The invention relates to a conditioning apparatus for conditioning a gaseous medium to yield a conditioned gaseous process medium, having
The invention further relates to a method for conditioning a gaseous medium and to an installation and a method for treating workpieces.
Conditioning apparatuses of the above-mentioned type are used for example in the automotive industry in installations for treating vehicle bodies and in this case in particular in treatment booths in which coated vehicle bodies are treated in the context of a painting process. These include in particular paint booths, and also for example evaporation booths, cooling booths and dryers, in each case having a treatment tunnel.
The tunnel air is circulated in such treatment booths and to this end is removed from the treatment tunnel as a gaseous medium to be conditioned and, after conditioning in a conditioning apparatus, resupplied to the treatment tunnel as conditioned process medium. However, the tunnel air contains aggressive constituents, which are released during treatment of the vehicle bodies. In a conditioning apparatus, the removed tunnel air passes through different conditioning stages, in which, among other things, aggressive constituents are removed and the humidity and temperature of the tunnel air are adjusted. The latter proceeds via heat exchangers.
However, heat exchangers have sensitive regions which may be damaged by the aggressive constituents of the tunnel air before they are removed from the tunnel air. Such sensitive regions are present in particular at heat exchanger tube connection points, which are generally soldered or brazed.
Components which are attacked by the aggressive constituents of the tunnel air therefore have frequently to be replaced after only a short service period, which drives up costs.
It is an object of the invention to provide a conditioning apparatus and a method for conditioning a gaseous medium and an installation and a method for treating workpieces which take account of these issues.
This object is achieved for a conditioning apparatus of the above-mentioned type in that
The invention is based on the recognition that effective protection of such sensitive regions of a heat exchanger may thereby be achieved. In principle, the protective gas may be any gas which is economically feasible and does not have any undesired properties. For example, compressed air from external sources, or indeed inert gases such as nitrogen or carbon dioxide may be used. Good use is made of the resources available if gas from the conditioning apparatus is used; this will be addressed in greater detail below.
In the simplest variant, the protective gas could be blown directly onto sensitive regions of the heat exchanger for example via one or more nozzles. It is however more effective for the heat exchanger protection system to comprise at least one protective housing, which surrounds one or more sensitive regions of the heat exchanger and to which protective gas may be supplied via a protective gas line.
It is particularly resource-efficient for the protective gas line to be connected to the flow path or downstream of the final conditioning stage in such a way that partly conditioned gas or process medium from the conditioning apparatus and serving as protective gas may be conveyed into the protective housing.
Advantageously, the protective housing comprises at least one protective gas outlet through which protective gas may flow, after flowing through the protective housing, into the heat exchange chamber. In this way, the protective gas is, as it were, circulated in the conditioning apparatus and may in this way once again contribute to the conditioned process medium.
In order to be able to adjust the volumetric flow rate of the protective gas, it is favorable for a protective gas blower and/or an adjusting valve to be arranged in the protective gas line.
Such a heat exchanger protection system may be used particularly effectively if sensitive regions of the heat exchanger are formed by tube connection points at which tubes or tube sections of the heat exchanger are joined fluid-tightly together.
The exposure to protective gas is particularly effective if tubes or tube sections of the heat exchanger are welded together or soldered or brazed together at tube connection points. Joining may also proceed by adhesive bonding or the like. Such connection points may be effectively protected.
If a plurality of conditioning stages are present which comprise a heat exchanger, it is favorable for these heat exchangers to be integrated into the heat exchanger protection system.
The above-stated object is achieved in a method for conditioning a gaseous medium in that a conditioning apparatus having some or all of the explained features is used.
In an installation for treating workpieces, the above-stated object is achieved in that it comprises a conditioning apparatus having some or all of the explained features.
In a method for treating workpieces, the above-stated object is achieved in that the workpieces are treated in an installation having some or all of the features explained above in relation to the installation.
Exemplary embodiments of the invention are explained in greater detail below with reference to the drawings, in which:
Reference will be made first of all to
Such a gaseous medium 12 may for example contain an exhaust gas arising during a working process. In the exemplary embodiments described below, the gaseous medium 12 is by way of example at least in part exhaust air 16 which arises in a treatment means 18 with a treatment booth 20 of an installation, denoted overall 22, for treating workpieces 24.
Vehicle bodies are shown as examples of workpieces 24. The workpieces 24 may however also be other workpieces and in particular add-on or mounting parts of vehicle bodies such as bumpers, side mirrors or the like. Smaller workpieces 24 may optionally be arranged on a workpiece holder, which is not in itself shown.
The treatment booth 20 of the treatment means 18 defines a workspace in the form of a treatment tunnel 26 having a tunnel entry 26a and a tunnel exit 26b, through which the workpieces 24 to be treated are conveyed by means of a conveying system 28, as known per se and which need not be addressed in any more detail.
