Spray gun cleaning apparatus

A spray gun cleaning apparatus for containing and collecting toxic materials resulting from cleaning a spray gun with a cleaning fluid is disclosed. The apparatus includes an interior airflow passageway, a receptacle at an inflow end of the passageway for receiving the spray from the spray gun nozzle, and an outlet at the other end of the passageway for discharging airflow into the ambient environment. At least one filter/condenser is located within the passageway for condensing cleaning fluid vapor into liquid which flows into a waste container, preferably by gravity flow. The apparatus further includes a negative pressure generator connected to a source to compressed air for generating a negative air pressure within the passageway relative to ambient in a manner which causes air to flow through the filter/condenser so that cleaning fluid vapors sprayed from the gun nozzle during cleaning are substantially contained, condensed and removed by the filter/condenser before being returned to the ambient, the removed cleaning fluid and other toxic material such as waste paint flowing safely into the waste container. The spray gun is also connected to the source of compressed air and drives the cleaning fluid from the gun into the receptacle as an atomized spray.

FIELD 
The present invention relates to cleaning systems for cleaning air pressure 
powered spray guns. More particularly, the present invention relates to a 
novel spray gun cleaning apparatus which enables the gun nozzle and 
related plumbing to be cleaned in a manner limiting discharge of cleaning 
liquids, vapors, aerosols, and the like, into the ambient atmosphere. 
BACKGROUND 
While apparatus and methods have been proposed in the prior art for 
cleaning pneumatic pressure operated spray guns, whether for paint or 
other liquid materials, a hitherto unsolved need has arisen for a more 
effective cleaning apparatus which is simple, yet effective in minimizing 
discharge of unwanted, and often very toxic or dangerous chemicals into 
the ambient environment at the clean up area. 
For example, the Constantino U.S. Pat. No. 2,569,125 described a cleaning 
device for spray gun nozzles. The device essentially comprised three 
parts: a main reservoir tank, an auxiliary tank formed at one end of the 
main reservoir tank, and a hood or shroud portion over the main reservoir 
tank. A spray gun had its nozzle end inserted into a hole at the auxiliary 
tank end of the hood and had its suction tube inserted into the auxiliary 
tank which was filled with a suitable cleaning solvent. Then, air under 
pressure was flowed through the nozzle and sucked up cleaning fluid by 
operation of a venturi between the suction tube and a main airflow line 
leading to the nozzle. The droplets of cleaning fluid were said to be 
condensed and collected on the inside walls of the shroud and thereupon be 
returned by gravity flow into the main reservoir tank. 
U.S. Pat. Nos. 4,460,126 and 4,534,802 to Gates et al., and U.S. Pat. No. 
4,204,977 to Zwirlein disclose apparatus and methods directed to purging 
polyurethane foam spray gun apparatus. In Zwirlein, for example, positive 
pressure is provided through the gun to circulate solvent during periods 
of non-use in order to prevent any urethane foam within the gun and its 
nozzle from hardening. Complex pumping apparatus was required in order to 
carry out the necessary recirculation during periods of non use of the 
gun. 
U.S. Pat. No. 3,876,114 to Hicks et al, describes a cleaning apparatus for 
a hand held dispensing gun of the type used for dispensing synthetic resin 
liquid material. The air powered flush system first injected a small 
quantity of solvent into the mixing chamber of the gun, the then followed 
with a high pressure air blast which atomized the solvent and caused it to 
flush out all of the resin that might have remained in the mixing chamber 
within the gun. 
U.S. Pat. No. 3,240,225 to Barrows describes a turreted assembly for 
automatically connecting a wide variety of paint sources (typically 
holding different colored paints) to a single spray gun. This special 
apparatus included a purging cycle to purge the nozzle of the last used 
paint before the next used paint entered the gun. The application 
described for this special apparatus was assembly line painting of 
automobiles. Furthermore, in European Patent Application No. E.P. 230,245 
published July 29, 1987, of L. E. Stern et al, another cleaning device for 
spray guns is described. It comprises a suction system that generates a 
suction through a connecting element attached to the nozzle of the spray 
gun. With the suction system activated, cleaning solvent is sucked from 
the paint supply reservoir (can) portion of the gun through its discharge 
nozzle, directly into a confined filter, and thence to one or more waste 
collecting containers. The gun itself is neither connected to an 
independent source of compressed air nor is the trigger of the gun 
activated during cleaning. As a result the suction system must be 
positioned closely adjacent to the spray gun to maximize suction since the 
flow of the solvent/paint mixture from the spray gun is only a function of 
the relative low pressure generated by the suction system. Also there is 
not enough space to provide an enclosed path for the removed cleaning 
fluid and other toxic material. Instead, such fluid material must flow 
from a separation means (of a suitable filter material) into a large open 
washing bowl and thence to the waste container. But when the associated 
vapors are in the open bowl, they are directly exhausted to the ambient 
atmosphere. Further, the suction system employs a "Coanda Effect" to 
produce the suction, and the suction is split between drawing on the gun 
and on a small vapor hood over the open solvent bowl. The solvent bowl 
vapors are ejected directly to the atmosphere without filtration, 
condensation or collection. 
