Electrode and spacer element

Abstract

The invention relates to a heating resistor (1) for insertion into an exhaust pipe (4), the heating resistor (1) being formed in the shape comprising a plurality of heating rings (1.3) arranged adjacent to one another, forming a basic shape G, each heating ring (1.3) being composed of two strip shapes, namely a first strip shape and a second strip shape, the adjacent strip shapes (1.2 a, 1.2 b) of the heating rings (1.3) being connected to one another, 1.2b) are separated by a groove (1.1) having a groove axis (1.1 a), at least one first strip comprises a receiving opening (1.4a) having a cross-sectional shape A for receiving the insulator (2), and an adjacent second strip in the region of the receiving opening (1.4a): a) is flat or b) comprises a contact surface (1.4 b) having a cross-sectional shape F, the cross-sectional shape F differing from the cross-sectional shape A.

Description

[0001] The present invention relates to a heating resistor for insertion into an exhaust pipe for heating exhaust gases, wherein the heating resistor has a basic shape _G, wherein one or more heating rings arranged adjacent to each other are provided to form the basic shape _G, wherein each of the heating rings is composed of two strips coupled at their ends, namely a first strip and a second strip, wherein adjacent strips of the heating rings or adjacent strips of the heating rings are separated by a groove or a gap having a groove axis.

[0002] A heating resistor with spacing elements is already known from US Pat. No. 5,501,842 A. The heating resistor comprises a transverse groove into which an insulator element is inserted.

[0003] The object of the present invention is to design and arrange a heating resistor so as to improve its continuous load capacity.

[0004] According to the invention, this problem is solved in that at least one first strip comprises a receiving opening having a cross-sectional shape _A for receiving the insulator, wherein the adjacent second strip in the region of the opening:

[0005] a) is flat, or

[0006] b) comprising a contact surface having a cross-sectional shape_F, the cross-sectional shape_F being different from the cross-sectional shape_A. The cross-sectional shape_A or the cross-sectional shape_F may be circular, elliptical, polygonal or angular.

[0007] The different design of the contact surface on the adjacent second strip in the area of ​​the receiving opening prevents a positive locking between the insulator and the second strip, so that the insulator can be moved in two directions relative to the second strip and the groove axis. This allows a low-load relative movement between the insulator and the second strip when the heating resistor is heated. No relative movement between the first strip and the insulator is provided. The same effect can also be achieved if a receiving opening with a cross-sectional shape _F is provided as a contact surface, wherein the cross-sectional shape _F deviates from the cross-sectional shape _A or is larger than the cross-sectional shape _A, so that when the insulator is used, the second strip and the insulator can be subjected to a load-free relative movement in the direction of the groove axis. In the main exhaust gas flow direction, that is, perpendicular to the heating resistor surface, each insulator can be inserted into the receiving opening. With respect to the three translational spatial axes, there is at least one bidirectional support between the insulator and the first strip. However, the insulator can be in contact with the second strip at least in a direction perpendicular to the groove axis or perpendicular to the exhaust gas flow.

[0008] Furthermore, it is advantageous if the receiving opening comprises two side walls for ensuring a positive locking with the insulator to be inserted into the receiving opening in the direction of the groove axis. The insulator can form a positive locking contact with the first strip relative to a spatial axis running parallel to the groove axis. This means that a positive locking can be formed between the insulator and the first strip in both directions of the groove axis.

[0009] Further, a heating element is advantageous, which comprises a heating resistor as described above and an insulator mounted therein.

[0010] Furthermore, it is also advantageous if the insulator has a cross-sectional shape _L, wherein only the first strip comprises a receiving opening, the cross-sectional shape _A of the receiving opening corresponding to a portion of the cross-sectional shape _L, wherein each insulator forms a positive lock with the receiving opening in two directions relative to the groove axis. This means that the connection of the insulator to the first strip is sufficiently strong.

