ES2913651T3 - Radiator arrangement for an electric heater and electric heater - Google Patents

Abstract

Radiator arrangement having at least one radiator (1) that can be brought into heat conducting connection with a PTC heating element (8) to form an electric heater, the at least one radiator (1) having a first set of contact surfaces (20) to which another substantially identical radiator (50) can be attached and put into a heat-conducting connection, characterized in that the contact surfaces of the first group of contact surfaces (20) of the at least one radiator (1) have in their totality a curvature towards the outside, said curvature corresponding to a relaxed state of the at least one radiator (1).

Description

DESCRIPTION

Radiator arrangement for an electric heater and electric heater

The invention relates to a radiator arrangement for a heater according to the preamble of claim 1. In heaters, it is known to connect an electrically driven PTC heating element to a radiator in a heat-conducting manner. Such a PTC heating element has a positive temperature coefficient and is characterized by a self-regulating effect, as it has increasing resistance with increasing heat and conducts less current, thus reducing power consumption.

To improve heat transfer or heat extraction from the heater to a medium to be heated, eg air, the associated radiator is often designed with fins extending outside the PTC heating element.

In the Applicant's publications DE 299 06950 U1 and EP 1047168 B1, a heater for an electrical cabinet is disclosed in which a radiator is surrounded by a housing part. This forms airflow channels. The applicant knows of other heaters and radiators. For example, a known radiator has approximately radially extending fins on one side of the radiator, while the fins on the other side are oriented approximately parallel.

Document DE 102006 018 150 A1 or EP 1847 786 A1 discloses a heating device with a heat exchange body or radiator, in whose central main section PTC elements are housed. The radiator has bands extending from the main section, running on both sides and parallel to each other.

The heat extraction of these radiators essentially depends on the size and texture of their surface, so both parameters are determined by the production of the radiator. Consequently, the disadvantage of prior art radiators is that their heat extraction is invariable, so that a variety of heaters from one manufacturer is always associated with different radiators.

On the other hand, the invention is based on the task of creating a radiator and a heater whose heat extraction can be modified so that it can be used for different power ranges. It should be possible to create an intimate connection between the inner (central) contact surfaces and those of the other radiator.

This task is solved with a radiator arrangement with the features of patent claim 1 and with a heater with the features of patent claim 11.

The claimed radiator arrangement has at least one radiator, which can also be called a heat distribution element or a convection body, and is adapted to be brought into heat-conducting connection with a PTC heating element. Thus, an electric heater can be formed. According to the invention, the radiator has a first set of contact surfaces against which another substantially identical radiator can be placed and brought into heat-conducting connection, for example, by bonding or clamping or screwing or welding or flanging. . According to the invention, this results in a modular radiator arrangement consisting of identical parts with at least two selectable heat extraction stages. A correspondingly equipped heater can have a heat output of approx. 170 watts at -20°C.

According to the invention, the contact surfaces of a same group have an outward curvature in their entirety in a stress-free state of the radiator, so that, seen in cross section, these contact surfaces have an outwardly arcuate shape. In other words, a contact plane may have outward curvature such that, viewed in cross section, this contact plane has an outwardly arcuate shape. This creates a curvature through which an intimate connection of the inner (central) contact surfaces with those of the other radiator can be created.

Preferably, the contact surfaces of the first group are arranged in a first contact plane or can be brought into this contact plane by pressing them together with the other radiator. In this way, more than two contact surfaces can be brought into contact at the same time.

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

Other advantageous embodiments of the invention are described in the dependent patent claims.

In a particularly preferred further development, the radiator has a second group of contact surfaces on which another substantially identical radiator can also be placed and which can be brought into heat-conducting connection, for example, by gluing or clamping or screwing or welding or flanging. The result is a modular radiator made up of one, two or three identical pieces with three-stage selectable heat extraction.

If the contact surfaces of the second group are arranged in a second contact plane or can be brought into this second contact plane by pressing them together with the other radiator, more than two contact surfaces of the second group can also be brought into a conductive connection of heat at the same time. It is especially preferable that the two contact planes are symmetrical with respect to each other.

If the contact surfaces are spaced so that there are free spaces between the contact surfaces, the heated medium can be exchanged between the contact surfaces through the free spaces during operation if there are no other radiators adjacent to the contact surfaces . The contact surfaces of a group and the free spaces between them together form a wide side of the radiator.