None of the foregoing examples of the state of the art provide a very 
simple and low cost, yet highly effective cleaning apparatus for a point 
spray gun of the type commonly employed in automobile body repair shops 
throughout the world. In automobile body repair shops, while a paint spray 
booth may have been provided, the problem of free droplets of paint 
condensing onto adjacent vehicles being worked on created needless 
problems and required additional time to correct. Also, there has been a 
growing concern for not polluting the environment with toxic materials 
including spray paint and the like. The present invention addresses and 
solves these problems. 
SUMMARY 
A general object of the present invention is to provide a spray gun 
cleaning apparatus which overcomes the limitations and drawbacks of the 
prior art. 
A more specific object of the present invention is to provide a spray gun 
self cleaning apparatus which causes spray from the gun nozzle emitted 
during cleaning to be contained and circulated through a plurality of 
media for scrubbing the spray to condense and remove the cleaning fluid 
before being returned to the ambient atmosphere and for collecting the 
removed cleaning fluid and other toxic material such as waste paint safely 
into a suitable toxic waste storage container. 
Another object of the present invention is to provide a spray gun cleaning 
apparatus which creates both a negative pressure (suction through the 
apparatus to draw the discharge gas from a spray gun therethrough) and a 
positive pressure (compressed air through the gun) for scrubbing and 
discharge into the ambient environment. 
A spray gun cleaning apparatus in accordance with the present invention is 
provided e.g. for cleaning a spray gun with a cleaning fluid driven by air 
pressure provided from a compressed air supply through a nozzle of the 
spray gun to be cleaned. The apparatus includes an interior airflow 
passageway, an enlarged receptacle adjacent an inlet end of the passageway 
for receiving the spray gun nozzle and to permit condensation of vapors by 
cooling expansion of the compressed air supply, and an outflow end of the 
passageway for discharging airflow into the ambient environment. The 
apparatus further includes a waste container communicating with the 
passageway. 
At least one filter/condenser disposed within the passageway promotes 
condensation of the cleaning fluid vapor into liquid state, and/or 
stripping of the condensed liquid from the air, which liquid then passes 
into the waste container, preferably by gravity flow. The apparatus 
further includes a negative pressure generator, such as a venturi nozzle 
disposed in a discharge chamber at the outflow of the passageway. The 
negative pressure generator creates a negative air pressure relative to 
ambient in a manner which causes spray gun gases to be drawn from the 
receptacle through the filter/condenser and into the discharge chamber. 
Cleaning fluid vapors in the spray gun gases from the gun nozzle drawn 
into the inlet during cleaning flow within the passageway and are removed 
from the gases by the filter/condenser before being returned to the 
ambient. Simultaneously, the removed cleaning fluid and other toxic 
material such as waste paint drip or flow safely into the waste container. 
These and other objects, advantages, aspects and features of the present 
invention will be more fully appreciated by reference to the following 
detailed description of a preferred embodiment, presented in conjunction 
with the accompanying drawing.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
With reference to FIG. 1, a paint spray cleaning apparatus 10 in accordance 
with the present invention includes a conventional source or supply 12 of 
compressed air, typically provided by an electrically operated air 
compressor and storage tank. The apparatus 10 includes a main tube 14 
having a threaded fitting 16 at its lower end adapted to mate with a 
threaded opening of a conventional metal barrel 18, such as a 55 gallon 
steel drum container. Toxic liquid waste material, such as condensed 
cleaning solvents (symbolized by the drops 20), is collected in the drum 
18 and then disposed of safely as a liquid or sludge, whenever a 
sufficient quantity has accumulated to make disposition thereof desired. 
