An electric heater

Abstract

The utility model discloses an electric heater, it is characterized in that, it includes casing, heating band and at least two terminal post subassembly, casing is provided with the accommodation cavity, and the heating band is accommodated in the accommodation cavity, the surface of casing is provided with the through mounting hole, and the mounting hole is linked together with the accommodation cavity, and one end of terminal post subassembly is electrically connected with the heating band in casing, and the other end of terminal post subassembly projects to the outside of casing, terminal post subassembly includes ceramic insulating tube, T type sleeve and mounting column, ceramic insulating tube is sleeved on the mounting hole, and the heating band is fixedly connected with T type sleeve, and the heating band and T type sleeve all do not contact with casing, and T type sleeve and mounting column are fixedly connected through ceramic insulating tube. This patent adopts the electrically conductive sheet, nickel gasket and T type sleeve further electrically connected, avoids the local heating problem, guarantees its reliability. Adopt laser welding and brazing, avoid the contact resistance too big and influence the conductivity.

Description

Technical Field

[0001] This utility model relates to the field of electric heating, and in particular to an electric heater. Background Technology

[0002] The electric heater for the auxiliary SCR (Selective Catalytic Reduction) catalytic system belongs to the field of exhaust gas treatment technology. It is used to improve exhaust gas treatment efficiency and reduce emissions of nitrogen oxides (NOx) and other pollutants during vehicle cold start and low-temperature conditions.

[0003] During vehicle cold starts, the exhaust gas temperature is low, and traditional SCR catalytic converters cannot function effectively, resulting in the emission of large amounts of NOx and other pollutants into the atmosphere. Existing solutions include using electric heating devices to increase the catalytic converter inlet temperature. However, the current technology of combining electric heating devices with the catalytic converter suffers from problems such as low efficiency, uneven heating (uneven temperature distribution throughout the catalytic converter), complex structure, and large size, making miniaturization impossible. It is also unable to heat the catalytic converter to its active temperature range (typically 200-300°C) in a short time, and is not suitable for installation in confined spaces.

[0004] Therefore, there is an urgent need for a miniaturized electric heater that can heat quickly and evenly to improve the efficiency of exhaust gas treatment during the cold start phase. Utility Model Content

[0005] To at least solve one of the technical problems existing in the prior art, this utility model provides an electric heater. The specific technical solution is as follows:

[0006] This utility model provides an electric heater, characterized in that it includes a housing, a heating band, and at least two terminal block assemblies;

[0007] The housing has a receiving cavity, and the heating band is housed in the receiving cavity;

[0008] The housing surface has a through mounting hole that communicates with the receiving cavity. One end of the terminal assembly is electrically connected to the heating element inside the housing, and the other end of the terminal assembly extends out of the housing.

[0009] The terminal assembly includes a ceramic insulating tube, a T-shaped sleeve, and a mounting post; the ceramic insulating tube is fitted onto the mounting hole, the heating band is fixedly connected to the T-shaped sleeve, neither the heating band nor the T-shaped sleeve is in contact with the housing, and the T-shaped sleeve and the mounting post pass through the ceramic insulating tube and are fixedly connected.

[0010] As a preferred embodiment of the electric heater described in this utility model, the T-shaped sleeve includes a limiting part and a main body part. The heating band is provided with a through hole for passing through the main body part. The outer diameter of the limiting part is larger than the outer diameter of the main body part and the inner diameter of the through hole. The heating band is sleeved on the main body part and abuts against the ceramic insulating tube. The main body part of the T-shaped sleeve extends into the ceramic insulating tube, and the mounting post is fixedly installed in the main body part.

[0011] As a preferred embodiment of the electric heater described in this utility model, a T-shaped sleeve extends into a ceramic insulating tube, the inner wall of the T-shaped sleeve is provided with an internal thread, and the surface of the mounting post is provided with an external thread that matches the internal thread of the inner wall of the T-shaped sleeve. The mounting post extends from the outside of the shell and is fixedly screwed into the T-shaped sleeve.

