DE102022125694A1 - Heating element - Google Patents

Abstract

The invention relates to a heating element 1 for heating a gas flow 5 with a heating resistor 2 and with two contacts 3.1, 3.2 for applying an electrical voltage, wherein the heating resistor 2 has at least one current conductor 2a with a length 2f and a longitudinal axis 2b, which extends over its length 2f between both contacts 3.1, 3.2, wherein the longitudinal axis 2b depicts a main flow direction 2.0 of the electrical current, wherein at least three current conductor sections 2.1, 2.2, 2.3 are provided, wherein all at least three current conductor sections 2.1, 2.2, 2.3 form a common heating plane_H1 with respect to the longitudinal axis 2b, wherein at least two of the at least three current conductor sections 2.1, 2.2, 2.3 are arranged next to one another with respect to a direction perpendicular to the longitudinal axis 2b and delimit a gap 2c, wherein at least one Conductor section of the at least three conductor sections 2.1, 2.2, 2.3 is designed as a bridge_1 and bridges the gap 2c, wherein at least three further conductor sections 2.4, 2.5, 2.6 are provided, which form a common second heating level_H2 with respect to the longitudinal axis 2b, which is arranged at a distance e from the first heating level_H1, wherein at least one conductor section is provided which is designed as a bridge_2 and which bridges the distance_e.

Description

The invention relates to a heating element for heating a gas stream with a heating resistor and with two contacts for applying an electrical voltage, wherein the heating resistor has at least one current conductor with a length and a longitudinal axis, which extends over its length between the two contacts, wherein the longitudinal axis represents a main flow direction of the electrical current, wherein at least three current conductor sections are provided, wherein all at least three current conductor sections form a common heating plane_H1 with respect to the longitudinal axis, wherein at least two of the at least three current conductor sections are arranged next to one another with respect to a direction perpendicular to the longitudinal axis and delimit a gap, wherein at least one current conductor section of the at least three current conductor sections is designed as a bridge and bridges the gap.

The invention also relates to a spacer for a heating element.

There is already a heating element from the US$5,533,167 B with several conductor sections and connecting bridges, where all bridges are arranged parallel to the heating plane or at right angles to the respective gap plane. The bridges are somewhat narrower than the heating element itself.

From the KR 2005 008 7202 A A heating element with several conductor sections and connecting bridges is also known. According to the embodiment 1a all bridges are arranged parallel to the heating plane or at right angles to the respective gap plane. According to the embodiment 1b all bridges are aligned at right angles to the heating plane. The spiral-shaped heating element designated as state of the art has a central bridge that is aligned parallel to the heating plane.

The invention is based on the object of designing and arranging a heating element in such a way that an improved heat input is ensured.

The object is achieved according to the invention in that at least three further conductor sections are provided, which form at least one common second heating level_H2 with respect to the longitudinal axis, which is arranged at a distance_e from the first heating level_H1, wherein at least one conductor section is provided which is designed as a bridge and which bridges the distance_e. This ensures that a three-dimensional extension of the conductor sections and several parallel heating levels are provided.

The conductor sections within a heating level_H1 are spaced apart from one another, forming a gap. The focus is on the conductive part of the conductor section; any insulation or insulating spacers are to be ignored. The various conductor sections are only connected by the end bridge. The bridge therefore forms the essential part of a connecting loop between various conductor sections. The length of the heating resistor corresponds to the extent of its longitudinal axis.

By connecting several bridges in a row, a more complex redirection can be achieved within several heating levels. The number of heating levels is optional.

The current conductor is made of electrically conductive material that is in the form of a honeycomb, mesh, net or fabric structure. The orientation of part of the honeycomb walls or honeycomb, mesh, net or fabric wires deviates from the main flow direction of the current.

The object is also achieved according to the invention in that at least one first crossbar and at least one second crossbar are provided, which can be aligned parallel to the groove plane, wherein the first crossbar is arranged opposite the second crossbar with respect to the base body. The crossbars are arranged on both sides of the base body, so that the crossbars can be placed in opposite columns of opposite heating levels.

