EP1418794B1 - Heating unit for gases - Google Patents

Abstract

The electrical heating wire (5) is preformed in waves and contact areas to suit two parallel insulated plates (3) over which it is wound in one or more coils so that the area of contact with the support plate edges is minimized by the forming of the wire at greater than 40 degrees.

Description

The invention relates to an electric radiator for gaseous media with at least one support plate and at least a helix of a corrugated electrical resistance heating wire, which wound continuously around the support plate is and whose turns by means of bends of the Heating wire held on the longitudinal edges of the support plate are.

From DE 18 05 639 a radiator is known in which a heating wire around one or two parallel elongated support plates is wound in the form of insulating panels, wherein the heating wire by means of a press on both sides so pressed against the edges of the insulating panels, that bends arise, the plate edges clip-like include. However, a disadvantage of this embodiment is that the heating wire in the area of this bracket-like Bends due to its investment in the insulating panels gets too hot and starts to glow, reducing the life is severely impaired. On the other hand, the Heating wire based on a longitudinal extension of the insulating panels no sufficient length; for a high heat output to provide.

Consequently, it has been proposed in DE 26 44 093, a Heating wire helically around a single support plate wrap, with the heating wire over its entire length evenly waved to make this a larger one To obtain heating wire length. To the necessary stability to ensure the heating wire, also occurs in this Design of the heating wire in the area of the plate edges in clamp-like contact with the support plate, the contact length compared to the disclosure of DE 18 05 639 yet is enlarged, which also has the above disadvantages conditionally.

For this reason, in previously known generic Radiators where higher performance was required, for example in DE 25 35 478 and DE 195 05 930, suggested the tips of a substantially zigzag shaped heating wire through openings in two to each other Insert parallel support plates through. This However, also has the disadvantage that it is at the reversal points or tips of the wire due to the lower Air flow in these places to overheating and a glow of the wire can come. It is also at to regard such prior art radiators as disadvantageous, that the heating wire covers the entire space between the Loading plates takes and therefore it is not possible is a temperature element in the middle between the support plates to arrange. Moreover, it is in such an embodiment difficult due to the circumstances mentioned one-sided electrical connections for the radiator to provide a return conductor in the region of the plates. adversely is still the elaborate and therefore relatively expensive Manufacture of this type of radiators.

The invention is based on the object, a generic to create electric radiator that is for generating and to deliver the required heating power sufficient Has heating wire length, wherein the heating wire should heat relatively evenly over its entire length, in this way, overheating places too avoid, so that the radiator of the invention a long life possesses. The design should be special be suitable for transversely flowed radiator.

The task is with an electric radiator for gaseous Solved media of the type mentioned, that the heating wire is arranged such that it only Longitudinal sides and / or edges of the longitudinal narrow sides of Carrier plate touched and in the area of a convex bend is guided over the longitudinal narrow sides of the support plate, wherein the bending angle between both sides of the bend subsequent areas of the heating wire is greater than 40 °. Of course, this statement refers to those Longitudinal edges adjacent bends and their adjacent Areas in supported by a support plate state of the Heating wire. Preferably, the bending angle is essential greater than 40 °, for example greater than 60 °. In further preferred embodiment, the bending angle α is below 120 °, so that he in an extremely preferred embodiment at about 90 ° - 100 °. In this way, a flat Concern of the heating wire to the support plates in the area of Prevented edges, so it's not at this point too Overheating and therefore to damage of the heating wire comes.

In a further development of the radiator according to the invention is provided that the heating wire - for example, at regular intervals - in addition to between wave mountains and corresponding troughs arranged straight flanks has more straight sections, one opposite possess the flanks enlarged length. Preferably these straight sections at least twice as long as the Flanks. In this way, the heating wire moves away carried around the longitudinal narrow side of the support plate in its further course increasingly from the outside, so that overheating is effectively avoided. This is particularly advantageous for cross-flow radiators.