The treatment tunnel 26 has an air outlet 30 and an air inlet 32, between which the conditioning apparatus 10 is arranged, such that exhaust air 16 may be drawn out of the treatment tunnel 26, passed through the conditioning apparatus 10 and, once conditioning is complete, recycled to the treatment tunnel 26 as process air 34. The recycled process air 34 is guided to the workpieces 24 to be treated in a manner known per se via nozzles which are not in themselves illustrated.
This makes it possible to maintain the temperature and treatment conditions needed for effective treatment in the treatment tunnel 26. In a modification which is not in itself shown, the treatment tunnel 26 may also be subdivided into a plurality of tunnel sections, which each have a separate air outlet and air inlet which are connected to the conditioning apparatus 10. Optionally, each tunnel section present may also be associated with its own conditioning apparatus 10, such that different temperatures and treatment conditions may be established in each tunnel section, as is in each case most favorable for the treatment procedure.
The conditioning apparatus 10 comprises an inlet connection unit 36 and an outlet connection unit 38, between which a flow path is formed for gaseous medium 12 having a plurality of conditioning stages 40, and multiple flow chambers 42 arranged between the conditioning stages 40. In the exemplary embodiments according to
The conditioning apparatus 10 comprises a feed line 48 for gaseous medium 12 to be conditioned, which line leads into the inlet connection unit 36 and is connected on the inlet side with the air outlet 30 of the treatment means 18. A valve 50 is arranged in the feed line 48, such that the volumetric flow rate of the exhaust air 16 to the inlet connection unit 36 may be adjusted.
In the inlet connection unit 36, the exhaust air 16 firstly flows into an inlet chamber 52. The inlet connection unit 36 of the conditioning apparatus 10 is moreover connected with a fresh air line 54, via which fresh air 56 may be guided from a fresh air source 58 into the inlet chamber 52. A valve 56 is arranged in the fresh air line 54, such that the volumetric flow rate of the fresh air 56 to the inlet connection unit 36 may also be adjusted. The conditioning procedure for the gaseous medium 12, i.e. here the exhaust air 16 from the treatment tunnel 26, consequently also includes admixing with the gaseous medium 12 a proportion of an admix gas, in the present case thus a proportion of fresh air 56. As a consequence, a mixture of the gaseous medium 12 and fresh air 56 constantly flows through the conditioning apparatus 10; for the sake of simplicity, reference is made hereinafter however merely to the gaseous medium 12.
From the outlet connection unit 38 of the conditioning apparatus 10, a process medium line 62 with a valve 64 leads to the air inlet 32 of the treatment means 18. Furthermore, a secondary process medium line 66 with a valve 68 leads away from the outlet connection unit 38.
In the conditioning apparatus 10.1 shown in
In the conditioning apparatus 10.2 shown in
The preheating device 40.1, the cooling device 40.3 and the reheating device 40.4 serve to adjust the temperature of the gaseous medium 12 and are designed as heat exchangers 72, as illustrated by way of example in
The heat exchanger 72 comprises a heat exchange chamber 76 defined by a housing 74, which chamber accommodates a heat exchange element in the form of a heat exchange coil denoted overall 78.
The heat exchange coil 78 comprises an inflow tube 80 and an outflow tube 82, apparent only in
The heat exchanger tubes 86 take a serpentine course and to this end comprise tube sections 88 extending parallel to one another in a common plane, adjacent pairs of which are connected together in each case at alternate ends by a connecting tube in the form of a U-tube 90. In the present exemplary embodiment, each heat exchanger tube 86 comprises four parallel tube sections 88 and three U-tubes 90. The heat exchange medium 84 is supplied to the inflow tube 80 and flows from there through the heat exchanger tubes 86 into the outflow tube 82, via which the heat exchange medium 84 is then carried away and subjected to its own conditioning procedure.
The inflow tube 80, the outflow tube 82, the tube sections 88 and the U-tubes 90 are generally made of copper and connected together in a fluid-tight manner in a manner known per se at the respective tube connection points, just a few of which are denoted 92. The tubes may for example be soldered or brazed together, wherein solders or brazing metals known per se are accordingly likewise used. The tube connection points 92 may optionally also be formed by welding, for example if the tubes of the heat exchanger 72 are made from special steel.
The housing 74 has an inlet 94 and an outlet 96 for the gaseous medium 12, which are only shown in
As explained above, the tube connection points 92 in particular define regions of material in heat exchange coils 78 which are sensitive and may be damaged by the gaseous medium 12. The exhaust air 16 from the treatment tunnel 26, which flows through the conditioning apparatus 10, entrains aggressive constituents which attack the tube connection points 92 of the heat exchange coil 78 and endanger the tightness of the system.