A wye fitting 22 in the main tube 14 branches upwardly to a widened drain 
basin 24 which enables the user to pour excess waste material directly 
into the container 18. A flow restrictor 23 comprising a transverse, 
curved wall or dam with a small orifice in a depressed central region is 
disposed in the main tube 14 in order to prevent excessive loss of 
negative air pressure through the air chamber of the toxic waste container 
barrel 18. Also, in the event that the larger opening of the barrel 18 is 
plugged or is occupied by other apparatus, such as reclamation equipment, 
the small orifice acts as a vent for the interior of the barrel 18. 
A conventional paint spray gun 26 includes a gun cup 28 for holding a 
limited quantity of liquid material to be sprayed, and a nozzle 30 from 
which the liquid is dispensed as a fine mist spray by virtue of air flow. 
The gun 26 is shown placed into a gun receptacle 32 of the apparatus 10, 
the receptacle 32 being an upper end, angled extension of the main tube 
14. A fitting reduces the opening of the receptacle to a suitable size to 
receive the head end of the spray gun 26 including the nozzle. An air hose 
34 connects to a quick connect fitting 36 of the gun in conventional 
fashion. The hose 34 is connected through a piping and valve assembly 36 
to a second quick connect fitting 38. A second air hose 40 from the air 
supply 12 connects to the piping and valve assembly 36 enables pressurized 
air from the compressed air supply 12 to enter the apparatus 10. 
A pipe 44 downstream of the valve 42 leads to a venturi nozzle 46 within a 
discharge chamber 48 of an outlet 50. An outlet diffuser 52 at the 
downstream end of the discharge chamber 48 diffuses scrubbed air used to 
clean the spray gun 26 into the ambient environment. 
A central region of the main tube 14 comprises a tee fitting 54 with a main 
path lying in the vertical flow path of the main tube 14, and with a 
branch 55 extending horizontally away from the drain basin 24. This tee 
fitting 54 defines an interior chamber 56 which preferably contains a 
first condenser 58 preferably formed of fine mesh brass wool disposed 
therein in the airflow path leading from the gun receptacle 32 into the 
branch 55. The branch 55 leads to an elbow fitting 60 creating a 
vertically upward flow path. 
A second interior chamber 62 includes a second condenser 64 placed therein. 
The second condenser 64 is also preferably formed of fine mesh brass wool 
disposed across the airflow path. An activated charcoal media filter 66 
lies directly above the second brass wool condenser 64 in the airflow path 
which leads directly into the discharge chamber 48. 
In operation, the valve 42 is opened, and an airflow stream from the 
compressed air supply 12 via the valve 42 and pipe 44 is directed through 
the outlet diffuser 52 by the venturi nozzle 46. This primary airflow 
stream created by the nozzle 46 creates a negative pressure (vacuum) 
condition within the piping leading from the ambient and through the 
receptacle 32, through the first brass wool condenser 58, through the 
second brass wool condenser 64 and through the charcoal filter 66 and into 
the discharge chamber 48. This negative pressure condition causes air to 
flow along the path just described, as designated by the arrows in FIG. 1. 
Once this negative pressure condition is established within the system 10, 
the spray gun may then be operated by virtue of air pressure supplied to 
it via the hose 34. A suitable cleaning fluid in the cup 28 is then driven 
through the cup tube of the gun 26 and thence through the nozzle 30 
thereof. The cleaning fluid dilutes and dissolves paint and other material 
and they are then carried into the airstream generated by operation of the 
spray gun 26. 
The spray from the nozzle 30 is contained within the interior of the 
receptacle by the vacuum condition. The spray first expands, cools and 
condenses in enlarged receptacle 32, then encounters the first brass wool 
condenser 58 wherein a significant amount of the vaporized cleaning fluid 
that is condensed collects into drops 20 which fall freely into the waste 
container 18. Then, the remaining uncondensed vapor passes with the 
airflow stream through the second brass wool condenser 64 wherein further 
scrubbing of the airflow stream occurs and condensation removes most, if 
not all, of the remaining cleaning fluid vapor. The condensed fluid falls 
as drops into the interior bottom surface of branch 55 and gets returned 
to the waste container 18 with the other condensed cleaning fluid. Any 
remaining uncondensed vapor is collected in the activated charcoal filter 
66. Thus, it will be appreciated that the airflow stream reaching the 
discharge chamber 48 has been effectively scrubbed and purged of the 
cleaning fluid, and this discharge airflow stream is thereupon mixed in 
the discharge chamber with the primary airflow stream being put out by the 
venturi nozzle 46, further diluting any residual cleaning fluid vapor that 
might remain unpurged. 
