EP3378279A1 - Radiator arrangement for an electric heater, and electric heater - Google Patents

Abstract

Disclosed are a modular radiator for an electric heater as well as a corresponding electric heater; according to the invention, a single radiator or a plurality of adjoining radiators is used for radiating the heat generated by one or more heating elements.

Description

 Radiator assembly for an electric heater and electric heater

description

The invention relates to a radiator arrangement for a heater according to the preamble of patent claim 1.

In heaters, it is known to conductively connect an electrically operated PTC heating element with a radiator heat. Such a PTC heating element has a positive temperature coefficient and is characterized by a self-regulating effect, since it has an increased resistance with increasing heat and conducts less current, whereby the power consumption is reduced.

In order to transfer the heat or the heat from the heater to a medium to be heated, e.g. To improve air, the associated radiator is mostly designed with ribs extending away from the PTC heating element.

In the documents DE 299 06 950 U 1 and EP 1047168 B1 of the applicant discloses a heater for a control cabinet, in which a radiator is surrounded by a housing part. As a result, air flow channels are formed.

The Applicant various other heaters and radiators are known. A known radiator has e.g. Ribs which extend approximately radially away on one side of the radiator, while the ribs of the other side are aligned approximately parallel to each other.

DE 10 2006 018 150 A1 discloses a heating device with a heat exchanger body or radiator, in whose central main section PTC elements are accommodated. The radiator has webs extending from the main section, which extend on both sides and parallel to one another.

The heat extraction of such radiators depends essentially on their surface area and on the surface condition, both parameters with the production of the radiator. Accordingly, it is disadvantageous to the radiators of the prior art that their heat extraction is fixed, so that a variety of performance of heaters manufacturer always associated with different radiators.

In contrast, the invention is based on the object to provide a radiator and a heater whose heat output is variable, so that it is applicable to different power ranges.

This object is achieved by a radiator arrangement having the features of patent claim 1 and by a heater having the features of patent claim 12.

The claimed radiator assembly has at least one radiator, which may also be referred to as a heat spreader or convection body, and is configured to be placed in heat conductive communication with a PTC heater. This is an electric heater can be formed. According to the invention, the radiator has a first group of contact surfaces, to which a further substantially identical radiator can be applied and, for example, via bonding or clamping or screws or welding or soldering or crimping in heat conductive connection can be brought. Essentially identical here may mean that in a respective relaxed state, the contact surfaces of the first group of a radiator are in one plane, while contact surfaces of the other radiator have a curvature. According to the invention thus results in a modular radiator assembly consisting of identical parts with at least two-stage selectable heat extraction. An appropriately equipped heater can have a heat output of about 170 watts at -20 ° C.

Preferably, the abutment surfaces of the first group are arranged in a first abutment plane or can be brought into this abutment plane by being pressed together with the further radiator. Then more than two contact surfaces can be brought simultaneously in heat conductive connection.

In a particularly preferred production-optimized development, the radiator is an extruded profile preferably made of aluminum or an aluminum alloy. Thus, for example, at 175 mm length compared to the prior art, a weight reduction of 70 grams can be achieved. Preferably, the aluminum is anodized and / or painted. This results in a leveled temperature distribution with improved emission factor and further increased heat extraction.

Further advantageous embodiments of the invention are described in the dependent claims.

In a particularly preferred embodiment, the radiator has a second group of contact surfaces, to which also a further substantially identical radiator can be applied and, for example, via bonding or clamping or screws or welding or soldering or crimping in heat conductive connection can be brought. The result is a modular radiator arrangement consisting of one or two or three identical parts with three-stage selectable heat extraction.

If the abutment surfaces of the second group are arranged in a second abutment plane or can be brought into this second abutment plane by compression with the further radiator, more than two abutment surfaces of the second group can be brought into heat-conducting connection at the same time. It is particularly preferred if the two contact planes are symmetrical to each other.

