chamber rearwardly of said particle removing means having an entrance into the lower end thereof, means immediately above said entrance for converging 10 the flow of air into the central portion of said vertical chamber at the lower portion thereof, and horizontal deflector means spaced from the sides of said vertical chamber and positioned . in said converging air flow immediately above said converging means.
In the drawings: i Figure 1 is a perspective view of a simplified form Z of spray booth, which incorporates features of the present invention;
Figure 2 is a vertical sectional view taken sub-`l 20 stantially on line 2-2 of Figure l;
Figure 3 is a sectional view taken along line 3-3 of Figure 2; and Figure 4 is a sectional view taken along line 4-4 ~ of Figu~e 2.
; Figures 1 and 2 illustrate a spray booth 10 having a forwardly extending sheet metal enclosure defining a spray ' paintlng or working area 11 and an air intake opening 12 at one :
side thereof, and a rearwardly disposed exhaust outlet 14 at the ' top. Ob~ects to be spray painted, such as indicated at 16, are ::
supported in the working area 11 inwardly of the opening 12, and ~ :~
~, a spray of paint or coating material is directed toward the ob~ects by use of a spray device, such as shown schematically at 18. The paint may ~ ~.
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-` ~058396 compr~Be any number of the known coating materials, includ-i~g but not limited tt~ water and solvent based materials, such as alkyd~, nitrocell~lose laquers~ watei ba~e enamels, polyurethanes and epoxy resin Means are provided for forcibly drawing air horizontally throug~h the inlet openin~ 12 and verticallg~ up and out through the exhaust outlet 14 in æubstantially an L-pattern, such as a pt~wer driven ~an 20 located in the exha~st outlet. Excess paint mist and paint overspray~ at 10 the inlet is thus drawn into the interior of the spray bocth by a hlgh velocity air flt~w.
The working area leads rearwardly to the solids .
eli~inator portion of the spray booth or baf~le section and is surrounded by a top wall 22 and side walls 24.
Spaced rearward from the working area are a plurality of row~ of baffle plates 26, 28 and 30, the fir~t rt~w o~
plates 26 ln effect constituting the rear wall o~ the work-ing area. In general, the rt~w~ oi baffle plates are j arranged in a parallel relationship, and each row comprises t 20 a plurality of spaced, generally vertica~ members rigidly ~A supported by their ends $n a ~ixed position. ~
The ba~le plates 26 comprising the outermost row, , as shown in Figure~ 2 and 3 are substantially flat and are arranged substantially in a common plane which is substantial-ly pterpendicular to the direction of alr flow at the inlet, as indicated shhe~atically by the arrows. Ad~acent plates - are spaced from one a~other to derine ~arrow open vertical slots 32 therebetween. The baffles are ~rom about four to seven times ~ider than the ~idth of the slots, and the side 30 edges thereo~ are bent rearward on an obtuse angle ~or reason~ here~nafter m~re fully described.
; The second set of ba~fle plates 28 are similar to .
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-~058396 the first set in terms o~ width and spacing rrom each o~her, except said plates are slightly V shaped or concave rela~i~e to the direction of air flow, with the side edge~ being bent rearward on an obtuse a~gle. The longitudinal centerline of the second set of plates 28 coincides with the transverse vertical centerlines of the slots 32 whereby the first and second rows of baffles are arranged in a staggered relationship.
The third row ~f pl~tes 30 are relatively narrower th~n the plates of the first two rows and are located behind and are coextensive with the vertical slots 34 between the plates of the second row. The side edges of the plate~ are bent forwardly, and the ~pace between the third and second rows is less than the space between the ~irst and ~econd rows. The described spacing causes a progre~sive increase In velocity of air passing through successive rows of barrles .
It will be noted that the re~pective second and i third rows of baf~les 28 and 30 are not entlrely ~erticallg ~;~
coextensive with the first row 26; instead, the former ~re 6horter than the f~rst row and are suspended in a spaced relationship from a solid or non-per~eable web 36 extending downward and supported from the top of the enclosure in parallel with the first row Or baffles. Preferably, the length of the web 36 is abo~t one-third of the length of the first row of baffle plates 26. me web 36 serves to alter the normal rate of air flow from the top to bottom of the first two rows of baffle plates, such that the flow is equalized or uniform from top to bottom Or the plates and RO
area of the plates will be s~b~ected to a~ excessively high flow that would strip the oil~therefrom.
