DE102007003906A1 - Heating coil arrangement for heating by-passing gas substances - Google Patents

Abstract

The invention relates to a heating coil arrangement (1) for heating flowing gas substances, comprising a heating conductor (3) wound at least in sections into a heating coil (9) for converting electrical energy into thermal energy, with one at least partially wrapped by the heating coil (9) and in the axial direction ( 17) of the heating coil (9) extending support element (2) and with at least one at the axial end of the support member (2) mounted terminal contact (4) which is electrically conductively connected to the heating conductor (3). In order to provide a heating coil arrangement (1) with improved heat distribution, it is provided according to the invention that the ratio between the width (B) of the support element (2) and the axial distance (22 ') from the axial end of the support element (2) to the nearest point of passage (31). at which the heating conductor (3) passes a side surface (32) of the support element (3) is greater than or equal to three.

Description

The The invention relates to a heating coil arrangement for heating flowing gas substances, with at least in sections to a heating coil wound heating conductor for converting electrical Energy in heat energy, with one of the heating coil at least wrapped in sections and in the axial direction of the heating coil extending support element and with at least one on the axial End of the support element attached terminal contact, the is electrically connected to the heating conductor.

Heizwendelanordnungen The type mentioned are known from the prior art and are individually or as a set of several consecutive and / or next to each other arranged Heizwendelanordnungen used to pass gas, such as As air, to heat. So are the Heizwendelanordnungen for example in tumble dryers for generating a hot air flow, with which the laundry is dried, installed. Im installed Condition are the Heizwendelanordnungen a flow pressure the passing gas often exposed directly. there should the Heizwendelanordnungen one hand, the largest possible Heating surface as little flow resistance offer, but on the other hand be made so stable that no Vibrations caused by the gas stream can occur. Therefore becomes the heating conductor, usually called a resistance wire is formed to a strip-shaped support element wrapped around to a heating coil.

A method and an apparatus for producing such a Heizwendelanordnung is for example in the DE 2615013 C3 described. The according to the method of DE 2615013 C3 Coiled around the support member heating coil is connected by hand with plugged at both ends of the support member terminal contact. For this purpose, the ends of the heating element are each wrapped around a projection on the terminal contact and then welded to the terminal contact.

Other Heizwendelanordnungen from the prior art are for example in the DE 1 403 557 , of the EP 0 995 830 A2 and the FR 1 318 547 described.

The known Heizwendelanordnungen have the disadvantage that the heat distribution unevenly during operation of the Heizwendelanordnungen is. This will increase the airflow that the heating coil assemblies heat up should, unevenly heated, which, for example to an uneven drying of the laundry in a tumble dryer.

Of the Invention is therefore based on the object, a Heizwendelanordnung to provide with improved heat distribution.

These The object is achieved according to the invention that the ratio between the width of the support element to the axial distance from the axial end of the support element to the nearest point of passage at which the heating conductor a side surface of the support element happens is greater than or equal to three.

These Solution according to the invention is structurally surprising easy and has the advantage that the heating conductor opposite the known Heizwendelanordnungen further outward to the axial End of the support element is wound. This is the Surface of the heating coil increases, so that also the heat transfer to the passing Air is increased. Due to the wider heating coil the heat distribution is improved. Enlarged by this Surface can additionally also the heating temperature the Heizwendelanordnung with the same heat transfer and power can be lowered to save energy. So increased through the lower specific surface load the electrical safety. With achievable lower temperature difference between the passing air and the heating conductor can the efficiency of heat transfer of the Heizwendelanordnung be improved.

The Heizwendelanordnung invention can by different, mutually independent, each for advantageous embodiments are further developed, such as they are explained below.

The known Heizwendelanordnungen have the further disadvantage that in each case at least one manual working step is necessary to to connect the heating conductor with the connection contact or in a to bring suitable position for electrical connection. by virtue of This disadvantage is the production of the known Heizwendelanordnungen relatively low automated. Due to the low degree of automation are the manufacturing costs of the known Heizwendelanordnungen relatively high, which is especially in the production of large Quantities is particularly detrimental. To the heating coil arrangement more automated and with lower production costs can produce the heating conductor on the in the axial direction to Heizwendel pointing side of the connection contact be placed.