When the spray gun cleaning operation is complete, and it takes only a 
minute or so, the valve 42 is closed which cuts off the air supply to the 
system 10. Then, the cleaned spray gun 26 is removed from the receptacle 
32 and may be stored away. 
Since cleaning fluid vapor is the primary material being scrubbed by the 
condensers 58 and 64 and filtered by the filter 66, when these vapors 
condense into the liquid drops, the drops tend to carry away to the waste 
container 18 other unwanted material such as the paint removed from the 
spray gun 26. Thus, this apparatus 10 has a self cleaning and maintaining 
function which is a useful incident and byproduct of the main purpose of 
cleaning spray guns in an improved manner which enhances protection of the 
ambient environment well above whatever protection was achieved with prior 
apparatus and methods. 
Referring now to FIGS. 2, 3 and 4, a second preferred embodiment 100 of the 
present invention is shown. The paint spray cleaning apparatus 100 is 
formed as a cylindrical tower having dimensions of approximately 22 inches 
high by seven inches in diameter. It includes a central steel tube 102 
which threads into the small diameter (3/4") opening of the standard 55 
gallon drum or barrel 18 (the large (2") opening thereof shown in FIG. 2 
being closed by a plug). 
The apparatus 100 includes an outer cylindrical cover 104 preferably formed 
of molded, fiberglass reinforced cured polymer resin (epoxy) having a 
suitable attractive gel-coat finish. The outer cover 104 is secured to the 
uppermost end of the tube 102 by a suitable threaded annular fastener 106, 
and it integrally forms a funnel 108 with the tube 102 to provide for 
convenient disposal of excess toxic material into the barrel 18. 
A paint spray gun receptacle 110 (analogous to receptacle 32 of FIG. 1) 
provides an airflow inlet 112 for the apparatus 100. The receptacle 110 is 
sized and positioned for receiving the nozzle end of the paint spray gun 
26 to be cleaned. When the gun 26 is operated, spray from its nozzle 
passes through the inlet 112 and enters a series of concentric cylindrical 
passageways 114, 116 and 118, as denoted by the arrows in FIG. 3. These 
passageways are formed e.g. by steel tubes of appropriately increasing 
diameters, and annular end walls as shown in FIG. 3. 
The outer wall of the tube forming the passageway 118 is provided with a 
moisture-conductive fabric jacket 120. Moisture is wicked throughout the 
jacket 120 by capillary flow from a water reservoir 122 formed at the base 
of the apparatus 100. The metal surfaces forming the reservoir 122 are 
appropriately coated with moisture protection coatings, such as an epoxy. 
A filter/condenser cartridge ring 126 above the passages 114, 116 and 118, 
and directly communicating with the latter, promotes condensation and 
removal of solvent vapors and other toxics from the gases being discharged 
from the nozzle of the gun 26. The cartridge 126 may easily be removed, 
and a fresh cartridge inserted, merely by removing the outer cover 104. 
Airflow throughout the passages 114, 116 and 118, and through the 
filter/condenser 126 is preferably generated by a venturi nozzle 128. This 
nozzle has a suction orifice leading from the gas discharge side of the 
filter/condenser, and has a main airflow nozzle directed into an outflow 
chamber 130 in a manner which creates a whirlwind or cyclone action. 
Ultimately, the air is discharged along an outer annular passage 132 and 
exhausts to the ambient atmosphere adjacent the top wall of the barrel 18. 
The evaporative jacket 120 causes indirect evaporative cooling of the 
vapor-laden gases passing through the passageway 118, thereby promoting 
condensation of the solvent vapors; and it also acts as a sound deadening 
agent to reduce the noise otherwise generated by operation of the venturi 
nozzle 128. As with the FIG. 1 embodiment brass wool condensers/strippers 
(not shown) may be disposed within the passages 114, 116 and 118 as 
desired. 
