Endless paint separating member for paint spray booths

A system for removing paint from the paint-laden air extracted from a paint spray booth includes an endless paint receiving member formed from a plurality of linked channel members. Each channel member has air inlet apertures in the top surface thereof and an elongate plank arranged beneath said apertures such that air flowing through said apertures is diverted by the plank and deposits its paint thereon. The paint receiving member is circumgyrated so that each portion thereof on which paint has been deposited is subsequently moved through a series of washing baths containing solvents to remove the paint and aqueous solutions to rinse off the solvents.

BACKGROUND OF THE INVENTION 
This invention relates to a paint receiving member for removing paint from 
paint-laden air and to a system and a method for removing paint from the 
paint-laden air which is extracted from a paint spray booth during a 
spraying operation. 
The removal of unused paint from the air of a paint spray booth customarily 
involves the use of aqueous solutions to scrub particulate paint from the 
extracted air, wash any surfaces tending to acquire deposited paint, and 
convey the waste paint as a dispersion to a central accumulation and 
disposal reservoir. 
There are a number of inherent disadvantages in the use of such scrubbing 
means for waste paint removal. Thus, such scrubbing means involve the use 
of large volumes of water which is recirculated, and the power required to 
run the circulating pumps is significant. Furthermore, the accumulation 
reservoir contains large volumes of waste paint, water and air and thereby 
adds to the space requirements of the installation. The reservoir must 
also be equipped with mechanical means for dredging and scumming the waste 
paint. In addition, the water used for the scrubbing process humidifies 
the extracted air so that there is a consequent wastage of water. 
Paint extract systems for spray booths employing travelling band filters 
have been proposed but such filters have not been adopted for large 
booths. In this respect, if the material of the filter has a structure 
which is sufficiently intricate to ensure efficient removal of the paint 
from the air the cost of the filter material makes the cost of filter 
replacement prohibitive. The intricate nature of the filter material 
structure and the fact that paint is highly adhesive make it virtually 
impossible to clean and reuse the filter material. 
Furthermore, for applications where the articles to be painted are not 
suspended above the booth floor the use of a filter introduces an 
appreciable maintenance burden as the parts of the booth floor which are 
required to be load bearing cannot be protected by the filter and 
therefore have to be periodically cleaned. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a system for the 
removal of paint from the paint-laden air from a paint spray booth which 
minimizes the disadvantages of the conventional systems. 
According to a first aspect of the present invention a system for removing 
paint from the paint-laden air extracted from a paint spray booth 
comprises a paint receiving member and a paint removing zone, said paint 
receiving member being arranged such that the paint-laden air impinges on 
at least a portion thereof and deposits its paint thereon and said paint 
receiving member being movable through said paint removing zone. 
Preferably, the paint receiving member is an endless member movable so that 
portions thereof carrying paint are subsequently moved through said paint 
removing zone in which the paint is removed from the member. In this way, 
a paint free portion of the endless member can again be moved into the air 
flow and so the efficiency of the paint removing operation is not impaired 
by a build up of paint. 
Preferably the endless member comprises a surface including air inlet 
apertures and a plurality of plates arranged to be impinged on by air flow 
through said orifices and to divert the air flow so that the paint carried 
by the air is deposited on said elements. 
According to a further aspect of the present invention there is provided a 
paint receiving member for removing paint from paint-laden air, said paint 
receiving member comprising a surface including air inlet apertures and at 
least one plate arranged to be impinged on by air flow through said 
orifices and to divert the air flow such that paint carried by the air is 
deposited on said element. 
Preferably, the member is endless and a series of plates are provided, each 
plate being associated with one or more inlet apertures. 
Said plates may be supported on a conveyor chain or belt and subsequently 
moved through a washing bath or a series of such baths in which the 
deposited paint is removed. 