In order to ensure a simple production, the inventive Radiator when using several päralleler Support plates without spacers or the like. Between the Support plates and without additional fastening devices get by for the heating wire to the support plates. To this Purpose is in an extremely preferred embodiment of Radiator according to the invention provided that the straight Sections are substantially tangent to the turns extend the helix so that the heating wire in transition areas between straight and wavy sections to the Longitudinal edges of the support plates is held. This will be the support plates through the heating wire in their relative position fixed, so in an advantageous manner to additional Spacers between the plates are dispensed with can.

In a further preferred embodiment of the invention Radiator is provided that the heating wire when using a plurality of support plates in one area between the support plates a regular wave pattern comprising wave crests and troughs. Thereby wins the heating wire in this area to (inherent) stability and also has a opposite to a straight course increased length, resulting in improved heat dissipation results.

A development of the radiator according to the invention sees before that the heating wire between at opposite Longitudinal sides adjacent straight sections has at least one other wave trough, whose vertex abuts on an outer side of the support plate. By the the support plate only point-like heating wire wins the radiator according to the invention in addition to stability, without deteriorating the thermal properties.

Alternatively or additionally, a particularly preferred Embodiment of the radiator according to the invention before that the heating wire between at opposite ends Longitudinal sides adjacent straight sections two troughs has and that the heating wire in a section formed between them with a substantially M-shaped course is. Preferably, the heating wire touches it no place the outside of the support plate. In such a Design is a large heating wire length without Danger of local overheating and thus optimal Utilization of the available space guaranteed.

After a development of the radiator according to the invention it is envisaged that this one double or multiple helix in the form of at least two parallel wound Has heating wires. This can be different Produce heating stages, so that the radiator of the invention is particularly flexible. Alternatively or In addition, this is also done by intermediate taps along the To realize heating coil.

A development of the radiator according to the invention sees that when using multiple support plates in one area arranged between the support plates, a temperature element is. Such a temperature element arranged can be particularly fast and sensitive to a thermal Condition of the radiator of the invention react and also contributes to optimal utilization of the available standing space at.

To the heating wire of the radiator according to the invention against can secure lateral displacement, can be provided that the support plate grooves in their longitudinal narrow sides Inserting the Heizdrahtwicklungen has.

As part of a development of the radiator according to the invention it is still possible that the support plate Has breakthroughs in the coil. This favors on the one hand, the training of a purpose of improved heat dissipation desired turbulent flow, on the other hand can in the Area of such breakthrough the above Temperature element can be arranged.

Preferably, the heating wire of the invention Radiator a PTC characteristic on; the at rising Temperatures increase the resistance of the Heating wire leads. This makes it possible for high initial benefits a self-regulating temperature protection provided. A combination of conventional heating wire and PTC heating wire, in particular in parallel winding of two heating wires, is also suitable, the high Initial power and thus limit the power.

In an extremely preferred embodiment of the invention Radiator is provided that this one longitudinally the support plate variable number of Heizdrahtwicklungen per unit length. It is possible, the number of turns not constant over the entire winding length but in adaptation to the flow conditions variable. This is especially true for one Tangential blower advantageous because here on the radiator length different flow velocities of form gaseous medium.

To the heating resistor of the radiator according to the invention in A flexible production to the respective requirements to be able to adapt, it is provided that over a respective Measure of a depth of the troughs or height of the wave crests of the heating wire an electrical resistance of the Radiator is customizable.

In the course of optimal utilization of the available Space is in the course of a development of the invention Radiator provided that this one between Having the support plates guided return conductor. Preferably are still the two connection sides formed for the temperature element by the return conductor.

Fig. 1a

eine Vorderansicht eines erfindungsgemäßen Heizkörpers mit Gehäuse mit Blickrichtung entsprechend der Einströmrichtung des zu erhitzenden gasförmigen Mediums;

Fig. 1b

einen Schnitt durch den erfindungsgemäßen Heizkörper der Fig. 1a, entsprechend Ib-Ib;

Fig. 1c

einen Heizdraht eines erfindungsgemäßen Heizkörpers in abgewickeltem Zustand;

Fig. 2

eine Seitenansicht auf mit Heizdrahtwindungen versehene Tragplatten;

Fig. 3a

eine Seitenansicht eines weiteren erfindungsgemäßen Heizkörpers;

Fig. 3b

eine Vorderansicht des Heizkörpers der Fig. 3a;

Fig. 4b

eine Draufsicht auf eine Tragplatte eines erfindungsgemäßen Heizkörpers;

Fig. 5

eine Vorderansicht eines erfindungsgemäßen Heizkörpers mit einseitigen elektrischen Anschlüssen und einem Rückleiter mit integriertem Temperaturelement zwischen den Tragplatten; und

Fig. 6 .

einen Schnitt entsprechend der Fig. 1b zu einer weiteren Ausgestaltung.