It can also be advantageous if the respective heating level_H1, _H2 has a front side facing the gas flow to be heated and has a base area, wherein the first heating level_H1 and the at least second heating level_H2 delimit a groove over at least 70% of the base area, wherein the bridge bridges the groove. The heating level_H1 and the heating level_H2 are thus electrically coupled via the respective bridge. The base area is formed by all the current conductor sections arranged next to one another within the respective heating level. This includes the bridges. However, the groove does not extend over the bridges, so that only part of the base area is delimited by the groove, whereas the remaining part of the base area is assigned to the bridges.

Furthermore, it can be advantageous if the groove spans a groove plane and opposite gaps of adjacent heating planes_H1, _H2 span a gap plane, wherein the groove plane encloses an angle α of between 10° and 90° relative to the gap plane. As a rule, the angle α is 90°, because the several heating levels arranged parallel to one another extend in the direction of the exhaust gas flow, thus in a direction perpendicular to the respective heating level itself.

It can also be advantageous if the respective bridge has a central axis, whereby the central axis runs parallel to the heating level_H1, _H2 or at a right angle to the heating level_H1, _H2. The parallel alignment to the heating level_H1 ensures that the gap between the conductor sections is bridged. The right-angled alignment to the heating level_H1 or the heating level_H2 ensures that the groove between the two heating levels_H1, _H2 is bridged.

In this case, it can advantageously be provided that, using a Cartesian coordinate system with three spatial axes_x, _y, _z, the heating plane_H1 is aligned parallel to the x-y plane and the bridge_1 extends at least partially in the direction of the spatial axis_x with reference to the central axis to bridge the gap and the bridge_2 extends at least partially in the direction of the spatial axis_z with reference to the central axis to bridge the groove. The exhaust gas flow runs in the direction of the spatial axis_z. If the base area G has a round shape according to the exhaust pipe, the bridges located on the outer edge are also simply curved, with only one axis of curvature parallel to the spatial axis_z. In this respect, the bridges are not flat and cannot be assigned to any plane. The bridge_1 extends in the direction of the spatial axis_x to bridge the gap in the x-y plane, regardless of its width. The bridge_2 extends in the direction of the spatial axis_z to bridge the groove in the x-y plane, regardless of its width.

It can be of particular importance for the present invention if the main flow direction of the electric current can be guided alternately via the heating level_H1 and the heating level_H2. With this symmetrical voltage supply, the heating level_H1 facing the exhaust gas flow will be somewhat colder than the one downstream due to the incoming exhaust gas flow. The heating level_H2 lying in the exhaust gas shadow is exposed to somewhat warmer exhaust gas. The temperature difference between the heating level_H2 and the already heated exhaust gas flow emerging from the heating level_H1 is thus favored.

In connection with the design and arrangement according to the invention, it can be advantageous if the base body extends in the direction of the x-axis and the transverse webs extend in the direction of the z-axis, wherein the base body has a maximum width that corresponds to the distance e between two heating levels_H1, _H2 and wherein the respective transverse web has a width that corresponds to the gap width. The architecture of the spacer is thus adapted to the orientation and position of the gap or groove. If the base body has a rectangular cross-section, the maximum width refers to its diagonal because the base body has to be rotated about its longitudinal axis after being inserted into the groove. If the base body has a round cross-section, the maximum width refers to its diameter.

It can also be advantageous if the distance between the crosspieces corresponds to the width of the gap or if the distance between the crosspieces corresponds to twice the distance between the gaps. On the side of the respective gap where the bridge_1 is provided between adjacent conductor sections, no crosspiece is required. In this respect, the number of crosspieces can be reduced accordingly or by about half.

It can also be advantageous if the crossbars are of different lengths or have different dimensions and at least one crossbar can be positioned in the gaps of several heating levels. This can reduce the number of spacers required.