To ensure good heat transfer, it is especially preferred that the contact surfaces of the group extend over at least 50% of this wide side, while the free spaces correspondingly extend over a maximum of 50% of the same wide side. The contact surfaces can occupy, for example, 60 to 80% of the wide side, while the free spaces occupy, for example, 20 to 40% of the same wide side.

Especially between the contact surfaces of the second group, a gap-shaped free space can be formed through which another component can be attached to the radiator. The additional component can be the additional radiator or a fixing clip

A cross section of the radiator may have an approximately rectangular outer frame.

According to a first variant, the curvature or the curved shape according to the invention is produced by a pressing process, which preferably also holds the PTC heating element in the radiator. According to a second variant, the curvature or the curved shape is created during the extrusion of the radiator.

According to a particularly preferred design, the contact surfaces are arranged on respective contact elements in the form of a flat strip. The result is an elongated radiator that can be advantageously manufactured in the extrusion process. Thus, the radiator preferably has the shape of a cube.

Preferably, each of the four long parallel edges of the hub is formed by an outer edge of an outer contact element. In particular, the two outer contact elements of each group or each wide side can serve this purpose.

For the formation of chimneys and the optimization of the heat transfer, the contact elements can be attached to a main section through a respective band, in which the PTC heating element -preferably fastened- can be inserted in a conductive way from the heat. The bands are preferably arranged perpendicular to the respective contact element. The result is a T or L shape of the contact element with the respective band.

Preferably, the strip-shaped contact elements and/or the strip-shaped contact surfaces have a width corresponding to a multiple, eg, at least four times, the thickness of the associated strip material. Thus, chimneys are formed between the main section, the bands and the contact elements.

The PTC heating element is preferably held inside and is surrounded by the main section. In the case of the extruded profile, one of the two openings in the main section is provided for an electrical supply, while the other opening is completely closed with a gasket.

Preferably, on a first narrow outer side of the radiator there is a first slot, through which another component, such as a contact protector or a fixing clip (according to DIN) for the radiator or the heater formed with it, can be attached. Fixing can be done by means of screws that are screwed into the slot.

An anti-rotation device or a thermal insulation part is preferably placed between the radiator and the other component. A combined intermediate piece that accomplishes both tasks is preferred. The intermediate piece is then preferably made of thermal insulating material, preferably plastic. In this way, for example, the fastening clip according to the DIN standard can be protected from torsion on the one hand and from excessive temperatures (in particular temperatures above 95 °C) on the other.

If the slot has a widened slot base on which a channel for the screw is formed, a screw can also be screwed in there along the slot, in the case of the extruded profile along its extrusion direction. A further advantageous development of the radiator is the symmetry with respect to a central plane. A second slot may be provided on a second narrow outer side of the radiator, which is mirror-symmetrical to the first narrow outer side. Through this slot, one of the two components mentioned above, i.e. a mounting clip or a contact protector, can also be attached to the radiator. If the two slots each have a widened slot base on which a screw channel is formed in each case, a terminal block or connection housing for the PTC heating element can be securely attached to one end face of the radiator. by two screws.

The heater according to the invention has at least two radiators as described above, which are in heat-conducting connection with their respective group of contact surfaces. Only one of the radiators is in direct connection with a PTC heating element. The other radiator is in indirect heat conduction connection with the PTC heating element. Without fan, approx. 180 - 350 watts can be achieved and with fan > 500 watts at -20°C in each case. Preferably, the PTC heating element is attached to the main section of the radiator in question.

If the heater according to the invention has three radiators, a central radiator with the contact surfaces of each of its two groups is in heat-conducting connection with a respective outer radiator. According to a first variant, only the central radiator is in direct heat conducting connection with a PTC heating element. Also in this case, the PTC heating element is preferably attached to the main section of the central radiator in question. According to a second variant, only the two outer radiators are in direct heat conducting connection with a respective PTC heating element. Also in this case, the two PTC heating elements are preferably fixed in the respective main section of the two external radiators in question. Without fan, approx. 400 watts can be achieved and with fan approx. 530 watts at -20°C in each case.

A particular advantage of the radiator arrangement according to the invention is that more than three radiators can be assembled in a heat-conducting manner. The number of PTC heating elements is variable.

A heater with radiators whose outer contact elements are gripped around or behind by means of clips and thus held together is particularly preferred.

