Heater and methods for its manufacture and heating register

Abstract

Heater with an elongated heating element (2) comprising a sheathing tube (8) in which PTC heating elements (36) are thermally conductive and electrically insulated, wherein at least one radiator (4) is thermally conductively attached to the sheathing tube (8), wherein the sheathing tube (8) has at least one pressure tab (46) via which the at least one radiator (4) is subjected to a holding force, characterized in that a sealing element (10, 12; 210, 212) is provided on at least one of the two end sections of the sheathing tube (8), which has a sealing section (30) inserted into the end section of the sheathing tube (8) and a holding section (32; 232) by means of which the heater can be held in a fluid flow to be heated.

Description

Description

[0001] The invention relates to a heater according to the preamble of patent claim 1 and a heating register with several such heaters and a method for producing such heaters.

[0002] In air heaters used, for example, to heat the interior air of automobiles, it is common practice to transfer heat from energized electrical resistors, such as PTC heating elements, to an air stream via radiators, such as corrugated fins. The air stream is first guided through the heated radiators and then into the interior of the vehicle. The frequently used PTC heating elements have a positive temperature coefficient and are therefore self-regulating PTC thermistors. They build up increasing electrical resistance as they heat up, thereby reducing the electrical power consumed and thus the heating output.

[0003] EP 1 327 834 B1 discloses such an air heater for automobiles, in which several PTC heating elements are connected in a heat-conducting manner to heat-emitting elongated corrugated fins. A disadvantage of such air heaters is the electrical voltage between the exposed corrugated fins or the electrical potential of the corrugated fins, and the resulting limitation of the use of the air heater at higher voltages. Radiator plates are provided on the PTC side or inside of the corrugated fins, which are connected to the corrugated fins by bent longitudinal projections of the radiator plates. The documents US 2014 / 0 097 179 A1 and DE 103 60 159 A1 and EP 3 154 311 A1 and US 2009 / 0 020 619 A1 show adjacent prior art.

[0004] Furthermore, air heaters are known whose ducts and radiators do not carry any electrical voltage. For this purpose, the current-carrying components inside the duct are enclosed in an electrically insulating sheath.

[0005] EP 1 681 906 A1 discloses such an electrically insulated heater, in which a central cladding tube housing PTC heating elements and a fin-shaped radiator are formed integrally in a single component. A disadvantage of such heaters is that they cannot be modularly developed into heating registers.

[0006] The document DE 10 2013 103 433 A1 discloses an air heater and a corresponding heating register whose PTC heating elements, including external contact plates that are also under electrical voltage, are encased, thus preventing any exposed components from being exposed. More specifically, during the manufacture of the air heater, the PTC heating elements and the contact plates are encased in a Kapton sleeve. The sleeve, along with the internal components, is then inserted into an aluminum sheath and pressed into place. Corrugated fins are then mounted on the sheath from the outside.

[0007] A disadvantage of the air heaters mentioned in the latter publication is that the corrugated fins are glued, which requires an additional, complex process. Another disadvantage of these solutions is that the sealing and / or adhesive materials may contain silicone.

[0008] DE 10 2014 114 983 A1 discloses a heater having the features of the preamble of claim 1.

[0009] In contrast, the invention is based on the object of creating a heater, a heating register with such heaters and a method for producing such heaters, wherein none of the external components has an electrical potential during operation, and wherein the central cladding tube and the at least one external radiator can be easily connected to one another in a heat-conducting manner in terms of device technology and production technology.

[0010] The heater should be designed to be easily mounted in a fluid stream or in a stream of a gas to be heated. In particular, the heater should be mountable in an air duct or in a duct of the other gas, or it should be mountable on a frame of a higher-level heating register.

[0011] This object is achieved by a heater having the features of patent claim 1 and by a heating register having the features of patent claim 8 and by a method for producing a heater having the features of patent claim 14.