• 1a eine Frontansicht des Heizelements;
• 1b eine Seitenansicht von 1a;
• 1c eine Detailansicht aus 1a;
• 2a die rückwärtige Ansicht aus 1a;
• 2b die Seitenansicht aus 2a;
• 3a eine Ansicht des Heizelements nach 1a von oben;
• 3b eine Ansicht des Heizelements nach 1a von unten;
• 3c eine alternative Ausführungsform des Heizelements in der Ansicht von unten;
• 4a einen Abstandshalter in der Seitenansicht;
• 4b eine alternative Ausführungsform des Abstandshalters;
• 4c eine Stirnansicht eines Abstandshalters;
• 4d eine Stirnansicht eines Abstandshalters;
• 4e eine Stirnansicht eines Abstandshalters;
• 5 einen Heizwiderstand mit drei Heizebenen.

Further advantages and details of the invention are explained in the patent claims and in the description and shown in the figures. They show:

• 1a a front view of the heating element;
• 1b a side view of 1a;
• 1c a detailed view 1a ;
• 2a the rear view from 1a ;
• 2 B the side view 2a ;
• 3a a view of the heating element after 1a from above;
• 3b a view of the heating element after 1a from underneath;
• 3c an alternative embodiment of the heating element in the view from below;
• 4a a spacer in the side view;
• 4b an alternative embodiment of the spacer;
• 4c a front view of a spacer;
• 4d a front view of a spacer;
• 4e a front view of a spacer;
• 5 a heating resistor with three heating levels.

An Indian 1a The heating element 1 shown is formed from a conductor 2a with a longitudinal axis 2b and two contacts 3.1, 3.2 for applying an electrical voltage. The conductor 2a runs in a meandering shape and for this purpose has various conductor sections 2.1 to 2.6, which are arranged one behind the other and which are separated from one another by a gap 2c with a gap width of 2.9. The various conductor sections 2.1 to 2.6 form a circular base area 7. The various conductor sections are connected to one another at the end via a bridge 2.4 as a further conductor section, with the respective bridge 2.4 bridging the respective gap 2c. The meandering conductor sections with the base area 7 therefore form a heating level H1.

In the side view after 1b In addition to the heating level H1 just described, a further heating level H2 is provided, which is formed from corresponding conductor sections 2.5, 2.6. Both heating levels H1, H2 are connected to one another via a conductor section 2.4 designed as a bridge. Both heating levels H1, H2 delimit a groove 4.1 with a groove width 4.3. Gas flow 5 flowing in from the right initially enters through the first heating level H1 and after passing through the groove 4.1 it passes through the second heating level H2.

According to 1c , a detailed view of 1a , the current conductor 2a has a longitudinal axis 2b which, as shown in 1a runs in a meandering shape. The length of the current conductor therefore corresponds to the length of the longitudinal axis 2b. The bridge 2.2 shown serves to bridge the gap 2c. The bridge 2.2 has a longitudinal axis 2.2' which is aligned transversely to the gap 2c.

The back of the heating element 1 acc. 2a is constructed in a similar way. The various conductor sections form a meandering path, whereby appropriate bridges 2.4 alternate between the 1a shown front and the 2a shown back. Thus, the longitudinal axis 2b or a current 2.0 runs from the contact 3.1 downwards, changes there via a bridge 2.4 to the front as shown. 1a top left and then runs in a U-shape over two conductor sections back up to the upper end of the conductor section 2.3 and then changes over a bridge 2.4 to the back and again describes an arc on the back. The respective arc is formed by two conductor sections that are connected to each other by a bridge 2.2 and each delimit the gap 2c between them.

The groove 4.1 located between the two heating levels_H1, _H2 has a corresponding partially circular groove base, which is limited by the bridges 2.4 arranged below.

According to the embodiments shown here, both heating planes H1, H2 lie in or parallel to an x-y plane, spanned by the spatial axis x and the spatial axis y. The aforementioned groove plane 4.2 is also arranged or aligned parallel to this. The gap plane 2d, in turn, which is spanned by adjacent gaps 2c of the two heating planes H1, H2, runs at right angles to the groove plane 4.2, and thus lies in a spatial plane y-z, which is spanned by the spatial axis y and the spatial axis z.

In the view from above acc. 3a the bridges 2.4 arranged next to each other can be seen, via which the two heating levels _H1, _H2 are connected to each other. Between the various bridges 2.4, the bridges 2.2 can be seen, which each bridge the gap between two conductor sections. The bridges 2.2 are located at the lower edge of the heating element. The respective gap spans a gap level 2.d and has a gap width of 2.9.