Two drain holes 134 and 136 permit condensed liquid material to drip into 
the central tube 102 and flow by gravity into the barrel 18, as shown in 
FIG. 3. As a result, very little cleaning fluid and other toxic materials 
escape from the interior of the apparatus 100, since the following effects 
are cumulative: the condensation by expansion of compressed gases in 
receptacle 112, the stripping of fluid from entraining air upon collision 
of the air stream/cleaning fluid mixture with the exterior of the tube 
102; further stripping collisions in the passageways 114, 116 and 118; and 
in the filter/condenser ring 126; and final dilution by cyclone action. In 
addition, the fact that the air stream/fluid mixture passes adjacent to 
the tube 102 also adds a cooling effect and keeps evaporation of liquids 
within the barrel 18 (via the minimum area provided at the interior of the 
tube 102) to a minimum. 
A pipe 138 is provided for connection to the compressed air supply 12 and 
leads to a valve 140 operable at the outside of the cover 104. An internal 
pipe 141 supplies compressed air downstream of the valve 140 to the 
venturi nozzle 128. A hose 142 provides compressed air to the spray gun 26 
being cleaned in conjunction with the apparatus 100. 
A clip 144 enables the apparatus 100 to be positively secured to the barrel 
18 by attachment to its outer, upper rim. 
The filter/condenser cartridge 126, FIG. 4, preferably includes a suitable 
housing 152 which provides for a central opening 154, thereby enabling the 
cartridge to fit snugly over the main tube 102, as shown in FIG. 3. The 
cartridge 126 may be formed in a wide variety of shapes and fashions. In 
one form, it includes a lower wall 156 and a wall 158, both preferably 
formed of brass or bronze screen through which the airstream may freely 
flow. Suitable condenser media, such as bronze wool 160 and/or filter 
media such as activated carbon or charcoal 162 may be contained within the 
cartridge 126. In the form illustrated in FIG. 4, the bronze wool 160 
forms a lower layer transverse to the airflow, and the activated carbon 
162 forms an upper layer. 
Operation of the apparatus 100 is the same as for the apparatus 10 
discussed in connection with FIG. 1. 
IMPROVED EMBODIMENT 
FIGS. 5-9 illustrate yet another embodiment of the present invention in the 
form of an improved spray gun cleaning apparatus 165 comprising a cupola 
166 and an integrally molded basin support 167 of a fiberglass reinforced 
resin cured polymer. Basin support 167 is positioned atop a toxic waste 
container 168, typically the same as drum 18 in FIGS. 1-3. Its purpose is 
to funnel excess waste liquids from basin 171 and manifold 185 in cupola 
166 via drain 169 into the container 168. That is, the basin support 167 
is close in elevation to top surface 170 of the container 168, and hence 
allows the user to use less lifting effort when spent liquids must be 
poured into waste basin 171. Also, the compactness of the apparatus 165 
(as described in association with FIGS. 2 and 3) is maintained, since the 
apparatus 165 can be positioned atop the drum (container) 168 and does not 
overhang the edges thereof. 
Material selections and design are of importance in the efficient operation 
of present invention. As shown in FIG. 5, cupola 166 includes a closed top 
end wall 175, and a generally tapered cylindrical side wall 176 to define 
a central cavity 177. Cavity 177 is symmetrical about axis A--A, opens 
into the underside of basin support 167 to be in fluid contact with 
openings 179 in a depending skirt 180 of the basin support 167. Centrally 
supported within the cavity 177 are a manifold assembly 185 and canister 
assembly 186 which themselves form a disengagement space or passageway, 
generally indicated at 178. 
OVERALL VIEW 
Manifold assembly 185 and canister assembly 186, briefly perform the 
following functions, singly or in combination: (i) provide for 
condensation via expansion of the incoming spray mixture (composed of 
compressed air/cleaning fluid and suspended and absorbed paint) entering 
by way of receptacle or tube 187 to the manifold assembly 185, and (ii) 
stripping of liquid therefrom by collision of the mixture with baffle 250 
(side walls 188 of the receptacle (tube) 187 directing the condensing 
liquid/air mixture into the baffle 250); (iii) collection of the liquid at 
nadir region 191 of the manifold assembly 185 (FIGS. 5, 7 and 8); (iv) 
application of suction pressure to the receptacle (tube) 187 via suction 
system 193 atop canister assembly 186 to draw all elements of the incoming 
mixture into the apparatus 165 and prevent backflow in the direction of 
arrow 194; (v) direct air-born, lighter elements of the incoming mixture 
through passageway 178 in the direction of arrows 195; (vi) further 
separating the air-born, lighter elements from the carrier air in the 
canister assembly 186; and (vii) redirecting the pressurized air stream 
emanating from the suction system 193 in the direction of arrows 196 
through openings 179 in the skirt 180 into the atmosphere. As a result, in 
accordance with the invention there is provided a full closed path for 
containing organic compounds (i.e. cleaning fluids, solvents and the like) 
used in the clean up of spray gun 200 of FIG. 6. 