The heater can also be used as a pipe heater, for which roughly circular segment-shaped adapters are used in the areas between the radiators and an inner wall of the pipe. Preferably, the tube heater can be traversed in the direction of its extrusion and thus along its contact elements and bands.

If the heater has a fan, the heating output can increase considerably because the convection flow is increased.

The heater can also be used for a control cabinet.

Various embodiments of a heater according to the invention with one or more radiators are shown in the figures. In them:

Figure 1 shows in a longitudinal section a heater according to a first example of embodiment;

Figure 2 shows in cross section the heater of Figure 1;

Figure 3 shows in a perspective view a heater according to a second embodiment;

Figure 4 shows in a perspective view a further development of the heater of Figure 3;

FIG. 5 shows a heater according to a third exemplary embodiment in cross section as an exploded drawing;

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

Figure 7 shows in a perspective view a further development of the heater of Figure 6;

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

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

Figure 10 shows the fixing clip and intermediate piece of Figure 8 in another perspective view; Y

figure 11 shows a section of the heater of figure 8 with the fixing clip and the intermediate piece in a cutaway view.

Figure 1 shows a longitudinal section of a heater according to the invention in a first embodiment. It has a radiator 1 which is designed as an extruded aluminum profile. In a central area of radiator 1 there is a flat and tubular main section 2, which is closed at its end by a silicone gasket 4. The insulated connection wires 6 are led through one of the two joints 4, which are provided for the electrical supply of a PTC heating element 8 fixed in the main section 2. In addition, an insulating cover 10 made of kapton is provided for the PTC heating element 8.

Figure 2 shows the radiator of Figure 1 in cross section. In this cross section, the radiator 1 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. The two wide sides 12, 14 each have a slight protrusion towards outside in the relaxed state of the radiator 1 shown in Figure 2. These protrusions are insignificant in the first embodiment of the heater according to the invention with a single radiator 1 and serve to create an intimate heat-conducting connection in a radiator system with two or with three radiators 1, which is explained with reference to Figures 5 and 6.

The radiator 1 of the first embodiment holds the PTC heating element 8 in its main section 2, so that a heat-conducting connection is provided between the PTC heating element 8 and the radiator 1. Five contact elements 18 of a first group are arranged in the main section 2 in the region of the first wide side 12, on which respective outer side a contact surface 20 of the first group is formed. 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 the corresponding contact surface 24 of the second group is formed. A fifth contact element 22a of the second group, interrupted by another groove 28a, is arranged centrally on the second wide side 14, on which a contact surface 24a of the second group, interrupted by the groove 28a, is formed.

All contact elements 18, 22, 22a are elongated and strip-shaped and extend perpendicular to the drawing plane of Figure 2. Furthermore, all contact elements 18, 22 are connected to main section 2 through a respective band 26. In this way, chimneys are formed inside the radiator 1 between the bands 26 and the contact elements 18, 22, the cross section of which is enlarged compared to the star-shaped ribs of the prior art, so that the flow of a medium to be heated is improved and the accumulation of heat is avoided.

The radiator 1 is symmetrical about a central plane 32. On each of the two narrow sides 16 of the radiator 1 there is a slot 28, the base of which is formed by a screw channel 30. Figure 1 shows a retaining clip 34 which is fixed to the first narrow side 16. More specifically, the retaining clip 34 is fixed by means of a screw 36 screwed into the slot 28, which extends perpendicular to the base of the slot. Furthermore, longitudinal structures are formed on the flanks of the slot 28 which serve to firmly engage a screw 36 screwed into the slot 28. Figure 3 shows a perspective view of a second example of a heater according to the invention. In this case, the radiator 1 with the fixing clip 34 and the screw 36 corresponds to that of the first example of embodiment according to Figures 1 and 2. Only the electrical supply of the heater is modified. More specifically, a terminal block 38 is fixed to one of the end faces of the radiator 1. Two screws 40 are used for this, which are screwed into the two screw channels 30 that extend along the radiator 1 and which ( according to Figure 2) are formed at the bottom of the slots 28. Electrical contact can be easily established via the terminal block 38 by means of a power cable (not shown).

Figure 4 shows a perspective view of a further development of the second embodiment of the heater according to the invention with a radiator 1 as shown in Figure 3. The radiator 1 is covered on three sides, namely on the two wide sides 12, 14 and on the narrow side 16 opposite the fixing clip 34, with a contact guard 42. In the area of the two wide sides 12, 14, the contact guard has a plurality of ventilation slots 44 extending crosswise to the radiator 1. In addition, the contact guard 42 has a support section 46, which is attached to the narrow side 16 of the radiator 1 by means of two screws 48. For this, the two screws 48 are screwed into the slot 28 there.

