SE464222B - BEFORE SPRAY PAINTING SPECIFIED SPRAY CHAMBER - Google Patents

Description

20 25 30 35 464 222 2 The air flow thus sucked out of the chamber must be purified by means of a filter in order to protect the external environment and ducts. The filter is quickly filled with paint, which dries and releases solvents to the external environment. The rapid clogging means that the filter must be changed frequently, which is perceived as difficult by the staff, who are also exposed to hazardous paints and solvents.

In addition, production is disrupted.

When the filter is clogged, the air flow through the chamber decreases and the spray nozzles start to get dirty, which has the consequences discussed above. In general, the entire spray chamber becomes dirty and must be cleaned, which is expensive and dangerous to health. When the filters are clogged, the spray mist can not be removed from the chamber but swirls around inside it, which accentuates the problems of rebounding and excessive co-injection. As previously mentioned, this causes clogging of the spray guns and also requires frequent cleaning of the inner walls of the spray chamber, where the spray mist gets stuck.

The use of large air flows thus does not provide a solution to the problems and is also very costly because a lot of energy is required to heat the intake air and push the air through the spray chamber. The known solution also causes a large spill of paint, since a significant proportion of the paint gets stuck in the filter and on the inner walls of the spray chamber.

An object of the present invention is therefore to provide a spray chamber which solves the problems discussed above using considerably smaller air flows.

Another object is to provide a spray chamber, where the spray mist is utilized better than in known spray boxes and where so-called re-bouncing, co-injection and the inconveniences are thereby radically reduced.

A further object is to provide a spray chamber, the filter of which does not need to be changed as often as with known spray boxes and where paint mist which does not adhere to the article is collected in an efficient manner. 10 15 20 25 30 35 464 222 3 Another object is to reduce the amount of solvent that, despite filter equipment, is carried out of the spray chamber to the external environment.

These objects and also other objects, which will appear from the following description, have now according to the invention been achieved in an equally simple and ingenious manner by means of a spray chamber, which is of the type initially indicated and is characterized in that it in addition, it contains a capsule which contains the articles to be spray-painted and whose volume is considerably smaller than that of the spray chamber, and which each spray gun is placed outside the capsule just in front of or in an opening therein, the cross-sectional area of which is considerable less than the internal cross-sectional area of the canister perpendicular to the spray direction and in a plane through the article in question in the canister.

Further features of the invention are set out in the following claims.

The invention and its many advantages will be described in the following with reference to the accompanying drawings, which show some embodiments.

Fig. 1 schematically shows a vertical section through a spray chamber according to the invention.

Fig. 2 shows on a larger scale a section taken along the line II-II in Fig. 1.

Fig. 3 shows on a larger scale and with certain parts in section a section of the upper part of the spray chamber illustrated in Fig. 1.

Fig. 4 shows a lower part of a capsule, which is included in the spray chamber illustrated in Fig. 1.

Fig. 1 shows under the general reference numeral 1 a spray chamber according to the invention, which is intended for spray painting of articles 2, which according to this example consist of elongate wooden door frames. It should be pointed out that the spray chamber 1 can also be used for spray painting, spray gluing and the like. The spray chamber 1 has a lower part 3 in the form of an enclosed space, in which an air flow flows in the direction of the arrows. Furthermore, the spray chamber 1 has an upper part 4, where spray guns 5 are located (only one gun is shown in the figure).

The spray gun 5 is placed outside a capsule generally denoted by 6, which will be described in more detail later and through which the article 2 to be spray-painted passes and is preferably transported in a direction perpendicular to the plane of the drawing by means only a schematically shown transport device 7. From the spray gun 5 a diverging jet of color 8 is directed through an opening 9 in the capsule 6. the opening 9 is formed by a bore in a nozzle 10, which is mounted on the capsule 6 (see Figs. 2 and 3). The paint jet 8 thus hits the article 2, and so-called spray mist, ie paint that does not stick to it, is passed on by the air flow past the article 2.

The spray chamber 1 has in its lower part 3 a filter 11 for receiving paint particles which is passed with the spray mist in the air flow. Via an exhaust air outlet 12, the air is then led out of the spray chamber 1. At the outlet 12, negative pressure prevails in a known manner for the formation of a suction through the spray chamber 1.

Because the spray gun 5 is located just outside the special capsule 6 where the actual spray painting takes place, the amount of co-injected air is limited, ie air that accompanies the jet 8 from the spray gun 5's immediate surroundings and into the capsule 6. There is simply a very limited amount of air. which is drawn with the jet 8 from the space above the canister 6, through the opening 9 and towards the article 2. It is thus completely clean air that is co-injected into the canister 6. The reduced co-injected air flow reduces the so-called rebound of spray mist from the article 2 In general, the spray painting takes place in a limited volume inside the substantially closed capsule 6 with better control of the spray mist than has hitherto been possible in known spray boxes.