If the abutment surfaces are spaced apart from each other so that free spaces remain between the abutment surfaces, during operation, heated medium can be exchanged between the abutment surfaces through the free spaces, if no further radiator abuts on the abutment surfaces. The contact surfaces of a group and the spaces between them together form a broad side of the radiator.

In order to ensure a good heat transfer, it is particularly preferred if the contact surfaces of the group extend over at least 50% of this broad side, while the free spaces correspondingly extend over at most 50% of the same broad side. The contact surfaces can occupy, for example, 60 to 80% of the broad side, while the free spaces occupy, for example, 20 to 40% of the same broad side. In particular, centrally between the contact surfaces of the second group, a free space can be developed as a groove, via which a further component can be attached to the radiator. The further component may be the further radiator or a fastening clip.

A cross section of the radiator may have an approximately rectangular outer frame. As already mentioned, deviating or supplemental contact surfaces of one and the same group in their entirety can have a curvature towards the outside in a relaxed state of the radiator, so that viewed in cross section these contact surfaces have an arc shape to the outside. In other words, an abutment plane can have the curvature towards the outside, so that viewed in cross-section this abutment plane has an arc shape to the outside. For a crowning is created, via which an intimate connection of the inner (middle) contact surfaces with those of the other radiator can be produced.

The curvature or the arc shape is generated according to a first variant by a pressing process, by which preferably also the PTC heating element is clamped in the radiator. According to a second variant, the curvature or the arch shape is produced during extrusion of the radiator.

According to a particularly preferred embodiment, the contact surfaces are arranged on respective planar strip-shaped contact elements. This results in an elongate radiator, which can be produced advantageously in the extrusion process. Thus, the radiator is preferably in the shape of a cuboid.

Preferably, each of the four long and mutually parallel edges of the cuboid is formed by an outer edge of an outer abutment member. In particular, the two outer contact elements of each group or each broad side can serve this purpose.

For the formation of fireplaces and for optimized heat transfer, the contact elements can be fastened via a respective web to a main section into which the PTC heating element can be used with heat conductively-preferably clamped. The Webs are preferably arranged perpendicular to the respective contact element. This results in a T- or L-shape of the contact element with the respective web.

Preferably, the strip-shaped contact elements and / or the strip-shaped contact surfaces have a width which corresponds to a multiple, for example at least four times the material thickness of the associated web. Thus, chimneys are formed between the main section, the webs and the plant elements.

The PTC heating element is preferably clamped in and surrounded by the interior of the main section, in the case of the extruded profile one of the two openings of the main section is provided for a power supply, while the other opening is completely closed with a seal.

Preferably, in a first narrow outer side of the radiator, a first groove is provided over which a further component, such as e.g. a touch guard or a mounting clip (according to DIN) for the radiator or the heater thus formed can be attached. The attachment can be done by screws, which are screwed into the groove.

Between the radiator and the further component, an anti-twist device or a thermal insulating part is preferably provided. Particularly preferred is a combined intermediate piece, which fulfills both tasks. The intermediate piece is then preferably made of thermally insulating material, preferably plastic. Thus, e.g. the fastening clip according to DIN on the one hand against rotation and on the other hand against excessive temperatures (especially temperatures above 95 ° C) are protected.

If the groove has an extended groove base over which a screw channel is formed, a screw can also be screwed in along the groove there - in the extrusion profile along its pressing direction.

An advantageous development of the radiator is symmetrical to a median plane. In this case, in a second narrow outer side of the radiator, which is mirror-symmetrical to the first narrow outer side, a second groove may be provided. About this is also one of the two components mentioned above, so a mounting clip or a contact protection on the radiator fastened. If the two grooves each have an extended groove bottom, over each of which a screw is formed, a terminal block or a connection housing for the PTC heating element can be securely attached to one end of the radiator via two screws.