~he rows of baffle plates are arranged in a spaced o 7 _ ~L0583¢~6 .' '' st~ggered relationship tQ provide for s~ccessive positive and at least right angle de~lection of any paint and oil particles which emerge through the first group of ~ertical sl~ts 32, ~nd the final row of b¢a~fle plates 30 serve as collectors ~f oil ~nd solids p¢articles which m¢~y be car-ried through the downstre¢amipas~ges by the hlgh velocity air flow. The air velocity is alBO rapidly increased up to the final row of b¢affles in order to increase the strai~ht line momentumi of ¢~ny oil particles, which would otherwi~e tend to move in a tortuous path with the air flow around the b~ffles instead Or collecting on the fin¢al r¢~w i of b~ffles as desired. ~;
Me¢ans are provided for establishing a continuous and unirorm ilow of oll down the front surf¢aces of the first ~j; .
and second rows of baffle plates, 26 and 28 respectively.
A reservoir 38 of mineral oil is provided in the bottom of the enclosure, ¢and i$ connected, via a suitable pump 40 ¢and line ~2, to the top of the enclosure. The line 42 is con-nected to a bifurcated branch 44 leading into respective .~ .
2~ troughs 46 ¢and 48 located respectively over and coextensiYe ~ -with the first and second ro~ o~ b¢a~fle plates 26 and 28.
The troughs 46 ¢and 48 have lowered forward edges which ¢~llow !, the oil to 5pill over an~ do~n the front surfaces of the ¢ fir~t row of baffle plates 26 and web 36.
As shown ~n Figure 4, the lower edge portion of the web 36 is provided with a spaced ~eries of V-shaped channels 50 located above respective individual baffle ~` plates of the second row 28. The channels 50 serve to funnel or concentrate the oil moving downward on the web in-3Q to the central portio~ of the front surf~ce6 of baffles 28, which ha~ been found to minimize stripping and 105s 0~ oil by the air ~low as the oil moves down the ba~les. The ~ ;
, ~,. ' ~05~3g6 third row of baffle plate~ 28 are not directly supplied with oil and are ~upported by a bracket 51 secured to the rear æide of the web 36.
The lower ends of the front bafrles 26 are cQn-nected to a substantially horizontal drain board 52 spaced slightly above the oil level in the reservoir 38~ such that the paint laden oil falls a short distance into the reservoir3 which has been found to minimize ~plashing and build-up of paint scum on the sur~ace of the oil reservoir.
1~ ~he ~ere draining of oil onto the surface of the reser~oir may allo~ the paint solids to float and cling together, whereas a ~light drop allows for penetration of the surface.
The lower edges o~ the rear baffles 28 and 30 are spaced above the reservoir oil level to provide the same ef~ect.
It will be noted that the baffles 26, 28 and 30 are preferably inclined dcwn~ard and outward on a slight vertical angle, preferably in the order of 3 to 4 degrees and no greater than 5 degrees, in order to enhance the .
co~tlnuity of oil ~low thereon. An angle greater than 5 d~grees ~rom vertical i~ not desirable due to the tendency of the barfle edges to 108e their o~l coating.
Important features of the baffle system l~clude ~.
the substantial width or front~l sur~ace area of the baffles in com~ari~oa to the width of the air pas~age 810ts therebetween3 and the arrangement of the baf~leæ in a plane which i8 substantially perpendicular to the path of air flow through the booth. These features allow for a maximum exposure of the mcving films of oil to the contaminated air. Also, the planar or slightly conc~ve
3~ quality of the baf~les~ together wlth the uniform spacing of the air ælot~ therebetween~ permits a very high air flow thereo~er without the oil being wiped from the surface, ~058396 which would allow the undesirable accumulation of palnt on the bare surfaces. The ba~fles are free fr~m sharp corners, or corners which are less than 90 degreeæS because 8harp corners would be wiped clean of oil by the high velocity air, especially in the vicinity o~ the slots. Hence, the baffle deslgn described herein i8 particularly adapte~ to present large and eificlent oil coated surfaces which re-tain their oil coating under conditions of high velocity air flow, which, at the first set Or baffles may be 125 10 linear feet per minute and at the second set Or baffles, ~-in the order of 2300 linear feet per minute.
Another important feature in the design of the bafrle system is the existence Or a substantially uniform air flo~ from top to bottom and from side to æide in the inlet opening, Inoontrast wlth a water wash booth having a relatively æmall waterfall area and high resistance to air flo~, the present baffle system ofrers relativelg low resistanoe to air flow due to the length of the slit open-ings and spa~ing of the baffle rows, thus allo~ing use c~
2~ a relatively low horsepower motor.
As shown in Figure 2, located rearwardly or do~nstream of the first baffle system i~ a second baffle system, the primary purpose Or which is to collect and remove oil particles which escape from the flrst baffle system. Whereas the first baffle æystem is arranged in substantially a vertical plane, the second system is arranged horizontally in a verti~al exhauæt chamber 54 up- -stream from the exhaust outlet 14. The chamber 54 co~-prises a forward vertical wall 56 spaced rearward from the rirst bafrle system, which extends downward ~rom the top of the enclosure and terminates at a location above a forwardly sloping base 58 and below the tops of the rear .