CONSTRUCTIONAL DETAILS 
FIG. 6 shows that tube-like receptacle 187 extends through opening 198 in 
the manifold assembly 185, as well as depicts spray gun 200 in an active 
mode for providing a pressurizes spray within the receptacle 187. 
Spray gun 200 includes, in addition to reservoir 208 for the cleaning fluid 
to be used in the clean up operation, a coupler 209 for air line 210 and a 
trigger valve 211. As the trigger valve 211 is activated, a compressed air 
stream from supply 212 is directed through line 210 via coupler 209 to 
nozzle 213. The hook on the gun 200 can be hooked in hole 202, the spray 
gun locked in the "on" position, and let run without operator assistance 
for such time as is needed to clean the gun. Before the air stream exits, 
it creates a negative pressure that draws the cleaning fluid from 
reservoir 208 into contact with the air stream. The cleaning fluid exits 
from the nozzle 213 in atomized (aerosol) form, into tube-like receptacle 
187. Since the pressure within both the receptacle 187 and nadir region 
191 of the manifold assembly 185 is less that of compressed air stream of 
the gun 200, the cleaning fluid/air mixture undergoes expansion in 
accordance with Boyle's Law. Separation and removal of liquids associated 
with the mixture occurs in both the tube-like receptacle 187 and within 
the zone 191 as explained below in more detail. Angled entry of the 
receptacle 187 enhances operations since gravity flow is achieved; the 
fact that output drain coupler assembly 216 attached to nadir region 191 
is lower in elevation than the receptacle 187 also aids in this regard. 
FIGS. 7 and 8 illustrate the position of coupler assembly 216 relative to 
zone 191 of the manifold assembly 185 as well as illustrate details of 
both the manifold and canister assemblies 185, 186. Manifold assembly 185 
includes an outer housing 220 shaped like an inverted bowl that is 
preferably formed of fiberglass-reinforced plastic. Inverted crown 221 of 
the outer housing 220 is fitted with the coupler assembly 216 at the 
lowest elevational position of the manifold assembly 185, to form a drain 
for the nadir zone 191. Because of the elevational difference, spent and 
separated liquid generally indicated by arrows 222 associated with the 
incoming air spray can be easily collected and removed from the manifold 
assembly 185. 
Outer housing 220 of the manifold assembly 185 also includes a reserved 
band 223 at its highest elevational extent into which canister assembly 
186 is first fitted and then attached by means of metal screws 224. The 
band 223 is designed to be adjacent to a L-shaped segment 225 having a 
wide horizontal segment 226 to provide a plurality of openings 227, see 
FIG. 5. Mechanically, brim segment 225 is attached to the cupola 166 of 
FIG. 5 by means of a series of screws, one of which being illustrated at 
228. The above-mentioned mechanical connections fixes the canister and 
manifold assemblies 186, 185 relative to the cupola, but air line 205 is 
still permitted to connect to the suction system 193 atop the canister 
assembly 186 through one of the openings 227, see FIG. 6. 
Canister assembly 186 comprises a cylindrical housing 230 formed of metal 
such as aluminum having a constant diameter side wall 231 that fits within 
and is attached to the manifold assembly 185. Housing 230 terminates in an 
end (top) wall 232 having an opening 233 that communicates the interior of 
the canister assembly 186 (including combined filter/condenser subassembly 
240) to the suction system 193, which operates to remove organic compounds 
and prevent their passage into the atmosphere. 
FIG. 9 illustrates construction of a combined condenser/filter subassembly 
240 in detail. Subassembly 240 includes a solid continuous metallic sheet 
241 spiraling outward from a start position near the axis of symmetry. 
Between increasing diametered segments of the sheet 241 there is provided 
a continuous wire mesh 243. Mesh 243 is rolled first into a core 244 
centered at the central axis, and then is allowed to extend beyond the 
outer terminus 245 of the sheet 241 before being attached thereto as by 
rivets 246. Similarly, mesh discs 247 at top and bottom of the 
condenser/filter are attached at the ends of the rolled sheet 241 via hook 
connectors 248. 