The heater according to the invention has at least two above-described radiators, which are in thermal conduction with their respective group of contact surfaces in heat. Only one of the radiators is in direct heat conductive connection with a PTC heating element. The other radiator is in indirect heat conducting connection with the PTC heating element. Without a fan it is possible to reach approx. 180 - 350 Watt and with fan> 500 Watt each at -20 ° C. Preferably, the PTC heating element is clamped in the main portion of the affected radiator.

When the heater according to the invention has three radiators, a middle radiator with the abutment surfaces of each of its two groups is in heat conducting communication with a respective outer radiator. According to a first variant, only the middle radiator is in direct heat conducting connection with a PTC heating element. Again, the PTC heating element is preferably clamped in the main portion of the affected central radiator. According to a second variant, only the two outer radiators are in direct heat-conducting connection with a respective PTC heating element. Again, the two PTC heating elements are preferably clamped in the respective main section of the two outer radiators concerned. Without a fan it is possible to reach about 400 watts and with fan about 530 watts each at -20 ° C.

A particular advantage of the radiator arrangement according to the invention is that even more than three radiators can be composed of heat conductively. The number of PTC heating elements is variable.

Particularly preferred is a heater with radiators whose outer contact elements are gripped or gripped behind by means of clamps and are thus tensioned against one another. The heater can also be used as a tube heater, wherein approximately circular segment-shaped adapter are used in areas between the radiators and an inner wall of the tube. Preferably, the tube heater in the direction of its extrusion and thus can be flowed through along its contact elements and its webs.

If the heater has a fan, the output heat output can be increased significantly, as the convection flow is increased.

The heater can also be used for a control cabinet.

Several embodiments of a heater according to the invention with one or more radiators are shown in the figures. Show it:

Figure 1 in a longitudinal section a heater according to the invention according to a first embodiment;

 Figure 2 is a cross-section of the heater of Figure 1;

 Figure 3 is a perspective view of a heater according to a second embodiment;

 Figure 4 is a perspective view of a development of the heater of Figure 3;

Figure 5 in a cross section a heater according to a third embodiment as an exploded view;

 6 shows in a cross section a heater according to a fourth embodiment;

Figure 7 is a perspective view of a development of the heater of Figure 6;

 Figure 8 is a perspective view of the heater according to the second embodiment of Figure 3 with two mounting positions of a mounting clip with an intermediate piece;

 Figure 9 shows the mounting clip and the intermediate piece of Figure 8 in a perspective view;

 Figure 10 shows the fastening clips and the intermediate piece of Figure 8 in a further perspective view; and

Figure 1 1 shows a detail of the heater of Figure 8 with the mounting clip and the intermediate piece in a sectional view. Figure 1 shows a longitudinal section of a heater according to the invention according to a first embodiment. He has a radiator 1, which is designed as an aluminum extruded profile. In a central region of the radiator 1, a tubular flat main section 2 is provided, which is each closed at the end with a seal 4 made of silicone. Insulated connecting strands 6, which are provided for the electrical supply of a PTC heating element 8 clamped in the main section 2, are guided through one of the two seals 4. Furthermore, an insulating sheath 10 made of Kapton is provided for the PTC heating element 8.

Figure 2 shows the heater of Figure 1 in a cross section. The radiator 1 has in this cross section has an approximately rectangular outer frame, resulting in a first wide side 12 and a second wide side 14 and two narrow sides 16 of the radiator 1. In the relaxed state of the radiator 1 shown in FIG. 2, the two wide sides 12, 14 each have a slight curvature to the outside. These bulges are insignificant in the first embodiment of the heater according to the invention with only one radiator 1 and are used in a radiator system with two or three radiators 1 to produce an intimate heat conductive connection, which will be explained with reference to Figures 5 and 6.

