FR2575940A1 - Spray booth, in particular for the automatic painting of objects - Google Patents

Abstract

a. Spray booth, in particular for the automatic painting of objects. b. Spray booth, characterised in that the condenser 21 of the water-recycling circuit is connected to a heat source 27 and, via tubular conduits 24, 25, is connected to the heat exchanger 6 which is located in the chilled-air inlet 4. c. The invention relates to a spray booth, in particular for the automatic painting of motor vehicles.

Description

PROJECTION CABINET, PARTICULARLY FOR AUTOMATIC PAINTING
OBJECTS
The present invention relates to a spray booth, in particular for automatic painting of objects, comprising a fresh air inlet arranged in the upper area of the spray booth, a paint mist separator located in the area bottom of the projection booth and the corresponding air exhaust channel, as well as a coagulation installation to separate the paint residues from the water from the paint mist separator, a heat exchanger arranged in the fresh air inlet for heating the fresh air to a predetermined value and another heat exchanger for recovering the exhausted heat, in which the heat exchanger for recovering the exhausted heat is an evaporator of a heat pump whose condenser is used for indirect heating of fresh air.

 The structure of the projection booths is generally chosen, for example those in which car bodies are painted, so that the fresh air enters the projection booth from above, it being specified that the fresh air passes through completely. 'first by a heat exchanger which is in the fresh air inlet, then reaches the projection booth itself through a filtering ceiling. The air flow leaves the projection booth through the floor of the projection booth which, for example in the form of a grid, arrives in a paint mist separator placed below the floor and exits, largely cleared of the paint mist, in an air exhaust channel For the recovery of thermal energy from the exhaust air or water from the paint mist separator, a heat pump is provided by which at least partially recovering the evacuated heat which is brought to the inlet channel to heat the fresh air.

Installations of this type are for example described in documents DE-OS 29 42 184, DE-AS 29 45 899 and DE-PS 29 45 914.

 Known devices are designed so that the heat pump condenser is arranged in the inlet channel. Since, however, it is only for the appropriate outside temperatures that the energy recovered in the evacuated heat is sufficient to heat the incoming air to the desired temperature, known installations usually have a second heat exchanger to completely warm up to the temperature necessary in the projection booth the incoming fresh air, it being specified that this second heat exchanger is supplied by another source of energy.

 In cases where the thermal energy of the water found in the coagulation installation or in the exhaust air is greater than the energy required to heat the fresh air, in known installations, it cannot be not use unnecessary thermal energy.

 The object of the invention is therefore to provide an extension of a projection booth of the model indicated above so that with a single heat exchanger in the fresh air channel there is always achieved sufficient heating of the fresh air using full-.

the recovered energy.

 In a projection booth of the type mentioned, this goal is achieved by the means that the condenser of the water recycling circuit is connected to a heat source and, by tubular conduits, is connected to the heat exchanger which is in the fresh air supply.

 We must see in particular the advantages of the object of the invention in the fact that in the supply of fresh air it suffices with a single heat exchanger, to which the energy of the installation of heat recovery as energy from an additional heat source. In this way the arrangement of the capacitor in space is completely different, given that the condenser is connected, both on the primary side (refrigerant) and on the secondary side, by tubular conduits, to the corresponding groups of the system and can easily adapt the tubular conduits to the spatial arrangement of the capacitor.

 According to a preferred embodiment of the object and the invention, the water recycling circuit is part of a heating installation, in particular of a building heating installation, which has a heat source which can be switched on if necessary. With such a solution, we can, whenever necessary as well as in exceptional cases, for example in case of icing of the evaporator or in case of an incident on the installation of the heat pump, have the heat source of the building's heating system, the thermal power required for the heat exchanger in the fresh air supply.

Another advantage is that at times when the energy produced by the own heat is greater than the energy necessary for heating the fresh air, this superfluous heat is sent to the recycling circuit of the installation of heater.

 One embodiment of the invention consists in that the evaporator is connected to the water recycling circuit of the coagulation installation and in that there is provided a recycling pump mounted upstream or downstream of the evaporator. This arrangement constitutes an advantage insofar as it is possible, for the evaporator, to implement a substantially smaller embodiment than in the case of energy recovery from the exhaust air. In addition, unnecessary superfluous heat is not sent to the atmosphere, in the form of exhaust air, which is not absorbed by the refrigerant of the evaporator, but remains in the recycling circuit of the water from the coagulation plant.

