GB2098885A - Spray booth - Google Patents

Abstract

A spray booth includes an air purifier comprising two water tanks (1) placed under the spraying area, two water tanks (2) placed in the middle, two still areas (3) with drop separators (16), four final dry filtering areas (5) and four air discharge channels (6) leading to two fan intakes (7), the air being caused to follow a course indicated by (17). The booth is of the type which includes spray nozzles (13) [Fig. 2] mounted on a turntable (12). <IMAGE>

Description

SPECIFICATION Paint spraying cubicle The present invention relates to a cubicle for spraying pigments or paints on the surface of dressed hides, wooden panel or the like, equipped with an air purifier incorporated in the base of the cubicle itself.

Spray-painting dressed hides or panels is usually carried out by passing the objects to be painted, using a conveyor belt, underneath a series of spray guns mounted on a rotating turntable or on a mobile member with an alternating movement enclosed in a cubicle to prevent dispersion into the enviroment of the fumes produced by the paint.

The cubicle is normally equipped with means for exhausting the fumes, which are conveyed outside the work area.

One of the basic problems which arise in the use of this type of plant is the problem of providing a suitable device capable of purifying the air coming out of the spray cubicle, because the colorants used to pigment hides or the like, in addition to being harmful to health if inhaled, can be highly inflammable.

In installations of known type, the problem is partly solved by external purifiers which remove the air from inside the cubicle in order subsequently to purify it and release it into the atmosphere when it is pure enough.

This arrangement has a drawback due to the fact that the bottom of the cubicle and the piping which carries the air for purification to the purifier become fouled with pigments and resins and require periodic cleaning to avoid risk of fire.

The object of the present invention is to provide a device which overcomes this latter drawback simply and efficiently, by positioning the purifier immediately beneath the belt which transports the material to be pigmented or coloured.

The device according to the invention provides a set of tanks placed immediately beneath a spray area and containing water (or harmless solvent solution) through which the air to be purified is made to pass.

This is achieved by, for example, sub-dividing each tank into two areas one of which, under rotating spray guns, has an open surface and the other, separated from the first by a grille which dips beneath the level of the water, has a suction created in it by exhaust fans.

The difference in pressure between the two parts of the tank causes suction under the rotating spray guns, and causes the turbulent flow of the air to be purified into the water, so that the particles of pigment suspended in the air flow mix with the water in the tank and are deposited in a still area.

After a series of washings, the air passes through drop-separating bulkheads positioned downstream and then, through dry filters, goes into fans from which it is expelled to the outside.

The water in the tanks can be continuously filtered, forming a closed cycle in which only the water which evaporates has to be replaced.

An embodiment in accordance with the invention is hereinafter particularly described by way of non-limiting example, with reference to the accompanying drawings, wherein: Figure 1 is a plan view of a pigmenting device with air purifier; Figure 2 is a sectional view of the same taken on the line ll-ll in Fig. 1; Figure 3 is a sectional view of the same taken on the line Ill-Ill in Fig. 1; Figure 4 is a sectional view of the same taken on the line IV-IV in Fig. 1.

Fig. 2 shows that the pigmenting device is essentially conventional and consists of an electric motor 11 which rotates a turntable 1 2 on the bottom of which are fixed sprayers 1 3 which enable the product 1 4 being processed to be painted or pigmented.

The product 14 to be processed is moved on the conveyor belt 8, preferably of a type with parallel wires, in an area underneath the turntable 12.

A control device causes the pigment to come out of the sprayers 1 3 only when they are over the belt 8, in areas 8' and 8" (Fig.

1).

The air and the particles of colour suspended in it are sucked into the fans 7 (Fig.

1) and drawn through the grille 9 (Fig.

2), causing turbulent flow of water contained in a part of a tank 1 downstream of the grilles 9.

Grilles 9 are shown clearly in Fig. 4.

As can be seen in Fig. 3, the foam caused by the air, and the air itself, pass into assembly section 10 and then into tanks 2, from which they then go through grilles 9', thus increasing the level of air contained in area 2'.

The humidified air and the foam formed by the same then pass into area 1 5 equipped with drop-separating bulk-heads 1 6 which re pel the foam and water which collect in collecting area 4, from which they can be expelled from the purifier.

The air, on the other hand, goes into dryfilter area 5, where dry filters are provided, and is then expelled from the cubicle through channels 6.

The complete course followed by the air is indicated by the broken lines 17, and 3 indicates the area which contains the drop separators 16 (Fig. 3).

The device which purifies the air, coming out of a cubicle for the automatic spraying of hides or the like, inside the cubicle itself, provides as the above description shows a number of advantages, for example continu ous washing by a mist of water of all the surfaces of the machine exposed to the spray jets, a considerable reduction in bulk due to the absence of a purifier outside the machine and, which is very important, a reduction of the risk of the particles of pigment or paint in suspension in the air or deposited in the piping catching fire due to the fact that purification is carried out immediately downstream of the spray area, which means that all the outlet channels and air exhausters operate with purified air.

In addition there are the advantages deriving from the optimum purification of the air obtained by means of two or more successive treatments, with the consequent minimal need to clean the channels in which the air flows.

There is also an advantage in being able to recover the contaminated water and treat it with suitable filters positioned either inside or outside the spray cubicle, thus forming a closed cycle of purifying water.

The device according to the invention can also differ in shape and appearance from the one now described, its essential features remaining unchanged, without thereby departing from the scope of the appended claims.

Claims (3)

1. Cubicle, for spraying pigments or paints on dressed hides or the like, characterised in that it comprises a top part having a turntable, on the underside of which are fixed sprayers to paint or pigment the product being processed, and a bottom part having a number of tanks containing water or solvents, drop separators, filtration areas and discharge channels, through which air contaminated with sprayed particles of pigment passes due to the effect of suction created by fans, the air thus being purified inside the cubicle.

2. Cubicle, according to claim 1, characterised in that the fans by the suction which they create force air contaminated by sprayed particles of pigment, which have not been deposited on the material to be painted, to pass through grilles thus raising the level of the water, which causes bubbling of the air downtream of the grilles, the foam so formed and the air passing through assembly areas and being conveyed through grilles inside the tanks, (thus raising the level of water contained downstream of the grilles and fogging part of the water in a further area, which helps to keep the fine spray of resin or pigment in suspension over the water, the humid air then passing into a further area and being de-humidified by drop-separating bulkheads therein, the foam being repelled and collected in collecting areas, from which they are then expelled from the device, the air so treated being sent to a dry-filter area where it is further dry filtered and expelled from the cubicle through channels.

3. Cubicle, for spraying pigments or paints on dressed hides or the like, substantially as described herein with reference to the accompanying drawings.