[0012] As a preferred embodiment of the electric heater described in this utility model, the inner wall of the mounting hole is provided with an internal thread, and the surface of the ceramic insulating tube is provided with an external thread that matches the internal thread of the inner wall of the mounting hole. The ceramic insulating tube is screwed and fixed to the mounting hole of the shell.

[0013] As a preferred embodiment of the electric heater described in this utility model, the length of the ceramic insulating tube is greater than the thickness of the shell, and both ends of the ceramic insulating tube protrude outward from the inner and outer surfaces of the shell.

[0014] As a preferred embodiment of the electric heater described in this utility model, one end of the ceramic insulating tube is provided with a raised edge structure, the outer diameter of which is larger than the inner diameter of the corresponding mounting hole on the shell.

[0015] As a preferred embodiment of the electric heater described in this utility model, the heating strip is sleeved on the terminal assembly, and / or the heating strip and the terminal assembly are fixedly connected by laser welding and brazing.

[0016] As a preferred embodiment of the electric heater described in this utility model, there are multiple heating bands, which are spaced apart inside the housing along the airflow direction.

[0017] As a preferred embodiment of the electric heater described in this utility model, it also includes a connecting assembly, wherein two adjacent heating strips are electrically connected through the connecting assembly and the conductive sheet, and the outermost heating strip is connected to the corresponding terminal assembly.

[0018] As a preferred embodiment of the electric heater described in this utility model, the heating belt is connected to the corresponding connecting components, and two adjacent connecting components are electrically connected through conductive parts;

[0019] The connecting assembly includes bolts, an insulator, and a nut; the housing has a connecting hole, the insulator is housed in the connecting hole, the insulator has an insulating hole, the heating band and the conductive element are both sleeved on the bolt, the bolt passes through the insulating hole, and the nut is fixedly screwed onto the bolt. The insulator is configured such that the heating band, the conductive element, the bolt, and the nut are not electrically connected to the housing, while the heating band and the conductive element are electrically connected to the bolt.

[0020] As a preferred embodiment of the electric heater described in this utility model, the connecting assembly further includes a nickel gasket, which is sleeved on the bolt and is in contact with the heating band.

[0021] As a preferred embodiment of the electric heater described in this utility model, the nickel pad is a pure nickel pad.

[0022] As a preferred embodiment of the electric heater described in this utility model, the insulating component includes an insulating sleeve, a first insulating sheet, and a second insulating sheet; the insulating sleeve is housed within the connecting hole of the housing, and the first insulating sheet and the second insulating sheet are respectively disposed on both sides of the housing.

[0023] As a preferred embodiment of the electric heater described in this utility model, the heating belt includes one or more heating strips, which are bent in a zigzag shape or at right angles on the left and right sides. The zigzag bends and radially adjacent zigzag bends form a rectangular structure, and the contact parts of the bends of the same heating strip or two adjacent heating strips are fixedly connected.

[0024] As a preferred embodiment of the electric heater described in this utility model, a fixed bracket is also provided inside the accommodating cavity, and the heating belt is fixedly connected to the fixed bracket through an insulating fastener.

[0025] Compared with the prior art, the technical solution of this utility model has at least one or more of the following beneficial effects:

[0026] The electric heater of this patent is used in the exhaust system to rapidly heat the aftertreatment components of the exhaust gas; it is also used in SCR technology for exhaust gas recirculation; the exhaust gas flows through the heating belt and is heated by convection, and the heated exhaust gas transfers its heat to the catalyst along the flow direction.

[0027] Traditional stainless steel or copper gaskets have poor conductivity or temperature resistance. This patent replaces them with pure nickel gaskets, which have good conductivity and high temperature resistance.

[0028] This patent uses conductive sheets, nickel pads, and T-shaped sleeves for further electrical connection. If the terminal and heating band are only connected by welding, it is easy to generate large contact resistance and severe local heating, which makes the heating band easy to burn out. This patent adds a fixed electrical connection of conductive sheets, nickel pads, and T-shaped sleeves to avoid the problem of local heating and ensure its reliability.