In the view from below 3b the bridges 2.2 arranged next to each other to bridge the respective gap can be seen. Within the groove 4.1, the bridges 2.4 arranged above are shown, which run over the groove 4.1. The groove 4.1 spans a groove plane 4.2, whereby the groove plane 4.2 and the gap plane 2d enclose an angle α of 90°. The groove has according to. 1b a groove width 4.3, which corresponds to a distance_e between the two heating levels_H1, _H2.

While according to the embodiment described above the bridges 2.2, 2.4 used between the different conductor sections alternate, according to the embodiment 3c a representation from above or below is provided, in which a bridge 2.2 for bridging the gap is directly connected to the bridge 2.4 for bridging the groove. A current conductor section is provided between this double arrangement of the bridges 2.2, 2.4.

To maintain the distance e between the heating levels_H1, _H2 on the one hand and to maintain the gap width 2.9, a spacer element 6 is required in accordance with 4a to 4c The spacer element has an elongated base body 6.1, to which several crosspieces 6.2, 6.3 are connected. The crosspieces 6.2, 6.3 are each provided opposite to the base body 6.1 and have the gap width 2.9. The base body 6.1 has the groove width 4.3, which corresponds to the distance e between the two heating levels. By inserting the spacer 6, i.e. by inserting the base body 6.1 into the groove 4.1 on the one hand and inserting the crossbars 6.2, 6.3 into the gap 2c on the other hand, the necessary distance between the various conductor sections is ensured.

In the embodiment according to 4b the spacer has fewer crosspieces 6.2, 6.3. Such a spacer would be used in the area of the respective bridge 2.2 in which no crosspiece is necessary, so that only crosspieces are provided for the gaps that are not bridged by a bridge 2.2 or for the gap at the end of which no bridge 2.2 is provided.

According to view 4c the base body 6.1 has a maximum width that corresponds to the distance e between the heating levels. One edge length of the rectangle corresponds to the width of the crosspieces 6.2, 6.3. This can also be constructed differently so that different widths are used.

According to the example 4d the base body 6.1 has a round cross-section with a diameter corresponding to the distance e between the heating levels.

According to the example 4e the crosspiece 6.2 has a significantly larger extension a than the crosspiece 6.3. This variant is used for a heating resistor 2 with three heating levels that delimit two grooves 4.1. Due to the extension a, the crosspiece 6.2 then extends into the respective gap 2c of two adjacent heating levels_H1, _H1', while the crosspiece 6.2 is positioned in the respective gap of the third opposite heating level_H2.

The embodiment 5 shows a heating resistor 2 with three parallel heating levels_H1, _H1', _H2.

List of reference symbols

1

Heating element

2a

Conductor

2 B

Longitudinal axis

2c

gap

2d

Column level

2f

length

2

Heating resistor

2.0

Current direction, main flow direction

2.1

Conductor section

2.2

Conductor section, bridge_1

2.2'

Central axis

2.3

Conductor section

2.4

Conductor section, bridge_2

2.4'

Central axis

2.5

Conductor section

2.6

Conductor section

2.9

Gap width

3.1

Contact

3.2

Contact

4

front

4.1

Groove

4.2

Groove level

4.3

Groove width

5

Gas flow

6

Spacers

6.1

Base body

6.2

Crossbar

6.3

Crossbar

7

Floor space

a

Expansion of 6.2

e

Distance

Nomenclature:

• Bridge_1
• Bridge_2
• Level_E1
• Level_E2
• Heating level_H1
• Heating level_H1'
• Heating level_H2
• Spatial axis x
• Spatial axis y
• Spatial axis z
• x-y plane
• x-z plane
• y-z plane
• Angle α

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• US5533167 [0003]
• KR 20050087202 A [0004]

Claims (12)