To reduce and ideally to eliminate this harmful effect, a heat exchanger protection system 100 is provided. This comprises one or more protective housings 102, which each define a protective chamber 104 and which surround one or more such sensitive regions, i.e. in the present exemplary embodiment one or more of the tube connection points 92. Each protective housing 102 has a protective gas inlet 106. The protective gas inlet 106 is connected with an outlet connection 108a of a protective gas line 108, which is not shown in all the figures and via which a protective gas 110 may be supplied to the protective chamber 104. At the end thereof remote from the protective gas inlet 106, the protective gas line 108 has an inlet connection 108b. If multiple protective housings 102 are present, as is the case in
As an overarching concept, sensitive regions of the heat exchanger 72 may be exposed to the protective gas 110 by means of the heat exchanger protection system 100.
As a result of this measure, it is possible to prevent the sensitive regions from coming into contact with other media.
The protective housing 102 comprises a plurality of passage openings 112, through which the tube sections 88 of the heat exchange coil 78 extend, such that the connecting tubes thereof, i.e. in this case the U-tubes 90 and/or the 90° elbow 98 and above all the tube connection points 92, are arranged inside the protective housing.
These passage openings 112 are not sealed relative to the tube sections 88 or connected rigidly therewith, so making allowances for thermal expansion of the components, which might otherwise lead to material stresses. Instead, an annular gap 114 remains between the passage openings 112 and the tube sections 88, through which gap, after flowing through the protective housing 102, the protective gas 110 may flow into the heat exchange chamber 76 of the heat exchanger 72, where it mixes with the gaseous medium 12 flowing therein. The passage openings 112 of the protective housing 102 or the annular gap 114 in this way form protective gas outlets for the protective housing 102. If a sealed joint or at least largely sealed joint is possible between the protective housing 102 and the tube sections 88, the protective housing 102 has one or more separate protective gas outlets. Alternatively, a static pressure may be maintained in the protective housing 102 even without further outlets.
Overall, the protective gas 110 acts as a barrier gas, in the case of air therefore as barrier air, relative to the gaseous medium 12 in the heat exchange chamber 76. Conditioned process medium 14 or partly conditioned gas from the conditioning apparatus 10 serves as the protective gas 110 for the heat exchanger protection system 100. Partly conditioned gas is gas which is removed from the conditioning apparatus 10 before it flows into the process medium line 62, wherein this gas is conditioned such that it can no longer damage sensitive regions of the heat exchanger 72 or at least to a lesser degree than the gaseous medium 12.
In the exemplary embodiment according to
In a modification not in itself shown, the protective gas line 108 may also be connected downstream of the final conditioning stage 40, for example to the outlet connection unit 38 or to the process medium line 62. In this case, conditioned gas, i.e. here the conditioned, gaseous process medium 14, serves as protective gas 110.
As illustrated in
The protective gas line 110 leads to the preheating device 40.1, where it is connected with the protective housings 102 provided therein of the heat exchanger protection system 100; this is not visible in
However, one or more further conditioning stages 40, in which a heat exchanger 72 is present, may also be integrated into the heat exchanger protection system 100, and the protective housings 102 may in this case be connected with the protective gas line 108, to which end these are then branched into a corresponding number of side arms which then in turn optionally fork again as required into distribution arms 108c. In a modification, a separate protective gas line 108 may also lead to each conditioning stage 40 in question.
To clarify this, in the exemplary embodiment according to figure all the conditioning stages 40 present in the conditioning apparatus 10.1 which have heat exchangers 72 are integrated into the heat exchanger protection system 100. In this case, these are therefore the preheating device 40.1, the cooling device 40.3 and the reheating device 40.4. The side arms just discussed above of the protective gas line 108 are denoted 108d.
Unlike in the exemplary embodiment according to
In the exemplary embodiment according to
The exemplary embodiment according to
The statements made above in relation to the conditioning apparatus 10.1 apply mutatis mutandis to possible modifications.
In the exemplary embodiment according to
In a modification, the protective gas line 108 of the conditioning apparatus 10 of the treatment means 18.1 may also branch into a plurality of such secondary lines 136, to which the conditioning apparatus 10 of the treatment means 18.2 is connected.
In the exemplary embodiment according to
Otherwise, the statements made in relation to the other exemplary embodiments with regard to possible modifications of the line arrangements accordingly also apply mutatis mutandis to the variants according to
As is apparent from
For example, the protective gas conditioning unit 142 may be designed as a dehumidifier, if the protective gas 110 of the conditioning apparatus 10 is only removed downstream of the humidifier 40.5. An excessively humid protective gas 110 could put unnecessary strain on the tube connection points 92. However, heating or cooling units or indeed combinations with differently acting units may also be provided.
Number | Date | Country | Kind |
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10 2016 114 466.5 | Aug 2016 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2017/069735 | 8/3/2017 | WO | 00 |