Heating device

Abstract

The utility model discloses a heating device, and relates to the technical field of heating devices, the heating device comprises a bottom shell and a thick film heating disc, the thick film heating disc comprises a substrate and a thick film heating element arranged on the substrate, the substrate is arranged on one side of the bottom shell, a vacuum cavity is enclosed by the substrate and the bottom shell, and the thick film heating element is accommodated in the vacuum cavity; the substrate and the bottom shell are configured to be made of the same material and are connected through welding. According to the technical scheme of the utility model, the vacuum cavity for accommodating the heating element is enclosed by the substrate and the bottom shell, and the vacuum environment formed between the substrate and the bottom shell can destroy a convective heat transfer passage, so that more heat generated by the thick film heating element can be transferred to one side of the substrate for heating; the situation that heat is dissipated to the surrounding environment in a convection mode and the like is reduced, and therefore the heat utilization rate of the heating device is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of heating devices, in particular to a heating device. Background Art

[0002] Heating devices typically convert electrical energy or other forms of energy into thermal energy to generate heat. However, the thermal efficiency of existing heating devices is often affected by various factors. Most existing heating devices use resistive heating, which generates heat by passing an electric current through a resistive element. Due to the temperature difference between the heating element and the surrounding environment, some heat is inevitably dissipated into the surrounding environment through radiation, convection, and other methods. This reduces the energy available to heat the target medium, thereby reducing thermal efficiency. Utility Model Content

[0003] The main purpose of the utility model is to provide a heating device, aiming to improve the heat utilization rate of the heating device.

[0004] To achieve the above-mentioned purpose, the heating device proposed in the present invention includes:

[0005] bottom shell; and

[0006] A thick film heating plate includes a substrate and a thick film heating element arranged on the substrate. The substrate is arranged on one side of the bottom shell and encloses a vacuum cavity with the bottom shell. The thick film heating element is accommodated in the vacuum cavity. The substrate and the bottom shell are configured with the same material and are connected by welding.

[0007] In one embodiment, the heating device further includes a seal and two electrical connection terminals. The bottom shell is provided with a via hole. The electrical connection terminal passes through the via hole and is electrically connected to the thick film heating element. The seal is provided on the periphery of the electrical connection terminal and seals the via hole.

[0008] In one embodiment, the sealing member is configured as a glass medium, and the glass medium is sintered to seal the electrical connection terminal to the via hole.

[0009] In one embodiment, the electrical connection terminal includes a main body, a connecting part and an elastic member, the main body is provided with the via hole, the connecting part is provided in the vacuum chamber, one end of the elastic member is connected to the main body, and the other end is connected to the connecting part, so that the connecting part can elastically abut against the thick film heating element.

[0010] In one embodiment, the electrical connection terminal is welded to the thick film heating element.

[0011] In one embodiment, the substrate has a heating area and a mounting area arranged around the periphery of the heating area, the thick film heating element is arranged in the heating area, and the bottom shell includes a main board and a surrounding plate erected on the edge of the main board, and the surrounding plate is connected to the mounting area.

[0012] In one embodiment, a side edge of the enclosure away from the main board is provided with an outwardly extending flange, and the flange is connected to the installation area.

[0013] In one embodiment, the heating device also includes two electrical connection terminals, which are respectively a positive terminal and a negative terminal. The thick film heating element has a first end connected to the positive terminal and a second end connected to the negative terminal. The first end and the second end are spaced apart and arranged on the same side of the heating area close to the installation area.

[0014] In one embodiment, the bottom shell and the base plate are welded by vacuum furnace brazing or vacuum electron beam welding.

[0015] In one embodiment, the substrate and the bottom shell are made of stainless steel.

[0016] The technical solution of the present invention encloses a vacuum cavity for accommodating the heating element through the substrate and the bottom shell. The vacuum environment formed between the substrate and the bottom shell can destroy the convective heat transfer path, so that the heat generated by the thick-film heating element can be transferred more to the side of the substrate for heating, reducing the situation where heat is dissipated into the surrounding environment through convection and other means, thereby improving the thermal utilization rate of the heating device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0018] Figure 1 This is a structural diagram of an embodiment of a heating device provided by the present utility model;

[0019] Figure 2 for Figure 1 Exploded diagram;

[0020] Figure 3 for Figure 1 sectional view of

[0021] Figure 4 for Figure 3 A partial enlarged view of point A in the middle.