[0012] The claimed heater can be used in particular for heating air, but also other media such as liquids, granules or powders. It has a heating strand with an elongated cladding tube in which PTC heating elements are clamped in a heat-conducting manner. The PTC heating elements are electrically insulated from the cladding tube at least on one side, preferably on both sides or completely. Thus, none of the external components have an electrical potential. An external radiator is attached to the cladding tube in a heat-conducting manner on one or both sides. The cladding tube is preferably a rod-like, flattened aluminum extruded profile. The radiator or radiators are preferably corrugated fins. At least one pressure tab is formed integrally on the cladding tube, via which pressure tab the at least one radiator is subjected to a holding force and is thus clamped against the cladding tube in a heat-conducting manner.During the manufacture of the heater according to the invention, the pressure tab is bent toward the radiator. This provides a simple, heat-conductive connection between the central cladding tube and the at least one outer radiator, both in terms of device and manufacturing technology.

[0013] Each corrugated fin can be particularly easily fastened by applying a holding force on both sides if a corresponding number of pairs of pressure tabs parallel to one another are formed on the cladding tube, with the pressure tabs of each pair being bent towards one another.

[0014] According to the publication DE 10 2013 103 433 A1, circumferential seals are arranged on the outer end sections of the duct. These seals only exert their sealing effect in conjunction with another component on the end face of a higher-level heating register, which must engage around the seals. This additional component is an electronics housing on one side of the heating register and a so-called support part on the other side. The disadvantage of such air heaters is that additional devices and / or fastening devices are required to hold them in an air flow or air duct to be heated, or in a frame of a higher-level heating register.

[0015] A sealing element is provided on the front side of at least one of the two end sections of the cladding tube of the heater according to the invention. The sealing element can be made, for example, from silicone or fluororubber (FKM). Preferably, a sealing element is provided on each of the two end sections of the cladding tube. In an example not belonging to the invention, the at least one sealing element can be pushed completely into the respective end section. According to the invention, the at least one sealing element has a sealing section inserted into the end section of the cladding tube and a holding section formed integrally therewith. The heater can therefore be held in a fluid stream or in a stream of a gas to be heated via the holding section or preferably via the two holding sections. In particular, the heater is arranged in an air duct orCan be held in a duct of the other gas or attached to a frame of a higher-level heating register.

[0016] Preferably, the sealing section has an outer contour that corresponds to the inner contour of the cladding tube. The sealing section can then be inserted into the end section of the cladding tube with a clearance fit or a transition fit during assembly and then clamped in place by (radially) compressing the cladding tube.

[0017] In order to obtain a high-voltage heater, the electrical insulation can be realized with an insulating sleeve made of a plastic, e.g. polyimide, into which the PTC heating elements and two contact plates are inserted, or which is wrapped as a foil around the PTC heating elements and the contact plates.

[0018] In the context of this document, high voltage means at least 50 V. Such high-voltage heaters are suitable for use in the automotive high-voltage range or for industrial applications, typically up to 1,200 V.

[0019] Alternatively, the insulation can be applied on only one side. This allows one side of the PTC heating elements to be in contact with the sheathing tube, either directly or via a shim. This ensures that the sheathing tube and the radiators or corrugated fins are at an electrical potential, e.g., to the vehicle's ground. This design can be used for a heater in the low-voltage range (up to 50 volts). This simplifies the electrical connection because only one ground connection is required.

[0020] Preferably, the holding section has an approximately rectangular cross-section, which approximately corresponds to the cross-section of a recess, e.g., of the fluid channel or gas channel or of the frame. The holding section can then be inserted into the recess with a clearance fit or a transition fit, thereby holding the heater.

[0021] Further advantageous embodiments of the invention are described in the dependent patent claims.

[0022] The assembly of the sealing section is simplified if the end section of the cladding tube and the sealing section are mirror-symmetrical. This mirror symmetry is preferably formed with respect to a plane in which a longitudinal axis of the heater also lies.

[0023] In a first embodiment of the sealing element, the holding section is radially expanded relative to the sealing section.

[0024] In a second embodiment of the sealing element, the holding section has the same cross-sectional area as the sealing section. This makes the sealing element easy to manufacture as an extruded part.