[0029] The heating strips are fixed to the terminals and to each other using welding, employing both laser welding and brazing. Laser welding is used for initial fixing, followed by brazing to ensure sufficient contact between each heating strip or the terminal, preventing excessive contact resistance and further improving fixing strength and conductivity. In contrast, traditional resistance welding results in contact resistance, affecting conductivity, and also provides insufficient fixing strength.

[0030] The heating strip is fixed to the terminal block assembly and connecting assembly by welding. The insulating pad extends into the rectangular structure of the heating strip, and the end of the heating strip is fixed and tightened by nuts and mounting posts, which reduces the stress after assembly with the heating tape and improves the service life of the product.

[0031] The insulating pad has an indentation part and a separation part, which can stably support the heating belt, prevent the heating belt from shaking and deforming, and also avoid leakage.

[0032] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0033] To more clearly illustrate the technical solution of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the structure of an existing electric heater;

[0035] Figure 2 This is a three-dimensional structural schematic diagram of the heater for uniform heating described in this utility model;

[0036] Figure 3 This is a schematic diagram of the main structure of the heater for uniform heating according to the present invention;

[0037] Figure 4 This is a cross-sectional view of the heater for uniform heating described in this utility model.

[0038] Figure 5 yes Figure 4 A cross-sectional perspective view of the heater used for uniform heating;

[0039] Figure 6 yes Figure 5 A magnified view of the middle R section.

[0040] Among them, 1-shell, 2-heating belt, 3-terminal assembly, 4-connection assembly, 11-accommodating cavity, 13-fixed bracket, 14-fixed rod, 15-insulating pad, 21-heating strip, 211-first heating strip, 212-second heating strip, 31-ceramic insulating tube, 32-T-shaped sleeve, 321-limiting part, 322-main body, 33-mounting post, 41-bolt, 42-nut, 43-nickel washer, 441-insulating sleeve, 442-first insulating sheet, 443-second insulating sheet, 91-conventional electric heating belt. Detailed Implementation

[0041] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.

[0042] In the description of this utility model, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this utility model. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0043] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "provided with," "equipped with," "connected," "installed," "sleeved," "opened," and "fixed," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0044] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

[0045] Please refer to Figures 2-6 ,like Figures 2-6 As shown, this utility model provides an electric heater, which includes a housing 1, a heating band 2, and at least two terminal block assemblies 3;

[0046] The housing 1 has a receiving cavity 11, and the heating band 2 is housed in the receiving cavity 11;

[0047] A through mounting hole is provided on the surface of the housing 1, which is connected to the accommodating cavity 11. One end of the terminal assembly 3 is electrically connected to the heating band 2 inside the housing 1, and the other end of the terminal assembly 3 extends out of the housing 1.

[0048] The terminal assembly 3 includes a ceramic insulating tube 31, a T-shaped sleeve 32, and a mounting post 33. The ceramic insulating tube 31 is fitted onto the mounting hole, and the heating band 2 is fixedly connected to the T-shaped sleeve 32. Neither the heating band 2 nor the T-shaped sleeve 32 is in contact with the housing 1. The T-shaped sleeve 32 and the mounting post 33 pass through the ceramic insulating tube 31 and are fixedly connected.

[0049] The electric heater of this patent is used in the exhaust system to rapidly heat the aftertreatment components of the exhaust gas; it is also used in SCR technology for exhaust gas recirculation; the exhaust gas flows through the heating belt and is heated by convection, and the heated exhaust gas transfers its heat to the catalyst along the flow direction.

[0050] In the example, there are two terminal assembly 3: one positive terminal assembly 3 and one negative terminal assembly 3. In the example, the mounting post is electrically connected to an external power source.

[0051] Preferably, the heating band 2 is sleeved on the terminal assembly 3, and / or the heating band 2 and the terminal assembly 3 are fixedly connected by laser welding and brazing. In the example, the heating band 2 is sleeved on the T-sleeve 32, and the heating band 2 is laser welded and brazed onto the T-sleeve 32.