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~05839~;

baf`fle~ 28 and 30, preferably at a point approximately at the horizontal center line of said bai~fles. As shown by the arrows indicating air flo~, a1r entering at the top of the first set of ba~les is swept d~wnward around the wall 56 and then upward into the vertical chamber 54~
~ s shown, the second baffle ~ystem comprises, at the louer entrance of the chamber 54, a first pair of up-wardly converging baffles 60 connected to opposite chamber walls by respecti~e horizontal portions 62 having covered openings 64 therein to collect and drain away accumulated oil. The respective end edges Q~ the baffles 60 are sup-ported upon rods 66, said edges having a relatively wide space therebetween to channel and concentrate air flowing therethrough.
A deflecting baffle 68 supported on rode is pro-vided upstream from and in the outlet path of the converging baf~les 60. The baffle 68 comprises a horizontal portion which i8 wider than the outlet of baffles 60 and i5 connec-ted to opposite legs 70, whlch are dispose~ in a downward obtuse angle ~rom the horizontal portion, the endæ of said leg~ being spaced outward ~rom and about on the same level as the ends o~ the baffles 60. The legs 70 are spaced from the sides of the chamber 54, and air is cau~ed to flow in a tortuous path around the legs, causing oil to accumulate thereon and fall downward onto horizontal portions 62.
A pair of downwardly angle~ baffl~s 72 are connec-ted from the chamber w~118 above the legæ 70 of the deflect-ing baf~le 68. ~he ba~fleæ 72 are substantially planar and have terminal edges which extend over the juncture between the legs 70 and the horizontal portion of baffle 68. Thus, the baffles 72 are disposed in the path of the air which emerges around the baffle 68 and serve to further de~lect ~58396 the alr rlow toward the top of the underlying baffle 68.
Di~posed above baf~les 72 are a pair of permeable air filters 74 arranged in an inverted V-configuration.
The filters 74 may be composed of a mesh material composed ~f metal, glass fibers~ or the like, supported in a frame.
The filteræ 74 ser~e to remove the ~inal finite traces of oil before the air reaches the exhaust outlet 14.
~ he type of oil employed is preferably a mineral oil without detergents or other additives, and ha~ing a viscosity to easily ~low down the baffles at room tempera ture without undue vaporization. A mineral oil having a ~igcosity of 660 Standard Saybolt Units at 100F have been found to be suitable~ although other viscosi*ies ~ay be employed. A suitable oil ~low rate is approximately 8 gallons per minute for each foot of width of baffles, and the reservoir pre~erably conta~ns at least about 25 gallons per foot of bafrle width, to provide sufricient ~olume for settling of the paint solids.
Mineral oil o~fers se~eral advantages, including a hlgh fla~h point ~na burning point, and is incompa~ible and chemically unreactive with paint solids in current use. :- ;
Because the oil has a lower density than the paint solids, the solids tend to settle to the bottom of the reservoir where they may be removed~ M~reover, the flammable volatile solvent components of the paint are not absorbed by the oil and do not lower the flash point or burning point thereof~ me presence of paint solids which may re-main entra~ned in the circulating oil do not su~stantially a~fect the efficiency of the elimlnator baffles.
In operation, the fan 20 and oil pump 40 are activate~, such that oil is pumped from the reservoir 38 upward through the line 42 into the troughs 46 and 48. A