[0025] In a particularly preferred embodiment, the radially expanded holding section has four outer contact surfaces arranged at right angles to one another, or is essentially cuboid-shaped. The holding section can then be inserted with a clearance fit or a transition fit into a correspondingly cuboid-shaped recess, e.g., in the fluid channel or gas channel or in the frame, thereby holding the heater. Particularly preferred are correspondingly shaped holding sections for cuboid-shaped recesses on both sides of the heater, which are arranged along the heater's longitudinal axis. This can serve as a floating mount for the heater.

[0026] To prevent jamming and jamming, the cuboid can have chamfers or small recesses on its outer edges. For example, the cuboid has such chamfers or recesses on its four outer edges.

[0027] Preferably, the holding section has a circumferential cladding tube contact surface for a circumferential end face or a circumferential edge of the cladding tube. The sealing element can then be inserted into the end section to a defined depth during assembly of the heater according to the invention. The sealing section can be inserted completely into the end section.

[0028] Preferably, the holding section has at least one radiator contact surface for an end section of the at least one radiator. The end section of the radiator can be a terminal edge of the corrugated fin. This allows the radiator attached to the outside of the cladding tube to be additionally positioned and / or secured.

[0029] The sealing element is designed to be particularly simple in terms of device technology if the cladding tube contact surface and the at least one radiator contact surface are located in a common side surface of the cuboid or form this side surface.

[0030] A first variant of the heating register according to the invention has a heater as described above with one heating strand and two radiators, as well as several heaters as described above, each with one heating strand and only one radiator. Thus, the first variant has a comparatively high density of heating strands relative to the radiators.

[0031] A second variant of the heating register according to the invention has several heaters as described above, each of which has one heating element and two radiators. Thus, the second variant has a comparatively low density of heating elements relative to the number of radiators.

[0032] Both variants create an electrically insulated, moisture-protected and stable heating register that offers a high degree of flexibility (number of heaters, length, width, empty ducts, etc.).

[0033] The heating register preferably has a frame in which the heaters are held. For this purpose, the frame has the aforementioned recesses, into each of which a holding section is inserted.

[0034] In a particularly preferred embodiment of the heating register according to the invention, each heater has two sealing elements, the two holding sections of which are inserted into opposing recesses in a first and a second frame part of the frame. Furthermore, the frame can have a third and a fourth frame part, which extend approximately parallel to the heaters or their heating strands.

[0035] Preferably, the two heater support sections are inserted into the approximately opposite recesses in such a way that the heaters have play along their respective longitudinal axes. Such a floating mounting of the heaters in the frame allows for compensation of thermally induced length changes and / or length tolerances. Furthermore, vibrations transmitted from the fluid channel, particularly the air channel, to the frame can be better tolerated.

[0036] In a further development, the frame has an electronics housing. This is adjacent to the first frame part or formed integrally with it. Then, one of the two sealing elements of each heater has two through-holes through which electrical lines extend into the electronics housing.

[0037] The frame parts can be connected to each other at their end sections via positive, frictional, or material-fit connections. Such connections can be clip connections, dovetail joints, plug-in connections, ultrasonic welding, or similar.

[0038] The frictional connections of the frame parts can each be formed by a projection and a recess. It is particularly preferred if two of the recesses are formed by a continuous groove in one of the two additional frame parts, so that the two additional frame parts can be manufactured from extruded parts. This is simple in terms of manufacturing technology and offers the possibility of producing additional frame parts of different lengths, adapted to different heater lengths.

[0039] In an advantageous further development, recesses for fastening means are formed on the outer sides of the frame, via which the heating register can be fastened in the fluid flow or fluid channel to be heated, in particular air flow or air channel, and / or via which a further device, e.g. a thermostat or a temperature sensor, can be fastened to the frame.

[0040] Preferably, the recesses are arranged on the first and / or second frame part.

[0041] The method according to the invention serves to produce a heater as described above and comprises the following steps in the order mentioned: - Applying the at least one radiator to the cladding tube - preferably between the two pressure tabs of a pair formed on the cladding tube, which extend along the cladding tube; and - Fasten the radiator by bending at least one pressure tab - preferably by pressing the two pressure tabs together.

