Graphene infrared heater

Abstract

The present invention relates to a graphene infrared heater. It solves the problem of inconvenient connection of existing graphene heating tubes, and includes a conductive heating body, a detachable positioning structure, a first conductor and a second conductor. The first conductor is electrically connected to one end of the conductive heating body, and the second conductor is electrically connected to the other end of the conductive heating body. The end of the first conductor away from the electrical connection with the conductive heating body axially penetrates the inner side of the conductive heating body and extends toward the end of the conductive heating body with the second conductor. The end of the first conductor away from the electrical connection with the conductive heating body and the end of the second conductor electrically connected to the conductive heating body are located at the same end of the conductive heating body. The first conductor and the second conductor are positioned at the end of the conductive heating body through an insulating positioning structure. The present invention has the advantages of tight connection of various components, high reliability, convenient disassembly and assembly, strong sealing and good dustproof effect, and can heat corrosive chemical and biological liquids and gases.

Description

Technical Field

[0001] The invention belongs to the technical field of heating equipment, and in particular relates to a graphene infrared heater. Background Art

[0002] With the rapid development of graphene technology, the high cost of graphene has gradually eased, and more and more graphene products have been launched. Among them, graphene heating technology is slowly developing. The heat dissipated by graphene is mainly released in the form of far-infrared rays, which has higher thermal efficiency; it heats up as soon as it is turned on, avoiding the traditional inefficient convection heating method. When using existing graphene heating tubes, conductive connectors for connecting to the power supply need to be set at both ends of the tube body, which can easily cause problems such as inconvenient connection and disassembly during use. At the same time, the connection between the various connection points inside the graphene heating tube is not stable enough, and the failure rate is high, which greatly restricts the promotion and application of existing graphene heating tubes.

[0003] In order to solve the shortcomings of the existing technology, people have conducted long-term exploration and proposed various solutions. For example, a Chinese patent document discloses a method for manufacturing a graphene electric heating rod and a product structure [201910167297.3], which includes the following steps: welding two fixing seats to the two ends of the inner wall of the heating tube; stacking the insulating thermal conductive layer and the graphene conductive heating layer on the inner wall of the heating tube in sequence; fixing and installing the second ceramic insulating pad, the first conductive joint and the second conductive joint on each fixing seat in a stacked manner, so that the first conductive joint is in contact with the graphene conductive heating layer; welding the hexagonal external thread joint and the end cap at both ends of the heating tube; connecting the two wires of the cable to the two second conductive joints respectively; and putting the hexagonal cover on the port of the hexagonal external thread joint.

[0004] The above solution solves the problem of inconvenient external connection of the conductive joints of the existing graphene heating rod to a certain extent, and realizes the integration of two conductive joints at one end of the rod body. However, this solution still has many shortcomings. For example, the connection of the internal conductive joints is not stable enough, which easily leads to a high failure rate. Summary of the invention

[0005] The purpose of the present invention is to provide a graphene infrared heater with reasonable design, convenient wiring and high stability in view of the above problems.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: the graphene infrared heater comprises a conductive heating body with open ends and a hollow cylindrical shape, characterized in that one end of the conductive heating body is connected to the first conductor through a detachable positioning structure, and the other end is circumferentially sleeved with a second conductor, the first conductor is electrically connected to one end of the conductive heating body, and the second conductor is electrically connected to the other end of the conductive heating body, the end of the first conductor away from the electrically connected to the conductive heating body axially penetrates the circumferential inner side of the conductive heating body and extends toward the end of the conductive heating body having the second conductor, and the end of the first conductor away from the electrically connected to the conductive heating body and the end of the second conductor electrically connected to the conductive heating body are located at the same end of the conductive heating body, and the first conductor and the second conductor are positioned at the end of the conductive heating body through an insulating positioning structure. The first conductor is electrically connected to one end of the conductive heating body, the second conductor is electrically connected to the other end of the conductive heating body, and then the first conductor is extended to meet the second conductor, so that one end of the first conductor and the second conductor are located at the same end of the conductive heating body, which is convenient for external power supply, wherein the inside of the conductive heating body is electrically connected through the first conductor and the second conductor respectively, which improves the stability of the electrical connection.