[0022] Description of Figure Numbers:

[0023] 10. Heating device; 100. Bottom shell; 200. Thick-film heating plate; 300. Electrical connection terminal; 400. Seal; 110. Main board; 111. Via hole; 120. Enclosure; 130. Flanged edge; 210. Base plate; 211. Heating area; 212. Mounting area; 220. Thick-film heating element; 221. First end; 222. Second end; 310. Positive terminal; 320. Negative terminal.

[0024] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0026] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0027] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0028] The present invention provides a heating device 10 .

[0029] See also Figure 1 and Figure 2In one embodiment of the present invention, the heating device 10 includes a bottom shell 100 and a thick film heating plate 200. The thick film heating plate 200 includes a substrate 210 and a thick film heating element 220 arranged on the substrate 210. The substrate 210 is arranged on one side of the bottom shell 100 and encloses a vacuum cavity with the bottom shell 100. The thick film heating element 220 is accommodated in the vacuum cavity. The substrate 210 and the bottom shell 100 are configured with the same material and are connected by welding.

[0030] Specifically, the thick film heating disc 200 includes a substrate 210 and a thick film heating element 220. The substrate 210 is usually made of ceramic or metal and has good heat resistance and mechanical strength. The substrate 210 provides a stable support platform and also serves as an insulating layer to prevent the heating element from contacting the outside. The thick film heating element 220 is the core component of the thick film heating disc 200 and is used to generate heat to achieve the heating function. The thick film heating element 220 is formed by printing and sintering a conductive paste on the surface of the substrate 210. The conductive paste usually contains precious metal powder (such as platinum, palladium, etc.) and other additives. These materials are mixed and printed on the substrate 210 to form a film layer with a certain resistance value, that is, a thick film resistor layer is formed. In addition, in order to prevent the thick film resistor layer from directly contacting the external environment, a protective coating is usually applied to its outer surface. This protective layer not only improves the wear resistance of the thick film resistor layer, but also plays a certain insulating role to prevent the thick film resistor layer from contacting the outside world and causing short circuits or other safety problems. When current passes through the thick film resistor layer, due to the presence of resistance, electrical energy will be converted into thermal energy, allowing the thick film heating disk 200 to generate heat. It can be understood that the power supply provides current to the thick film heating element 220 through the connection terminal. When the current flows through the thick film heating element 220, it encounters resistance, generating a Joule heating effect, causing the temperature of the area where the thick film heating element 220 is located to rise, and the generated heat is transferred to the substrate 210 and other parts that need to be heated by heat conduction. The thick film heating disk 200 has a relatively low manufacturing cost, good reliability, and can withstand high operating temperatures. It can be widely used in applications that require rapid heating and high-temperature heating.

[0031] The substrate 210 and the bottom shell 100 enclose a vacuum chamber, and a secure sealing connection is achieved by welding. The thick-film heating element 220 is housed in the vacuum chamber. The vacuum environment within the vacuum chamber reduces heat loss caused by air convection, allowing more heat generated by the thick-film heating element 220 to be transferred to the side of the substrate 210 facing away from the thick-film heating element 220, i.e., the side that heats the heating target, thereby improving the thermal efficiency of the thick-film heating plate 200.

[0032] In addition, in a vacuum environment, the thick film heating element 220 is not easily oxidized, which reduces the possibility of corrosion of the thick film heating element 220, thereby extending the service life of the thick film heating element 220; the vacuum chamber can play a certain sound insulation effect, reducing the noise generated during the heating process; the vacuum chamber can isolate the external environment, preventing water vapor and the like from entering the circuit to cause problems such as short circuits, thereby increasing the safety of use; the vacuum chamber can also be filled with some heat-conducting media (such as thermal oil), which can better distribute the heat generated by the thick film heating element 220 evenly to the entire heating surface, thereby achieving the purpose of improving heat conduction. Welding the substrate 210 and the bottom shell 100 to form a whole can improve the sealing between the substrate 210 and the bottom shell 100 to ensure that the vacuum chamber maintains its vacuum environment; it can also increase the stability of the connection between the substrate 210 and the bottom shell 100 to prevent loosening or deformation due to long-term use.