Further advantages and features will become apparent from the claims and the accompanying drawings, in which embodiments of the radiator according to the invention are shown. It shows:

Fig. 1a

a front view of a radiator according to the invention with housing with viewing direction corresponding to the inflow direction of the gaseous medium to be heated;

Fig. 1b

a section through the radiator according to the invention of Figure 1a, corresponding to Ib-Ib.

Fig. 1c

a heating wire of a radiator according to the invention in unwound state;

Fig. 2

a side view of provided with Heizdrahttwindungen support plates;

Fig. 3a

a side view of another radiator according to the invention;

Fig. 3b

a front view of the radiator of Fig. 3a;

Fig. 4b

a plan view of a support plate of a radiator according to the invention;

Fig. 5

a front view of a radiator according to the invention with unilateral electrical connections and a return conductor with integrated temperature element between the support plates; and

Fig. 6.

a section corresponding to FIG. 1b to a further embodiment.

Figs. 1a and 1b show the front and sectional views an electric heater 1 in a cross-section rectangular housing 2, by a current P of a to be heated gaseous medium, such as air, is interspersed, for example across to its extension. Inside the case 2 are two parallel support plates 3a, 3b in the form of Insulating panels arranged in lateral openings 4a, 4b of the housing 2 are held. To the two Insulating plates 3a, 3b are in the illustrated embodiment bifilar two resistance heating wires 5a, 5b helical wound. Of course, but only a heating wire or more than two heating wires available be.

The heating wires 5a, 5b are at their ends by contact parts 6, 6 'held on the insulating plates 3a, 3b attached and through the lateral openings 4a, 4b of the Housing are led to the outside, being at the same time represent the electrical connections for the heating wires 5a, 5b.

In a region between the support plates 3a, 3b is a Temperature element consisting of fuse 21 and temperature sensor 22, provided.

Fig. 1b shows in a sectional view accordingly Ib-Ib in Fig. 1a, a first winding guide of the heating wires 5a, 5b around the support plates 3a, 3b. Due to the inherent stability the heating wires 5a, 5b, their particular configuration explained below with reference to FIGS. 1c, 2 and 3a is, are between the support plates 3a, 3b no Spacers or the like required. In addition, will the entire space within the housing 2 exploited to in this way over an increased length of the heating wires 5a, 5b provide a high heating power available can.

A first embodiment of a heating wire for a radiator according to the invention is shown in Fig. 1c (see below Fig. 3a). The heating wire 5 (in Fig. 1c unwound and partially shown) in sections 11 is a regular wave pattern of wave crests 11a and troughs 11b. Between the corresponding Vertexes of the wave peaks 11a and troughs 11b extend essentially straight flanks 11c. The sections 11 ends on both sides in a bend 12 whose bending angle α substantially greater than 40 °, in the embodiment shown preferably about 90 °. Here and in the following the bending angle α is always that of the wire edges included angles, i. α = 0 ° in a fully bent, running wire in parallel with itself; α = 180 ° for an unbent, straight wire.

At the bends 12 then has the heating wire in regular, periodic intervals straight sections 13, the opposite the flanks 11c an enlarged length (at Embodiment of FIG. 1c a doubled length) exhibit. Between individual straight sections 13 has the heating wire 5 turns 16, between which at shown embodiment, another wave trough 17 is arranged is.

The heating wire 5 described above with reference to FIG. 1c is further down in Fig. 3a in wound state shown and comes with a radiator according to the invention according to the Fig. 3b used.

