Patent Application
20120321285
The invention relates to a heat exchanger for heating flowable media, in particular high-viscosity materials, coating materials, or the like, comprising a profile body having at least one flow channel section of a flow channel of the heat exchanger and a heating device, which is arranged in the profile body, the heating device having at least two electrical heating elements.
Heat exchangers of this type are sufficiently known and are regularly used as a continuous flow heater for heating coating materials in the field of spraying technology. The coating material is conveyed by means of a pump through the flow channel of the heat exchanger, heating of the coating material being performed through the contact thereof with heat exchanger surfaces inside the flow channel. Electrical heating elements are typically used for generating the heat energy, which are arranged in a body of the heat exchanger that forms at least a section of the flow channel. The heating element or elements must be arranged in the body in such a manner that uniform heating of the flow channel occurs. It is disadvantageous here in particular that the heat transfer from the heating elements to the coating material only occurs indirectly and the body, which is formed from metal, must first be heated.
Furthermore, embodiments of heat exchangers are known in which a heating element is arranged directly in the flow channel. Rapid and effective heating of the coating material is possible here, however, in the case of the comparatively small heat exchanger surface of the heating element, the danger exists of overheating of the coating material. The coating material can also easily bake or accumulate on a heating element surface, which can in turn result in clogging of the flow channel. In contrast, a comparatively smaller temperature gradient between a flow channel inner surface and the coating material is achievable with the arrangement of the heating elements in the body, but in this case a comparatively long flow channel must be implemented to implement a required larger heat exchanger surface. A more complicated channel guide or a more complex structure of the body results therefrom in a disadvantageous way, in particular since the heat exchanger is frequently used in combination with a mobile spraying device and must therefore be relatively compact in its dimensions.
Cleaning of the flow channel is also frequently necessary, for example, in the event of a change of the coating materials, in the event of clogging, or after ending a coating procedure, the heat exchanger and in particular the flow channel typically being cumbersome to disassemble or difficult to clean. This is predominantly the case in the heat exchangers known from the prior art, since the flow channel forms bends or curves in the body, which can only be reached using a cleaning tool with difficulty or which require time-consuming disassembly of the heat exchanger.
The present invention is therefore based on the object of proposing a heat exchanger which has a simple and compact, easy-to-clean structure and nonetheless allows improved heat transfer.
This object is achieved by a heat exchanger having the features of claim 1.
The heat exchanger according to the invention for heating flowable media, in particular high-viscosity materials, coating materials, or the like, comprises a profile body having at least one flow channel section of a flow channel of the heat exchanger and a heating device arranged in the profile body, the heating device having at least two electrical heating elements, a first heating element being arranged in a heating element receptacle implemented in the profile body, and a second heating element being arranged in a sleeve element of the heating device, the sleeve element being arranged in the flow channel section implemented in the profile body in such a manner that the heating elements are sealed in relation to the flow channel.
In particular the heating of the profile body using a heating element and the use of the sleeve element, which is also heated, in the flow channel section allow particularly effective heat transfer to the flowable medium, since the effectively heated heat exchanger surfaces are relatively large. The flowable medium thus comes into contact with a flow channel inner surface and a sleeve element surface, which are heated by the first or the second heating element, respectively. It is advantageous that the flow channel section is implemented by a profile body, which is geometrically uniform and therefore easy to clean. A profile body does not have bends or openings, in which possible accumulations could only be removed with difficulty, and is additionally simple to produce and available in arbitrary lengths. Because of the effective heating, the flow channel of the heat exchanger can be dimensioned as relatively short, without a heating element coming into direct contact with the medium. Local overheating of the medium also can hardly occur in the flow channel section because of the uniform heat distribution via the heat exchanger surfaces implemented in this manner. The negative effects connected thereto are thus avoided in particular because the heating elements cannot come into contact with the medium.
The heat exchanger can advantageously comprise a plurality of profile bodies arranged in parallel. A flow rate can thus be increased or alternatively a flow channel section can be lengthened. The heat exchanger can in particular be implemented so that a modular structure of the heat exchanger having a number of profile bodies suitable for the respective application is possible. Adaptation of the heat exchanger to special customer wishes or requirements is therefore easily possible without greater production expenditure.
The heat exchanger can also comprise a cover element and a base element, which are each arranged on profile ends of the profile body. For example, a plurality of profile bodies can be mounted between the cover element and the base element by means of the cover element and the base element. The cover element and the base element can also be sealed in relation to the profile ends so that the flowable medium cannot exit from the heat exchanger in an undesired manner.
Attachment channels of the flow channel can also be implemented in the cover element and/or in the base element. The attachment channels then do not have to be arranged in one or more profile bodies, but rather can simply be arranged on the above-mentioned elements, depending on the use requirement of the heat exchanger. A plurality of connection channels can also be provided on different sides of the cover element and/or the base element for optional use. The unused attachment channels can then be closed using a screw connection, for example.
It is particularly advantageous if at least one connection channel for connecting flow channel sections is implemented in the cover element and/or in the base element. Multiple flow channel sections can thus be connected one behind another in series. The number of connection channels can vary depending on the number of profile bodies used. Therefore, it is merely necessary to replace cover element and/or base element having the corresponding number of identical profile bodies to implement heat exchangers having different heating powers.