[0011] It is advantageous if the adjacent second strip in the region of the receiving opening comprises a contact surface with a cross-sectional shape _F, wherein the insulator comprises a contact zone with a cross-sectional shape _Z, wherein the cross-sectional shape _Z differs from the cross-sectional shape _F. The deviated cross-sectional shape _F ensures a load-free relative movement between the second strip and the insulator.

[0012] For this purpose, it is advantageous if the cross-sectional shape_F comprises a radius_R and the cross-sectional shape_Z comprises a radius r, where R>r or R>=2r. This ensures that the insulator has sufficient freedom of movement relative to the first strip in the direction of the groove axis.

[0013] Furthermore, it is also advantageous if a gap is provided between the contact area of ​​the insulator and the adjacent second strip. This allows the groove width or the gap width to be reduced when the heating resistor is heated until the insulator contacts the second strip. Thus, the pressure acting on the insulator or the strip in a direction perpendicular to the groove axis can be reduced.

[0014] Furthermore, it is advantageous if the receiving opening comprises a bottom opening, wherein the insulator forms a positive lock with the first strip in a Q direction perpendicular to the axis of the groove. A considerable gap may exist between the insulator and the adjacent second strip (in the cooled state). During heating of the heating element, the gap may decrease or increase. However, regardless of the size of the gap, the insulator always remains in the first strip. Therefore, the insulator is always prevented from sliding out of the receiving opening in a Q direction perpendicular to the axis of the groove. The insulator resting on the second strip is mounted in a positive locking manner relative to two spatial axes. A third free spatial axis is used to insert the insulator into the receiving opening.

[0015] Furthermore, it is also advantageous if the receiving opening has a cross-sectional shape_A which is circular, elliptical, polygonal or angular and / or if at least the portion of the insulator received by the receiving opening has a cross-sectional shape_A which is circular, elliptical, polygonal or angular. This also prevents the insulator from rotating in the receiving opening.

[0016] The insulator is made of a ceramic material or is designed as a metal pin with a ceramic coating.

[0017] Furthermore, a system consisting of a heating element as described above and at least a part of an exhaust system in the form of an exhaust pipe is advantageous, wherein the heating resistor is arranged in the exhaust pipe.

[0018] Further advantages and details of the invention are explained in the claims and the description and are shown in the drawings.

[0019] The attached figure shows:

[0020] Figure 1 is a three-dimensional diagram of a heating element;

[0021] Figure 2a-3c It is a detailed diagram.

[0022] Figure 1 The heating element 10 shown comprises a heating element in the form of a heating resistor 1. The heating resistor 1 comprises a plurality of heating rings 1.3, which are formed by two strips 1.2a, 1.2b or a first strip and a second strip (hereinafter referred to as 1.2a and 1.2b) connected at their ends. Adjacent strips 1.2a, 1.2b are separated from each other by a groove 1.1 having a groove axis 1.1a. Insulators 2 are respectively provided in the end regions of the grooves 1.1 to ensure the distance between adjacent heating rings 1.2a, 1.2b. The heating resistor 1 has a circular basic shape _G, which ensures that it can be installed in an exhaust pipe 4 which is also circular.

[0023] Figures 2a to 3c The detail view in shows the end region of the groove 1.1 between two adjacent strips 1.2a, 1.2b. The two strips 1.2a, 1.2b are separated from each other by the groove 1.1. An insulator 2 is arranged in the end region of each groove, which is accommodated in the strip 1.2a. To this end, the strip 1.2a comprises a receiving opening 1.4a, which has a cross-sectional shape _A, which extends laterally along the groove axis 1.1a. The insulator 2 is supported in the receiving opening 1.4a. The cross-sectional shape _L of the part of the insulator 2 embedded in the receiving opening 1.4a corresponds to the cross-sectional shape _A. The insulator 2 is located at the contact surface 1.4b of the adjacent first strip.