[0033] The substrate 210 and the bottom case 100 can be made of ceramic or metal, such as stainless steel, aluminum and its alloys, copper and its alloys, molybdenum and its alloys, nickel-based alloys, titanium and its alloys, iron-based alloys, etc. Using the same material as the bottom case 100 makes welding more convenient and easier, eliminating the need for multiple welding operations using adapters.

[0034] The technical solution of the present invention encloses a vacuum cavity for accommodating the heating element through the substrate 210 and the bottom shell 100. The vacuum environment formed between the substrate 210 and the bottom shell 100 can destroy the convection heat transfer path, so that the heat generated by the thick-film heating element 220 can be transferred more to the side of the substrate 210 used for heating, reducing the situation where heat is dissipated into the surrounding environment through convection and other means, thereby improving the thermal utilization rate of the heating device 10.

[0035] In one embodiment, see Figures 2 to 4 The heating device 10 also includes a sealing member 400 and two electrical connection terminals 300. The bottom shell 100 is provided with a through hole 111. The electrical connection terminal 300 passes through the through hole 111 and is electrically connected to the thick film heating element 220. The sealing member 400 is provided on the outer periphery of the electrical connection terminal 300 and seals the through hole 111.

[0036] The electrical connection terminal 300 is used to connect an external power source to the thick film heating element 220, so that the current of the external power source can be connected to the thick film heating element 220 through the electrical connection terminal 300, so that the thick film heating element 220 can achieve the heating function. The electrical connection terminal 300 is generally made of a metal material with good conductivity, such as copper or a copper alloy, and is usually silver-plated or nickel-plated to enhance conductivity and corrosion resistance. The electrical connection terminal 300 can specifically be an electrode sheet, a probe connector, a power cord, etc.

[0037] The vias 111 on the bottom case 100 are designed to allow the electrical connection terminals 300 to pass through the bottom case 100 and establish an electrical connection with the thick-film heating element 220. A single via 111 can be provided, with the two electrical connection terminals 300 passing through the same via 111, but the electrical connection terminals 300 are insulated by an insulating medium. Alternatively, two vias 111 can be provided at intervals, with the two electrical connection terminals 300 passing through the corresponding two vias 111, respectively. The electrical connection terminals 300 and the edges of the vias 111 also need to be insulated.

[0038] The main function of the seal 400 is to ensure that the vacuum cavity inside the heating device 10 is not affected by the external environment and to prevent impurities such as moisture and dust from entering. It also plays the role of electrical insulation and fixation of the electrical connection terminal 300. The seal 400 is usually made of a heat-resistant material, such as a ceramic material, a glass medium, or a composite material formed by ceramics and fibers, which can maintain good sealing performance at high temperatures. During the installation process, the seal 400 will be placed on the periphery of the electrical connection terminal 300. After the electrical connection terminal 300 is fixed to the bottom shell 100, the seal 400 will completely seal the via 111 to ensure the vacuum environment inside the vacuum cavity and prevent foreign matter from entering the vacuum cavity.

[0039] The electrical connection terminal 300 is electrically connected to the thick film heating element 220, and the thick film heating element 220 is formed by solidifying a metal conductive paste deposited on the surface of the substrate 210 by a screen printing process. Therefore, the electrical connection terminal 300 actually forms an electrical path with the thick film heating element 220. The electrical connection terminal 300 and the thick film heating element 220 can be electrically connected in various ways, such as the electrical connection terminal 300 can be directly welded or bonded to the thick film heating element 220 by a conductive adhesive, so that the current is effectively introduced into the thick film heating element 220 to ensure a good electrical connection between the two; in order to facilitate assembly and maintenance, the thick film heating element 220 can be connected to the external terminal by a slender metal lead, which can extend from the edge of the thick film heating plate 200 and then be connected to the metal terminal installed on the edge of the substrate 210; the electrical connection terminal 300 can also be embedded in the substrate 210, which can provide better mechanical stability and reduce the loose connection caused by vibration or thermal expansion.