In an embodiment each of said plates is an elongate plank supported 
downstream, in the direction of air flow, of a substantially planar 
surface in which one or more air inlet apertures are provided. Preferably, 
each said surface is provided on a channel member within which a 
respective elongate plank is supported. If required, the sides of adjacent 
channel members can be linked together so that the provision of a separate 
conveyor belt or chain is not required. 
The endless member may form the floor of a paint booth or may be supported 
beneath the grille forming the floor of a conventional spray booth. 
In a preferred embodiment the upper run of the endless member is arranged 
to be impinged on by the air flow and the lower run is received within a 
washing bath containing solvents and the like. 
The present invention also extends to a paint spray booth incorporating a 
system for removing paint from the paint-laden air thereof as described 
above. 
The invention also extends to a method of removing paint from the 
paint-laden air extracted from a paint spray booth comprising impinging 
the paint-laden air on at least a portion of a paint receiving member such 
that the paint is deposited on said member and subsequently moving said 
portion of the paint receiving member through a zone in which the paint is 
removed therefrom. 
Preferably, the paint-laden air is arranged to flow through said portion of 
the paint receiving member such that the direction of the air flow is 
changed when it impinges on said plates whereby the paint carried by the 
air flow is deposited.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention is applicable to any paint spray booth used to spray 
paint onto articles. An end elevation of such a paint spray booth is shown 
in FIG. 1. The booth comprises a spraying enclosure 10 defined by walls 
11, a roof structure 12 and a generally horizontal floor 13. The floor 13 
is in the form of a grid or grille and defines the roof of an enclosure 14 
positioned beneath the spraying enclosure 10. The paint-laden air from the 
spraying enclosure 10 is extracted through the openings in the floor 13 
and enters the enclosure 14 in which the paint is removed from the air and 
is deposited on a paint receiving member 15. 
As is shown most clearly in FIG. 2, the system for removing the paint from 
the paint-laden air comprises an endless paint receiving member 15 
arranged in the enclosure 14 to be circumgyrated by way of two drive 
sprockets 16. The upper run of the endless member 15 is supported by an 
angle 17. The sub-floor 18 of the enclosure 14 is shaped to define a 
trough in which the lower run of the endless member 15 is received. 
The structure of the endless paint receiving member 15 can be seen more 
clearly in FIG. 3. The member 15 comprises a plurality of elongate channel 
members 19 each extending transversely to the longitudinal extent of the 
member 15. Each channel member 19 has two spaced parallel sidewalls 21 and 
23 bridged by a substantially planar top surface 20. The sidewall 21 of 
each member 19, which forms the leading wall of each member 19 when the 
endless member 15 is circumgyrated, has an outwardly extending portion 24 
projecting from its free end and an upstanding flange 25 projecting from 
the end of the portion 24. The trailing sidewall 23 of each channel member 
19 has an inwardly inclined portion 22 which is arranged to be inserted 
between the sidewall 21 and the flange 25 of the adjacent, following 
channel member 19 and to engage against the flange 25. A plurality of 
inlet apertures, which as shown in FIG. 1, are in the form of slots 26 are 
provided along the length of the surface 20 of each channel member 19. 
An air impact member in the form of an elongate plank 27 is mounted within 
each channel member 19 and extends along the length thereof, that is 
transversely of the endless member 15. In the embodiment illustrated each 
end of each plank 27 is supported by a respective end wall (not shown) 
attached to the ends of the respective channel member 19. 
It will be appreciated from the above description that paint-laden air 
extracted through the floor 13 of the spray enclosure 10 flows through the 
inlet apertures 26 of the endless member 15. As can be clearly seen from 
FIG. 3, as the air travels through the apertures 26 it impinges on the 
upper surface of the planks 27 and is forced to change direction as 
indicated by the arrows. As the air flow changes direction it deposits the 
paint it is carrying onto the upper surface of the planks 27. 