[0052] In the example, ceramic insulating tube 31 is a ceramic insulating tube with an alumina content greater than 95%.

[0053] Preferably, the length of the ceramic insulating tube 31 is greater than the thickness of the shell, and both ends of the ceramic insulating tube 31 protrude outward from the inner and outer surfaces of the shell, so that the heating band 2, the T-shaped sleeve 32, and the mounting post 33 do not contact the shell 1. Preferably, one end of the ceramic insulating tube 31 is also provided with a raised edge structure, the outer diameter of which is larger than the inner diameter of the corresponding mounting hole on the shell 1. During installation, it is only necessary to make the raised edge of the ceramic insulating tube 31 abut against the shell 1 to ensure that the heating band 2, the T-shaped sleeve 32, and the mounting post 33 do not contact the shell 1. Of course, this patent is not limited to this, and insulating sheets can also be provided on both sides of the shell, provided that the heating band 2, the T-shaped sleeve 32, and the mounting post 33 are not electrically connected to the shell 1.

[0054] In the example, the inner wall of the mounting hole is provided with internal threads, and the surface of the ceramic insulating tube 31 is provided with external threads that match the internal threads of the mounting hole. The ceramic insulating tube 31 is fixedly screwed onto the mounting hole of the housing 1. In the example, the length of the ceramic insulating tube 31 is greater than the thickness of the housing 1, and both ends of the ceramic insulating tube 31 protrude outward from the inner and outer surfaces of the housing. The heating band 2 is installed on the T-shaped sleeve 32, and the heating band 2 abuts against one end of the ceramic insulating tube 31. There is a gap between the heating band 2 and the inner wall of the housing.

[0055] Preferably, the heating band 2 is electrically connected to the T-shaped sleeve 32. In the example, the heating band 2 is threaded onto the T-shaped sleeve 32 and fixedly connected to the T-shaped sleeve 32 by laser welding and brazing.

[0056] Preferably, the T-shaped sleeve 32 extends into the ceramic insulating tube 31, the heating band 2 does not contact the housing 1, the inner wall of the T-shaped sleeve 32 is provided with internal threads, the surface of the mounting post 33 is provided with external threads that match the internal threads of the inner wall of the T-shaped sleeve 32, and the mounting post 33 extends from outside the housing and is fixedly screwed into the T-shaped sleeve 32.

[0057] In this example, the T-shaped sleeve 32 includes a limiting part 321 and a main body 322. A through hole is provided on the heating band for passing through the main body 322. The outer diameter of the limiting part 321 is larger than the outer diameter of the main body 322 and the inner diameter of the through hole. The heating band 2 is sleeved on the main body 322 and abuts against the ceramic insulating tube 31. The main body 322 of the T-shaped sleeve 32 extends into the ceramic insulating tube 31. The mounting post 33 is fixedly installed inside the main body 322. In this example, the outer diameter of the limiting part 321 is larger than the inner diameter of the ceramic insulating tube 31.

[0058] In a preferred embodiment, such as Figures 4-5 As shown, there are at least two heating bands 2, which are spaced apart within the housing 1 along the direction of airflow.

[0059] Preferably, two adjacent heating bands 2 are connected in series, and there are two terminal assembly 3s, with the outermost heating band 2 connected to the corresponding terminal assembly 3.

[0060] More preferably, adjacent heating bands 2 are electrically connected via connecting components 4. In this example, the heating bands 2 are connected to their respective connecting components 4, and adjacent connecting components 4 are electrically connected via conductive elements.

[0061] like Figures 2-6As shown, the connecting assembly 4 includes a bolt 41, an insulating component, and a nut 42; a connecting hole is provided on the housing, the insulating component is housed in the connecting hole, and an insulating hole is provided on the insulating component. The heating band 2 and the conductive component are both sleeved on the bolt 41, the bolt 41 is sleeved in the insulating hole, and the nut 42 is fixedly screwed onto the bolt 41. The insulating component is configured such that the heating band 2, the conductive component, the bolt 41, and the nut 42 are not electrically connected to the housing, while the heating band 2 and the conductive component are electrically connected to the bolt 41.