The radiator 1 of the first embodiment biases the PTC heating element 8 in its main section 2, so that a heat-conducting connection between the PTC heating element 8 and the radiator 1 is given. On the main section 2, five contact elements 18 of a first group are arranged in the region of the first wide side 12, on the respective outer side of which a respective contact surface 20 of the first group is formed. In a manner which is comparable in principle, four contact elements 22 of a second group are arranged in the region of the second wide side 14, on the respective outer side of which a corresponding contact surface 24 of the second group is formed. In the middle in the second wide side 14, a fifth contact element 22a of the second group interrupted by a further groove 28a is arranged, on which a contact surface 24a of the second group interrupted by the further groove 28a is formed. All contact elements 18, 22, 22a are elongate and strip-like and extend perpendicular to the plane of the figure 2. Furthermore, all contact elements 18, 22 are connected via a respective web 26 with the main section 2. For this purpose, chimneys are formed in the interior of the radiator 1 between the webs 26 and the abutment elements 18, 22, whose cross-section is enlarged relative to the star-shaped ribs of the prior art, so that the flow through a medium to be heated is improved and heat accumulation is avoided.

The radiator 1 is designed mirror-symmetrically to a center plane 32. On the two narrow sides 16 of the radiator 1, a groove 28 is provided in each case, whose respective groove base is formed as a screw channel 30. FIG. 1 shows a fastening clip 34 which is fastened to the first narrow side 16. More specifically, the mounting clip 34 is attached via a screw 36 screwed into the groove 28, which extends perpendicular to the groove bottom. In addition, longitudinal structures are formed on flanks of the groove 28, which serve for the fixed engagement of a screw 36 screwed into the groove 28.

Figure 3 shows a perspective view of a second embodiment of a heater according to the invention. In this case, the radiator 1 with the mounting clip 34 and the screw 36 corresponds to that of the first embodiment shown in Figures 1 and 2. Only the power supply of the heater is changed. More specifically, a terminal block 38 is attached to one of the end faces of the radiator 1. Serve for this purpose are two screws 40, which are screwed into the two screw 30, which extend along the radiator 1, and which are formed (according to Figure 2) on the groove bottom of the grooves 28. About the terminal block 38, the electrical contact by means (not shown) supply line is easy to implement.

4 shows a perspective view of a development of the second embodiment of the heater according to the invention with a radiator 1 according to FIG 3. The radiator 1 is on three sides, on the two wide sides 12, 14 and on the mounting clip 34 opposite narrow side 16th covered with a shock protection 42. In the region of the two wide sides 12, 14 of the contact protection has a plurality of transverse to the radiator 1 ventilation slots 44. Furthermore, the touch contactor 42 a support portion 46 which is attached via two screws 48 on the narrow side 16 of the radiator 1. For this purpose, the two screws 48 are screwed into the local groove 28.

Figure 5 shows an exploded view or in a not yet assembled state, a heater according to a third embodiment. It contains the heater of the first exemplary embodiment according to FIG. 2 with the radiator 1 and additionally a further identical radiator 50 into which no PTC heating element is inserted. The two radiators 1, 50 are brought into abutment with their respective first wide sides 12. More precisely, the five contact surfaces 20 of the first group of the first radiator 1 with the five contact surfaces 20 of the first group of the further radiator 50 are thermally tensioned against each other. For bracing and securing brackets 52 are pushed over the outer abutment elements 18 on each side.

As has been explained with reference to Figure 2, the radiator 1, which is provided with the PTC heating element 8, a crowning, ie a curvature of the contact surfaces 20 of the first group. This crowning has been produced either during the compression of the radiator 1 with the PTC heating element 8 or during the extrusion of the radiator 1 designed as an aluminum profile.

In the embodiment shown in FIG 5, the further radiator 50 has no crowning, so that the contact elements 18 of the first group are arranged in a plane and are aligned parallel to the contact elements 22 of the second group of the other radiator 50. Due to the interaction of the curved first group of the radiator 1 with the planar first group of the other radiator 50 results in compressing the outer abutment elements 18 via the brackets 52 in each case, for. B. even with larger manufacturing tolerances, an intimate connection and the three inner contact surfaces of the first groups.