The automatic production is possible in this embodiment, because the heating conductor only has to be moved in the axial direction to the terminal contact prior to connection to the terminal contact. This axial movement of the heating conductor can be easily automated by a mounting device, so that the manual operation of the known Heizwendelanordnungen deleted by the inventive solution. By thus enabling fully automated production of the heating coil arrangement, large numbers of heating coil arrangement can be produced with low unit costs.

The Heat distribution during operation of the Heizwendelanordnung can be improved if the axial distance of a Heizwendelabschnitts, in which the heating conductor with a substantially constant slope to Heating coil is wound, to the axial end of the support element smaller than the width of the support element. Furthermore, can the axial distance from the axial end of the support element to nearest passing point at which the heating conductor the side surface of the support element happens to be smaller or equal to 5 mm.

In an advantageous development, the support element essentially run in a support plane and the passing points can lie in the support plane. So can Gas substances containing the heating coil arrangement in a plane parallel to the support plane flow around the flow direction, especially to be heated well.

Further For example, the heating conductor may be formed as a ribbon-shaped flat wire and welded flat with the connection contact be. This has the advantage that flat, so flat superimposed Surfaces can be welded automatically well, because they have a relatively large contact area, which represents a secure electrical connection. It is also suitable Welding especially good for automated production. The automatically moved to the junction end of the heating element For example, with the terminal contact by spot welding or Resistance welding bonded cohesively become.

alternative the heating conductor with the terminal contact, for example, by an electrically conductive adhesive, by crimping or by a clip element are connected.

Around in the automated production of Heizwendelanordnung the heating conductor The heating conductor can be safely moved to the connection contact in a projection in the axial direction outside of the heating coil be placed on the connection contact. It has been shown that that End of the heating conductor after winding the heating coil in the axial Projection tangential from the diameter of the heating coil to the outside protrudes. Thus, it is advantageous that in this embodiment the terminal contact in the axial projection outside of Heating coil runs and aligned with the end of the heating element.

In In a further advantageous embodiment, a connecting portion of the terminal in which the heat conductor is placed, essentially run transversely to the winding axis of the heating coil. This has the advantage that the heating conductor for connecting to the terminal contact easily can be moved against the connecting portion. The connecting section may also be substantially transverse to the end of the support element run to complete with the support element and do not stick out. So forms the connecting section no interference contour, for example to a housing, in which the Heizwendelanordnung is attached, from.

Around the connection contact simple and yet stable with the support element to connect, the terminal contact at least one locking means have, through which the terminal contact with the support element is mechanically locked. The locking means engages in a corresponding Counter-locking means in the support element and prevents a release of the terminal of the support element. The counter-locking means in the support member may, for example be an opening or a depression, for example even when bending out the locking element from the terminal contact can be embossed into the support element. Also for attaching the terminal, the terminal contact at least a retaining element enclosing the support element have, which is pressed around the support element. Therefor For example, the terminal can be made of an electrically good be made of conductive metal sheet, which is plastically light deform.

Around to prevent the automated movement of the heating element The support element is obstructed or blocked, the Support member spaced at the axial end of the heating element be. For this purpose, the support element at each end one each Have recess.

Around the heat distribution of the invention Heizwendelanordnung to further improve, the axial distance the Heizwendelabschnitts, to the axial end of the support element less than four times, preferably less than three, slope amount of the heating coil.

For a particularly compact design of the invention Heizwendelanordnung can the above axial distance from the end the Heizwendelabschnitts to the end of the support element less than 15 mm, preferably less than 10 mm.

To the surface and the stability of the Heat conductor to improve, the heating element can be designed as a vertical standing flat wire.

Further the support element can the heating coil at attachment points support the side surface of the support element. So the heating coil is stable on the support element and in the longitudinal direction fixed slip-resistant.