Fig. 2 shows the side view of a turn of a Heating wire 5 corresponding to the heating wires 5a, 5b according to Fig. 1a and 1b, which differs from the above-described embodiment differs according to the Fig. 1c in partial areas. Basically, every single heating wire winding has the same wave pattern on. But there are also different ones Pattern feasible. In the wave pattern shown in Fig. 2 has the heating wire winding in sections 11 between the insulating plates 3a, 3b a substantially regular wave pattern according to Fig. 1c, wherein the bends 12 on the narrow sides 20 of the insulating panels 3a, 3b are positioned. The bending angle α of the turn 12 is about 100 °. The two sides in the area from outsides 14 of the insulating plates 3a, 3b to the Sections 11 subsequent substantially straight sections 13 of the heating wire 5 are due to the helical shape of the heating wire substantially tangential to Heizdrahtwicklung arranged. The insulating plates 3a, 3b are - as mentioned - with their narrow sides 20th and their edges 20a in the convex bends 12 in FIG Transition region between the corrugated sections 11 and the straight sections 13 of the heating wire 5 and are characterized also fixed without housing in their relative position, what the handling of the radiator according to the invention essential facilitated.

The above division of the bends of Heating wire 5a, 5b follows from its relative arrangement the support plates 3a, 3b, with bends, in their areas the wire has a convex course, accordingly are referred to as convex bends. Those turns, where the wire path relative to the arrangement the support plates 3a, 3b is concave, are therefore concave Turns. Specifically, convex or concave can be Turns with a bending angle 0 ° <α <180 ° also as Wave peaks or troughs denote and vice versa (see. Fig. 1c).

The straight sections 13 each end as in Fig. 1c in another convex bend 16 on which a concave Turn 17 (wave trough) follows. More straight sections 18 lead the heating wire 5 in two excessive Wellenbergen.19 centered together, with the heating wire 5 in this section due to the wave crests 19 and the straight sections 18 has an M-shape. Through the wave pattern in sections 11 between plates 3a, 3b the stability of the heating wire arrangement, in particular against in the direction of the double arrow 11 acting lateral forces ensures so that the radiator 1 according to the invention according to 1a without additional stabilizing elements (spacers) gets along.

The just described embodiment of Heizdrahtwicklungen on the one hand has the advantage that through the straight section 13 in the region of the outer side 14 of the plates 3a, 3b a resting or approaching of the heating wire 5 on the or to the outer sides 14 of the insulating plates 3a, 3b prevented is and instead of the heating wire 5 only point-like on the narrow sides 20 and / or their edges 20a on the plates 3a, 3b rests. This will reliably a Overheating of the heating wire 5 in the edge region of the plates 3a, 3b prevented. On the other hand, this version uses by the excessive wave crests 19 optimally to her Available space in the housing 2 from (see Fig. 1b). The wave pattern can also be other, to the concrete Requirements adapted, embodiments, which in addition, from winding to winding along the Can change support plates 3a, 3b.

Thus, Figs. 3a and 3b show views of a substantially the embodiment of the shown in Fig. 1c Heizdrahts 5 corresponding simpler embodiment of the Heizdrahtwindungen. It is preferably used when the height of the housing 2 for reasons of space significantly lower must be as in the previous example of FIG. 2 or 1b. Between the insulating material 3a, 3b is the Heating wire 5 running in regular waves. In turn are the narrow sides 20 and / or edges 20a of Isolierstoffplatten 3a, 3b in convex bends 12 of Heating wire 5 and are thereby fixed (Fig. 3a). As with the Embodiment of Fig. 2 closes in the area of Outer sides 14 of the plates 3a, 3b on both sides a straighter Section 13, so that the heating wire 5 at the Isolierstoffplattenrändern only in the area of the narrow sides 20 and / or edges 20a is applied and thereby overheating of the wire 5 is prevented in this area. As in Fig. 2 close to the straight sections 13th on both sides more convex bends 16, which the Heating wire 5, however, in the middle - according to the embodiment in Fig. 1c - in a single concave turn 17th Merge (Wellental) that with her (his) Apex on the outsides 14 of the plates 3a, 3b rests.