FIG. 6 shows in a cross section an already mounted fourth exemplary embodiment of the heater according to the invention. He has a radiator system consisting of three substantially identical radiators 1, 50, wherein the heat conductive connection of the central radiator 1 with the (in Figure 6 lower) further radiator 50 of those Figure 5 corresponds. The upper radiator 50 in FIG. 6 is additionally tensioned to the middle radiator 1, more precisely to the contact surfaces 24, 24a of its second group. A peculiarity results here that the interrupted by the further groove 28a abutment surface 24a of the second group of the central radiator 1 comes into contact with the central contact surface 20 of the first group of the upper further radiator 50. Again, this results from the brackets 52 an intimate and heat-conducting system, since (according to Figure 5) and the contact surfaces 24, 24a of the second group of the radiator 1 are curved.

FIG. 7 shows, in a perspective view, the fourth exemplary embodiment according to FIG. 6 of the heater according to the invention with the radiator system composed of three radiators 1, 50. It can be seen that two clamps 52 are provided on each side for each connection of two radiators 1, 50. On the middle radiator 1, the clamping block 38 and the fastening clip 34 are screwed on (compare FIG. 3). Thus, the heater according to Figure 3 by attaching two further radiators 50 is modularly extended so that its surface is increased by a multiple, and that record (not shown in Figure 7) single average PTC heating element a comparatively large power and convert it into heat can. This applies in particular if, in addition, a fan (not shown) is provided which conveys an air flow along the strip-shaped contact elements 18, 22, 22a and the corresponding webs 26.

FIG. 8 shows the heater according to the second exemplary embodiment of FIG. 3 in a perspective view, in particular its second broad side 14. Thus, the further groove 28a of the second broad side 14 and, moreover, also the groove 28 of the first narrow side 16 are visible. The two grooves 28, 28 a provide two mounting options of the mounting clip 34th

In addition, an intermediate piece 54 can be seen in each case. It is arranged between the mounting clip 34 and the radiator 1 and made of a good thermal insulating plastic, eg PPS. Thus, the intermediate piece serves as a thermal insulation of the fastening clip 34 with respect to the hot radiator. 1 In addition, the intermediate piece 54 serves as an anti-rotation device for the fastening clip 34 with respect to the Ra- diator 1. For this purpose, the intermediate piece 54 has two shoulders 56, between which the fastening clip 34 is received or secured against rotation.

Figures 9 and 10 show the mounting clip 34 and the intermediate piece 54 of Figure 8 each in a perspective view. The intermediate piece 54 has on its side facing the radiator 1 two cams 58, which together with (the thread) of the screw 36 form a row, and which dive together into the groove 28, 28 a. Thus, the two cams 58 serve as anti-rotation of the intermediate piece 54 relative to the radiator. 1

Figure 1 1 shows a section of the heater or the radiator 1 of Figure 8 in a sectional view of the mounting clip 34 and the intermediate piece 54, which are arranged on the narrow side 16. The screw 36 and the two cams 58 have approximately the same diameter, which corresponds to a width of the groove 28. The visible in Figure 1 1 flank of the groove 28 has the longitudinal structure 60th

The first and the second groove 28, which are respectively arranged on a narrow side 16 of the radiator 1, and the further groove 28 a, which is arranged on the second wide side 14 of the radiator 1, each have on their two flanks such a longitudinal structure 60 Thus, the screws 36, 48, which are screwed perpendicular to the groove base, given firm grip.