[0062] In the example, bolt 41 is a conductive bolt, and nut 42 is a conductive nut.

[0063] In the example, the conductive element is a conductive sheet 51, which is located on the outside of the housing 1.

[0064] Further preferably, the connecting assembly 4 also includes a nickel gasket 43, which is sleeved on the bolt 41 and is in contact with the heating strip 21. In this example, the nickel gasket 43 is located on the side of the heating strip 21 away from the insulating component. In this example, the nickel gasket 43 is a pure nickel gasket. Traditional stainless steel or copper gaskets have low conductivity or temperature resistance; this patent uses a pure nickel gasket with good conductivity and high temperature resistance.

[0065] This patent uses conductive sheets, nickel pads, and T-shaped sleeves for further electrical connection. If the terminal and heating band are only connected by welding, it is easy to generate large contact resistance and severe local heating, which makes the heating band easy to burn out. This patent adds a fixed electrical connection of conductive sheets, nickel pads, and T-shaped sleeves to avoid the problem of local heating and ensure its reliability.

[0066] Preferred, such as Figures 4-6 As shown, the insulating component includes an insulating sleeve 441, a first insulating sheet 442, and a second insulating sheet 443. The insulating sleeve 441 is housed within a connecting hole in the housing, and the first insulating sheet 442 and the second insulating sheet 443 are respectively disposed on both sides of the housing 1. In this example, the insulating hole sequentially passes through the first insulating sheet 442, the insulating sleeve 441, and the second insulating sheet 443.

[0067] In the example, the nickel gasket 43, heating band 2, first insulating sheet 442, insulating sleeve 441, second insulating sheet 443, and conductive component are sequentially threaded onto bolt 41, and nut 42 is screwed onto bolt 41 for fixation. In the example, the nickel gasket 43, heating band 2, and first insulating sheet 442 are located inside the housing 1, while the second insulating sheet 443, conductive component, and nut 42 are located outside the housing 1. In the example, insulating sleeve 441 is made of ceramic material.

[0068] In the example, one end of the conductive element is threaded onto a bolt of a connecting component 4, and the other end of the conductive element is threaded onto a bolt of another connecting component 4. Two adjacent heating bands 2 are connected in series through the connecting component 4 and the conductive element.

[0069] In the example, the terminal block assembly 3 and the connection assembly 4 are symmetrically arranged on both sides of the housing.

[0070] In a preferred embodiment, such as Figures 2-3 As shown, the heating band 2 includes one or more heating strips 21. These heating strips 21 are bent in alternating left-right V-shapes or right-angle bends. The contact portions of the same heating strip 21 or two adjacent heating strips 21 are fixedly connected. In this example, the right-angle bend at the end of the heating strip 21 is used to connect to a terminal block.

[0071] Preferably, the shape of the heating band 2 conforms to the cross-sectional shape of the shell, where the cross-section is the plane containing the heating band 2. In the example, the shell 1 has a cylindrical cross-section, and the heating band 2 is a disc-shaped heating band. Preferably, the diameter of the heating band is <150mm, and / or the diameter of the heating band is ≥60mm. It should be noted that conformity here does not mean that the shape of the heating band 2 is strictly identical to the radial shape of the shell (i.e., completely the same), and disc shape here does not mean that the heating band is strictly disc-shaped, but rather that the shape of the heating band 2 is substantially close to the cross-sectional shape of the shell, and the outer contour of the heating band can be approximated as disc-shaped (e.g., in this application). Figure 3 (As shown).