In use the endless member 15 is circumgyrated by means of the drive 
sprockets 16. In the embodiment illustrated the endless member is moved 
longitudinally with respect to the spraying enclosure 10. It will 
therefore be appreciated that the upper run of the endless member 15 on 
which the air flow impinges is continuously being replaced by further 
portions of the member 15. The paint carrying portions of the member 15 
move around one of the drive sprockets 16 and into the sub-floor 18. The 
movement of the member 15 around a drive sprocket 16 articulates each 
channel member 19 relative to the adjacent channel member to ensure that 
adjacent channel members do not become stuck together by the paint. 
The sub-floor 18 is divided into sections by way of transverse bars 28. 
Hence, different liquids can be inserted in the various sections thereof. 
Generally, the first sections of the sub-floor in the direction of 
movement of the endless member 15, would be filled with solvents and the 
following sections of the sub-floor would be filled with aqueous solutions 
to rinse off the solvents. The raised transverse bars 28 not only separate 
the various sections of the tank 18 but also serve to articulate the 
endless member 15 as it passes thereover to ensure that the liquids can 
freely enter the channel members. 
The air flowing through the channel members 19 flows into the interior of 
the endless member 15. Exhaust openings 29 communicate with the interior 
of the endless member 15 to receive the air therefrom. Exhaust fans are 
provided to remove the extracted air through these exhaust openings 29. 
The air in the exhaust openings 29 can be fed back into the spraying 
enclosure if required after suitable treatment to remove solvent vapour. 
It will be appreciated that the treatment of the air is simplified because 
it is not laden with water vapour. 
It will be seen from FIG. 1 that the endless member 15 is comprised of 
three sections. These sections can be moved together as a single member or 
moved independently of one another. In the embodiment illustrated in FIG. 
1, as most of the waste paint exits through the central area of the floor, 
the two outer sections are simply plain channel members without the inlet 
apertures. The minimal amounts of paint deposited on these outer sections 
can easily be removed in the tank 18. 
The embodiment illustrated has been described above with particular 
reference to the spraying of wet paint which will adhere to the upper 
surface of the planks 27. When the paint being sprayed is in powder form, 
that is, is dry paint, it is necessary to ensure that the powder adheres 
to the upper surface of the planks 27. If required, a suitable oil spray 
generator (not shown) may be provided to load the atmosphere local to the 
floor 13 of the spraying enclosure 10 with an inert dispersion of 
relatively large oil droplets. The dispersion will be drawn into the inlet 
apertures 26 to deposit on the upper surface of the planks 27, thus 
providing an adhesive film to retain the dry powder particles as they are 
subsequently deposited from the spraying enclosure. The oil is chosen to 
meet this function, and, at the same time, serve as a release agent to 
render removal of the powder easier in the tank 18. Alternatively, a resin 
based liquid may be used to provide the adhesive film on the upper surface 
of the planks 27. 
In the embodiment illustrated the endless member 15 moves longitudinally of 
the spraying enclosure. Thus, if required, the endless member 15 could be 
utilised to move the articles through the spraying enclosure. In some 
applications, the floor 13 could then be dispensed with. 
If required, the endless member can be arranged to move transversely of the 
paint spraying booth. This may well be of advantage where the longitudinal 
extent of the booth is considerable. 
It will be appreciated that the speed of circumgyration of the endless 
member 15 can be chosen so that the length of time the lower run thereof 
spends in the tank 18 ensures that the paint is efficiently removed 
therefrom. 
In the embodiment illustrated the air inlet apertures 26 are in the form of 
rectangular slots. Of course, other shaped apertures could be provided. 
FIG. 4 shows a further embodiment of the endless member 15. In this 
embodiment the free end of each sidewall 21, 23 of the channel member 19 
is curved and receives the curved end of the sidewall of the adjacent 
channel member. The curved ends can be engaged by conventional sprocket 
wheels to drive and guide the endless member. 
In the embodiments described above, each elongate plank 27 is associated 
with a plurality of air inlet apertures. However, if required, a separate 
impact element can be associated with each aperture. In this case, the 
impact elements may comprise individual plates individually supported 
relative to the respective aperture at a suitable setting with respect 
thereto.