The Invention relates in addition to the above-mentioned Heizwendelanordnung in their different embodiments also a Heating assembly for heating a hot air stream for example, in a tumble dryer, with at least a Heizwendelanordnung and with a holding means on which the Heating coil arrangement can be flowed through by the hot air flow is appropriate. To provide a heating assembly opposite known heating assemblies produced with lower production costs can be, is inventively provided that the Heizwendelanordnung according to one of the above embodiments is trained.

in the The invention will now be described by way of example with reference to the accompanying drawings Drawings explained. The different features can being combined independently, as above already explained in the individual advantageous embodiments has been.

It demonstrate:

1 a schematic perspective view of an exemplary embodiment of the invention Heizwendelanordnung;

2 a schematic representation of a terminal contact of the Heizwendelanordnung invention 1 ;

3 a schematic representation of a support element of the Heizwendelanordnung 1 ;

4 an enlarged view of one end of the Heizwendelanordnung 1 ;

5 a schematic sectional view of the Heizwendelanordnung 4 in the direction of arrow A;

6 a schematic representation of the Heizwendelanordnung 1 ;

7 a schematic representation of part of another embodiment of the invention Heizwendelanordnung;

8th a schematic representation of a heating assembly according to the invention.

First, the general structure of a Heizwendelanordnung invention 1 with reference to the 1 to 6 described.

The heating coil arrangement 1 includes a support element 2 , one around the support element 2 wound heating conductor 3 and two on the support element 2 attached, with the heating conductor 3 connected connection contacts 4 ,

The support element 2 In the exemplary embodiment, FIG 1 to 6 as a substantially in a support plane E extending strip with flat side surfaces 32 educated. The side surface 32 forms a narrow side of the support member, which the wider, substantially parallel to each other upper and lower sides 33 . 34 combines. The support element 2 is made of an electrically insulating material, for example, pressed mica. At its axial ends, the strip-shaped support element 2 each a rectangular recess 5 on. In the area of the recess 5 is the width B 'of the Isolierlements 2 smaller than the width B of the support member 2 between the recesses 5 , Furthermore, the support element 2 an opening at each axial end 6 on which the support element 2 penetrates transversely to the axial direction.

The heating conductor 3 is in the embodiment of the 1 to 6 as a to the support element 2 edgewise wound flat wire formed. In a heating coil section 7 between the ends of the support element 2 is the heating conductor 3 with a substantially constant slope 8th to a heating coil 9 wound up, which at the same time a center line of the support element 2 forms. The slope may alternatively vary, for example to achieve predetermined temperature distributions during operation. The heating coil 9 is one in the axial direction 17 running winding axle 29 wound. As in 4 shown, is the heating conductor 3 in the area of the heating coil 9 tight to the support element 2 adjacent or in notches 10 arranged. The heating coil 3 rests on attachment points 35 on the side surfaces 32 of the support element 2 are arranged, from. In the embodiment of the 1 to 6 is the heating coil 9 essentially cylindrical wound and has an outer diameter D and an inner diameter d. The outer diameter D is larger and the inner diameter d is smaller than the width B of the support member 2 educated. That's how every turn takes effect 11 of the heating coil 9 on the inner circumference at the attachment points 35 in the support element 2 and stands on the outer circumference on the support element 2 out.

At passages 31 the heating conductor passes 3 each the narrow side surface 32 of the support element 2 and penetrates the support plane E. In the region of the recess 5 of the support element 2 are the Passi Create 31 from the support element 2 spaced.

The heating conductor 3 is made as a resistance heating element of a suitable metal wire or metal strip, which heats up when it is traversed by electrical energy.

The two connection contacts 4 are each at the axial end of the support element 2 attached and are made of a highly electrically conductive metal sheet. Each connection contact 4 is in a holding section 12 with the support element 2 connected. In this holding section 12 has the connection contact 4 a locking means 13 and a holding tab 14 on. The locking means 13 is formed as a partially punched, substantially circular tongue, which in the assembled state with the opening 6 of the support element 2 Aligns and at least partially in the opening 6 is pressed in. The retaining tab 14 is U-shaped and surrounds the end of the flat support member 2 from above and below. Im in 1 shown assembled state of the invention Heizwendelanordnung 1 is the retaining tab 14 around the support element 2 pressed.