 Particularly advantageous is a projection booth in which a basin of the coagulation installation comprises portions of metal walls designed as an evaporator for the germinating coolant. In this way there is no heat loss through the connecting pipes between the coagulation basin and the evaporator and on the other hand this prohibits the constituents of the paint which are in the recycling circuit of the calf from pollute the heat-generating lechane and therefore lower its efficiency. According to a first embodiment of the evaporator, the portions of walls of the coagulation basin which form the evaporator are constructed from two sheets placed one against the other. the other so that at least one coolant passage channel is formed between the sheets. Thanks to this construction, no additional parts are required for the evaporator, but the already existing parts of the coagulation basin are used judiciously for the transfer of heat or the transport of energy. interesting design of the device consists in that the sheets placed on the internal face of the coagulation tank are smooth and in that the external sheets have at least one molding which forms the channel The smooth interior surface of the coagulation tank allows cleaning without complications of the pool, especially if the cleaning device moves along the side walls.

 The moldings produced on the outer sheet may have various shapes, the fact of providing a single evaporator channel with long development or a large number of parallel sections of evaporator depending on different boundary conditions. Thus, for example, the molding may have the shape of a meander and may extend from a coolant inlet to a connection of the com pr-esseur intake pipe.

 According to a variant embodiment of the evaporator, it consists of a metal sheet of the coagulation basin on which are fixed, in good heat conductive connection, flat tubes or profiled tubes for the passage of the refrigerant. An execution of this kind has the advantage that there is no need for sealing between two channels as it would for example be necessary in the case of sheets placed one on the other.

 Insofar as the evaporator is not a constituent of the coagulation basin, this can be placed in the water recycling circuit of the paint mist separator and in series with it or also in an additional water recycling circuit placed parallel to the paint mist separator.

The first mentioned execution has the advantage that the assembly expense is lower.

 The device according to the invention is however also suitable for use cases where the evaporator is arranged in the air exhaust channel and influenced by the exhaust air flow.

Other characteristics and advantages of the invention are better understood on reading the description which follows of several examples of embodiments and with reference to the appended drawings in which
Figure 1 shows a projection booth with heat recovery using a heat pump whose evaporator is arranged in the air exhaust channel.

 Figure 2 shows a projection booth with heat recovery, where the evaporator is arranged in a water recycling circuit of the coagulation installation.

 FIG. 3 represents a variant of the execution of FIG. 2.

 FIG. 4 represents a variant of the execution of FIG. 2, where the evaporator of the heat pump recycling circuit forms an assembly with the coagulation installation.

 Figure 5 is a schematic representation of a section of the coagulation installation with integrated evaporator.

 FIG. 6 is a side view of a coagulation installation according to FIG. 5.

 In Figure 1, in a building 1 is arranged a projection booth 2 which is suitable for example for painting automobile bodies. In the upper part of the building 1 there is a fresh air inlet 4 by which fresh air enters in the direction of the arrow 5. In the fresh air inlet 4 is arranged a heat exchanger 6 which serves to reheat the entering air to a predetermined temperature. In the upper zone of the projection booth 2 there is a filtering ceiling 7 in which the fresh air is freed of the particles, so that only dust-free air enters the projection booth 2. The projection booth floor 2 consists of a grid 8 through which air leaves the projection booth with a significant proportion of paint mist. Below grid 8 is a paint mist separator 9 in which the air stream charged with paint mist must pass through a film of liquid and in which the paint mist is therefore almost completely, or for the most part, separated from the exhaust air.

 The lower part of the paint mist separator 9 is formed by a tank 10 in which the water, laden with paint particles, collects and is then sent, by a tubular conduit, to a coagulation installation 12. In the coagulation system 12 the constituents of the paint are bound and precipitated, then removed from the coagulation system 12 by means of an evacuation device 13. The water purified in this way is brought again, by a pipe tubular 14, to the paint mist separator 9. The water is recycled by a recycling pump 15 which leads to the paint mist separator 9.

 The evacuated, purified air leaving the paint mist separator 9 in the direction of the arrow 16 is brought into an air exhaust channel 17 in which an evaporator 18 of a heat pump is arranged. The exhaust air passes through the evaporator 18 and exits into the atmosphere according to the arrow 19. In addition to the evaporator 18, the heat pump comprises a compressor 20, a condenser 21, an expansion valve 22, as well as tubular conduits 23 for connecting the various components. The capacitor 21 is connected to a water recycling circuit and, by tubular conduits 24 and 25, it is connected to the heat exchanger 6 which is located in the fresh air inlet 4. In the conduit tubular 24 is a tap 26 which is bridged, by a bypass, to an additional heat source 27. The heat source 27 is for example a hot water tank of a hot water recycling circuit connected to the network central heating of the building, it being specified that an upstream pipe 35 leads to the heat exchangers (not shown in the drawing) for heating the building and that a downstream pipe 36 brings these exchangers back to the heat source 27. In the event of a running incident on the heat pump or in the event of a risk of icing of the evaporator 18, by closing the stop valve 26- and by opening another tap 37 which is in the connection pipe between the pipe upstream 35 of the central heating and the tubular pipe 24 which leads to the heat exchanger their 6 which is in the fresh air inlet 4, thermal energy can be available to heat the fresh air. Insofar as the heat pump provides more thermal power than is necessary to heat the air in the fresh air supply 4, the central heating can be supplied with superfluous heat.