[0007] In the above-mentioned graphene infrared heater, the conductive heating body comprises a carrier tube made of non-conductive material and in a hollow cylindrical shape, a graphene conductive heating coating is provided on the circumferential outer wall of the carrier tube, and a first conductive electrode electrically connected to one end of the graphene conductive heating coating is provided on the circumferential outer wall of one end of the carrier tube, and a second conductive electrode electrically connected to the other end of the graphene conductive heating coating is provided on the circumferential outer wall of the other end. Specifically, the conductive heating body here comprises a carrier tube supported by a quartz material or a ceramic material, the circumferential outer wall of the carrier tube is plated with a graphene conductive heating coating, and the first conductive electrode and the second conductive electrode are high-temperature conductive silver paste.

[0008] In the above-mentioned graphene infrared heater, the first conductor includes a conductive seat made of conductive material and sealed at the open end of the carrier tube, the inner side of one end of the conductive seat is in contact with the outer side of one end of the carrier tube, and the conductive seat is electrically connected to the first conductive electrode, and the end of the conductive seat away from the open end of the carrier tube is provided with a conductive rod axially penetrating the inner side of the carrier tube, and the conductive rod extends to the open end of the carrier tube. That is, the conductive seat can seal one end of the conductive heating body, and the other end is sealed by the first conductor, the second conductor and the insulating positioning structure, thereby improving the sealing and dustproof effect of the conductive heating body.

[0009] In the above-mentioned graphene infrared heater, the detachable positioning structure includes a recessed portion arranged at the center of the end surface of one end where the conductive seat and the conductive rod body are connected, the center of the recessed portion has a positioning boss connected to the conductive rod body, and an annular positioning groove is formed between the positioning boss and the circumferential inner side of the conductive seat, and one end of the carrier tube is inserted into the annular positioning groove, and the first conductive electrode at one end of the carrier tube and the circumferential inner side of the conductive seat are electrically connected to each other. Obviously, by inserting one end of the carrier tube into the annular positioning groove of the conductive seat, the positioning boss and the inner wall of the carrier tube are tightly matched, and the outer wall of the carrier tube and the circumferential inner side of the conductive seat are tightly matched and electrically connected.

[0010] In the above-mentioned graphene infrared heater, the second conductor is in the form of a tubular structure sleeved on one end of the carrier tube, the circumferential inner side of one end of the second conductor is in contact with the circumferential outer side of one end of the carrier tube, and the second conductor and the second conductive electrode are electrically connected to each other, and the conductive rod is passed through the circumferential inner side of the second conductor.

[0011] In the above-mentioned graphene infrared heater, the insulating positioning structure includes an insulating seat that is cylindrical and arranged between the circumferential outer side of one end of the conductive rod and the circumferential inner side of one end of the second conductive body, and the circumferential outer side of the insulating seat and the circumferential inner side of the second conductive body abut against each other, and one end of the conductive rod has a connecting portion coaxially arranged with the conductive rod, and the circumferential inner side of the insulating seat and the circumferential outer side of the connecting portion abut against each other. Preferably, the insulating seat here can be made of ceramic material, and the conductive rod of the first conductive body and the second conductive body are positioned inside and outside the insulating seat respectively, and the conductive rod, the insulating seat and the second conductive body are arranged from inside to outside to close the end of the conductive heating body.

[0012] In the above-mentioned graphene infrared heater, the second conductor has an annular convex ring on the inner side in the circumferential direction, the end face of one end of the carrier tube is set against one side of the annular convex ring, and the end face of one end of the insulating seat is set against the other side of the annular convex ring. Here, limiting steps are formed between one side of the annular convex ring and the inner side of one end of the second conductor in the circumferential direction, and between the other side of the annular convex ring and the inner side of the other end of the second conductor in the circumferential direction, respectively, so as to limit the carrier tube and the insulating seat respectively.