[0042] This means that the central cladding tube and at least one radiator are connected to each other in a heat-conducting manner in terms of device technology and manufacturing technology.

[0043] In a preferred development of the method, the bending of the at least one pressure tab takes place over its length simultaneously, e.g. by means of a stamp or successively, e.g. by means of a roller.

[0044] According to the invention, the following steps are carried out beforehand in the order mentioned: - Inserting the PTC heating elements into the cladding tube, - Inserting the sealing section(s) into the end section(s) of the duct, and - Compressing the cladding tube.

[0045] The latter step serves to create a heat-conducting system between the PTC heating elements and the cladding tube and to create a sealing system between the sealing section(s) and the end section(s) of the cladding tube.

[0046] The cladding tube can be compressed by applying a pressing force approximately in the center of the cladding tube or off-center at two bending sections that extend along the two narrow sides of the cladding tube and that are approximately curved or U-shaped in the cross-section of the cladding tube.

[0047] Various embodiments of the heater according to the invention designed as an air heater and of the heating register according to the invention are shown in the drawings.

[0048] It shows Fig. 1 shows a perspective view of several air heaters according to the invention according to a first embodiment and an air heater according to the invention according to a second embodiment, Fig. 2 shows a perspective view of a heating register according to the invention according to a first variant with the air heaters from Fig. 1, Fig. 3 in a longitudinal section the heating register from Fig. 2, Fig. 4a shows a perspective view of a first embodiment of a sealing element, Fig. 4b shows a perspective exploded view of the air heater according to the invention according to the second embodiment of Fig. 1, Fig. 5 to 8 each show in cross section the air heater according to the invention according to the second embodiment from the Fig. 1 and Fig. 4 in different production steps, Fig. 9 shows a perspective view of a supply-side sealing element according to a second embodiment, Fig. 10 in a perspective view an embodiment of a heater with the sealing elements from the Fig. 9 and Fig. 11, Fig. 11 shows a perspective view of another sealing element according to the second embodiment for the heater from Fig. 10, Fig. 12 shows a perspective partial view of a heating register according to the invention, and Fig. 13 in a perspective longitudinal section the heating register from Fig. 12.

[0049] Fig. Figure 1 shows a first variant of the heating register according to the invention without a frame in an exploded view. The heating register has several air heaters 1, each with a heating strand 2 and only one corrugated fin 4 according to the first embodiment, and an air heater 101 according to the invention with one heating strand 2 and two corrugated fins 4 according to the second embodiment (in Fig. 1 below). The corrugated fin(s) 4 is / are in each case intimately connected to a cladding tube 8 of the heating element 2. Thus, the first variant of the heating register has a comparatively high density of heating elements 2 relative to the corrugated fins 4.

[0050] In each heating line 2 there are several (in Fig. 1 not shown) PTC heating elements are arranged one behind the other, from which electrical lines 6 and (in Fig. 1 (also not shown) is converted into heat. The heat is transferred via the cladding tube 8 and the corrugated fin(s) 4 to a medium to be heated, for example, an air stream.

[0051] The cladding tube 8 is designed as an extruded profile and is made of an aluminum alloy. In general, the cladding tube 8 could also be made of another metal or alloy that can be molded into the desired shape. For example, copper or brass would be possible.

[0052] In the sheath tube 8, a subassembly consisting of the PTC heating elements and the two contact plates and an electrical insulating sheath is accommodated, which can be used, for example, in Fig. 4b. The pre-assembly is pressed together with two sealing elements 10, 12 according to the invention into the cladding tube 8. More precisely, a sealing element 10 on the supply side is inserted in sections into a supply-side end section of the cladding tube 8, which sealing element has two feedthroughs for the electrical lines 6, while another sealing element 12 is inserted in sections into the other end section of the cladding tube 8. The sealing elements 10, 12 are described with reference to the Fig. 3, Fig. 4a and Fig. 4b is explained in more detail.

[0053] In principle, each of these air heaters 1; 101 represents a saleable product, for example, if only little power is required or only little space is available (example: neck heater in a headrest of a motor vehicle).