Heating element (1) for heating a gas flow (5) with a heating resistor (2) and with two contacts (3.1, 3.2) for applying an electrical voltage, wherein the heating resistor (2) has at least one current conductor (2a) with a length (2f) and a longitudinal axis (2b), which extends over its length (2f) between both contacts (3.1, 3.2), wherein the longitudinal axis (2b) represents a main flow direction (2.0) of the electrical current, wherein at least three current conductor sections (2.1, 2.2, 2.3) are provided, wherein all at least three current conductor sections (2.1, 2.2, 2.3) form a common heating plane H1 with respect to the longitudinal axis (2b), wherein at least two of the at least three current conductor sections (2.1, 2.2, 2.3) are arranged next to one another with respect to a direction perpendicular to the longitudinal axis (2b) and have a Limit the gap (2c), wherein at least one conductor section of the at least three conductor sections (2.1, 2.2, 2.3) is designed as a bridge_1 (2.2) and bridges the gap (2c), characterized in that at least three further conductor sections (2.4, 2.5, 2.6) are provided which, with respect to the longitudinal axis (2b), form at least one common second heating level_H2 which is arranged at a distance_e from the first heating level_H1, wherein at least one conductor section is provided which is designed as a bridge_2 and which bridges the distance_e. Heating element (1) after Claim 1 , characterized in that the respective heating level_H1, _H2 has a front side (4) facing the gas flow to be heated and having a base area (7), wherein the first heating level_H1 and the at least second heating level_H2 delimit a groove (4.1) over at least 70% of the base area (7), wherein the bridge_2 bridges the groove (4.1). Heating element (1) after Claim 2 , characterized in that the groove (4.1) spans a groove plane (4.2) and that opposite gaps (2c) of adjacent heating planes_H1, _H2 span a gap plane (2d), wherein the groove plane (4.2) encloses an angle α between 10° and 90° relative to the gap plane (2d). Heating element (1) according to one of the preceding claims, characterized in that the respective bridge_1, _2 has a central axis (2.2', 2.4'), wherein the central axis runs parallel to the heating plane_H1, _H2 or runs at right angles to the heating plane_H1, _H2. Heating element (1) after Claim 4 , characterized in that, using a Cartesian coordinate system with three spatial axes_x, _y, _z, the heating plane_H1 is aligned parallel to the xy plane and the bridge_1 extends at least partially in the direction of the spatial axis_x with reference to the central axis (2.2') for bridging the gap (2c) and the bridge_2 extends at least partially in the direction of the spatial axis_z with reference to the central axis (2.4') for bridging the groove (4.1). Heating element (1) according to one of the preceding claims, characterized in that the main flow direction (2.0) of the electric current can be guided alternately over the heating level_H1 and the heating level_H2. Spacer (6) for a heating element (1) according to one of the preceding claims with a base body (6.1) which can be aligned parallel to the groove plane (4.2), characterized in that at least one first transverse web (6.2) and at least one second transverse web (6.3) are provided which can be aligned parallel to the groove plane (4.2), wherein the first transverse web (6.2) is arranged opposite the second transverse web (6.3) with respect to the base body (6.1). Spacer (6) after Claim 7 , characterized in that the base body (6.1) extends in the direction of the x-axis and that the transverse webs (6.2) extend in the direction of the z-axis, wherein the base body (6.1) has a maximum width which corresponds to the distance_e between two heating planes_H1, _H2 and wherein the respective transverse web (6.2, 6.3) has a width which corresponds to the gap width (2.9). Spacer (6) after Claim 7 or 8th , characterized in that the distance between the transverse webs (6.2) corresponds to the gap width (2.9) of the column (2c) or that the distance between the transverse webs (6.2) corresponds to twice the distance of the column. Spacer (6) according to one of the Claims 7 - 9 , characterized in that the transverse webs (6.2, 6.3) are of different lengths and at least one transverse web (6.2) can be positioned in the gaps of several heating levels. Heating element (1) according to one of the Claims 1 - 6 , characterized in that the heating resistor (2) has at least three heating levels, the heating level_H1, the heating level_H1' and the heating level_H2. System consisting of a heating element (1) according to one of the Claims 1 - 6 or 11 with min at least one spacer (6) arranged therein according to one of the Claims 7 - 10 .