An advantageous mounting of the sleeve element is possible if the sleeve element is fixedly connected to the cover element. To clean the flow channel, the cover element must then merely be disassembled from the profile body, the cover element then being removed together with the sleeve element from the profile body or from the flow channel section. The sleeve element surface and also the flow channel inner surface are thus easily accessible for cleaning. The first heating element, which is arranged in the heating element receptacle of the profile body, can preferably also be connected to the cover element in a suitable manner.
The heat exchanger can be produced particularly simply if the flow channel section and the heating element receptacle are implemented as passage boreholes in the profile element in the longitudinal direction of the profile element.
In order to implement a heat exchanger surface which is greatly enlarged in relation to a conventional heating element, the sleeve element can implement a polygonal cross-section.
If the sleeve element has a plurality of longitudinal grooves distributed around the periphery on its peripheral surface, in such a manner that the sleeve element forms a star-shaped cross section, a heat exchanger surface or sleeve element surface can be enlarged still further.
Particularly large heat exchanger surfaces are possible if an external diameter of the sleeve element essentially corresponds to an internal diameter of the flow channel section. A flow channel cross-section is then solely implemented by the intermediate space, which is annular in cross-section, between flow channel inner surface and sleeve element surface.
A plurality of partial channels of the flow channel section can thus also be implemented between the sleeve element and the profile body. If the sleeve element surface at least sectionally comes into contact with the flow channel inner surface, a particularly good seat of the sleeve element in the flow channel section is additionally ensured.
In an advantageous embodiment, the heat exchanger can have heating elements in a ratio of two second heating elements to one first heating element.
A simple, joint attachment of all heating elements to a power supply or subdistributor is made possible if the heat exchanger has an attachment device for attaching the heating elements on the cover element. The attachment device can comprise a housing, which is sealed in relation to the surroundings, having devices for the subdistribution for the electrical heating elements and control or regulating devices.
At least one temperature sensor can be arranged in the flow channel to implement a temperature regulation. Multiple temperature sensors can optionally be provided to ascertain a temperature differential along the flow channel. A temperature regulation can preferably be performed based on measured values of the temperature sensor using a programmable logic controller (PLC).
The flow channel itself can be implemented as meandering, for example, by flow channel sections arranged in series one after another, which are connected via connection channels. A compact embodiment of the heat exchanger can thus be implemented particularly simply.
The heat exchanger can advantageously have an insulation device, which minimizes possible heat losses to an environment. Furthermore, the insulation device can protect operating personnel from possible burns.
The invention is explained in greater detail hereafter with reference to the appended drawings.
In the figures:
A consideration of
Furthermore, the heat exchanger 10 comprises a cover element 28 and a base element 29, which are arranged on profile ends 30 to 33 of the profile bodies 11 or 12 and are fixedly screwed thereon by means of screws 34. Furthermore, two connection channels 35 and 36 are implemented like a transverse borehole in the base element 29 and are each closed using a screw 37. The connection channel 35 connects the flow channel sections 13 and 15 and the connection channel 36 connects the flow channel sections 14 and 16, respectively. A connection channel 38 having a screw 37, which connects the flow channel sections 13 and 14, is also provided in the cover element 28. Furthermore, attachment channels 39 and 40 are implemented like a borehole in the cover element 28, which are connected to the flow channel sections 15 or 16. Attachment screw connections 41 for attaching the heat exchanger 10 to a supply line or drain line (not shown here) of a spraying device are screwed into the attachment channels 39 and 40. Overall, through the relative arrangement of the flow channel sections 13 to 16 and the connection channels 35, 36, and 38, a meandering implementation of a flow channel 42 results.
Seals 43 are arranged on the profile ends 30 to 33 to seal the cover element 28 and the base element 29 with the profile bodies 11 and 12. Furthermore, the sleeve elements 17 are provided on their upper ends 44 with a peripheral groove 45 and a thread 46. The sleeve elements 17 are thus fixedly screwed into the cover element 28 by means of the thread 46. The peripheral groove 45 is essentially used for improved distribution of the medium to be heated.
Furthermore, an attachment device 47 having an attachment housing 48 and an attachment terminal 49 is arranged on the cover element 28. The attachment terminal 49 is essentially used for the electrical connection of the first heating elements 22 and second heating elements 24 to a central power supply. The attachment housing 48 is formed from a housing ring 50 having a housing cover 51, which are connected to the cover element 28 so that a sealed attachment chamber 52 is formed.
A temperature sensor 53 is arranged in the attachment channel 39 or in the cover element 28 and a temperature sensor 54 is arranged in the profile body 12 or in the flow channel section 15. Both temperature sensors 53 and 54 are connected to a PLC (not shown here) for regulating the temperature.
For disassembly to clean the heat exchanger 10 it is solely necessary to remove the screws 34 from the cover element 28 and thus to disconnect the cover element 28 from the profile bodies 11 and 12, the sleeve elements 17 then being able to be pulled out of the flow channel sections 13 to 16. The flow channel inner surface 19 can now be mechanically cleaned easily, if necessary, the base element 29 also being able to be removed from the profile bodies 11 and 12 easily by loosening the screws 34. The sleeve element surface 20 which is then exposed can also be cleaned easily.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2009 038 762.5 | Aug 2009 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2010/062167 | 8/20/2010 | WO | 00 | 5/9/2012 |