[0054] In Fig. In contrast, Figure 1 shows a cascading arrangement in which several air heaters 1; 101 are arranged one above the other. This creates an essential part of a first variant of a heating register according to the invention. It is possible to vary the output of the heating register. For example, the heating strands 2 can be longer with more PTC heating elements arranged one behind the other. Or the heating strands 2 can be wider with transversely installed PTC heating elements. Or the heating register can have more or fewer than the six air heaters 1; 101 shown. Furthermore, instead of just one air heater 101 with corrugated fins 4 on both sides according to the second exemplary embodiment, all air heaters 101 can also be designed with corrugated fins 4 on both sides. This would create the second variant of the heating register, which, compared to the first variant, has a lower density of heating strands 2 in relation to the corrugated fins 4.

[0055] In Fig. Figure 2 shows the entire first variant of the heating register in perspective. It consists of the air heaters 1; 101 made of Fig. 1 and a surrounding frame 14. This frame has two opposing frame parts 16, 18, into which the sealing elements 10, 12 are inserted in sections. Two further frame parts 20, 22, also opposite one another, are inserted into the first-mentioned frame parts 16, 18 by means of dovetail joints 24 and secured by means of snap hooks. The frame 14 can be made of various plastic materials, for example, polyamide (PA) or, for greater thermal stability, polyphenylene sulfide (PPS). In addition to its function as protection for the internal air heaters 1; 101 (in particular their corrugated fins 4) and for securing them, it also has a design function.

[0056] The first two frame parts 16 and 18 have recesses 28 on the outside that can be used to mount the heating register. This allows it to be secured to or in an air duct with screws, for example. Clipping, sliding, or similar methods are also possible.

[0057] Furthermore, recesses 26 can be seen on the first-mentioned frame parts 16, 18, through which additional elements, for example a temperature sensor or a thermostat, can be attached to the frame 14.

[0058] On the left side according to Fig. 2 shows the electrical lines 6, which extend from one of the first-mentioned frame parts 16. In the illustrated embodiment, these are insulated stranded wires, i.e., cables. Alternatively, a heating register is also possible in which the electrical lines 6 are routed into an electronics housing (not shown), into which electronics for controlling the heating register are installed. Alternatively, the electrical lines 6 can be designed as flat elements (contact tabs, flat plugs).

[0059] Fig. 3 is a sectional view of the heating register from Fig. 2. Here, too, the four frame parts 16, 18, 20, 22 are shown, in particular their dovetail joints 24 with snap hooks.

[0060] In Fig. 3 further shows that the air heaters 1; 101 are mounted in a floating manner in the frame 14, more precisely in the first-mentioned frame parts 16, 18, via their sealing elements 10, 12, so that longitudinal expansions, either due to thermal expansion during operation or due to tolerance fluctuations of the individual components, can be absorbed.

[0061] With reference to the Fig. 4a and Fig. 4b, the sealing elements 10, 12 have a sealing section 30 inserted into the end section of the cladding tube 8 and pressed there, the cross-section of which corresponds to the inner cross-section of the cladding tube 8. Furthermore, the sealing elements 10, 12 have a holding section 32 formed integrally with the sealing section 30. The holding section 32 is radially expanded compared to the sealing section 30 and is essentially cuboid-shaped.

[0062] The cross section of the holding section 32 corresponds essentially to the cross section of a respective recess 34 formed on the inner sides of the first-mentioned frame parts 16, 18 (cf. Fig. 3), and into which the holding sections 32 are inserted. The wording "essentially" can mean that on the four outer edges of each holding section 32 there are chamfers or small recesses 32a (cf. Fig. 4a) are provided, which have no equivalent in the recesses 34 of the frame parts 16, 18. In this case, four outer contact surfaces of the holding section 32 remain, arranged at right angles to each other, as in Fig. 4a and Fig. 4b shown.

[0063] The cross sections of the sealing sections 30 and the end sections of the associated cladding tubes 8 and the cross sections of the holding sections 32 and the associated recesses 34 are perpendicular to the plane of the drawing of the Fig. 3 arranged.