~058396 continuous supply of oil flows down over the ~irst and æecond rows of baffles, 26 and 28, and air is drawn through the inlet opening 12 at a rate of at least 60 linear feet per minute and preferably in excess o~ 100 linear ~eet per minute.
Wlth the booth in readiness, objects, such as indicated at 16, are diæpo~ed in or near the opening 12, and a paint æpray device 18 i~ located upstream of the ob~ect and i8 aimed at the ob~ect.
Atomized paint which does not adhere to the object -~
16 i$ carried by the high air flow into contact with the first ba~fle~ 26, which are entirely covered with a continu-ously moving film of oil. As a result~ the solid paint particles are entrained in the oil and flow downward into the reservoir 38, where the paint solids are allowed to settl~. Paint particles which avoid the first baffle3 26 an~ p~s8 through the air slots 32 increase in momentum and are depo~ited on the second set of baffles 28, and any particles passing the baffles 28 through the slots 34 are collected by the baffles 30, which are normally wetted by oil removed from ~he first two rows of baffles.
After the air has passed through the eliminator baffles, it passes un~er the barrier wall 56 and moves upwardly in the chamber 543 thereby encouraging elimination of oil mist by gravity forces. Also, the chamber 54 presents a relatively larger volume than the volume near the eliminator baffles, which causes a reduction in air velocit~ and ~ecreases the ability of the air to carry any residual oil.
me air is deflected off the successive ba~fle~
60, 68 and 72 such that virtually all residual oil is re-moved from the air and is returned to the reservoir. The , . . .

filters 74 serve aæ a final precaution to the e~cape of minute particles into the air.
After the booth has been used over a period of ~ime, the paint solids which have collected in the bottom of the reservoir may be removed and reclaimed.
In comparison to other known spray boothæ, the ~pray booth offers the following advantages: very low emission of particulates into the atmosphere since the booth will normally operate at 99 or 100% efficicncy; easy collection and recla~mation o~ coating material solids and ability to accommodate a greater variety of coatings;
easier cleaning of booth and no corrosiQn of booth material~; quieter operation and uni~orm air velocity at ~ace, les8 electrical power required; and various other advantages mentioned hereinbefore.

3o

Claims (13)