Due to the distance from the plate edges is no To fear overheating of the heating wire 5. Furthermore are by the support of the heating wire 5 both the insulating panels 3a, 3b and the heating wire 5 itself better fixed.

Also in the embodiment of Fig. 3a, the bending angle α of the turn 12 about 100 °.

Fig. 4 shows a plan view of the insulating panels 3a, 3b of the radiator 1 according to the invention in this exemplary embodiment are at the longitudinal edge of the insulating panels 3a, 3b grooves 8 formed in the Heating wire 5a, 5b is inserted during winding and thereby secured against lateral displacement. In the side Area the plates have openings 10, by tabs the contact parts 6 are penetrated and for a clamping attachment of the contact parts 6 to the plates 3a, 3b. More tabs 7 of the contact parts 6 hold the Ends of the heating wires 5a, 5b, the fuse 21 and the temperature sensor 22 (Fig. 1a).

Central openings 10 'are used by the inventive Radiator 1 flowing medium P a turbulent Imprinting flow behavior, resulting in an improved Heat dissipation is achievable. In addition, the in 1a and 5, temperature element 21 shown by way of example, 22 in the area of such openings 10 'order to the Optimal use of available space.

Regarding the contacting of the heating wires 5, 5a, 5b According to the invention, a plurality of possibilities are provided. Thus, in addition to the already above with reference to FIG. 1a attributed two-sided contact arrangement for the Case that the connectors are not on different sides of the housing 2, but led out only on one side should be, according to Fig. 1a, the possibility that Return lead over the housing 2. That's it left-side contact part 6 'via a temperature element consisting from fuse 21 and temperature sensor 22, as well a connecting conductor 23 connected to the housing 2, so that the current through the housing 2 to a right-side Terminal 9 is routed.

In the embodiment of Fig. 3b, the electrical Connections on two sides over the contact parts 6, wherein the heating wires 5a, 5b in tabs 7 of the contact parts. 6 are held. Temperature elements are not shown here (See Figures 1a and 5).

Fig. 5 shows an embodiment of the invention Radiator with unilateral connections on the left Side, in which a return conductor 24 of the heating wire 5 as conductive wire connection between the right and left side Contact parts 6 of the upper plate 3a spaced therefrom between the plates 3a, 3b is guided. at the same time is in the return line 24, a temperature element in the form a fuse 21 and a temperature sensor 22 integrated.

In the course of this embodiment of the return conductor 24 is the helical 5 especially around two plates advantageous, since here between the plates 3a, 3b sufficient Space for the temperature element 21, 22 is present. The position of the temperature sensor 22 is thus freely selectable. Of course it is also possible constructively for a two-sided connection version, the temperature elements without simultaneous return function between the To arrange plates.

Fig. 6 shows a cross section similar to that of Fig. 1b with arranged in a rectangular in a rectangular housing 2 electric radiator 1. The housing 2 has two arranged parallel to each other gas or air guide walls 2a, which is substantially parallel to the Gas or air flow P are aligned. The radiator 1 is arranged in the housing 2a such that in the flow direction P the support plates 3a, 3b to the guide walls 2a are inclined and in the illustrated embodiment a Include angle β of about 10 °.

LIST OF REFERENCE NUMBERS

1

electric radiator

2

casing

3a, 3b

support plate

4a, 4b

Breakthrough (in 2)

5, 5a, 5b

heating wire

6, 6 '

contact part

7

Tab (from 6)

8th

Groove (from 3a, 3b)

9

connection

10, 10 '

breakthrough

11

corrugated heating wire section

11a

crests

11b

troughs

11c

flanks

12

turn

13

straight heating wire section

14

Outside (from 3a, 3b)

16

turn

17

Turn (wave trough)

18

straight section (out of 5)

19

excessive wave mountain

20

Longitudinal narrow side (of 3a, 3b)

20a

Edges (from 20)

21

fuse

22

temperature sensor

23

connecting conductors

24

return conductor

α

bending angle

P

gas flow

Claims (20)