[0040] In one embodiment, see Figure 2 and Figure 4 The sealing member 400 is configured as a glass medium, and the glass medium is sintered to seal the electrical connection terminal 300 in the via hole 111 .

[0041] Glass dielectrics are typically sintered at high temperatures to melt the glass and form a strong seal during cooling. Glass seal 400 provides excellent sealing, preventing external moisture, oxygen, and other substances from entering the vacuum chamber while also preventing the vacuum environment within the chamber from being disrupted. Glass dielectrics have excellent chemical stability, resisting corrosion from a variety of chemicals and suitable for use in a variety of corrosive environments. Glass itself is a good insulating material, providing reliable electrical insulation to ensure there is no electrical connection between the electrical connection terminals 300 and the bottom housing 100. Formed through high-temperature sintering, glass seal 400 possesses high mechanical strength and is stable in high-temperature and high-pressure environments.

[0042] In one embodiment, the electrical connection terminal 300 includes a main body, a connecting part and an elastic member. The main body is provided with a through hole 111, the connecting part is provided in the vacuum chamber, one end of the elastic member is connected to the main body, and the other end is connected to the connecting part, so that the connecting part can elastically abut the thick film heating element 220.

[0043] The main body extends through the via 111 in the bottom case 100 and extends externally to connect to an external power source or control system. The main body must have sufficient mechanical strength to withstand the stresses of installation and possess good electrical conductivity. Copper or copper alloys are typically used, and may be plated to enhance conductivity and corrosion resistance. The connector, located within the vacuum chamber, directly contacts the thick-film heating element 220, transferring current to the heating element. The connector must possess good electrical conductivity and be stable at high temperatures. Furthermore, the connector must be designed to ensure good contact with the thick-film heating element 220 to ensure proper operation. The elastic member provides elastic support between the main body and the connector, ensuring that the connector remains in close contact with the thick-film heating element 220 and maintains good electrical contact even under temperature fluctuations or vibrations. The elastic member is typically made of a highly elastic and electrically conductive material, such as spring steel or a specific elastic alloy. The elastic member must provide sufficient elastic force to ensure that the connector maintains contact with the thick-film heating element 220. The design of the elastic member can ensure that the contact between the connecting portion and the thick film heating element 220 will not become unstable due to mechanical vibration or temperature change, thereby improving the reliability of the entire system.

[0044] In another embodiment, the electrical connection terminal 300 is welded to the thick film heating element 220 .

[0045] The electrical connection terminal 300 and the thick film heating element 220 are electrically connected by welding to ensure reliable electrical connection between the two, and can remain stable under high temperature and vibration conditions. The electrical connection terminal 300 and the thick film heating element 220 can be electrically connected by spot welding, and an electric current is applied at a specific position by a spot welder to produce local heating, so that the metal contact surface of the electrical connection terminal 300 and the thick film heating element 220 is melted and fused together. The electrical connection terminal 300 and the thick film heating element 220 can also be electrically connected by brazing, using a filler metal (brass) with a melting point lower than that of the parent material, and when heated to the brazing melting point but at a temperature lower than the melting point of the parent material, the brazing is melted and fills the gap between the parent materials to form a firm connection. Commonly used brazing materials include silver-based, copper-based, etc. The electrical connection terminal 300 and the thick film heating element 220 can be electrically connected by laser welding, using a high-energy-density laser beam as a heat source to locally melt and fuse the metal.

[0046] In one embodiment, see Figure 2 The substrate 210 has a heating area 211 and a mounting area 212 arranged around the outer periphery of the heating area 211. The thick film heating element 220 is arranged in the heating area 211. The bottom shell 100 includes a main board 110 and a surrounding plate 120 erected on the edge of the main board 110. The surrounding plate 120 is connected to the mounting area 212.

[0047] The heating area 211 occupies most of the area of ​​the substrate 210, including the central area of ​​the substrate 210. The heating area 211 can be circular, rectangular or other shapes according to the shape of the substrate 210. The thick film heating element 220 is installed in the heating area 211 and is responsible for generating heat. The heating area 211 usually requires high temperature resistant materials to withstand the high temperature environment during the heating process. The installation area 212 surrounds the outer periphery of the heating area 211 to form a circle. The installation area 212 is circular, rectangular or other shapes according to the shape of the heating area 211. The installation area 212 is used to fix and connect the enclosure 120 of the bottom shell 100 to achieve a stable connection between the bottom shell 100 and the substrate 210.