The diameter of the tongue-shaped locking means 13 is substantially equal to the diameter of the opening 6 so that's in the opening 6 engaging locking means 13 the connection contact 4 against removal from the support element 2 locked. Also around the support element 2 pressed retaining tab 14 attaches the connection contact 4 on the support element 2 and prevents a relative movement. The connection contact 4 is so on the support element 2 attached that he has the recess 5 not covered.

The connection contact 4 is at a junction 15 with the heating conductor 3 electrically connected. In the in the 1 to 6 illustrated embodiment is the heating conductor 3 at the connection contact 4 in the area of the junction 15 applied and welded together. The connection point 15 is located at the end of the heating element 3 and in a connecting section 16 of the connection contact 4 , At the connection contact 4 in 2 is a raised welding area 15 ' formed in which the junction 15 after welding. In the embodiment of the 1 to 6 is the connecting section 16 essentially flat and transverse to the holding section 12 and across the support element 2 educated. As in 6 shown, the connecting section runs 16 essentially parallel to the turns 11 of the heating coil 9 , As in 5 represented, is the connection point 15 in a projection in an axial direction 17 of the heating coil 9 outside the coil diameter D of the heating coil 9 , The heating conductor 3 lies with its flat side on the likewise flat trained connection contact 4 flat on. The connection contact 4 is in the connecting section 12 as a contact plate for the heating conductor 3 educated.

The connection contacts 4 each have a transverse to the connecting portion 16 extending contact pin 26 on. The contact pin 26 is in the mounted state in the axial direction over the support element 2 out. In the embodiment of the 1 to 6 runs the contact pin 26 in the axial direction 17 ,

In an automated production of Heizwendelanordnungen invention 1 First, the heating conductor 3 around the support element 2 wound. At the end of the winding process, the ends of the heating conductor remain free. Here are the ends of the heating element 3 in an axial projection, as in 5 , tangential to the diameter of the heating coil 9 , at an angle α off. This angle α is for example about 10 to 15 degrees to a perpendicular to the support element 2 , Subsequently, the connection contact 4 axially on the support element 2 attached. The connection contact 4 can be either prefabricated or on the support element 2 be formed by multiple bending. After the connection contact 4 on the support element 2 is attached, the projecting end of the heat conductor 3 in the axial direction 17 to the connection section 16 of the connection contact 4 moves it to the terminal contact 4 touched and rests or is present. Now the heating conductor is lying flat 3 with the connection contact 4 in the connection point 15 welded.

The connecting section 16 is designed to be in a projection in the axial direction 17 with the end 18 of the heating conductor 3 flees. This has the advantage that the movement of the end to be performed 18 to the connection contact 4 It is so simple that it can be carried out automatically. As for the above-described automated connection of Heizleiter 3 and connection contact 4 relatively little space on the Heizwendelanordnung 1 is required, the Heizwendelabschnitt 7 be formed relatively large, as in 6 is shown. An axial total length 19 of the support element 2 is how in 6 represented about 80% of the Heizwendelabschnitt 7 that has an axial length 20 has taken. Each side of the Heizwendelabschnitt 7 there are connection sections 21 that are about the same size. In the exemplified embodiment of the 1 to 6 is the axial length 22 each connection section 21 about three to four times the slope 8th , about 8 to 10 mm. The smaller this length 22 So the axial distance 22 of the heating coil section 7 to the axial end of the support element 2 The better for the heat distribution during operation.

The heating coil arrangement 1 heats up during operation a flowing in a flow direction S gas stream. In the connection sections 21 the heat transfer of the Heizwendelanordnung invention is lower in operation, since the heating conductor 3 in the connection section 21 with an increased slope 8th' opposite the heating coil section 7 runs. The slope 8th' is greater than the slope 8th in the heating coil section 7 because the ends 18 of the heating conductor 3 as described above, after winding to the joint 15 at the connecting section 16 have been moved and the connection contact 4 rest. Consequently, it is advantageous that the connection sections 21 the Heizwendelanordnung invention 1 are relatively small.

It is also advantageous that a distance 22 ' , respectively from the axial end of the support element 2 to the nearest extreme point in the axial direction 31 is particularly low. The heating conductor 3 happens in the area of the passages 31 the support element 2 in the flow direction S. In the heating coil arrangement according to the invention, the distance 22 ' smaller than the width B of the support member. In the exemplary embodiment in FIG 1 is the distance 22 ' in particular smaller than half the width B, ie smaller than 5 mm. Here, the ratio between the width B and the axial distance 22 ' greater than or equal to three.