[0024] According to embodiments 2a to 2d, the contact surface 1.4b of the strip 1.2b or its cross-sectional shape _F is flat in the region of the insulating body 2 or in the region of the adjacent receiving opening 1.4a. The same applies to Figure 2b Here, the contact surface 1.4b is also flat, wherein the size of the contact surface is limited to the extension of the required groove in the strip 1.2b.

[0025] according to Figures 2a to 2e In an embodiment, there is virtually no gap 3 (in the cold state) or a very small gap 3 between the insulator 2 and the adjacent strip 1.2b. This gap 3 may change when the heating element heats up. However, no fixed seat is provided for the insulator 2 in the receiving opening 1.4a; the insulator 2 can move in the Q direction perpendicular to the groove axis 1.1. The cross-sectional shape _L of the insulator 2 embedded in the receiving opening 1.4a corresponds to the cross-sectional shape _A. Against the background of the maximum achievable gap width, the insulator 2 may slide out of the receiving opening 1.4a in the Q direction perpendicular to the groove axis 1.1. However, as Figure 2a As shown, the insulating body 2' rests on the adjacent strip 1.2b or the contact surface 1.4b. This means that the insulating body 2 is always at least partially held in the receiving opening 1.4a.

[0026] according to Figures 3a to 3c In an embodiment, the insulator 2 is received in the strip 1.2a by positive locking relative to the Q direction perpendicular to the groove axis 1.1. To this end, the strip 1.2a or the receiving opening 1.4a comprises a bottom opening 1.5. Thus, positive locking of the insulator 2 with the strip 1.2a relative to the groove axis 1.1a in both directions is ensured. There is a considerable gap 3 (in the cooling state) between the insulator 2 and the adjacent strip 1.2b. This gap 3 may decrease or increase when the heating element heats up. However, regardless of the size of the gap 3, the insulator 2 always remains in the strip 1.2a. Thus, the insulator 2 is always prevented from sliding out of the receiving opening 1.4a in the Q direction perpendicular to the groove axis 1.1.

[0027] according to Figure 2a , 2e , 3a, the embedded part of the insulating body 2 has a circular cross-sectional shape _L, wherein the receiving opening 1.4a has a corresponding semicircular cross-sectional shape _A. Figure 3a , the depth t of the receiving opening 1.4a is greater than the radius r of the circular insulator 2, thereby ensuring cutting in from the bottom.

[0028] according to Figure 2cIn an embodiment of the present invention, the embedded part of the insulator 2 has an elliptical cross-sectional shape _L. The receiving opening 1.4a accordingly has a partially elliptical cross-sectional shape _A, so that the insulator 2 can be inserted into the receiving opening 1.4a in a direction perpendicular to the drawing. A bottom opening of the receiving opening 1.4a is provided here. This is not necessary, because the insulator 2 rests on the strip 1.2b or its contact surface 1.4b.

[0029] according to Figure 3b In the embodiment, the insulator 2 has a cross-sectional shape _L which is a trapezoid as a whole, and according to Figure 3c , the insulator 2 has a truncated cone cross-sectional shape _L including a circular contact area 2.1 or a cross-sectional shape _Z. Figure 2b , 2d 3b, the contact area 2.1 is flat.

[0030] according to Figure 2e , 3c In the two embodiments, the contact surface 1.4b or its cross-sectional shape _F is circular. The radius R of the contact surface 1.4b is approximately twice the radius r of the contact area 2.1 of the insulator 2 or the radius r of the cross-sectional shape _Z. This allows the contact area 2.1 of the insulator 2 to have a minimum form fit with the opposing strip 1.2b in a direction parallel to the groove axis 1.1.

[0031] Figure 3a 'Shows Figure 3a Here we can see the two side walls 1.41, 1.42 of the receiving opening 1.4a.