[0064] The holding section 32 of the Fig. 4a and Fig. 4b shown sealing element 12 and the one in Fig. 4b has a circumferential cladding tube contact surface 32b for a circumferential end face or a circumferential edge of the cladding tube 8. Thus, during assembly of the air heater 101, the sealing element 10, 12 is inserted into the end section to a defined depth at which its sealing section 30 is completely inserted into the end section.

[0065] Furthermore, the holding section 32 has two radiator contact surfaces 32c, each for an end section of a corrugated fin 4. This additionally positions and / or secures the corrugated fins 4 attached to the outer sides of the cladding tube 8. The cladding tube contact surface 32b and the two radiator contact surfaces 32c lie in a common side surface of the essentially cuboid-shaped holding section 32, which faces the cladding tube 8 and the two corrugated fins 4.

[0066] According to the invention, the sealing elements 10, 12 have a dual function: On the one hand, they seal the affected cladding tube 8 with the internal pre-assembly (PTC heating elements, contact plates, insulating sleeve), and on the other hand, they form a floating guide or bearing of the air heater 1; 101 in the frame 14 along the longitudinal axis 35. The optimized resistance to vibration is also advantageous.

[0067] Fig. 4b shows an exploded view of the second (lower) embodiment of the air heater 101 from Fig. 1. During assembly, the two contact plates 38 (e.g., made of aluminum, brass, or similar alloys), to which the electrical lines 6 are connected, e.g., by crimping, are positioned on the PTC heating elements 36. If necessary, a positioning frame (not shown) made of, e.g., plastic or pressed mica (micanite) can also be used. Alternatively, the PTC heating elements 36 and contact plates 38 can be positioned by means of an adhesive process.

[0068] A package of PTC heating elements 36 and contact plates 38 is then inserted into an insulating sleeve 40. This insulating sleeve 40 is made of a material with good electrical insulation, such as a polyimide film (e.g., the product 'Kapton' from Dupont). The insulating sleeve 40 is prefabricated and folded at the ends or, as a film, is directly wrapped one or more times around the package.

[0069] The supply-side sealing element 10 is then pushed onto the electrical lines 6. The electrical lines 6, formed by stranded wires or cables, are threaded through through-holes 42. This pre-assembly is then inserted into the duct 8.

[0070] After the pre-assembly and the supply-side sealing element 10 have been inserted into the cladding tube 8, only the further sealing element 12 has to be inserted into the cladding tube 8 opposite.

[0071] A first pressing step then follows (step 3 of assembly). After pressing, the supply-side sealing element 10 also serves as strain relief for the electrical cables 6.

[0072] Also visible are the two corrugated fins 4, which are positioned on the heating strand 8 after it has been pressed and are also pressed (steps 4 and 5 of the assembly).

[0073] The corrugated fins 4 consist of a strip of aluminum or an aluminum alloy, which is suitably folded. It is advisable to introduce beads (not shown) into the approximately vertical fin areas for stabilization and to prevent "popping" and compression to form flat "reversion areas." In addition to the use of tightly folded corrugated fins 4, the use of corrugated fins 4 with larger spacing (Z-rib, U-rib, or delta rib) is also possible.

[0074] The Fig. 5 to 8 each show cross sections through the components of the heating strand 2 in the order of its assembly.

[0075] First, in step 1, the extruded aluminum profile serving as the cladding tube 8 is cut according to Fig. 5. The various pressing geometries are clearly visible in this illustration: the "ears" serving as bending sections 44 on the narrow sides of the cladding tube 8 are later pressed in such a way that they exert an elastic preload force on the pre-assembly over the lifetime of the air heater 101. Only in this way is reliable contact and cooling of the PTC heating elements 36 possible.

[0076] Furthermore, two pressing tabs 46 for the corrugated fins 4 are formed on the top and bottom of the cladding tube 8. These will later be pressed inward onto the corrugated fins 4.

[0077] According to Fig. 5, in step 2, the pre-assembly consisting of PTC heating elements 36, contact plates 38, and insulating sleeve 40 is then inserted into the recess of the cladding tube 8. Above the inserted pre-assembly, a gap initially remains, which allows for easy insertion and is later closed.