The small axial distance 22 ' , that is, the particularly coiled outward heating coil 9 has the advantage that the overall surface of the heating coil is increased, which reduces the specific surface load of the heating wire at the same power and provides greater electrical safety. In addition, the heat distribution is improved over a less broadly wound heating coil.

As in 1 shown, the heating conductor runs 3 in the connection section 21 through the recess 5 of the support element 2 and is from the support element 2 spaced. Through the recess 5 will be the end 18 of the heating conductor 3 in the automated movement to the connection contact 4 not from the support element 2 retained.

7 shows a section of the Heizwendelanordnung invention 1 in a further embodiment. The clipping in 7 shows the Heizwendelanordnung 1 in the area of the heating coil section 7 , In contrast to the embodiment of the 1 to 6 is the heating conductor 3 in the embodiment in 7 at the inner diameter d with a rif felung 23 Mistake. The ribbing 23 became the heating coil before winding the flat wire 9 pre-deformed. The corrugation is a plastic deformation of the heat conductor 3 too many undulating bows. As a result of this pre-deformation and the resulting weakening of the flat wire, a set deformation on the inner diameter results during winding due to a deformation of the corrugation. Due to this concentration of the deformation on the inside diameter range, a plastic deformation on the outside diameter of the heating coil is reduced 9 , which reduces the risk of cracking on the outer diameter. In addition, the heating coil arrangement 1 This embodiment is immune to vibration because of the heating conductor 3 particularly stable on the support element 2 is fixed.

8th shows an exemplary embodiment of a heating assembly according to the invention 24 For example, in a tumble dryer for heating a hot air stream 30 is installed. In this case, the Heizwendelanordnung is installed so that the flow direction S parallel to the support plane E thus extends the support element 2 forms the lowest possible flow resistance. For the same purpose is the side surface 32 the support element formed as small as possible. The heating module 24 For example, includes a designed as a sheet metal frame holding means 25 , in the direction of flow S in the installed state in the tumble dryer from the hot air flow 30 is flowed through. In the flow direction S is the holding means 25 open and transverse to the flow direction S, it is closed. Within the exemplary holding means 25 in 8th are two Heizwendelanordnungen 1 arranged transversely to the flow direction S. For attachment is a contact pin 26 through appropriate openings 27 in the holding means 25 through put. For electrical connection to a power source are the contact pins 26 outside of the holding means 25 with a connection cable 28 electrically connected. During operation of the heating module 24 gets electrical energy through the connection lines 28 through the heating conductors 3 the Heizwendelanordnungen 1 passed. The electrical energy is through the Heizwendelanordnung 1 converted into heat energy that flows past the stream of air 30 is delivered.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 2615013 C3 [0003, 0003]
• - DE 1403557 [0004]
• EP 0995830 A2 [0004]
• FR 1318547 [0004]

Claims (19)