 The heat contained in the air evacuated in the air evacuation channel 17 is taken from the air stream which passes through the evaporator 18 and brought, in the manner known in the case of heat pumps, to the condenser. 21 which supplies this thermal energy to the water recycling circuit and therefore brings it to the heat exchanger 6 which is located in the fresh air inlet 4.

 Figure 2 shows a spray booth 2 dansunbâti ment 1, for example for painting car bodies 3. The fresh air intake arrangement 4 (in the direction of arrow 3) and the heat exchanger 6 which corresponds, as well as the filtering ceiling 7 and the grid 8 coincides with FIG. 1 and therefore comprises in the same reference numbers. This also applies to the paint mist separator 9 with its tank 10 arranged from below, for the tubular pipes 11 and 14 as well as for the coagulation installation 12, with the discharge device 13 and the recycling pump 15 The evacuated air passes through the air evacuation channel 17, according to arrow 16 and, through the paint mist separator 9, arrives in the atmosphere according to arrow 19.

 Starting from the coagulation installation 12, a tubular pipe 28 leads to an evaporator 29 which is part of a heat pump which includes a compressor 20, a condenser 21 and an expansion valve 22 as well as corresponding connection pipes. 23. From the evaporator 29, another tubular conduit 31 leads to a recycling pump 32 and from there, by another tutular conduit 33, we return to the coagulation installation 12. As in the case of FIG. 1, the condenser 21 is connected, by tubular conduits 24 and 25, to the heat exchanger 6 which is located in the fresh air inlet 4, it being specified that a recycling pump 34 ensures the necessary recycling of the In the tubular pipe 24 there is a stop valve 26 to which corresponds, in a bypass pipe, an additional heat source 27.

 In the case of the installation shown in FIG. 2, the passage of the air current through the spray booth 2 and through the paint mist separator 9 takes place exactly as in FIG. 1. When passing through the film of liquid in the paint mist separator 9, the current of hot air gives up a significant part of its thermal energy to the liquid, so that it is 11 heated water which reaches the coagulation installation 12. In this coagulation installation, water is taken which is brought, via the tubular conduit 28, to the evaporator 29 and which is pumped again, by means of the recycling pump 32, for the return to the coagulation installation 12 by the tubular conduits 31 and 33. In the evaporator 29, therefore, the water from the coagulation installation is taken from the heat that is sent, in the usual way in the case heat pumps, in the condenser 21 to the circuit for recycling hot water of, so that the hot water heated in the condenser can reach, via the tubular pipe 24, the heat exchanger 6 which is in the fresh air supply.

 FIG. 3 represents an alternative embodiment of FIG. 2, in which the device coincides with the description of FIGS. 1 and 2 with regard to the marks 1 - 17 and 19, so that - to avoid repetitions - we return to previous executions. In contrast to FIG. 2, the evaporator 29 of the heat pump installation is mounted in the tubular duct 14 which goes from the coagulation installation 12 to the paint mist separator 9. In this way it is not no longer necessary to have a second water recycling circuit, as described in FIG. 2 with the tubular conduits 28, 31, 33, and requiring a separate recycling pump. The water evacuated from the evaporator 29 does not reach therefore more in the coagulation installation 12, but directly in the paint mist separator 9, without a mixture with hotter batten from the coagulation installation 12 being able to arrive. The compressor 20, the expansion valve 22, the capacitor 21 and the tubular conduits 23 which connect these components correspond to those of FIG. 2. Similarly, the execution of the tubular conduits 24 and 25 as well as of the pump 34, of the expansion valve 26 and of the heat source 27 correspond to what ad already described in FIG. 2. However, however, this hot water recycling circuit is connected to the central heating network of the building, so that, from the heat source 27, for example a hot water tank, an upstream pipe 35 leads to the heat exchangers and a downstream pipe 36 brings the latter to the heat source 27. In the event of a running incident or in the event of insufficient power from the heat pump installation, a switching of the positions of the valves 26 and 37 and there is then, which is linked to it, thermal energy coming from the heat source 27, as has already been described for FIG. 1. Insofar as the heat pump provides a thermal power higher than that which is necessary to heat the fresh air which is in the arrival of fresh air 4, one can send in the central heating the superfluous heat.