The embodiments of the invention in which an ex-clusive property or privilege are claimed are defined as follows:
1. A paint spray booth comprising, in combina-tion, an enclosure having side and top walls defining therein a spray painting chamber, an air inlet in one side of said chamber and an air outlet in the other side of said chamber, means for drawing air through said inlet and said chamber and discharging it through said outlet, substan-tially vertical wall means in said enclosure between said chamber and said outlet extending from side wall to side wall and from top to bottom thereof, said vertical wall means including a plurality of longitudinally spaced sets of vertically extending laterally spaced baffle plates, the baffle plates of the first set having broad front faces exposed to said chamber and forming a rear wall for said chamber against which spray painting operations may be performed, the baffles of said first set being mounted closely adjacent to define narrow vertical slits between said plates for escape of air from said chamber, the baffle plates of each succeeding set being staggered relative to the plates of the preceding set with each plate of each succeeding set being aligned with and laterally broader than a respective one of the spaces between the plates of the pre-ceding set and spaced slightly rearwardly therefrom as to cause air passing through said sets of plates to be diverted into tortuous paths around the plates of each set, the sets of baffle plates succeeding said first set being shorter than the first set and suspended therebehind by an imperfor-ate web coextensive with the upper portions of the baffle plates of the first set, said web equalizing the greater air flow over and through said first set of baffle plates and thus throughout said chamber, an oil reservoir in said enclosure beneath said baffle plates, oil in said reservoir the level of which is spaced below the lower ends of said baffle plates, means between the lower ends of said baffle plates and the oil in said reservoir for preventing passage of air below said baffle plates and for constraining the air to pass through said sets of baffle plates, means for continuously pumping oil from said reservoir to the upper ends of the baffle plates of at least the first and second sets and for gravitationally flowing a film of oil uniformly over the front faces of the baffle plates of the first and second sets, whereby particles of paint sprayed against the baffle plates of the first set and carried in the air pass-ing through the slits between the baffle plates of the first set are entrained in the oil and flushed thereby into the reservoir, the oil flowing over said baffle plates being re-turned to said reservoir and having a free fall from the lower edges of said baffle plates to the level of the oil in the reservoir whereby to cause the entrained paint particles to penetrate the surface of the oil and become immersed therein and to sink to the bottom on the reservoir, the baffle plates of the first set having the side edges thereof bent rearwardly toward the baffle plates of said second set and the baffle plates of said second set having a central concave portion for catching and retaining oil and paint particles passing thereto from the preceding set of plates, the baffle plates of the last set each having the side edges thereof bent forwardly into spaced generally parallel relation with the side edges of the respective plates of the preceding set for catching and retaining oil and paint particles passing thereto from the preceding set, whereby the paint particles are entrained in the oil and deposited in the reservoir and air substantially free of paint and oil particles is delivered to said outlet, and a second baffle system in said enclosure between the last set of said baffle plates and said outlet, said second baffle system comprising a vertical chamber rearwardly of said last set of baffle plates extending from sidewall to sidewall of said enclosure and including a vertical wall spaced rearwardly from said last set of baffle plates and terminating at its lower edge in upwardly spaced relation to the lower ends of said baffle plates to define an entrance into the lower end of said vertical chamber, a pair of laterally spaced baffles converging upwardly from the walls of said vertical chamber above said entrance, and a horizontal deflecting baffle mounted centrally in said vertical chamber above the upper ends of said converging baffles, said horizontal baffle being wider than the space between the upper ends of said converging baffles and having edges bent downwardly into spaced generally parallel overly-ing relation with an adjacent one of said converging baffles, said baffles in said vertical chamber causing the air passing therethrough to strike several baffle surfaces and to travel in a tortuous path having several sharp turns therein for removing substantially all traces of paint and oil from the air, said vertical chamber having a bottom wall sloping toward said reservoir for returning to the reservoir all oil removed from the air.
2. A paint spray booth as set forth in Claim 1, wherein the succeeding sets of baffle plates are at least two in number and wherein the longitudinal spacing between successive sets of baffle plates is progressively smaller so as to cause a progressive increase in the velocity of the air passing through the successive rows of the baffle plates to increase the air scouring action thereof.
3. A paint spray booth as set forth in Claim 1, wherein said means for pumping oil from said reservoir to the upper end of said baffle plates includes header means at the upper end of said first set of baffle plates and header means at the upper edge of said imperforate web, the lower edge of said web being provided with a spaced series of channels located above the central concave portion of each respective baffle plate of the second row to funnel a flow of oil onto the front surface of the central portion of each of the baffle plates in the second row.
4. A paint spray booth as set forth in Claim 1, wherein said second baffle system includes a pair of lateral-ly spaced baffles converging downwardly from the walls of said vertical chamber above said horizontal baffle, the lower ends of said downwardly converging baffles being spaced above said horizontal baffle and having terminal edges which extend over the juncture between said horizontal baffle and the downwardly bent side edges thereof, and permeable air filter means above said downwardly converging baffles for removing the last finite traces of oil from the air.
5. A paint spray booth comprising, in combination, an enclosure having side and top walls defining therein a spray painting chamber, an air inlet in one side of said chamber and an air outlet in the other side of said chamber, means for drawing air through said inlet and said chamber and discharging it through said outlet, substantially vertical wall means in said enclosure between said chamber and said outlet extending from side wall to side wall and from top to bottom thereof, said vertical wall means including a plural-ity of longitudinally spaced sets of vertically extending laterally spaced baffle plates, the baffle plates of the first set having broad front faces exposed to said chamber and forming a rear wall for said chamber against which spray painting operations may be performed, the baffle plates of said first set being mounted closely adjacent to define narrow vertical slits between said plates for escape of air from said chamber, the baffle plates of each succeeding set being staggered relative to the plates of the preceding set with each plate of each succeeding set being aligned with and laterally broader than the respective one of the spaces between the plates of the preceding set and spaced slightly rearwardly therefrom so as to cause air passing through said sets of plates to be diverted into tortuous paths around the plates of each set, an oil reservoir in said enclosure beneath said baffle plates, oil in said reservoir the level of which is spaced below the lower ends of said baffle plates, means between the lower ends of said baffle plates and the oil in said reservoir for preventing passage of air below said baffle plates and for constraining the air to pass through said sets of baffle. plates, means for pumping oil from said reservoir to the upper ends of the baffle plates of at least the first and second sets for gravitationally flowing a film of oil uniformly over the front faces of the baffle plates of the first and second sets, whereby particles of paint sprayed against the baffle plates of the first set and carried in the air passing through the slits between the baffle plates of the first set are entrained in the oil and flushed thereby into the reservoir, the baffle plates of the first set having the broad front faces thereof in substantially a common plane and having the side edges thereof bent rearwardly toward the baffle plates of said second set, the baffle plates of said second set having a central concave portion aligned with the slits be-tween the baffle plates of the first set for receiving the flowing film of oil and for catching and retaining oil and paint particles passing thereto from said first set of plates, and a third set of baffle plates rearwardly of said second set to which oil is not supplied, the baffle plates of said third set having the side edges thereof bent for-wardly into spaced generally parallel relation with the side edges of the respective plates of the second set for catch-ing and retaining oil and paint particles passing thereto from said second set, the longitudinal spacing between the successive sets of baffle plates being progressively smaller so as to cause a progressive increase in the velocity of the air passing through the successive rows of the baffle plates to increase the air scouring action thereof, the spacing of said baffle plates above the oil level causing the oil flowing over said baffle plates to be returned to said reservoir with a free fall from the lower edges of said baffle plates to the level of the oil in the reservoir where-by to cause the entrained paint particles to penetrate the surface of the oil and become immersed therein to sink to the bottom of the reservoir.