[0078] According to Fig. 6, in the next step 3, the pre-assembly including the two sealing elements 10, 12 (cf. Fig. 4a and Fig. 4b) using a pressing force F. The application of the pressing force F to the central area, i.e., directly to the inner pre-assembly, is shown. However, it is generally also possible to apply the pressing force F to the bending sections 44. Fig. 6 shows the pressed state in which the bending sections 44 are deformed and over-tensioned to such an extent that a permanent contact force is applied to the pre-assembly.

[0079] According to Fig. 7, in the penultimate step 4, the corrugated fins 4 are then applied to the heating element 2 or its cladding tube 8, i.e., in the second embodiment of the air heater 101 according to the invention, they are inserted between the pressure tabs 46 on both sides. A gap (barely visible in the illustration) is present. It is important that the corrugated fins 4 rest as flatly as possible on the cladding tube 8 in order to achieve a good thermal coupling later.

[0080] According to Fig. 8, step 5 then involves applying the pressure tabs 46 to the corrugated fins 4 using a pressing force F1, F2. This step can be performed by applying a linear force using a pressing ram or by a rolling process.

[0081] Alternatively, it is also possible to perform the two pressing steps 3 and 5 together. This would further simplify the installation. To install a heating register of the first variant according to Fig. 1 to 3, a heating element 2 must be positioned and pressed onto each corrugated fin 4 on both sides (i.e., top and bottom). Alternatively, several air heaters 101 could be used according to the second embodiment (cf. Fig. 1 below), can be stacked to form a heating register according to a second variant.

[0082] Fig. 9 shows in a perspective view the supply-side sealing element 210 and Fig. 11 shows the further sealing element 212 according to a second embodiment. The respective sealing section 30 and the respective holding section 232 have the same cross-section throughout, so that the two sealing elements 210, 212 can be manufactured as extruded parts and easily cut to the required length.

[0083] Fig. 9 shows the two through-holes 42 of the supply-side sealing element 210, which are used to pass through the two electrical lines 6 of the heater 201 from Fig. 10 serve.

[0084] Fig. 10 shows a perspective view of another embodiment of a heater 201 with the sealing elements 210, 212 from the Fig. 9 and Fig. 11. These are partially inserted into the respective end section of the cladding tube 8. The inserted part is the (in Fig. 10) and the protruding part is the respective holding section 232, with which the heater 201 can be held in the frame 14 in the manner described above.

[0085] In an example not belonging to the invention, the sealing elements 210, 212 can also be completely inserted into the respective end section of the cladding tube 8.

[0086] Fig. 12 shows a perspective partial view of a heating register according to the invention, more precisely a corner of the frame 214 with a frictional connection of the frame parts 216, 220.

[0087] Fig. 13 shows in a perspective longitudinal section the heating register from Fig. 12, in which the frictional connection 224 of the frame parts 216, 220 can be seen. It has a projection 224a on the frame part 216, which can be formed by a pin or a tongue, and a recess 224b on the frame part 220. The same applies to the three other corners of the frame 214. The frictional connection 224 is created by a slight oversize of the projection 224a.

[0088] All disclosed details can be combined with each other, even if this goes beyond the embodiments shown.

[0089] Disclosed are an electrically insulated heater and a method for its assembly, comprising a heating element and radiators arranged on one or both sides, which can be configured as corrugated fins. Clamping tabs for clamping the radiator(s) are formed on the cladding tube. The heating element is sealed at least on one side, preferably on both sides, with sealing elements having retaining sections. The fluid heater can be held in a frame of a higher-level heating register or in a fluid channel via the retaining section(s). List of reference symbols 1; 101; 201 heater / air heater 2 heating circuits 4 Radiator / corrugated fin 6 electrical cable 8 Sheath tube 10; 210 supply-side sealing element 12; 212 additional sealing element 14; 214 frames 16; 216 frame part 18 frame part 20; 220 additional frame part 22 additional frame part 24 positive connection / dovetail connection 26 Recess 28 recess 30 sealing section 32; 232 stopping section 32a small recess 32b Cladding tube contact surface 32c Radiator contact surface 34; 234 recess 35 Longitudinal axis 36 PTC heating element 38 contact plate 40 insulating cover 42 Through recess 44 bending sections 46 pressure tab 224 frictional connection 224a projection 224b recess F, F1, F2 pressing force

