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