6. A paint spray booth as set forth in Claim 5, wherein the sets of baffle plates succeeding said first set are shorter than the first set and are suspended there-behind by an imperforate web coextensive with the upper portions of the baffle plates of the first set.
7. A paint spray booth as set forth in Claim 5 including a second baffle system in said enclosure between the last set of said baffle plates and said outlet, said second baffle system comprising a vertical chamber rearwardly of said last set of baffle plates and having an entrance into the lower end thereof, means in said vertical chamber immediately above said entrance for causing the air enter-ing through said entrance to be converged upon itself generally centrally of said vertical chamber, and a horizontal deflecting baffle mounted centrally in said vertical chamber above said converging means and having side edges bent downwardly laterally outwardly from said converging means, said converging means and said horizontal baffle causing the air passing through said vertical chamber to strike said baffle and to travel in a tortuous path hav-ing several sharp turns therein for removing substantially all traces of oil from the air.
8. A paint spray booth comprising, in combination, an enclosure having side and top walls defining therein a spray painting chamber, an air inlet in one side of said chamber and an air outlet in the other side of said chamber, means for drawing air through said inlet and said chamber and discharging it through said outlet, substantially vertical wall means in said enclosure between said chamber and said outlet extending from sidewall to sidewall and from top to bottom thereof, said vertical wall means includ-ing a plurality of longitudinally spaced sets of vertically extending laterally spaced baffle plates, the baffle plates of the first set having broad front faces exposed to said chamber and forming a rear wall for said chamber against which spray painting operations may be performed, the baffle plates of said first set being mounted closely adjac-ent to define narrow vertical slits between said plates for escape of air from said chamber, the baffle plates of each succeeding set being staggered relative to the plates of the preceding set with each plate of each succeeding set being aligned with and laterally broader than a respective one of the spaces between the plates of the preceding set and spaced slightly rearwardly therefrom so as to cause air passing through said sets of plates to be diverted into tortuous paths around the plates of each set, the sets of baffle plates succeeding said first set being shorter than the first set and suspended therebehind by an imperforate web coextensive with the upper portions of the baffle plates of the first set, an oil reservoir in said enclosure beneath said baffle plates, oil in said reservoir, means for pumping oil from said reservoir to the upper ends of the baffle plates of at least the first and second sets for gravitationally flowing a film of oil uniformly over the front faces of the baffle plates of the first and second sets, whereby particles of paint sprayed against the baffle plates of the first set and carried in the air passing through the slits between the baffle plates of the first set are entrained in the oil and flushed thereby into the reservoir, the oil flowing over said baffle plates being re-turned to said reservoir for recirculation over said plates.
9. A paint spray booth as set forth in Claim 8, wherein the oil is pumped from the reservoir to the upper ends of the baffle plates of the first set and to the upper edge of said imperforate web, whereby oil is flowed down-wardly over the front faces of the baffle plates of the first set, the front face of said imperforate web and the front races of the baffle plates of the second set, the lower edge of said imperforate web being provided with a spaced series of channels located above the central portion of each of the respective individual baffle plates of the second set to funnel a flow of oil into the central portion of the front surface of each of the baffles of the second set.
10. A paint spray booth as set forth in Claim 9, wherein the baffle plates of the first set have the side edges thereof bent rearwardly toward the baffle plates of said second set, the baffle plates of said second set have a central concave portion aligned with the slits between the baffle plates of the first set for receiving the flow of oil from said imperforate web and for catching and re-taining oil and paint particles passing thereto from said first set of plates, and a third set of baffle plates rear-wardly of said second set to which oil is not supplied, the baffle plates of said third set having the side edges thereof bent forwardly into spaced generally parallel rela-tion with the side edges of the respective plates of the second set for catching and retaining oil and paint particles passing thereto from said second set.
11. A paint spray booth comprising, in combination, an enclosure having side and top walls defining therein a spray painting chamber, an air inlet in one side of said chamber and an air outlet in the other side of said chamber, means for drawing air through said inlet and said chamber and discharging it through said outlet, means in said enclos-ure between said chamber and said outlet for removing from the air passing through said chamber the majority of the paint particles resulting from the spray painting operations, and a baffle system between said particle removing means and said outlet for further cleaning the air and removing there-from substantially all traces of paint, said baffle system comprising a vertical chamber rearwardly of said particle removing means having an entrance into the lower end thereof, means immediately above said entrance for converging the flow of air into the central portion of said vertical chamber at the lower portion thereof, and horizontal deflector means spaced from the sides of said vertical chamber and positioned in said converging air flow immediately above said converg-ing means.
12. A paint spray booth as set forth in Claim 11, wherein said converging means comprises a pair of laterally spaced baffles converging upwardly from the walls of said vertical chamber immediately above said entrance, and wherein said deflector means comprises a horizontal baffle mounted centrally in said vertical chamber above the upper ends of said converging baffles, said horizontal baffle being wider than the space between the upper ends of said converging baffles and having side edges bent downward-ly into overlying relationship relative to said converging baffles.
13. A paint spray booth as set forth in Claim 12, including a pair of laterally spaced baffles converging downwardly from the walls of said vertical chamber above said horizontal baffle, the lower ends of said downwardly converging baffles being spaced above said horizontal baffle and having terminal edges which extend over the juncture between said horizontal baffle and the downwardly bent side edges thereof, and permeable air filter means above said downwardly converging baffles, said baffles causing the air passing through said vertical chamber to strike several baffles and to travel in a tortuous path having several sharp turns therein for removing substantially all traces of paint from the air, said permeable air filter means removing the last finite traces of paint from the air.
CA238,073A 1975-10-21 1975-10-21 Spray booth Expired CA1058396A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA238,073A CA1058396A (en) 1975-10-21 1975-10-21 Spray booth