Claims

[1] Heater with an elongated heating strand (2) which has a sheathing tube (8) in which PTC heating elements (36) are accommodated in a heat-conducting and electrically insulated manner, wherein at least one radiator (4) is attached to the sheathing tube (8) in a heat-conducting manner, wherein the sheathing tube (8) has at least one pressure tab (46) via which the at least one radiator (4) is subjected to a holding force, characterized by that a sealing element (10, 12; 210, 212) is provided on at least one of the two end sections of the cladding tube (8), which sealing element has a sealing section (30) inserted into the end section of the cladding tube (8) and a holding section (32; 232) via which the heater can be held in a fluid flow to be heated. [2] Heater according to claim 1, wherein one or two pairs of mutually parallel pressure tabs (46) are formed on the cladding tube (8). [3] Heater according to claim 1, wherein the cladding tube (8) and the sealing element (10, 12; 210, 212) are mirror-symmetrical. [4] Heater according to claim 1 or 3, wherein the holding section (32) has four outer contact surfaces arranged at right angles to one another or substantially in the shape of a cuboid. [5] Heater according to one of claims 1 to 4, wherein the holding section (32) has a cladding tube contact surface (32b) against which an edge or an end face of the cladding tube (8) rests. [6] Heater according to one of claims 1 to 5, wherein the holding portion (32) has at least one radiator contact surface (32c) against which an end portion of the at least one radiator (4) rests. [7] Heater according to one of claims 4 to 6, wherein the cladding tube contact surface (32b) and the at least one radiator contact surface (32c) lie in a side surface of the cuboid. [8] Heating register with a heater (101; 201) according to one of the preceding claims, which has a heating strand (2) and two radiators (4), and with a plurality of further heaters (1) according to one of the preceding claims, each having a heating strand (2) and a radiator (4), wherein the heaters (1; 101; 201) are held in a frame (14; 214) which has recesses (34; 234) into which a holding section (32; 232) is inserted in each case. [9] Heating register with a plurality of heaters (101; 201) according to one of claims 1 to 7, each having a heating strand (2) and two radiators (4), wherein the heaters (1; 101; 201) are held in a frame (14; 214) which has recesses (34; 234) into which a holding section (32; 232) is inserted. [10] Heating register according to claim 8 or 9, wherein each heater (1; 101; 201) has two sealing elements (10, 12; 210, 212), the two holding sections (32; 232) of which are inserted into approximately opposite recesses (34; 234) of a first and a second frame part (16, 18; 216) of the frame (14). [11] Heating register according to claim 10, wherein the two holding sections (32; 232) of each heater (1; 101; 201) are inserted into approximately opposite recesses (34; 234) such that the heaters (1; 101; 201) have play along their respective longitudinal axis (35). [12] Heating register according to one of claims 10 or 11, wherein the frame parts (16, 18, 20, 22; 216, 220) are connected to one another at their end sections via positive, frictional or material-locking connections (24; 224). [13] Heating register according to one of claims 8 to 12, wherein recesses (26, 28) for fastening means are formed on outer sides of the frame (14; 214), by means of which the heating register can be fastened in the fluid flow to be heated or in the fluid channel, and / or by means of which a further device can be fastened to the frame (14; 214). [14] A method for manufacturing a heater (1; 101; 201) according to any one of claims 1 to 7, comprising the steps of: - Attaching the at least one radiator (4) to the cladding tube (8); and - Fastening the radiator (4) by bending at least one pressure tab (46), whereby the following steps are carried out beforehand in the order mentioned: - Inserting the PTC heating elements (36) into the cladding tube (8), - inserting the sealing section(s) (30) into the end section(s) of the cladding tube (8), and - Compress the cladding tube (8). [15] Method for producing a heater (1; 101) according to claim 14, wherein the bending of the at least one pressure tab (46) takes place simultaneously or successively over its length.

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