The capsule 6, which is preferably elongated in the direction perpendicular to the plane of the drawing, has a considerably smaller volume than the spray chamber 1. The spray mist which nevertheless forms is either carried further out of the capsule 6 and gets stuck in the filter. 11 or sticks to the lower inner walls of the canister 6, which are easy to clean. The paint particles which do not adhere to the article 2 or the capsule 6 are thus carried further downwards and out through an outlet 14 in a lower funnel-shaped portion 15 of the capsule 6, which will be described in more detail later. The special design of the canister 6 with the largest arch in its central portion gives a favorable spraying result and contributes effectively to the removal of spray mist from the canister 6 and the accumulation of spray mist which gets stuck therein. The spray mist can thus be removed with very little air flow.

In order that the co-injection of air into the canister 6 should not be too large, the opening 9 has a considerably smaller cross-sectional area than the internal cross-sectional area of the canister 6 perpendicular to the spraying direction and in a plane through the said article 2 in the canister 6. - marked by a dashed line 13 in Fig. 1. The beam 8 thus diverges through the opening 9 and strikes the article 2, which is suitably located centrally inside the capsule 6.

According to this embodiment, a certain amount of co-injected air through the opening 9 is unavoidable and in some cases even desirable given that there must be an air flow through the spray chamber 1. Therefore, the cross-sectional area of the opening 9 is preferably adjustable by means of a special device which will described in more detail later. The co-injected air through the opening 9 affects the color jet 8, the appearance and behavior of which is therefore controlled from the outside by the service personnel, who, if necessary, adjust the cross-sectional area of the opening 9 in such a way that a nice jet 8 is obtained. The color beam 8 must not be "worried".

As previously mentioned, a certain amount of excess paint adheres to the lower inner walls of the canister 6, which will thereby serve as a wet separator. Due to the fact that the lower part 15 of the capsule 6 is substantially funnel-shaped, excess paint flows down along the lower inner walls of the capsule 6 and 464 222 10 15 20 25 30 35 6 is collected in a lower wet-separating paint trap or collection pocket 16. The excess paint is then passed on to a recycling bin 17 via the outlet 14. It is of course a great advantage that the excess paint is collected in the spray direction. Preferably, the collecting pocket 16 of the canister 6 has a certain inclination in the longitudinal direction, so that the excess paint can accumulate at one end of the canister 6 and be easily led down into the vessel 17. An advantage in this connection is that the recycling vessel 17 is placed inside the spray chamber 1. whether the air flow passes by or through it. In the case of previously known spray chambers, it is usually necessary to use special ventilation devices for such recovery vessels.

The collection and recovery of excess paint described above has proved to be extremely effective in practical experiments. Since a large part of the spray mist is already collected inside the capsule 6, the amount of paint particles which are passed on is very small. Thus, the air that passes through the filter ll contains a low proportion of paint particles, so the filter ll does not need to be changed as often as with previously known spray cans. The filter 11 is simply not clogged as quickly as before.

Since the spray guns 5 are placed outside the special capsule 6, they are not clogged as quickly as before. The amount of spray mist that bounces up against the nozzle of the spray gun 5 is considerably reduced in comparison with what is the case with previously known spray boxes.

Furthermore, in the practical experiments it has been possible to reduce the required air flow very significantly. In previously known spray booths, air flows of 5000-6000 m3 / h are normally used, which gives very large power requirements in terms of both heating of the intake air and fan equipment. In the spray chamber according to the invention, air flows as small as 500-600 m3 / h have been used with very satisfactory results. The outflow generated by the negative pressure in the suction chamber only needs to be slightly greater than the sum of the co-injected air flow and the air flow generated by the spray air operation of the spray guns. 10 15 20 25 30 35 464 222 7 A person skilled in the art immediately realizes what cost savings will thereby be possible with regard to investments in equipment and current operating and maintenance costs. As the filters do not need to be replaced or cleaned as often as before, the number of downtime is also reduced while the need for personnel is reduced.

In Fig. 2, to which reference is now made, a stand 18 is illustrated, which is placed outside and at a distance from the capsule 6 and on which the spray gun 5 is mounted by means of a schematically shown fastening member 19, which may, for example, be in the form of a clamping screw. The spray gun 5 is placed just above the nozzle 10, the diverging, truncated conical bore forming the opening 9. According to a variant not described in more detail here, the spray gun 5 is positionable in the longitudinal direction, whereby the distance between the spray gun nozzle 5 and the nozzle 10 can be changed.

The nozzle 10 is provided with a device 20 for adjusting the cross-sectional area of the opening 9. The device 20 can be of a type known per se, for example a damper. The nozzle 10 is preferably replaceable to other nozzles, which may have other types of openings and / or adjusting devices.