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA238,073A CA1058396A (en) 1975-10-21 1975-10-21 Spray booth

Publications (1)

Publication Number Publication Date
CA1058396A true CA1058396A (en) 1979-07-17

Family

ID=4104320

Family Applications (1)

Application Number Title Priority Date Filing Date
CA238,073A Expired CA1058396A (en) 1975-10-21 1975-10-21 Spray booth

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Country Link
CA (1) CA1058396A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101943137A (en) * 2009-07-06 2011-01-12 歌美飒创新技术公司 System for the circulation of filtered air inside the wind turbine
CN112058520A (en) * 2020-09-14 2020-12-11 明德新材料科技(浙江)股份有限公司 Full-automatic powder spraying device for water-soluble fluorocarbon transfer printing simulation metal material
CN113957390A (en) * 2020-07-21 2022-01-21 宝山钢铁股份有限公司 Vacuum coating device with air cushion buffer cavity

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101943137A (en) * 2009-07-06 2011-01-12 歌美飒创新技术公司 System for the circulation of filtered air inside the wind turbine
CN113957390A (en) * 2020-07-21 2022-01-21 宝山钢铁股份有限公司 Vacuum coating device with air cushion buffer cavity
CN113957390B (en) * 2020-07-21 2024-03-08 宝山钢铁股份有限公司 Vacuum coating device with air cushion buffer cavity
CN112058520A (en) * 2020-09-14 2020-12-11 明德新材料科技(浙江)股份有限公司 Full-automatic powder spraying device for water-soluble fluorocarbon transfer printing simulation metal material

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