[0048] The bottom shell 100 includes a main board 110 and a panel 120. The main board 110 is the main part of the bottom shell 100. A through hole 111 is provided on the main board 110 for the power connection terminal 300 to pass through. The panel 120 is vertically arranged at the edge of the main board 110 and connected to the mounting area 212 of the substrate 210. The main board 110 and the substrate 210 are arranged opposite to each other, and the panel 120 connected therebetween, together form a closed space, that is, a vacuum chamber. The panel 120 is connected to the mounting area 212 of the substrate 210 by welding to ensure the stability and sealing of the connection. The electrical connection terminal 300 passes through the through hole 111 on the main board 110 and is sealed by a glass medium or other sealing material to maintain the integrity of the vacuum chamber.

[0049] The centralized design of the heating area 211 improves thermal efficiency and ensures that heat is concentrated on the part that needs to be heated. The design of the mounting area 212 facilitates the operation of the base plate 210 and the bottom shell 100 during welding, as well as the reliability and stability of the connection between the base plate 210 and the enclosure 120.

[0050] In one embodiment, see Figure 2 and Figure 4 A flange 130 extending outward is provided on one side of the enclosure 120 away from the main board 110 , and the flange 130 is connected to the mounting area 212 .

[0051] The flange 130 is provided on one side of the enclosure 120 away from the main board 110, and the flange 130 is used to connect to the mounting area 212 of the substrate 210. The contact area between the flange 130 and the mounting area 212 is larger, and the stability of the connection between the flange 130 and the substrate 210 is better, thereby improving the mechanical strength of the connection between the two to prevent loosening due to vibration or impact during use. At the same time, even if a slight offset occurs between the flange 130 and the substrate 210 during the welding process, the larger contact area between the flange 130 and the mounting area 212 can ensure that the flange 130 and the substrate 210 are welded in place, thereby ensuring the vacuum environment inside the vacuum chamber. The bottom shell 100 can be integrally formed, such as by stamping; or the main board 110, the enclosure 120 and the flange 130 can be welded.

[0052] In one embodiment, see Figure 2 The heating device 10 also includes two electrical connection terminals 300, which are a positive terminal 310 and a negative terminal 320 respectively. The thick film heating element 220 has a first end 221 connected to the positive terminal 310 and a second end 222 connected to the negative terminal 320. The first end 221 and the second end 222 are spaced apart and arranged on the same side of the heating area 211 close to the mounting area 212.

[0053] The two electrical connection terminals 300 are respectively a positive terminal 310 and a negative terminal 320. The positive terminal 310 is electrically connected to the first end 221 of the thick film heating element 220 and is responsible for providing positive power to the thick film heating element 220. The negative terminal 320 is electrically connected to the second end 222 of the thick film heating element 220 and is responsible for providing negative power to the thick film heating element 220. Accordingly, the first end 221 is responsible for receiving positive power, and the second end 222 is responsible for receiving negative power.

[0054] The first end portion 221 and the second end portion 222 are disposed in the heating area 211 and are positioned near the mounting area 212, such that the positive terminal 310 and the negative terminal 320 extend from an area near the edge of the bottom case 100. The remaining area of ​​the bottom surface of the bottom case 100 can be placed directly on the platform, and this area is relatively large, facilitating the stable placement of the heating device 10. For a rectangular heating area 211, the first end portion 221 and the second end portion 222 can be disposed on the same side of either the wide side or the long side of the heating area 211.

[0055] In other embodiments, the first end portion 221 and the second end portion 222 may not be on the same side. For example, the first end portion 221 and the second end portion 222 are arranged on two adjacent sides of the same diagonal corner of the heating area 211 .

[0056] In one embodiment, the bottom case 100 and the base plate 210 are welded by vacuum furnace brazing or vacuum electron beam welding.

