GB2087068A - Spray booth - Google Patents

Abstract

Spray booth includes nozzles 17 which increase the velocity of ventilating air adjacent the side walls 3, 4 and sweep over the side walls towards an exit 9, so as to entrain particles in the atmosphere and prevent them from being deposited on the side walls. The nozzles 17 are formed by the restricted outlets of chambers 16 which extend longitudinally of the booth, the chambers being mounted on the lower side of a grid supporting a filter 8 at the air inlet 7. <IMAGE>

Description

SPECIFICATION A booth for painting, conditioning, or treating an article by a spray treatment TECHNICAL FIELD OF THE INVENTION The invention relates to booth for painting, conditioning, or treating an article by a spray treatment, particularly a spray booth for painting bodies of vehicles such as cars.

BACKGROUND ART Proposed paint spray booths, in which vehicle bodies are painted often suffer from the disadvantage that the side walls, and any lights on the roof often become coated with paint particles which are entrained in the ventilating medium, usually air. This is because the air at or adjacent the walls has a greatly reduced downward velocity with the result that paint particles are not carried away. Also, because of heat from the lights, the air often actually rises towards the inlet at or adjacent the walls, with the result that coating of the ceiling lights with paint ensues.

Another disadvantage is that when the rising air, carrying paint particles reaches the upper part of the booth, it is deflected downwardly to the booth zones when operatives spraying the bodies stand.

Thus necessarily causes a very unpleasant working environment. A corollary of this is that the entrained paint particles carried downwards also impinge on the article being painted so resulting in a poor finish.

DISCLOSURE OF THE INVENTION It is an object of the invention to seek to mitigate the disadvantages of the prior art booths, and to increase the efficiency of a booth without increasing energy expenditure.

According to the invention there is provided a booth for painting, conditioning, or treating an article by a spray treatment, comprising spaced substantially parallel walls between which the article is to be painted, conditioned or treated, an inlet for ventilating medium, an exit for ventilating medium, means to pass ventilating medium from the entry to the exit, and means to increase the velocity of the ventilating medium at or adjacent at least one of the walls.

Using the invention it is possible to provide a booth in which contamination of walls and of the working zones by paint chemicals and the like entrained in ventilating medium is substantially avoided, without increasing energy expenditure.

The means to increase the velocity of the medium may be within the booth. This construction provides a relatively simple yet effective arrangement.

The means to increase the velocity may be at or adjacent each wall of the booth. This construction provides an optimum arrangement of the associated parts of the booth and may provide a particularly effective way of maintaining the walls free of surplus paint, chemicals and the like.

The or each means for increasing the velocity of the ventilating medium may extend longitudinally of the booth adjacent a wall.

The or each means may comprise a chamber for ventilating medium having a restricted exit for passage of medium from the chamber into the booth. The restricted exit provides a iet of medium of velocity which is increased adjacent the walls of the booth, relative to that of the main body of the medium passing through the booth.

A paint spray booth embodying the invention is hereinafter described, by way of example, with reference to the accompanying drawings, which shows a transverse sectional view through a booth for painting vehicle bodies.

Referring to the drawing, there is shown a paint spray booth 1 for painting vehicle bodies (not shown) which are conveyed longitudinally of the booth on a tow conveyor 2.

The booth 1 has longitudinally extending spaced apart side walls 3 and 4 with upper pitched roof sections 5 and 6 in which lights (not shown) are situated.

There is an inlet 7 for ventilating medium, in this case air, which inlet extends across the booth between the pitched roof sections 5 and 6. The air passes through a filter 8 before entering the booth.

There is an exit 9 forthe air defined between spaced lateral free edges 10 and 11 of solid floors 12 of the booth, the air passing over inclined lower wall sections 13 which are flooded with water from manifolds 14 to a side exhaust stack 1 5 where entrained water and paint particles mix and separate from the air.

Adjacent each wall 3 and 4 there is means in the form of a chamber 1 6 with a restricted exit 1 7 which is for increasing the velocity of the air adjacent the walls 3 and 4 and roof sections 5 and 6. The chamber 1 6 each extend longitudinally of the booth 1, and the exit 17 of each one is directed towards its associated adjacent wall 3, 5 and 4, 6. Each chamber 1 6 is mounted on the lower (as viewed) side of a grid supporting the filter and which provides the inlet 7. Each chamber 1 6 has convergent boundary wall parts 18 and 19 which converge, though terminating before they contact one another, in order to provide the exit, or nozzle, 17.

In operation, a car, say, body (not shown) is conveyed into the booth, either continuously or intermittingly on the tow conveyor. It is spray painted by spray equipment, usually held manually by operatives in stand zones A and B.

Ventilating air is delivered by a fan, not shown, to a plenum chamber 20 whence it passes through the filter 8 and then through the inlet 7 into the booth 1. The speed of the air is typically one metre per second. Some of the air passes into the chambers 1 6. In the chambers 16 the air looses energy but increases velocity so that the velocity of the nozzle 17 is about four times that passing through the rest of the inlet 7. Thus the air exiting the chambers 1 6 has a velocity of four metres per second in the embodiment shown. The air exiting the nozzles sweeps down the associated side wall 4, 6 (as shown by the arrows 'X' at the right hand side, as viewed) and acts as an entrainment jet which entrains paint particles in the atmosphere and sweeps them with the rest of the air, towards and through the exit 9 for subsequent treatment.

The walls 3 and 4, including the pitched roof parts 5 and 6 are therefore maintained substantially free of deposited paint articles, and paint particles are swept through the zones A and B without falling on the operatives.

It will be understood that although spray painting has been referred to, any similar treatment, such as rust-proofing, shot blasting or the like can be used, on any suitable article, not necessarily a car body, to be treated. Further, the article may remain static in the booth; in which case the tow conveyor is dispensed with. In every embodiment, the distribution and effectiveness of the ventilating medium in the booth is enhanced without having to increase energy expenditure e.g.

by providing a bigger fan.

Claims (6)

1. A booth for painting, conditioning, or treating an article by spray treatment, comprising spaced substantially parallel walls between which the article is to be painted, conditioned or treated, an inlet for ventilating medium, an exit for ventilating medium, means to pass ventilating medium from the entry to the exit, and means to increase the velocity of the ventilating medium at or adjacent at least and of the walls.

2. A booth according the Claim 1 , the means to increase the velocity of the medium being within the booth.

3. A booth according the Claim 1 or Claim 2, there being means to increase the velocity at or adjacent each wall of the booth.

4. A booth according to any of Claims 1 to 3, the or each means extending longitudinally of the booth adjacent a wail.

5. A booth according to any preceding Claim, the or each means comprising a chamber for ventilating medium having a restricted exit for passage of medium from the chamber into the booth.

6. A booth for painting, conditioning or treating an article by spray treatment, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.