[0032] List of reference numerals:

[0033] 1Heating element, heating resistor

[0034] 1.1 Groove

[0035] 1.1a Groove axis

[0036] 1.2a The first bar

[0037] 1.2b The second bar

[0038] 1.3 Heating ring

[0039] 1.4a Receiving opening

[0040] 1.41 Sidewall

[0041] 1.42 Sidewall

[0042] 1.4b Contact surface

[0043] 1.5 Bottom opening

[0044] 2 Insulator

[0045] 2'Insulator

[0046] 2.1 Contact area

[0047] 3. Clearance

[0048] 4 Exhaust pipe

[0049] 10 Heating element

[0050] t Depth

[0051] Q is perpendicular to the direction of 1.1a

[0052] R Radius

[0053] r Radius

[0054] Basic shape of heating resistor_G

[0055] Cross-sectional shape of receiving opening_A

[0056] Cross-sectional shape of the contact surface_F

[0057] Cross-sectional shape of the insulator_L

[0058] Cross-sectional shape of the contact area_Z

Claims

1. A heating resistor (1) for insertion into an exhaust pipe (4), the heating resistor (1) having a basic shape _G, wherein one or more heating rings (1.3) arranged adjacent to each other are formed, wherein each heating ring (1.3) is composed of two strips (1.2a, 1.2b) coupled at their ends, the two strips (1.2a, 1.2b) being a first strip (1.2a) and a second strip (1.2b), the adjacent strips (1.2a, 1.2b) defining a groove (1.1) having a groove axis (1.1a), characterized in that At least one first strip (1.2a) comprises a receiving opening (1.4a) having a cross-sectional shape _A for receiving an insulator (2), wherein an adjacent second strip (1.2b) in the region of the receiving opening (1.4a): a) is flat; or b) comprises a contact surface (1.4b) having a cross-sectional shape_F, said cross-sectional shape_F being different from said cross-sectional shape_A.

2. The heating resistor (1) according to claim 1, characterized in that The receiving opening (1.4a) comprises two side walls (1.41, 1.42) for ensuring positive locking with an insulator (2) to be inserted into the receiving opening (1.4a) in the direction of the groove axis (1.1a).

3. A heating element (10) comprising a heating resistor (1) according to any one of the preceding claims and an insulator (2) mounted therein.

4. The heating element (10) according to claim 3, characterized in that The insulator (2) has a cross-sectional shape _L, wherein only one first strip (1.2a) includes a receiving opening (1.4a), and the cross-sectional shape _A of the receiving opening (1.4a) corresponds to a portion of the cross-sectional shape _L, wherein each of the insulators (2) can form a positive lock with the receiving opening (1.4a) in two directions relative to the groove axis (1.1a).

5. The heating element (10) according to claim 4, characterized in that The adjacent second strip (1.2b) in the area of ​​the receiving opening (1.4a) comprises a contact surface (1.4b), the contact surface (1.4b) having a cross-sectional shape _F, wherein the insulator (2) comprises a contact area (2.1), the contact area (2.1) having a cross-sectional shape _Z, and the cross-sectional shape _Z is different from the cross-sectional shape _F.

6. The heating element (10) according to claim 5, characterized in that The cross-sectional shape_F includes a radius_R, and the cross-sectional shape_Z includes a radius r, where R>r or R>=2r.

7. The heating element (10) according to any one of claims 3 to 6, characterized in that A gap (3) is provided between the contact area (2.1) of the insulator (2) and the adjacent second strip (1.2b).

8. The heating element (10) according to any one of claims 3 to 7, characterized in that The receiving opening (1.4a) comprises a bottom opening (1.5), and the insulator (2) forms a positive lock with the first strip (1.2a) in a Q direction perpendicular to the groove axis (1.1a).

9. The heating element (10) according to any one of claims 3 to 8, characterized in that The receiving opening (1.4a) has a cross-sectional shape _A, which is circular, elliptical, polygonal or angular, and / or at least the portion of the insulator (2) received by the receiving opening (1.4a) has a cross-sectional shape _A, which is circular, elliptical, polygonal or angular.

10. A system comprising a heating element (10) according to claim 4 and at least a part of an exhaust system in the form of an exhaust pipe (4), wherein the heating resistor (1) is arranged in the exhaust pipe (4).

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