1. Electric heater for gaseous media comprising at least one support plate and at least one spiral made from a wavy electric resistance heating wire, which is continuously wound around the support plate and whose windings are held on the longitudinal edges of the support plate through bending of the heating wire, characterized in that the heating wire (5, 5a, 5b) is disposed such that it merely contacts the longitudinal narrow sides (20) and/or edges of the longitudinal narrow sides (20) of the support plate (3a, 3b) and that the heating wire (5, 5a, 5b) is guided, in the region of a convex bend (12), over the longitudinal narrow sides (20) of the support plate (3a, 3b), wherein a bending angle (α) between regions of the heating wire (5, 5a, 5b) adjacent to each side of the bend (12) is larger than 40°.
2. Electric heater according to claim 1, characterized in that the bending angle (α) is larger than 60°.
3. Electric heater according to claim 1 or 2, characterized in that the heating wire (5, 5a, 5b) comprises, in addition to straight flanks (11c) disposed between wave crests (11a) and corresponding wave troughs (11b), further straight sections (13) which are longer than the flanks (11c).
4. Electric heater according to claim 3, characterized in that the straight sections (13) have at least twice the length of the flanks (11c).
5. Electric heater according to claim 3 or 4, characterized in that the straight sections (13) extend substantially tangentially to the windings of the spiral.
6. Electric heater according to any one of the claims 1 through 5, characterized in that the heating wire (5, 5a, 5b) comprises a regular wavy pattern of wave crests (11a) and wave troughs (11b) in a region (11) between the support plates (3, 3b), wherein a plurality of support plates (3a, 3b) are used.
7. Electric heater according to claim 6, characterized in that the heating wire (5, 5a, 5b) is held on the support plates (3a, 3b) in transition regions (12) between the straight sections (13) and the wavy sections (11).
8. Electric heater according to claim 7, characterized in that the heating wire (5, 5a, 5b) comprises, between straight sections (13) bordering mutually opposite longitudinal narrow sides (20), at least one further wave trough (17) whose bottom abuts an outer side (14) of the support plate (3a, 3b).
9. Electric heater according to claim 6 or 7, characterized in that the heating wire (5, 5a, 5b) has two wave troughs (17) between straight sections (13) bordering mutually opposite longitudinal narrow sides (20), and the heating wire (5, 5a, 5b) extends substantially in the shape of an M in a section between these two wave troughs (17).
10. Electric heater according to any one of the claims 1 through 9, characterized in that it comprises a double or multiple spiral in the form of at least two parallel wound heating wires (5a, 5b).
11. Electric heater according to any one of the claims 1 through 10, characterized in that a temperature element (21, 22) is disposed in a region between the support plates (3a, 3b), wherein several support plates (3a, 3b) are used.
12. Electric heater according to any one of the claims 1 through 11, characterized in that the support plate (3a, 3b) has grooves (8) in its longitudinal narrow sides (20) for inserting the windings of the heating wire (5, 5a, 5b).
13. Electric heater according to any one of the claims 1 through 12, characterized in that the support plate (3a, 3b) has openings (10') in the region of the spiral.
14. Electric heater according to any one of the claims 1 through 13, characterized in that the heating wire (5, 5a, 5b) has a PTC characteristic.
15. Electric heater according to any one of the claims 1 through 14, characterized by a number of heating wire windings per unit of length which can be varied along the support plate (3a, 3b).
16. Electric heater according to any one of the claims 1 through 15, characterized in that the electric resistance of the heater (1) can be adjusted through a respective degree of depth of the wave troughs (11b, 17) or height of the wave crests (11a, 19) of the heating wire (5, 5a, 5b).
17. Electric heater according to any one of the claims 1 through 16, characterized by a return wire (24) which is guided between a plurality of support plates (3a, 3b).
18. Electric heater according to any one of the claims 11 through 17, characterized in that two connecting sides for the temperature element (21, 22) are formed by the return wire (24).
19. Electric heater according to any one of the claims 1 through 18, characterized in that a return path is guided via a heater housing (2).
20. Electric heater according to any one of the claims 1 through 19, characterized in that, in the flow direction, the at least one support plate (3a, 3b) subtends an angle relative to the guiding walls (2a) of a housing (2), the angle having a value other than zero and smaller than 90°.

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