Figure 5 shows an exploded view of a heater in a state not yet assembled according to a third embodiment. It contains the heater of the first embodiment according to Figure 2 with radiator 1 and, in addition, another identical radiator 50, in which no PTC heating element is inserted. The two radiators 1, 50 contact each other with their respective first wide sides 12. More specifically, the five contact surfaces 20 of the first group of the first radiator 1 are held together in a heat-conducting manner with the five contact surfaces 20 of the first group of the first radiator 1. contact 20 of the first group of the additional radiator 50. The clamps 52 slide over the outer contact elements 18 on each side to reinforce and secure.

As explained with reference to Figure 2, the radiator 1 provided with the PTC heating element 8 has a bulge, that is, a curvature of the contact surfaces 20 of the first group. This bending has occurred during the pressing of the radiator 1 with the PTC heating element 8 or during the extrusion of the radiator 1, which is designed as an aluminum profile.

In the exemplary embodiment shown in Figure 5, the other radiator 50 has no curvature, so that the contact elements 18 of the first group are arranged in one plane and are aligned parallel to the contact elements 22 of the second group of the radiator. another radiator 50. Due to the interaction of the first curved group of the radiator 1 with the first flat group of the additional radiator 50, when the outer contact elements 18 are pressed against each other through the clamps 52, an intimate connection also occurs between the three inner contact surfaces of the first groups in any case, eg even with larger manufacturing tolerances.

Figure 6 shows a cross section of a fourth assembled example of the heater according to the invention. It has a radiator system consisting of three essentially identical radiators 1, 50, in which the heat-conducting connection of the central radiator 1 with the (in Figure 6 below) additional radiator 50 corresponds to that of Figure 5. The radiator upper 50 of Figure 6 is additionally fastened to the central radiator 1, or more precisely to the contact surfaces 24, 24a of its second group. A special feature is that the contact surface 24a of the second group of the central radiator 1, which is interrupted by the additional groove 28a, comes into contact with the central contact surface 20 of the first group of the additional upper radiator 50. Here too it is achieved an intimate and heat-conducting contact through the clamps 52, since (according to Figure 5) the contact surfaces 24, 24a of the second group of the radiator 1 are also curved.

Figure 7 shows a perspective view of the fourth embodiment according to Figure 6 of the heater according to the invention with the radiator system consisting of three radiators 1, 50. It can be seen that two brackets 52 are provided on each side to each connection of two radiators 1, 50. The clamping block 38 and the fixing clip 34 are screwed to the central radiator 1 (see Figure 3). In this way, the heater shown in Figure 3 is modularly expanded by placing two other radiators 50, so that its surface is multiplied and the single central PTC heating element (not shown in Figure 7) can absorb a quantity of comparatively large energy and convert it into heat. This applies in particular if a fan (not shown) is additionally provided, which conveys a flow of air along the strip-shaped contact elements 18, 22, 22a and the corresponding strips 26.

Figure 8 shows the heater according to the second embodiment of Figure 3 in a perspective view, in particular on its second wide side 14. Thus, the additional groove 28a of the second wide side 14 and furthermore also the groove 28 are visible. of the first narrow side 16. The two slots 28, 28a provide two fixing options for the fixing clip 34.

Furthermore, in each case an intermediate piece 54 can be seen. It is arranged between the fixing clip 34 and the radiator 1 and is made of a good heat-insulating plastic, eg PPS. The intermediate part thus serves as thermal insulation of the fixing clip 34 against the hot radiator 1. In addition, the intermediate part 54 serves as a protection against the rotation of the fixing clip 34 against the radiator 1. For this, the intermediate part 54 has two shoulders 56 between which the fixing clip 34 is held or held against rotation.

Figures 9 and 10 show the attachment clip 34 and intermediate piece 54 of Figure 8, each in perspective view. The intermediate piece 54 has two cams 58 on its side facing the radiator 1, which together with (the thread of) the screw 36 form a row, and which together enter the slot 28, 28a. The two cams 58 thus serve to prevent the intermediate piece 54 from rotating with respect to the radiator 1.

Figure 11 shows a section of the heater or radiator 1 of Figure 8 in a sectional view of the fixing 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 flank of the groove 28 visible in Figure 11 has the longitudinal structure 60.