[0013] In the above-mentioned graphene infrared heater, the circumferential outer wall of the carrier tube is provided with a protective layer covering the outside of the graphene conductive heating coating and / or the circumferential outer side of the carrier tube is sleeved with a protective sleeve, one end of the protective sleeve is closed and the circumferential inner side of the end is sleeved on the circumferential outer side of the conductive seat and fits tightly with each other, and the circumferential inner side of the other end is sleeved on the circumferential outer side of the second conductor and fits tightly with each other. When the conductive heating body here is used alone, for example, when used for heating non-liquid substances, preferably, the protective layer here can use a coating with higher hardness, for example, a ceramic coating can be used to improve the wear resistance effect. In order to adapt to liquid heating, the circumferential outer side of the carrier tube is sleeved with a protective sleeve, and the protective sleeve here can be selected from quartz sleeves, etc., so that the conductive heating body can be protected and isolated, and the heater can quickly reach a very high temperature, radiate medium-wave infrared rays, pass through the quartz sleeve, and radiate heat in the form of infrared rays. That is, only a protective layer can be provided on the circumferential outer wall of the conductive heating body. When used for heating in the fields of liquids, gases, soft materials, etc., a protective sleeve needs to be provided on the circumferential outer side of the conductive heating body. The two can also be combined with both a protective layer and a protective sleeve.

[0014] In the above-mentioned graphene infrared heater, the end surface of one end of the protective sleeve, the end surface of one end of the second conductor, the end surface of one end of the insulating seat and the end surface of one end of the connecting part are all flush with each other.

[0015] In the above graphene infrared heater, the conductive seat has a seat head at one end away from the conductive rod, and the seat head is arc-shaped or conical. When the seat head is a pointed tip, the graphene heater can be used to insert some soft materials for contact heating.

[0016] Compared with the existing technology, the advantages of the present invention are: simple structure, tight connection of various components, high reliability, one end of the first conductor and the second conductor are located at the same end of the conductive heating body, which is convenient for external power supply and easy disassembly and assembly, and the two ends of the conductive heating body are closed, which improves the sealing and dustproof effect of the conductive heating body. At the same time, the heating layer carrier adopts a quartz tube and an outer cover quartz tube, which has high chemical stability and is easy to deform, so that this heater can heat corrosive chemical and biological liquids and gases in a very small enclosed space. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural cross-sectional view of the present invention;

[0018] Figure 2 It is a structural exploded diagram of the present invention;

[0019] Figure 3 This is a schematic diagram of the structure of the present invention when it is used for heating liquid;

[0020] Figure 4 yes Figure 3 Structural cross-section view from CC perspective;

[0021] In the figure, a conductive heating body 1, a protective layer 11, a protective sleeve 12, a carrier tube 13, a first conductive electrode 131, a second conductive electrode 132, a graphene conductive heating coating 14, a first conductor 2, a conductive seat 21, a seat head 211, a recessed portion 212, a positioning boss 213, an annular positioning groove 214, a conductive rod 22, a second conductor 3, an insulating positioning structure 4, an insulating seat 41, a connecting portion 42, and an annular convex ring 43. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1-2 As shown, the graphene infrared heater comprises a conductive heating body 1 which is open at both ends and is in the shape of a hollow cylinder. One end of the conductive heating body 1 is connected to the first conductor 2 through a detachable positioning structure, and the other end is circumferentially sleeved with a second conductor 3. The first conductor 2 is electrically connected to one end of the conductive heating body 1, and the second conductor 3 is electrically connected to the other end of the conductive heating body 1. The end of the first conductor 2 which is away from the electrical connection with the conductive heating body 1 axially penetrates the circumferential inner side of the conductive heating body 1 and extends toward the end of the conductive heating body 1 having the second conductor 3. The end of the first conductor 2 which is away from the electrical connection with the conductive heating body 1 and the end of the second conductor 3 which is electrically connected to the conductive heating body 1 are located at the same end of the conductive heating body 1, and the first conductor 2 and the second conductor 3 are positioned at the end of the conductive heating body 1 through an insulating positioning structure 4. The first conductor 2 is electrically connected to one end of the conductive heating body 1, the second conductor 3 is electrically connected to the other end of the conductive heating body 1, and then the first conductor 2 is extended to the second conductor 3, so that one end of the first conductor 2 and the second conductor 3 are located at the same end of the conductive heating body 1, which is convenient for external power supply, wherein the inside of the conductive heating body 1 is electrically connected through the first conductor 2 and the second conductor 3 respectively, which improves the stability of the electrical connection.