[0072] This patented heating strip eliminates the spiral design that hinders miniaturization. The heating strips feature alternating left and right bends in a V-shape, with two V-shaped bends forming a rectangular structure. The right-angle bends at the ends of the heating strips connect to the connecting posts. The bent heating strips are elongated, and multiple parallel heating strips form a circular heating strip. The two heating strip groups are symmetrically arranged, eliminating the internal wave structure and further reducing the size of the structure, making it suitable for use in small-space pipes (diameter <150mm) and easy to install. This patented heater can be as small as φ60mm. During uniform heating tests, the patent development team found that the heating strip structure of this patent is 91% superior to traditional electric heating strips with internal wave structures (e.g., ...). Figure 1 The uniformity shown is better. Figure 1 The maximum deviation of the surface temperature of the electric heater in the previous model is 20℃, while the maximum deviation of the surface temperature of the electric heater in this patent is within 10℃. The research and development team speculates that this is because the heating belt structure layout of this patent has higher uniformity and a more reasonable heat dissipation / heat transfer path. Although the heat dissipation fins have been eliminated, more uniform heating can be achieved.

[0073] Preferably, the shell 1 is a cylindrical structure with openings at both ends.

[0074] Preferably, the axis of the housing 1 is not parallel to the plane formed by the heating band 2. More preferably, the axis of the housing 1 is perpendicular to the plane formed by the heating band 2.

[0075] In the example, one or more heating bars 21 alternately bend in a Z-shape or at right angles, and the Z-shape bends and radially adjacent Z-shape bends form a rectangular structure.

[0076] Preferably, the contact portions of two adjacent heating bars 21 are fixedly connected by laser welding and brazing.

[0077] Preferably, the heating strip 21 is fixedly connected to the terminal assembly 3 by laser welding and brazing.

[0078] Preferably, the heating band 2 and the terminal assembly 3 are fixedly electrically connected by a conductive structure.

[0079] In a preferred embodiment, the heating strip 21 includes a first heating strip 211 and a second heating strip 212. The first heating strip 211 and the second heating strip 212 are paired together, with adjacent pairs bent in a V-shape to form a rectangular structure. The contact portions of the first heating strip 211 and the second heating strip 212 are fixedly connected. In the example, the first heating strip 211 and the second heating strip 212 are bent in a V-shape multiple times to form multiple rectangular structures. The contact portions of the first heating strip 211 and the second heating strip 212 after bending are fixedly connected by laser welding and brazing. In the example, the axial direction of the rectangular structure is perpendicular to the length direction of the heating strip 21. In the example, both ends of the heating strip 21 extend symmetrically to the vicinity of the inner walls on both sides of the housing 1. In the example, the heating strip 21 is a stamped heating strip. The stamped heating strip results in a surface free of scratches and deformation, shortened processing time, no tension within the heating strip, flatness throughout the heating strip, and complete adhesion between the layers of heating strips.

[0080] Preferably, the first heating strip 211 and the second heating strip 212 constitute a heating strip group, and the contact portions of adjacent heating strip groups are fixedly connected. More preferably, the heating band 2 includes two heating strip groups, which are symmetrically arranged, and the adjacent edges of adjacent heating strip groups are fixedly connected by laser welding and brazing. In the example, the two heating strip groups form a circular heating band 2, which is housed within a cylindrical shell 1. In the example, adjacent portions of adjacent heating strip groups can also form multiple rectangular or polygonal structures. In the example, the contact portions of adjacent heating strip groups are fixedly connected by laser welding and brazing.

[0081] The heating band of this patent is composed of two or more symmetrically combined heating strips, or even one, two, or more heating bands, the length of which determines the length acting on the current path. To obtain heating effects with different power, the resistance or structure of the heating band is changed to adapt to different power requirements. Methods for changing the resistance include altering the width or length of the heating band; then the heating resistance is set within the desired range, for example, 150mΩ to 750mΩ. Heat resistance is determined by the cross-sectional area and length, and materials with constant resistance are particularly preferred. Therefore, the length of the heating conductor and the resulting heating resistance can be adjusted by the width or length of the heating band.

[0082] The heating strips are fixed to the terminals and to each other using welding, employing both laser welding and brazing. Laser welding is used for initial fixing, followed by brazing to ensure sufficient contact between each heating strip or the terminal, preventing excessive contact resistance and further improving fixing strength and conductivity. In contrast, traditional resistance welding results in contact resistance, affecting conductivity, and also provides insufficient fixing strength.

