Spray booth with hybrid electrical heating

Abstract

 Spray booth with the heating obtained by the combination of electrical radiant panels (1) with diffused heat and integrative electrical radiant panels (2) at high temperature, the latter usually placed on the top of the side walls (3), at heights from the floor (4) that can not be reached by the operator during the normal working process.

Description

[0001] The invention concerns a spray booth particularly adapted to be used for the painting of the bodywork of vehicles and of its parts, with the heating of the painted parts to be dried executed by electrical energy.

[0002] There are known spray booths in which, after the painting cycle of the surface of vehicles bodywork or parts of it, the drying unit is activated in order to make the heated air circulating inside the booth, normally with this circulation directed from the filtering ceiling to the floor of the booth. The air flow which operates the drying of the painted surfaces has normally a temperature from 35° to 90° C.

[0003] In one case this air flow is heated inside an heat exchanger provided with special burner, in another case the heating is made by electrical resistors lapped by the air which has to be heated before passing throughout the painting/drying room.

[0004] The use of heating units with burners requires a more complex elaboration of the booth and so that an higher cost and a considerable complexity of working.

[0005] This kind of booth requires also the connection to the plant which distributes the combustible gas or to an autonomous tank of combustible supply, with all disadvantages that this can cause.

[0006] The use of electrical units for the heating of the air involves the solution of problems concerning the realization of the electrical insulation and of the locating of the heating units, since the heating surfaces, which can reach a temperature of more than 150 - 200°C, must not be reachable by the operator casually.

[0007] That means that the normal surfaces heated by the passage of the electrical current should not be inside the painting and drying room, but should be dislocated in the air way at the external of said painting/drying room, with all the insulating problems that this can involve, in order that the thermal exchanges are reduced with the external upstream of the filtering ceiling.

[0008] This disadvantage has been overcome by the owner of the present invention who has used electrical radiant panels with diffused heat provided at their inside with a thermo-electrical tissue with a high electrical insulation which is the subject matter of Patent Application PCT/IT99/00193, in which panels the temperature of the heated surface is relatively low, according to the safety standards which provide that the temperature of said surfaces not exceed 150° C.

[0009] Booths which have the painting/drying room defined in the perimetrical walls by this kind of heated panels have resulted particularly advantageous because of the structure of the booth will be simplified; it is not necessary to have any combustion heating unit; the temperature inside the painting/drying room results relatively low and easy to be regulate; there is no pollution produced; the painting room appears well-finished.

[0010] This kind of booths with radiant panels with diffused heat result particularly advantageous because of the heating is carried on mainly on the masses inside the painting/drying room. This kind of booths have the disadvantage of not supplying sufficient heat to allow the masses inside the painting/drying room to reach a temperature of about 60-70°C, as it is required for some kind of paints, for example for water paint, or to reach temperatures of about 40-50°C, as it is required for the drying of surfaces covered with common paint, in case the booth is installed in particularly cold areas or during the winter time, when the temperatures are rough and the thermal exchanges with the external increase.

[0011] An aim of the present invention is the realization of a spray booth in which the required heat to heat the masses at its inside has only an electrical origin, also when the required temperatures are relatively high.

[0012] Another aim of the present invention is the realization of a booth in which the production of the heat is concentrated inside the painting/drying room, in order to limit the wasting of the heat with the external, without needing expensive and particular insulations during the circulation way of the air flow.

[0013] Another aim of the present invention is the realization of a booth which has a heating plant that is not dangerous for the operator when he is inside the painting/drying room.

[0014] Finally, another aim is to realize a heating plant which has an easy regulation to adjust the value of the heating of the masses inside the painting/drying room to the particular executed painting, that means to reach on the masses inside said painting/drying room the optimum operating temperature, also if the outside temperature is very low, for example when the spray booth is installed in very cold countries or it is used during the coldest winter periods.

[0015] These and other aims are achieved with the present invention that is relative to a spray booth with hybrid electrical radiation heating, obtained by the combination of electrical radiant panels with diffused heat, distributed on the perimetrical walls of the painting/drying room, and electrical radiant panels at high temperature, the second ones being integrative of the first ones and usually placed towards the top of the side walls of said room and at a height from the floor such that the operator, during the course of normal work, does not reach them, according to the safety standards.

[0016] This kind of spray booth results advantageous since it uses only electrical energy, it is constructively simple, it presents a high quality of finishing and it does not produce pollution due to combustible products.

[0017] It results also advantageous since the high temperature electrical radiant panels which are placed towards the top of the side walls irradiate thermal energy which invest mainly the upper parts of the painted surfaces located inside the painting/drying room which are directly invested by the drying air flow, which tends to make them cold, so that said upper parts need a greater heating.

[0018] The plurality of the electrical radiant panels with diffused heat allows to bring the temperature of the surfaces of the masses inside the painting/drying room to the required conditions or near to the required conditions, in order to operate the drying process in optimal conditions.

[0019] The plurality of the electrical panels at high temperature allows to operate a thermal integration and to lead the temperature of these surfaces to the retained optimal value to carry on the drying process on the painted surfaces also in unfavourable environment conditions.

[0020] This integrative intervention is required at least in cases in which the reached temperature on the surfaces of the masses inside the painting/drying room by means of the effect of the only electrical radiant panels with diffused heat is insufficient. The electrical radiant panels at high temperature allow to carry out the required energetic integration, by the regulation of their energetic flow.