[0024] Specifically, the conductive heating body 1 here comprises a carrier tube 13 made of non-conductive material and in a hollow cylindrical shape, a graphene conductive heating coating 14 is provided on the circumferential outer wall of the carrier tube 13, and a first conductive electrode 131 electrically connected to one end of the graphene conductive heating coating 14 is provided on the circumferential outer wall at one end of the carrier tube 13, and a second conductive electrode 132 electrically connected to the other end of the graphene conductive heating coating 14 is provided on the circumferential outer wall at the other end. Preferably, the conductive heating body 1 here comprises a carrier tube 13 supported by a quartz material or a ceramic material, a graphene conductive heating coating 14 is plated on the circumferential outer wall of the carrier tube 13, and the first conductive electrode 131 and the second conductive electrode 132 are high-temperature conductive silver paste.

[0025] The first conductor 2 includes a conductive seat 21 made of conductive material and sealed at one end of the carrier tube 13. The inner side of one end of the conductive seat 21 contacts the outer side of one end of the carrier tube 13 and the conductive seat 21 is electrically connected to the first conductive electrode 131. The end of the conductive seat 21 away from the open end of the carrier tube 13 is provided with a conductive rod 22 axially penetrating the inner side of the carrier tube 13, and the conductive rod 22 extends to the other end of the carrier tube 13. That is, the conductive seat 21 can seal one end of the conductive heating body 1, and the other end is sealed by the first conductor 2, the second conductor 3 and the insulating positioning structure 4, thereby improving the sealing and dustproof effect of the conductive heating body 1.

[0026] Preferably, the detachable positioning structure here includes a recessed portion 212 arranged at the center of the end surface of one end where the conductive seat 21 and the conductive rod body 22 are connected, and the center of the recessed portion 212 has a positioning boss 213 connected to the conductive rod body 22, and an annular positioning groove 214 is formed between the positioning boss 213 and the circumferential inner side of the conductive seat 21, and one end of the carrier tube 13 is inserted into the annular positioning groove 214, and the first conductive electrode 131 at one end of the carrier tube 13 and the circumferential inner side of the conductive seat 21 are electrically connected to each other. Obviously, by inserting one end of the carrier tube 13 into the annular positioning groove 214 of the conductive seat 21, the positioning boss 213 and the inner wall of the carrier tube 13 are tightly matched, and the outer wall of the carrier tube 13 and the circumferential inner side of the conductive seat 21 are tightly matched and electrically connected.

[0027] Furthermore, the second conductor 3 here is a tubular structure sleeved on one end of the carrier tube 13, the circumferential inner side of one end of the second conductor 3 is in contact with the circumferential outer side of one end of the carrier tube 13, and the second conductor 3 and the second conductive electrode 132 are electrically connected to each other, and the conductive rod 22 is penetrated through the circumferential inner side of the second conductor 3.

[0028] In order to insulate the conductive rod 22 and the second conductive body 3, the insulating positioning structure 4 here includes an insulating seat 41 which is cylindrical and is arranged between the circumferential outer side of one end of the conductive rod 22 and the circumferential inner side of one end of the second conductive body 3, and the circumferential outer side of the insulating seat 41 and the circumferential inner side of the second conductive body 3 abut against each other, one end of the conductive rod 22 has a connecting portion 42 coaxially arranged with the conductive rod 22, and the circumferential inner side of the insulating seat 41 and the circumferential outer side of the connecting portion 42 abut against each other. Preferably, the insulating seat 41 here can be made of ceramic material, and the conductive rod 22 of the first conductive body 2 and the second conductive body 3 are positioned inside and outside the insulating seat 41 respectively, and the end of the conductive heating body 1 is closed by the conductive rod 22, the insulating seat 41 and the second conductive body 3 being arranged from inside to outside.

[0029] Preferably, the second conductor 3 here has an annular convex ring 43 on the inner circumferential side, the end face of one end of the carrier tube 13 is set against one side of the annular convex ring 43, and the end face of one end of the insulating seat 41 is set against the other side of the annular convex ring 43. Here, limiting steps are formed between one side of the annular convex ring 43 and the inner circumferential side of one end of the second conductor 3 and between the other side of the annular convex ring 43 and the inner circumferential side of the other end of the second conductor 3, respectively, so as to limit the carrier tube 13 and the insulating seat 41 respectively.