Disclosed are a modular radiator for an electric heater and a corresponding electrical heater, wherein either a radiator alone is used or a plurality of radiators are used adjacent to each other to deliver the heat of one or more heating elements. LIST OF REFERENCE NUMBERS

1 radiator

 2 main section

 4 seal

 6 strand

 8 PTC heating element

 10 insulating cover

 12 first broad side

 14 second wide side

 16 narrow side

 18 contact element

 20 contact surface

 22 contact element

 24 contact surface

 22a interrupted by another groove contact element

24a interrupted by another groove contact surface

26 footbridge

 28 groove

 28a more groove

 30 screw channel

 32 median plane

 34 fixing clip

 36 screw

 38 terminal block

 40 screw

 42 Touch protection

 44 ventilation slot

 46 supporting section

 48 screw

 50 more radiators

52 bracket Adapter shoulder cam

longitudinal structure

Claims

claims 1 . Radiator arrangement with at least one radiator (1), which is used to form a  electrical heater in heat conductive connection with a PTC heating element (8) can be brought, characterized in that the radiator (1) has a first group of contact surfaces (20) to which a further substantially identical radiator (50) attachable and in Heat conductive connection can be brought. 2. radiator assembly according to claim 1, wherein the radiator (1) is an extruded profile. 3. Radiator arrangement according to claim 1 or 2, wherein the radiator (1) has a second group of contact surfaces (24, 24a), to which a further substantially identical radiator (50) can be placed and brought into heat conductive connection. 4. Radiator arrangement according to one of the preceding claims, wherein the radiator (1) has an approximately rectangular outer frame in cross section. 5. Radiator arrangement according to one of the preceding claims, wherein in a relaxed state of the radiator (1), the contact surfaces (20, 24, 24a) of a group in its entirety have a curvature to the outside. 6. Radiator arrangement according to one of the preceding claims, wherein the contact surfaces (20, 24, 24 a) on respective flat strip-shaped contact elements (18, 22, 22 a) are arranged. 7. radiator assembly according to claim 6, wherein the abutment elements (18, 22) via a respective web (26) on a main portion (2) are fixed, in which the PTC heating element (8) is heat conductively insertable. 8. radiator arrangement according to one of the preceding claims, wherein in a narrow side (16) or in a wide side (12, 14) has a groove (28, 28 a) pre is seen, over which a contact protection (42) or a fastening clip (34) for the radiator (1) or the heater formed therewith can be fastened thereto. 9. radiator assembly according to claim 8 wherein between the radiator (1) and the contact protection (42) or the mounting clip (34) an intermediate piece (54) is provided which serves as anti-rotation and / or as a thermal insulating part. 10. radiator assembly according to claim 8 or 9, wherein the groove (28) has a groove bottom, via which a screw channel (30) is formed, into which a screw (40) along the groove (28) can be screwed. 1 1. Radiator arrangement according to one of the preceding claims, wherein the radiator (1) is symmetrical to a median plane (32). 12. A heater with a radiator assembly according to any one of the preceding claims, the radiators (1, 50) via respective contact surfaces (20) in heat conductive connection, wherein in at least one of the radiators (1) a PTC heating element (8) used is, so that this radiator (1) in direct heat conductive connection with the PTC heating element (8). 13. A heater according to claim 12, wherein a central radiator (1) via both groups of abutment surfaces (20, 24, 24 a) with a respective outer radiator (50) in heat conductive connection, and wherein in the middle radiator (1) a PTC heating element (8) is inserted, so that the middle radiator (1) is in direct heat-conducting connection with a PTC heating element (8), or wherein in each of the two outer radiators a PTC heating element (8) is inserted, so that these two radiators are in direct heat conducting connection with the respective PTC heating element (8). 14. Heater according to claim 12 or 13, wherein more than three radiators are on their contact surfaces in heat conductive connection. 15. Heater according to one of claims 12 to 14 with a radiator assembly according to claim 6, wherein the outer contact elements (18, 22) by means of clamps (52) are embraced and clamped against each other. 16. Heater according to one of claims 12 to 15, which is designed as a tube heater, wherein on the radiators (1, 50) are provided approximately kreissegmentformige adapter. 17. Heater according to one of claims 12 to 16 with a fan.