According to a variant, the nozzle 10 is also axially adjustable with respect to the direction of the steel 8. Likewise, the nozzle 10 can be movable between the openings 9 in the capsule 6.

Fig. 2 further shows how the elongate capsule 6 is advantageously divided into several sections or modules.

Only one section is shown here, which is delimited by two partitions 21 and 22 inside the capsule 6. The capsule 6 preferably contains several such sections, each of which has its own spray gun 5 and nozzle 10. in that there is only one spray gun 5 in each such section. their color jets 8 will not be able to disturb each other, which provides safer control of the spray mist. Under certain conditions, there may also be two spray guns 5 in each section, which are then placed close to each other.

In Fig. 3, to which reference is now made, another location of the spray gun 5 is illustrated in more detail, namely the capsule 6 is preferably provided with several openings or nozzles 10 for spray painting in different desired directions. Therefore, the spray guns 5 are movable between different positions on the frame 18. Preferably, spray painting should be possible in any direction with respect to the semicircular shape formed by the upper part of the capsule 6 as well as the arcuate frame 18 (cf. Fig. 1). Of course, it is also conceivable that several spray guns 5 spray simultaneously against the article 2 in different directions.

According to a variant not shown in more detail here, the spray gun 5 is mounted directly in the opening 9 in the capsule 6, the spray nozzle itself being substantially level with the inner wall of the capsule 6. The co-design from the space above the capsule 6 then becomes substantially equal to zero, and only the jet 8 of the spray gun 5, which is usually driven by compressed air, generates the air flow down through the capsule 6. If you want a certain co-design, small channels can be taken up in the capsule 6 in direct connection to the spray gun's 5 mounting point. Furthermore, a setting device for the cross-sectional area of the opening can be located directly at the nozzle of the spray gun 5. In addition, the spray gun 5 may be mounted in the nozzle 10.

Fig. 4 shows in more detail how the lower funnel-shaped portion 15 of the capsule 6 is formed, in particular the collecting pocket 16 where the excess paint accumulates and then is drained via the outlet 14. The funnel-shaped portion 15 is supported or supported by holders 23, 24, which can also serve to slightly vibrate the lower part of the capsule 6, so that excess paint flows down the inner walls more quickly.

In conclusion, it should be pointed out that in the preceding description only such components have been included as are required to explain the inventive concept. For obvious reasons, many components have thus been omitted, such as supply lines for paint and compressed air to the spray guns. Furthermore, there may be photocells and other sensors as well as time-controlled devices for controlling the spray painting with regard to the transport of the articles through the canister. Finally, it should also be noted that the invention is by no means limited to the embodiments described above, without many modifications being conceivable within the scope of the inventive concept, which is defined in the following claims.

Claims (8)

464 222 10 15 20 25 30 35 10 PATENT CLAIMS For spray painting, spray painting, spray gluing and the like treatment of articles intended spray chamber, which is permeated by an air flow and which comprises at least one spray gun (5) directed at the article (2) in question, preferably several guns, characterized in that it in addition, it contains a capsule (6), which contains the articles (2) to be spray-painted and whose volume is considerably smaller than that of the spray chamber (1), and that each spray gun (5) is placed outside the capsule (6) just in front or in an opening (9) therein, the cross-sectional area of which is considerably smaller than the inner cross-sectional area of the canister (6) perpendicular to the spray direction and in a plane (13) through the article (2) in question in the canister (6). Spray chamber according to Claim 1, characterized in that there is a device (20) at each opening (9) for adjusting the cross-sectional area of the opening (9). Spray chamber according to Claim 1 or 2, characterized in that the opening (9) is delimited by a nozzle (10) with a truncated conical bore, which diverges in the spray direction. Spray chamber according to one of the preceding claims, characterized by a stand (18), which is located outside and at a distance from the canister (6) and on which the spray guns (5) are mounted so that they are movable between different openings. (9) in the capsule (6) for spraying in different directions towards the article in question (2). Spray chamber according to one of the preceding claims, characterized in that the capsule (6) is elongate and divided into several sections, which are delimited by means of partitions (21, 22) and which each contain a spray gun (5). 10 15 20 25 30 35 464 222 11 Spray chamber according to one of the preceding claims, characterized in that the capsule (6) has a substantially funnel-shaped portion (15), which forms a pocket (16) for wet separation and collection of excess paint. Spray chamber according to claim 6, characterized in that the collecting pocket (16) of the canister (6) leads to a recovery vessel (17), which is placed inside the spray chamber (1) and thereby ventilated by the air flow. Spray chamber according to any one of the preceding claims, comprising an air outlet (12) and a filter (II) placed in front of it with the direction of air flow with a negative pressure prevailing therebetween, characterized in that the collecting pocket (16) is located before the filter (II) with respect to the air flow direction.