Heating coil arrangement ( 1 ) for heating flowing gas substances, with at least partially to a heating coil ( 9 ) wound heating conductor ( 3 ) for converting electrical energy into thermal energy, with one from the heating coil ( 9 ) wrapped at least in sections and in the axial direction ( 17 ) of the heating coil ( 9 ) extending support element ( 2 ) and at least one at the axial end of the support element ( 2 ) attached connection contact ( 4 ), which is connected to the heating conductor ( 3 ) is electrically conductively connected, characterized in that the ratio between the width (B) of the support element ( 2 ) to the axial distance ( 22 ' ) from the axial end of the support element ( 2 ) to the nearest point of 31 ), on which the heating conductor ( 3 ) a side surface ( 32 ) of the support element ( 3 ) happens to be greater than or equal to three. Heating coil arrangement ( 1 ) according to claim 1, characterized in that the heating conductor ( 3 ) on the in the axial direction ( 17 ) to the heating coil ( 9 ) facing side of the terminal contact ( 4 ) is launched. Heating coil arrangement ( 1 ) according to claim 1 or 2, characterized in that the axial distance ( 22 ' ) from the axial end of the support element ( 2 ) to the nearest point of 31 ), on which the heating conductor ( 3 ) the side surface ( 32 ) of the support element ( 3 ) happens to be less than or equal to 5 mm. Heating coil arrangement ( 1 ) according to claim 1, 2 or 3, characterized in that the axial distance ( 22 ' ) from the axial end of the support element ( 2 ) to the nearest point of 31 ), on which the heating conductor ( 3 ) the side surface ( 32 ) of the support element ( 2 ) is smaller than the width (B) of the support member (FIG. 2 ). Heating coil arrangement ( 1 ) according to one of the preceding claims, characterized in that the axial distance ( 22 ) a Heizwendelabschnitts ( 7 ), in which the heating conductor ( 3 ) with a substantially constant slope ( 8th ) to the heating coil ( 9 ) is wound, to the axial end of the support element ( 2 ) is smaller than the width (B) of the support element ( 2 ). Heating coil arrangement ( 1 ) according to any one of the preceding claims, characterized in that the supporting element ( 2 ) runs substantially in a support plane (E) and that the passing points ( 31 ) lie in the support plane (E). Heating coil arrangement ( 1 ) according to one of the above claims, characterized in that the heating conductor ( 3 ) formed as a ribbon-shaped flat wire and with the terminal contact ( 4 ) is welded flat. Heating coil arrangement ( 1 ) according to one of the above claims, characterized in that the heating conductor ( 3 ) in a projection in the axial direction ( 17 ) outside of the heating coil ( 9 ) at the connection contact ( 4 ) is launched. Heating coil arrangement ( 1 ) according to one of the above claims, characterized in that the connection contact ( 4 ) in a connecting section ( 16 ), in which the heating conductor ( 3 ) is placed, substantially transversely to the winding axis ( 29 ) runs. Heating coil arrangement ( 1 ) according to claim 9, characterized in that the connection contact ( 4 ) in the connecting section ( 16 ) substantially transversely to the axial end of the support element ( 2 ) runs. Heating coil arrangement ( 1 ) according to one of the above claims, characterized in that the terminal contact ( 4 ) at least one latching means ( 13 ) through which the terminal ( 4 ) with the support element ( 2 ) is mechanically locked. Heating coil arrangement ( 1 ) according to one of the above claims, characterized in that the terminal contact ( 4 ) at least one support element ( 2 ) enclosing retaining tab ( 14 ), which around the support element ( 2 ) is compressed. Heating coil arrangement ( 1 ) according to any one of the preceding claims, characterized in that the supporting element ( 2 ) at the axial end of the heating conductor ( 3 ) is spaced. Heating coil arrangement ( 1 ) according to claim 13, characterized in that the supporting element ( 2 ) at the axial end in each case a recess ( 5 ), by which the support element ( 2 ) from the heating conductor ( 3 ) is spaced. Heating coil arrangement ( 1 ) according to one of the preceding claims, characterized in that the axial distance ( 22 ) of the heating coil section ( 7 ) to the axial end of the support element ( 2 ) Less than 4 times, preferably less than 3 times, the pitch of the heating coil ( 9 ) is. Heating coil arrangement ( 1 ) according to one of the preceding claims, characterized in that the axial distance ( 22 ) of the heating coil section ( 7 ) to the axial end of the support element ( 2 ) is less than 15 mm, preferably less than 10 mm. Heating coil arrangement ( 1 ) according to any one of the preceding claims, characterized in that the supporting element ( 2 ) the heating coil ( 9 ) is supported electrically isolated. Heating coil arrangement ( 1 ) according to any one of the preceding claims, characterized in that the supporting element ( 2 ) the heating coil ( 9 ) at attachment points ( 35 ) of the side surface ( 32 ) of the support element ( 2 ) is supported. Heating assembly ( 24 ) for heating a hot air flow, for example in a tumble dryer, with at least one heating coil arrangement ( 1 ) and with a holding means ( 25 ), on which the heating coil arrangement ( 1 ) is flowed through by the hot air flow, characterized in that the Heizwendelanordnung ( 1 ) is designed according to one of the above claims.