[0083] In the example, there are two heating bands 2, namely a first heating band and a second heating band. The terminal assembly 3 includes a first terminal assembly and a second terminal assembly. The connecting assembly includes a first connecting assembly and a second connecting assembly. One end of the first heating band is electrically fixedly connected to the first terminal assembly, and the other end of the first heating band is electrically fixedly connected to the first connecting assembly. The first connecting assembly and the second connecting assembly are electrically connected through a conductive sheet. One end of the second heating band is electrically fixedly connected to the second connecting assembly, and the other end of the second heating band is electrically fixedly connected to the second terminal assembly. In the example, the first terminal assembly and the first connecting assembly are symmetrically arranged at both ends of the first heating band, and the second terminal assembly and the second connecting assembly are symmetrically arranged at both ends of the second heating band.

[0084] In the example, the insulating sleeve is a ceramic insulating sleeve with an alumina content of more than 95%.

[0085] In a preferred embodiment, such as Figures 4-5 As shown, a fixed bracket 13 is also provided inside the accommodating cavity 11, and the heating strip 21 is fixedly connected to the fixed bracket 13 through an insulating fastener.

[0086] Preferably, the fixing element is a fixing rod 14, which passes through the rectangular or polygonal gap in the heating band 2 and is fixedly connected to the fixing bracket 13. Preferably, fixing brackets 13 are provided on both sides of the heating band 2, and after the fixing rod 14 passes through the rectangular or polygonal gap in the heating band 2, both ends of the fixing rod 14 are fixed to the corresponding fixing brackets 13. In the example, the fixing rod is a heat-resistant steel fixing rod.

[0087] Preferably, an insulating pad 15 is also provided on the fixing rod 14. The insulating pad 15 is fitted onto the fixing rod 14 and is placed between the heating belt 2 and the fixing bracket 13.

[0088] Preferably, if there are at least two heating bands 2, an insulating pad 15 is also provided between each pair of heating bands 2.

[0089] In the example, insulating pad 15 is a ceramic insulating pad with an alumina content greater than 95%.

[0090] More preferably, the insulating pad 15 includes an insert portion and a spacer portion. The insert portion extends into the space between the heating strips of the heating band, and the spacer portion is configured to separate the heating band from the fixed bracket, or between the heating bands. In the example, the outer diameter of the insert portion is the same as the width of the rectangle, and the insert portion extends into the rectangle of the heating band 2. The outer diameter of the spacer portion is larger than the rectangular width of the heating band 2, and the spacer portion is placed between the fixed bracket 13 and the heating band 2 and / or between two heating bands 2. The insulating pad, with its insert portion and spacer portion, can stably support the heating band, prevent the heating band from shaking and deforming, and also avoid leakage. In addition, the insulating pad also helps prevent the heating band from rotating during the assembly of the terminal assembly and the connecting assembly. Specifically, before the terminal assembly and the connecting assembly are fixedly assembled, the insert portion of the insulating pad is first inserted into the heating band 2, and then the mounting post is tightened into the T-sleeve, or the nut is fixedly screwed onto the bolt, to prevent the heating band from rotating and deforming during the tightening process.

[0091] In the example, the fastener is an insulating fixing pin.

[0092] The heating strip is fixed to the terminal block assembly and connecting assembly by welding. The insulating pad extends into the rectangular structure of the heating strip, and the end of the heating strip is fixed and tightened by nuts and mounting posts, which reduces the stress after assembly with the heating tape and improves the service life of the product.

[0093] The technical features of all components in the above specific embodiments can be freely combined without conflict.

[0094] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "yet another embodiment," "another embodiment," "other embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0095] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications and variations to the above embodiments within the scope of the present invention.