[0021] So that it is obtained a drying process in the best conditions, both in function of the type of paint that has to be dried and in function of the environment and the temperature of the environment where the booth is installed. All this permits to operate, in case of favourable environment conditions, with a limited heating of the masses inside the painting/drying room using only the electrical radiant panels with diffused heat which panel it, with a considerable saving of energy. However, in any condition there are considerable savings of energy and of insulation.

[0022] These and other advantages will be particularly clear to the technicians of this field by the reading of the following detailed description, with reference to the embodiment exemplified in the schematic drawings reproduced on the enclosed table, in which:

• figure 1 is the perspective view of the internal of the painting/drying room of a spray booth according to the present invention;
• figure 2 shows, in a different scale, the distribution of the thermal panels and the luminous panels on a side wall of the painting/drying room;
• figure 3 shows a high temperature electrical radiant panel;
• figure 4 shows the irradiation of the heat operated by the electrical radiant panels and the current air flow of the drying process inside the booth where a vehicle is placed.

[0023] It is understood that the drawings have only an exemplified aim to facilitate the comprehension of the present invention, without being a limitation for it.

[0024] Substantially the invention consists of a booth, particularly suitable for the spray painting of the bodywork of vehicles and/or their parts and for their drying, provided with a heating unit obtained by the combination of electrical radiant panels 1 with diffused heat and integrative electrical radiant panels at high temperature 2, the second ones intended to intervene every time the required thermal conditions are not reached with the only use of the electrical radiant panels 1 with diffused heat, the peculiarity of which is to operate with relatively low temperatures and with large surfaces of thermal exchange.

[0025] Inside the painting/drying room of this booth, the electrical radiant panels with diffused heat are distributed on the perimetrical walls 3 and in particular on the longitudinal side walls and, in case, on the wall faced to the entrance of the booth. They can be also located on the entrance wall, where there is the entrance door. They are usually located in rows parallel to the floor 4 and usually they are intercalated with illuminating panels and/or units 5, distributed in rows at different heights, in order to have a diffused lighting, so as to eliminate the shades on the surfaces that have to be painted and to facilitate the work of the operator who has to distribute the paint on the bodywork of the vehicle or on its parts, or on anything else that has to be painted.

[0026] The electrical radiant panels at high temperature 2 are usually placed towards the top of the perimetrical walls, at heights from the floor that can not be reached by the operator during the normal working process, in order that he can not accidentally get in contact with these panels, according to the present safety standards.

[0027] They can be also placed at a low level and have the high temperature element(s) 6 (resistive threads or straps) protected by a grate 7 oriented towards the internal of the painting/drying room in order to impede accidental contacts. These panels 2, in the exemplified solution of the drawings, realize oblique surfaces which connect the top of the side walls to the filtering ceiling.

[0028] The arrangement of the electrical panels at high temperature 2 on one side assures the safety of the operator when he enters into the booth and the system is working, on the other side it allows their thermal radiations to invest the upper parts of the painted masses located inside the painting/drying room. In fact, the upper parts of the painted masses are directly invested by the air flow 8, coming from the filtering ceiling, so they tend to maintain lower temperatures and consequently they require a higher thermal irradiation.

[0029] All of these electrical radiant panels at high temperature 2 can be activated, or only some of them, or all of them can be partly activated.

[0030] They are normally combined with a divider system, by means of which the thermal effect they produce and, therefore, the thermal power of the radiation they generate are regulated.

[0031] The present spray booth has therefore a painting/drying room where the painted surfaces of the masses at its inside are heated by irradiation of thermal energy produced by electrical radiant panels of two different kinds, the first one with diffused heat the second ones with high temperature.

[0032] During the realization the combination of the electrical radiant panels of the two types, with which the irradiation heating of the surfaces of the masses located inside the booth has to be carried on, can be carried out with different modalities and schemes, keeping steady the logic at the base of this invention, defined by the following claims.

Claims

1. A spray booth with a hybrid electrical heating, wherein the heating unit is characterized by the fact that include the combination of electrical radiant panels with diffused heat (1) and integrative electrical panels at high temperature (2), the first ones being characterized by the fact to be distributed on the perimetrical walls of the painting/drying room, the second ones by the fact to be usually placed towards the top of said walls at heights from the floor that can not be reached by the operator during a normal working process.

2. The spray booth, as claimed in claim 1, characterized by the fact that the electrical radiant panels with diffused heat (1) are intercalated with illumination panels and/or units (5).

3. The spray booth, as claimed by claim 1, characterized by the fact that the electrical radiant panels at high temperature (2) realize oblique surfaces, from the top of the side walls (3) to the filtering ceiling (9).

4. The spray booth, as claimed in claim 1, characterized by the fact that the electrical radiant panels at high temperature (2) have the high temperature element or elements (6) protected by a grate (7) oriented towards the internal of the painting/drying room.

5. The spray booth, as claimed in claim 1, characterized by the fact that the electrical panels at high temperature (2) are combined with a divider system to regulate the thermal effect they produce.

6. The spray booth, as claimed in any one of the previous claims, characterized by the fact that the painted surfaces of the masses placed inside the painting/drying room are heated by irradiation with thermal energy produced by the electrical radiant panels with diffused heat (1) and by the electrical radiant panels at high temperature (2).

Drawing