[0030] like Figure 1 As shown, in this embodiment, when the conductive heating body 1 here is used directly, for example, when it is used to heat non-liquid substances, such as, for example, when it is used to heat cotton, tobacco and other items, in order to protect the graphene conductive heating coating 14 on the outer wall of the carrier tube 13 to prevent scratches, the circumferential outer wall of the carrier tube 13 here is provided with a protective layer 11 covering the outside of the graphene conductive heating coating 14. Preferably, the protective layer 11 here can adopt a coating with higher hardness, for example, a ceramic coating can be adopted, so as to improve the anti-scratch and wear-resistant effect of the graphene conductive heating coating 14, and ensure light transmittance.

[0031] More specifically, the end surface of the protective sleeve 12, the end surface of the second conductor 3, the end surface of the insulating seat 41, and the end surface of the connecting portion 42 are all flush with each other. The conductive seat 21 has a seat head 211 at one end away from the end connected to the conductive rod 22, and the seat head 211 is arc-shaped or conical. When the seat head 211 is a pointed tip, the graphene heater can be used to insert some soft materials, such as cotton, tobacco, etc. for contact heating.

[0032] like Figure 3-4As shown, in order to realize that the heater can be used for heating in liquid and other fields, a protective sleeve 12 is sleeved on the outer side of the carrier tube 13. One end of the protective sleeve 12 is closed and the end is sleeved on the outer side of the conductive seat 21 and fits tightly with each other. The other end is sleeved on the outer side of the second conductor 3 and fits tightly with each other. One end of the protective sleeve 12 is sleeved on one end of the conductive seat 21 and is closed. In this way, insulation between the conductive seat 21 and the material to be heated can be achieved, and it can also play a protective role. The closed end of the protective sleeve 12 can be arc-shaped or straight. The protective sleeve 12 can be made of quartz sleeve, etc., so that the heater can quickly reach a very high temperature, radiate medium-wave infrared rays, pass through the quartz sleeve, and radiate heat in the form of infrared rays. That is, when used in non-liquid heating fields, only the protective layer 11 can be set on the circumferential outer wall of the carrier tube 13. When used for heating in liquids and other fields, the protective sleeve 12 needs to be set on the circumferential outer side of the carrier tube 13. The two can also be combined with each other, with both the protective layer 11 and the protective sleeve 13.

[0033] Among them, the main reasons why quartz or ceramics are used as the materials for the carrier tube 13, the protective layer 11 or the protective sleeve 12 are: 1. They are poor conductors of heat, which can achieve much faster heating and cooling of the graphene heating layer; 2. When the existing carrier tube is made of metal, it will deform at high temperatures, making it unusable in precision applications, while quartz or ceramics have almost no deformation; 3. Chemical stability. Our heating layer carrier quartz tube and outer cover quartz tube are both highly chemically stable, allowing this heater to heat corrosive chemical and biological liquids and gases in a very small enclosed space. 4. The infrared transmittance of the quartz tube is high, and it can quickly reach a very high temperature, radiate medium-wave infrared rays, pass through the quartz jacket, and radiate heat in the form of infrared rays.

[0034] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0035] Although the present invention uses more terms such as conductive heating body 1, protective layer 11, protective sleeve 12, carrier tube 13, first conductive electrode 131, second conductive electrode 132, graphene conductive heating coating 14, first conductor 2, conductive seat 21, seat head 211, recess 212, positioning boss 213, annular positioning groove 214, conductive rod 22, second conductor 3, insulating positioning structure 4, insulating seat 41, connecting portion 42, annular convex ring 43, etc., it does not exclude the possibility of using other terms. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