Claims

1. An electric heater, characterized in that, It includes a housing (1), a heating band (2), and at least two terminal block assemblies (3); The housing (1) has a receiving cavity (11), and the heating belt (2) is housed in the receiving cavity (11); A through mounting hole is provided on the surface of the housing (1), which is connected to the accommodating cavity (11). One end of the terminal assembly (3) is electrically connected to the heating band (2) inside the housing (1), and the other end of the terminal assembly (3) extends out of the housing (1). The terminal assembly (3) includes a ceramic insulating tube (31), a T-shaped sleeve (32), and a mounting post (33); the ceramic insulating tube (31) is fitted onto the mounting hole, the heating band (2) is fixedly connected to the T-shaped sleeve (32), neither the heating band (2) nor the T-shaped sleeve (32) is in contact with the housing (1), and the T-shaped sleeve (32) and the mounting post (33) pass through the ceramic insulating tube (31) and are fixedly connected.

2. The electric heater according to claim 1, characterized in that, The T-shaped sleeve (32) includes a limiting part (321) and a main body (322). The heating band is provided with a through hole for passing through the main body (322). The outer diameter of the limiting part (321) is larger than the outer diameter of the main body (322) and the inner diameter of the through hole. The heating band (2) is sleeved on the main body (322) and abuts against the ceramic insulating tube (31). The main body (322) of the T-shaped sleeve (32) extends into the ceramic insulating tube (31). The mounting post (33) is fixedly installed in the main body (322).

3. The electric heater according to claim 1 or 2, characterized in that, The T-shaped sleeve (32) extends into the ceramic insulating tube (31). The inner wall of the T-shaped sleeve (32) is provided with an internal thread. The surface of the mounting post (33) is provided with an external thread that matches the internal thread of the inner wall of the T-shaped sleeve (32). The mounting post (33) extends from the outside of the housing and is fixedly screwed into the T-shaped sleeve (32).

4. The electric heater according to claim 1, characterized in that, The inner wall of the mounting hole is provided with an internal thread, and the surface of the ceramic insulating tube (31) is provided with an external thread that matches the internal thread of the inner wall of the mounting hole. The ceramic insulating tube (31) is screwed and fixed to the mounting hole of the housing (1).

5. The electric heater according to claim 1, characterized in that, The ceramic insulating tube (31) is longer than the shell thickness, and both ends of the ceramic insulating tube (31) protrude outward from the inner and outer surfaces of the shell; and / or One end of the ceramic insulating tube (31) is provided with a raised edge structure, the outer diameter of which is larger than the inner diameter of the corresponding mounting hole on the housing (1).

6. The electric heater according to claim 1, characterized in that, The heating band (2) is fitted onto the terminal assembly (3), and / or the heating band (2) is fixedly connected to the terminal assembly (3) by laser welding and brazing.

7. The electric heater according to claim 1, characterized in that, There are multiple heating bands (2), which are spaced apart in the housing (1) along the airflow direction; it also includes a connecting component (4), which connects adjacent heating bands (2) to conductive sheets through the connecting component (4), and the outermost heating band (2) is connected to the corresponding terminal assembly (3).

8. The electric heater according to claim 7, characterized in that, The heating band (2) is connected to the corresponding connecting component (4) respectively, and two adjacent connecting components (4) are electrically connected through conductive parts; The connecting component (4) includes a bolt (41), an insulating element, and a nut (42); the housing has a connecting hole, the insulating element is housed in the connecting hole, the insulating element has an insulating hole, the heating band (2) and the conductive element are both sleeved on the bolt (41), the bolt (41) is sleeved in the insulating hole, the nut (42) is fixedly screwed onto the bolt (41), the insulating element is configured such that the heating band (2), the conductive element, the bolt (41) and the nut (42) are not electrically connected to the housing, and the heating band (2) and the conductive element are electrically connected to the bolt (41).

9. The electric heater according to claim 1, characterized in that, The connecting assembly (4) also includes a nickel gasket (43), which is fitted onto the bolt (41) and is in contact with the heating band (2).

10. The electric heater according to claim 9, characterized in that, The nickel pad (43) is a pure nickel pad; and / or The insulating component includes an insulating sleeve (441), a first insulating sheet (442), and a second insulating sheet (443); the insulating sleeve (441) is housed in the connecting hole of the housing, and the first insulating sheet (442) and the second insulating sheet (443) are respectively disposed on both sides of the housing (1).

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