As shown in FIG. 7, suction system 193 consists of a tee housing 235 
supporting a venturi nozzle 236. The housing 235 consists of an entry arm 
237, suction air arm 238 above opening 233 and an exit arm 239. 
As indicated in FIG. 8, the present invention uses a 
condensation/collision/stripping technique to first separate the incoming 
spray that enters the manifold assembly 185 through receptacle 187 and 
opening 198. The impact of the collisions is provided mostly by the 
pressurized spray, and other factors include the negative pressure 
generated by suction system 193 and the positioning of shield 250 relative 
to opening 198. 
FIG. 8 shows that baffle (shield) 250 is attached to side wall 218 of the 
manifold assembly 185 by rivets 251 so as to be positioned with its main 
segment 252 across the opening 198 in the path of the flow of the mixture. 
Angle 0, defined between a vertical and the projection of the main segment 
252, identifies the relative position of the shield 250 relative to side 
wall 218 of the manifold assembly 185. 
OPERATIONS 
In the operation of the apparatus 165 of the present inventions, assume 
that the air line 205 for the suction vacuum system 193 (FIGS. 5 and 6) 
has been connected to source 212 of compressed air via tee coupler 260 
elbow couplers 261, 262, valve 263 and hose 264. Note the remaining arm of 
the tee coupler 260 includes fitting 265 and hose 210 for providing 
compressed air to the spray gun 200 as previously mentioned. The valve 263 
is adjusted to provide the suction system 193 with a sufficient negative 
pressure to draw the atomized spray into the receptacle 187 with minimum 
blowback. 
Liquid associated with the atomized spray (such spray comprises organic 
cleaning fluid and diluted toxic paint or other materials; generally 
indicated at 270 in FIG. 8) is easily removed from the manifold assembly 
185. Such removal occurs upon collision with metallic baffle 250 after the 
spray is directed into the baffle by the side wall 188 of the tube 187. 
While a large proportion of the organic compounds used in the cleaning 
solvent are collected as liquid (such liquid being generally indicated by 
arrows 222 in FIG. 8), a portion can be in vapor form. In order to collect 
the latter, the present invention establishes a negative pressure within 
the canister assembly 186 as well as within manifold assembly 185 via the 
suction system 193. As a result, a vacuum-induced air stream generally 
indicated by the arrows 195 is created because of the action of venturi 
nozzle 236 of the system 193. 
FIGS. 5 and 6 illustrate that after exiting and mixing with the compressed 
air of the suction system, the mixed stream passes along an annular-like 
path 204 between side wall 176 of cupola 166 and the abutting side walls 
231, 218 of the canister assembly 186 and manifold assembly 185, 
respectively. Upstream openings 227 (FIG. 6) and downstream openings 179 
in skirt 180 permit the mixed stream to exit to the atmosphere essentially 
free from organic fluids used in the cleaning process. 
In addition, note that before the mixed air stream exits via openings 179 
in the skirt 180, the stream is directed about coupler 216 and line 217 
connected to drain 169. In that way during cleaning of the spray gun 
(i.e., with the suction system 193 activated), a cooling effect is added 
and keeps evaporation of any vapors with the line 217 to a minimum. In 
addition because the drain 169 is of a minimum size, evaporation of 
liquids (from the toxic waste container 168 when the suction system 193 is 
deactivated and the spray cleaning apparatus 165 is idle) is also minimum. 
The path through line 217 and thence through manifold and canister 
assemblies 185, 186, effectively dictates re-condensing of any evaporate. 
Evaporation is limited to the narrow path through the drain 169. Moreover, 
any evaporation path is never permitted to cross into or affect 
vacuum-included discharge paths to allow organic vapors to be directly 
passed into the atmosphere via the suction system 193. Thus in accordance 
with the present invention, the vacuum induced path through the manifold 
and canister assemblies 185, 186, prevents escape of any organic compounds 
that arrive at the manifold assembly 185 regardless of source. 
Having thus described an embodiment of the invention, it will now be 
appreciated that the objects of the invention have been fully achieved, 
and it will be understood by those skilled in the art that many changes in 
construction and widely differing embodiments and applications of the 
invention will suggest themselves without departing from the spirit and 
scope of the invention. The disclosures and the description herein are 
purely illustrative and are not intended to be in any sense limiting.