 The arrangement according to FIG. 4 coincides with the description of FIG. 2 with regard to the marks 1 - 17, 19, 21, 24 -27 and 34, so that - to avoid repetitions - reference is made to the executions of the figure 2. In the installation shown in FIG. 4, the coagulation installation 12 is produced so that a coagulation basin 40 is joined, at the point of construction, with an evaporator 39. From the condenser 21, a tubular pipe 23, with intermediate mounting of an expansion valve 22, leads to an evaporator 39 and another tubular pipe 23 leads from the evaporator 39 to a compressor 20 which is connected to the condenser 21 by a tubular pipe. assembly, construction, the evaporator 39 and the coagulation basin 40, the heat of the water which is in this basin, made up of portions of metal walls, is directly transmitted to the refrigerant which is in the evaporator. This not only has the advantage of largely avoiding heat losses in the water recycling circuit, but also makes it possible to save additional components, such as, for example, tubular pipes, a pump and a separate evaporator.

 FIG. 5 schematically represents a section of a coagulation basin 40, the section of which corresponds substantially to that of a funnel. This coagulation tank 40 is formed by portions of metal walls 41 consisting, at least in the zone of side walls, of two sheets 42, 43 placed one against the other. While the sheets 42 arranged on the inner face of the basin 40 are smooth - this is advantageous for reasons of cleaning the basin 40 -, the external sheet 43 comprises 43 comprises a large number of moldings 44 which form channels 45 for the passage of the coolant. In this way each of the side walls of the basin 40 constitutes an evaporator 39 which has in its lower zone a coolant inlet 46 and which is connected in its upper zone to an inlet pipe of the compressor 47. Preferably the sheets 42 and 43 are provided, on their surfaces placed one against the other, with a sealing means and they are for example connected by a sufficient number of solder points.

 As a variant embodiment, the channels of the evaporator which allow the passage of the refrigerant can also be formed by flat or profiled tubes fixed, in a heat conducting connection, on the external face of the sheet 42. Depending on each time the design, it is possible to provide several evaporator sections mounted in parallel.

  Figure 6 shows the view along arrow VI-VI of Figure 5. From this representation we can see that the channel through which the coolant passes is formed by a molding 44 in the form of a meander which extends from the arrival of the refrigerant 46 up to the intake pipe of the compressor 47. Instead of the meander-shaped routing, it is also possible to have several silages running in parallel and connected in common to the arrival of the refrigerant 46 and to the pipe compressor inlet 47.

 Of course, various modifications can be made by those skilled in the art to the devices or methods which have just been described only by way of nonlimiting examples without departing from the scope of the invention.

Claims (11)

 1. Spray booth, in particular for the automatic painting of objects, comprising a fresh air inlet arranged in the upper area of the spray booth, a paint mist separator located in the lower area of the spray booth. projection and the corresponding air evacuation channel, as well as a coagulation installation to separate the paint residues from the water from the paint mist separator, a heat exchanger arranged in the inlet of fresh air to heat the fresh air to a predetermined value and another heat exchanger for recovering the exhausted heat, in which the heat exchanger for recovering the exhausted heat is an evaporator of a heat pump of which the condenser is used for indirect heating of fresh air, characterized in that the condenser (21) of the water recycling circuit is connected to a heat source (27) and, by tubular conduits (24, 25) , is re linked to the heat exchanger (6) which is located in the fresh air supply (4).  2. Projection booth according to claim 1, characterized in that the water recycling circuit is part of a heating installation (35, 36) and that, if necessary, a source can be switched on there heat (27) of a heating installation.  3. Projection booth according to claim 1 or claim 2, characterized in that the evaporator (29) is connected to the water recycling circuit of the coagulation installation (12) and in that it is provided a recycling pump (15, 32) mounted upstream or downstream of the evaporator (29).  4. A projection booth according to claim 1 or claim 2, characterized in that a coagulation tank (40) has portions of metal walls designed as an evaporator (39).  5. Projection booth according to claim 4, characterized in that the portions of walls of the coagulation tank (40) which form the evaporator (39) consist of sheets placed one against the other and in that between the sheets (42, 43) forms at least one channel (45) for the passage of the refrigerant.  6. Spray booth according to claim 5, characterized in that the sheets (42) arranged on the internal face of the coagulation tank (40) are screwed and in that the outer sheets (43) have at least one molding (44 ) which forms the channel (45).  7. Projection booth according to claim 6, characterized in that the molding (44) has the shape of a meander and extends from a coolant inlet (46) to an inlet pipe of the compressor (47 ).  8. A projection booth according to claim 4, characterized in that the wall portions of the coagulation tank (40) forming the evaporator (39) consist of a metal sheet on which are fixed, in a good conductive connection of heat, flat tubes or profiled tubes for the passage of the refrigerant.  9. Spray booth according to claim 3, characterized in that an additional water recycling circuit (28, 31, 33) is provided for the evaporator (29) arranged parallel to the paint mist separator ( 9).  10. Spray booth according to claim 3, characterized in that the water recycling circuit is that of the paint mist separator (9) and in that the evaporator (29) is arranged in series in front of it.  11. Projection booth according to claim 1, characterized in that the evaporator is arranged in the air exhaust channel (17) and in that it is influenced by the exhaust air flow.