Method and apparatus for applying paint on basically flat parts

Abstract

Spray booth (21) for applying paint on basically flat parts (22), said spray booth having a plenum (24) and comprising a conveying system (25) for conveying the flat parts (22) to be painted, at least a device (23) for applying paint on said moving parts, and at least a suction system, wherein the plenum (24) of the spray booth has a semi-cylindrical shape, having its axis perpendicular to the direction of the advancing part (22).

Claims

1. A spray booth for applying paint on basically flat moving parts, said spray booth having a plenum and comprising: a conveying system adapted to convey the moving parts to be painted; at least one device adapted to apply paint on said moving parts; and at least one suction system, wherein a top of the plenum of the spray booth is defined by a cover consisting of a continuous arcuate wall disposed over the conveying system, the cover having its longitudinal axis perpendicular to a direction of travel of the moving parts on the conveying system, wherein the conveying system extends longitudinally along a bottom of the spray booth to carry the moving parts under the plenum, and wherein the plenum is configured to enable a flow therethrough of air into the spray booth, the continuous arcuate wall causing the air to generate a whirl within the spray booth under the plenum and the paint to be applied on the moving parts to be captured in the whirl, thereby limiting overspray dispersion.

2. The spray booth according to claim 1, wherein a direction of air flow is perpendicular to an inner surface of the arcuate wall.

3. The spray booth according to claim 2, wherein at least one diffuser uniformly distributes air in a volume upstream of the arcuate wall.

4. The spray booth according to claim 1, further comprising at least one device adapted to force the air into the spray booth.

5. The spray booth according to claim 1, wherein the conveying system is a belt conveying system.

6. The spray booth according to claim 1, wherein the suction system comprises dry filters.

7. The spray booth according to claim 6, wherein the suction system comprises waterfall filters.

8. The spray booth according to claim 1, wherein the device for applying paint is chosen from the group consisting of reciprocators, rotating system, carousel-rotating system, gantry robots, and anthropomorphic robots.

9. A spray booth for applying paint on basically flat moving parts, said spray booth having a plenum and comprising: a conveying system adapted to convey the moving parts to be painted; at least one device adapted to apply paint on said moving parts; and at least one suction system, wherein a top of the plenum of the spray booth is defined by a cover extending over the conveying system and consisting of a continuous arcuate wall permeable to air, the cover defining a ceiling of a tunnel, a bottom wall of the tunnel being formed at least in part by the conveying system, the plenum defining a rectangular footprint and a curve of the arcuate wall extending from a first side of a rectangle to a second, opposite side of the rectangle corresponding to two straight edges of a perimeter of the arcuate wall, the arcuate wall further having its longitudinal axis parallel to an axis of the tunnel and perpendicular to a direction of travel of the moving parts on the conveying system, wherein the conveying system extends longitudinally along a bottom of the spray booth to carry the moving parts under the plenum, and wherein a flow of the air enters into the spray booth through the plenum, the continuous arcuate wall causing the air to move in whirling motion within the spray booth under the plenum and the paint to be applied on the moving parts to be captured in the whirl, thereby limiting overspray dispersion.

10. The spray booth according to claim 1, wherein the suction system comprises air inlets defined at opposing lateral ends of the conveying system, the air inlets receiving the air moving with whirling motion in the spray booth.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and features of the present invention are disclosed in the following description, in which exemplary embodiments of the present invention are explained in detail on the basis of the enclosed drawings, showing:

(2) FIGS. 1a and 1b is a view of a longitudinal section of two prior art examples having flat and sloping plenums, respectively;

(3) FIG. 2 is a view of a longitudinal section of the present invention on the whole;

(4) FIG. 3 is a view of a detail of a longitudinal section showing the air flow generated in the present invention;

(5) FIG. 4 is an axonometric view of the air flow generated in the spray booth of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(6) FIGS. 1a and 1b show on the whole a prior art spray booth 1, wherein a flat part 2 moves forward carried by conveying system 5; the thin arrow shows its direction. The flat part 2 is painted by spray guns 3. FIG. 1a shows a spray booth having a flat plenum 4, while FIG. 1b shows a spray booth having a sloping dual plenum 4. In both cases the bold arrows show the air flow coming from its plenum, respectively.

(7) FIG. 2 shows a section of the spray booth 21 of the present invention along its longitudinal axis. The spray guns 23 spray paint on flat part 22 moving forward in the sense indicated by the thin arrow. The semi-cylindrical plenum 24 generates an air flow perpendicular to its semi-cylindrical surface, as shown by bold arrows. A diffuser 26 uniformly distributes air in an orderly way within spray booth 21; the diffuser 26 is upstream the semi-cylindrical plenum 24. The arrows 27 show the path of the overspray intercepted by suction and filtering system.

(8) Upstream diffuser 26 there is optionally provided a device (not shown) for forcing air into spray booth 21, e.g. a fan or an independent device external to the spray booth itself.

(9) FIG. 3 shows a detail of an overspray whirl 28 generated in spray booth 21. The semi-cylindrical shape of plenum 24 allows to have a whirl 28 much easier controllable with respect to what occurs in the prior art spray booth, especially those having flat plenums.

(10) FIG. 4 shows an axonometric view of spray booth 21, wherein the top part of spray booth is not shown, for better clarity. White arrow 30 shows the direction of the advancing flat part, while whirling flow indicated as arrow 28 is indicatively shown, up to air inlet 29 on both sides of the conveying system 25. In fact a whirling flow 28 develops, having shape and dimensions similar to those of the semi-cylindrical plenum 24, and an axis perpendicular to the conveying direction 30 of parts 2. The black bold arrows show the path of the air flow controlled by diffuser 26.

(11) When spray booth 21 is installed at the final user's premises, usually its parameters must be adjusted for painting process optimization. On one side the plenum geometry is essential, but according to the dimensions of the spray booth, the devices for applying paint, and especially the kind of paint, the air flow is to be adjusted in different ways.

(12) As shown in in-house comparative tests, with the semi cylindrical plenum of the present invention the optimization of the parameters of spray booth 21 was surprisingly simpler and faster compared to the spray booth having different plenum.

(13) Another advantage of the present invention is linked to suction system filter change. As a matter of fact, when filters are dirty, up to their removal the overspray control progressively deteriorates, and returns to optimal level when filters are changed. With the semi-cylindrical plenum of the present invention, the overspray control is much less sensitive to dirty accumulation on filters, leading to a steadier quality of the process.