Claims

1. A graphene infrared heater, comprising a conductive heating body (1) with two ends open and in a hollow cylindrical shape, characterized in that: One end of the conductive heating body (1) is connected to the first conductive body (2) via a detachable positioning structure, and the other end is sleeved with a second conductive body (3) on the circumferential outer side, the first conductive body (2) is electrically connected to one end of the conductive heating body (1), and the second conductive body (3) is electrically connected to the other end of the conductive heating body (1), the end of the first conductive body (2) away from the conductive heating body (1) electrically connected axially penetrates the conductive heating body (1) circumferentially inward and extends toward the end of the conductive heating body (1) having the second conductive body (3), and the end of the first conductive body (2) away from the conductive heating body (1) electrically connected and the end of the second conductive body (3) electrically connected to the conductive heating body (1) are located on the conductive heating body (1). ), and the first conductor (2) and the second conductor (3) are positioned at the end of the conductive heating body (1) through an insulating positioning structure (4); the conductive heating body (1) comprises a carrier tube (13) made of non-conductive material and in a hollow cylindrical shape, a graphene conductive heating coating (14) is provided on the circumferential outer wall of the carrier tube (13), and a first conductive electrode (131) electrically connected to one end of the graphene conductive heating coating (14) is provided on the circumferential outer wall of one end of the carrier tube (13), and a second conductive electrode (132) electrically connected to the other end of the graphene conductive heating coating (14) is provided on the circumferential outer wall of the other end; the first conductor (2) comprises a conductive material and sealed in the carrier tube ( The conductive seat (21) is provided at one open end of the carrier tube (13), the inner side of one end of the conductive seat (21) is in contact with the outer side of one end of the carrier tube (13), and the conductive seat (21) is electrically connected to the first conductive electrode (131). The end of the conductive seat (21) away from the open end of the carrier tube (13) is provided with a conductive rod (22) axially penetrating the inner side of the carrier tube (13), and the conductive rod (22) extends to the open end of the carrier tube (13); the detachable positioning structure comprises a recessed portion (212) arranged at the center of the end surface of the conductive seat (21) and the conductive rod (22), and the center of the recessed portion (212) has a conductive rod (22) connected to the conductive rod (22). A positioning boss (213), and an annular positioning groove (214) is formed between the positioning boss (213) and the circumferential inner side of the conductive seat (21), and one end of the carrier tube (13) is inserted into the annular positioning groove (214), and the first conductive electrode (131) at one end of the carrier tube (13) and the circumferential inner side of the conductive seat (21) are electrically connected to each other; the second conductor (3) is in a tubular structure sleeved on one end of the carrier tube (13), the circumferential inner side of one end of the second conductor (3) is in contact with the circumferential outer side of one end of the carrier tube (13), and the second conductor (3) and the second conductive electrode (132) are electrically connected to each other, and the conductive rod (22) is inserted into the circumferential inner side of the second conductor (3);The insulating positioning structure (4) comprises an insulating seat (41) which is cylindrical and arranged between the circumferential outer side of one end of the conductive rod (22) and the circumferential inner side of one end of the second conductive body (3), and the circumferential outer side of the insulating seat (41) and the circumferential inner side of the second conductive body (3) are mutually abutted, one end of the conductive rod (22) has a connecting portion (42) coaxially arranged with the conductive rod (22), and the circumferential inner side of the insulating seat (41) and the circumferential outer side of the connecting portion (42) are mutually abutted; the circumferential outer wall of the carrier tube (13) is provided with a protective layer (11) covering the outer side of the graphene conductive heating coating (14) and / or the circumferential outer side of the carrier tube (13) is sleeved with a protective sleeve (12), one end of the protective sleeve (12) is closed and the circumferential inner side of the end is sleeved on the circumferential outer side of the conductive seat (21) and are tightly matched with each other, and the circumferential inner side of the other end is sleeved on the circumferential outer side of the second conductive body (3) and are tightly matched with each other. ; 2. The graphene infrared heater according to claim 1, characterized in that: The second conductor (3) has an annular convex ring (43) on the inner side in the circumferential direction, one end face of the carrier tube (13) is arranged against one side of the annular convex ring (43), and one end face of the insulating seat (41) is arranged against the other side of the annular convex ring (43).

3. The graphene infrared heater according to claim 1, characterized in that: One end surface of the protective sleeve (12), one end surface of the second conductor (3), one end surface of the insulating seat (41) and one end surface of the connecting portion (42) are all flush with each other.

4. The graphene infrared heater according to claim 1, characterized in that: The conductive seat (21) has a seat head (211) at one end away from the end connected to the conductive rod (22), and the seat head (211) is in an arc shape or a pointed cone shape.

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