[0057] The bottom case 100 and base plate 210 can be brazed using a vacuum furnace. This process is typically performed at a temperature above the melting point of the brazing filler metal but below that of the base material. Brazing in a vacuum environment prevents oxidation and other impurities from affecting the soldering process, while maintaining a vacuum environment within the chamber. The vacuum furnace provides a uniform heating environment, ensuring even heating across the weld area. It effectively prevents oxidation, improves weld quality, and allows for the simultaneous welding of multiple parts.

[0058] The bottom case 100 and the base plate 210 can also be welded using vacuum electron beam welding. In vacuum electron beam welding, a focused, high-speed electron beam strikes the workpiece surface, generating high temperatures that melt the metal and form a weld joint. This process is also performed in a vacuum environment to prevent atmospheric impurities from affecting weld quality while maintaining a vacuum environment within the vacuum chamber. Electron beam welding enables highly precise welding, boasts high energy density, fast welding speeds, and high efficiency.

[0059] The bottom shell 100 and the base plate 210 are fixedly connected by vacuum furnace brazing or vacuum electron beam welding. Since the welding is carried out in a vacuum environment, a vacuum state inside the vacuum cavity can be achieved. At the same time, welding spatter is reduced during the welding process, and the quality of the welding surface is improved.

[0060] In one embodiment, the substrate 210 and the bottom case 100 are made of stainless steel.

[0061] Stainless steel has excellent corrosion resistance, heat resistance, and mechanical strength. It can withstand high temperatures and is not easily deformed at high temperatures. The base plate 210 and the bottom shell 100 are made of the same stainless steel material, which not only improves structural strength, corrosion resistance, and heat resistance, but also makes welding the two easier.

[0062] Furthermore, conventional heating structures utilize die-cast aluminum, which has a significant power attenuation in the resistance wire used for heating. Furthermore, the die-cast aluminum only generates significant heat in the area where the resistance wire is located, resulting in poor heating uniformity. The heating device 10 proposed in the present invention utilizes a thick-film heating plate 200, whose base plate 210 and bottom shell 100 are both directly welded from stainless steel. This not only provides more uniform heating but also simplifies the welding process.

[0063] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A heating device, characterized in that: include: bottom shell; as well as A thick film heating plate includes a substrate and a thick film heating element arranged on the substrate. The substrate is arranged on one side of the bottom shell and encloses a vacuum cavity with the bottom shell. The thick film heating element is accommodated in the vacuum cavity. The substrate and the bottom shell are configured with the same material and are connected by welding.

2. The heating device according to claim 1, wherein The heating device further includes a seal and two electrical connection terminals. The bottom shell is provided with a through hole. The electrical connection terminal passes through the through hole and is electrically connected to the thick film heating element. The seal is provided on the periphery of the electrical connection terminal and seals the through hole.

3. The heating device according to claim 2, wherein: The sealing member is configured as a glass medium, and the glass medium is sintered to seal the electrical connection terminal to the via hole.

4. The heating device according to claim 2, wherein: The electrical connection terminal includes a main body, a connecting part and an elastic part. The main body is provided with the via hole. The connecting part is provided in the vacuum chamber. One end of the elastic part is connected to the main body, and the other end is connected to the connecting part, so that the connecting part can elastically abut against the thick film heating element.

5. The heating device according to claim 2, wherein: The electrical connection terminal is welded to the thick film heating element.

6. The heating device according to claim 1, wherein: The substrate has a heating area and a mounting area arranged around the heating area. The thick film heating element is arranged in the heating area. The bottom shell includes a main board and a surrounding plate arranged upright on the edge of the main board. The surrounding plate is connected to the mounting area.

7. The heating device according to claim 6, wherein: A flange extending outward is provided on one side of the enclosure away from the main board, and the flange is connected to the installation area.

8. The heating device according to claim 6, wherein: The heating device also includes two electrical connection terminals, which are respectively a positive terminal and a negative terminal. The thick film heating element has a first end connected to the positive terminal and a second end connected to the negative terminal. The first end and the second end are spaced apart and arranged on the same side of the heating area close to the installation area.

9. The heating device according to claim 1, wherein: The bottom shell and the base plate are welded by vacuum furnace brazing or vacuum electron beam welding.

10. The heating device according to claim 1, wherein: The substrate and the bottom shell are made of stainless steel.

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