The first and second slots 28, each arranged on a narrow side 16 of the radiator 1, and the other slot 28a, arranged on the second wide side 14 of the radiator 1, each have such a longitudinal structure 60 in its two flanks. In this way, a firm hold is provided for the screws 36, 48, which are screwed perpendicular to the base of the slot.

A modular radiator for an electric heater and a corresponding electric heater is disclosed, in which a single radiator or multiple radiators adjacent to each other are used to dissipate heat from one or more heating elements.

Reference symbol list

1 radiator

2 main section

4 seal

6 threads

8 PTC heating element

insulating cover

first wide side

second wide side

narrow side

contact element

contact surface

contact element

contact surface

a contact element interrupted by another groove a contact surface interrupted by another groove band

slot

to another slot

screw channel

center plane

fixing clip

screw

clamping block

screw

touch protection

ventilation slot

support section

screw

additional radiator

clamp

intermediate piece

shoulder

cam

longitudinal structure

Claims (16)

1. Radiator arrangement having at least one radiator (1) which can be brought into heat conducting connection with a PTC heating element (8) to form an electric heater, the at least one radiator (1) having a first set of surfaces of contact (20) to which another substantially identical radiator (50) can be attached and put into heat-conducting connection, characterized in that the contact surfaces of the first group of contact surfaces (20) of the at least one radiator (1) have in its entirety an outward curvature, said curvature corresponding to a relaxed state of the at least one radiator (1). 2. Radiator arrangement according to claim 1, wherein the at least one radiator (1) is an extruded profile. Radiator arrangement according to claim 1 or 2, wherein the at least one radiator (1) has a second group of contact surfaces (24, 24a) to which another substantially identical radiator (50) can be coupled and put it in heat conductive connection. 4. Radiator arrangement according to any of the preceding claims, wherein the at least one radiator (1) has an outer frame of approximately rectangular cross-section. Radiator arrangement according to any of the preceding claims, wherein the contact surfaces (20, 24, 24a) are arranged on the respective strip-shaped flat support elements (18, 22, 22a). Radiator arrangement according to claim 5, wherein the contact elements (18, 22) are fixed via a respective band (26) to a main section (2) in which the heating element can be inserted PTC (8) in a heat conducting manner. Radiator arrangement according to any of the preceding claims, wherein a slot (28, 28a) is provided on a narrow side (16) or on a wide side (12, 14), by means of which a contact protection (42) or a fixing clip (34) for the at least one radiator (1) or the heater formed with it. 8. Radiator arrangement according to claim 7, wherein between the at least one radiator (1) and the contact protection (42) or the fixing clip (34) an intermediate piece (54) is provided that serves as a anti-rotation and/or thermal insulation piece. Radiator arrangement according to claim 7 or 8, wherein the slot (28) has a slot base on which a screw channel (30) is formed into which a screw (40) can be screwed through. along the slot (28). 10. Radiator arrangement according to any of the preceding claims, wherein the at least one radiator (1) is symmetrical with respect to a central plane (32). 11. Heater comprising a radiator arrangement according to any of the preceding claims, having a plurality of radiators (1, 50) that are in heat-conducting connection through respective contact surfaces (20), wherein a PTC heating element (8) is inserted in at least one of the radiators (1) in such a way that this radiator (1) is in direct heat-conducting connection with the PTC heating element (8). 12. Heater according to claim 11, wherein a central radiator (1), which has two groups of contact surfaces (20, 24, 24a), is in heat-conducting connection with a respective outer radiator (50) a through both groups of contact surfaces (20, 24, 24a), and wherein a PTC heating element (8) is inserted in the central radiator (1), so that the central radiator (1) is in direct connection with heat conduction with a PTC heating element (8), or wherein a PTC heating element (8) is inserted in each of the two outer radiators such that these two radiators are in direct heat conduction connection with the respective element PTC heater (8). Heater according to claim 11 or 12, wherein more than three radiators are in heat-conducting connection through their contact surfaces. 14. Heater according to any of claims 11 to 13, with a radiator arrangement according to claim 5, wherein the outer contact elements (18, 22) are clamped and held together by means of clamps (52 ). Heater according to any one of claims 11 to 14, which is designed as a tubular heater, approximately circular segment-shaped adapters being provided on the radiators (1, 50). 16. Heater according to any of claims 11 to 15 with a fan. Ċ