An electric heating device

Abstract

This invention discloses an electric heating device, including a substrate with a metal film resistive heating layer and a temperature sensor integrated on it. This integration improves the device's integration density and allows for application in smaller spaces. The main function of the metal film resistive heating layer is to transfer heat from the resistor to the substrate. The temperature sensor detects the temperature of the heating module, enabling precise temperature control through a temperature control system. By using a ceramic substrate and a suitable resistive heating layer, combined with a highly sensitive temperature sensor, a uniform and consistent temperature field can be achieved in the heating module.

Description

Technical Field

[0001] The present invention relates to the field of temperature control, and in particular to an electric heating device for precise temperature control used in the medical industry and other fields. Background Art

[0002] The electric heating device usually includes components such as a substrate, a heating wire and a conductive wire. The substrate is generally made of ceramic or metal, and the heating wire is generally made of nickel-chromium wire. The heating wire is buried in a metal sheet or a preformed structural ceramic, and then filled with magnesium oxide or aluminum oxide powder to form an integrated heating core structure.

[0003] During operation, the nickel-chromium wire heats up and transfers the heat to the substrate through the filler. Since the nickel-chromium wire is prone to aging due to repeated use and is prone to burning during use, its operating stability is poor. In addition, the temperature detection device is independent of the electric heating device. Therefore, when measuring temperature, there are problems such as response lag and low measurement accuracy, which cannot meet the needs of high-reliability and precision temperature control equipment in the medical industry, such as medical analysis instruments, PCR fluorescence quantitative testing, virus detection, and vaccine development. In addition, the current electric heating device also has the problem of low integration, so it is difficult to apply to areas with smaller spaces. Summary of the invention

[0004] The object of the present invention is to provide an electric heating device which can effectively solve the problems of low temperature control accuracy and low integration.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] An electric heating device comprises a substrate on which a metal film resistance heating layer and a temperature sensor are arranged. The metal film resistance heating layer is used to transfer heat to the substrate, and the temperature sensor is used to detect temperature information of the substrate.

[0007] Preferably, the substrate is a sheet structure, and in some special application scenarios, a curved structure may also be selected.

[0008] Preferably, the metal film resistance heating layer includes a first heating layer and a second heating layer symmetrically arranged on the upper surface of the substrate.

[0009] Preferably, the temperature sensor is disposed between the first heat-generating layer and the second heat-generating layer.

[0010] Preferably, a first pad and a second pad are provided on the upper surface of the substrate, the temperature sensor is connected to the first pad, and the metal film resistive heating layer is connected to the second pad.

[0011] Preferably, the first pad is provided with two terminals, the second pad is provided with four terminals, the two terminals on the first pad are connected to two terminals on the second pad, and the four terminals on the second pad are connected to wires.

[0012] Preferably, the wire is a high temperature resistant polyimide or polytetrafluoroethylene flexible terminal block wire.

[0013] Preferably, the substrate is aluminum oxide, zirconium oxide, aluminum nitride, silicon nitride ceramic or stainless steel.

[0014] Preferably, the metal film resistor heating layer is a ruthenium-based or palladium-based electronic paste that is thickly printed on the upper surface of the substrate, and the thickness of the heating film is usually greater than 10 microns or more.

[0015] Preferably, the upper surface of the metal film resistance heating layer and / or the lower surface of the substrate is covered with a high temperature resistant and wear resistant insulating protective layer, generally made of lead-free environmentally friendly glass glaze filled with fine ceramic powder.

[0016] Compared with the prior art, the above technical solution has the following advantages:

[0017] The electric heating device provided by the present invention includes a substrate, a metal film resistance heating layer and a temperature sensor are provided on the substrate, that is, the temperature sensor can be integrated on the substrate, which can improve the integration of the electric heating device and the assembly density, so that it can be applied to smaller space scenes. The main function of the metal film resistance heating layer is to transfer the heat of the resistor when working to the substrate. The temperature information of the heating module can be detected by the temperature sensor, and the temperature control and regulation system can be used to achieve the purpose of precise temperature control. By adopting a ceramic substrate and setting a resistance heating layer with appropriate power density and thickness, and cooperating with a high-sensitivity temperature sensor, the temperature field of the heating substrate module can be uniform and consistent. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 The present invention is a schematic structural diagram of an electric heating device provided in a specific embodiment of the present invention.

[0020] The reference numerals are as follows:

[0021] 1 is a substrate, 2 is a temperature sensor, 3 is a first heating layer, 4 is a second heating layer, 5 is a first soldering pad, 6 is a second soldering pad, and 7 is a wire. DETAILED DESCRIPTION

[0022] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0023] In the following description, specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in a variety of other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0024] Please refer to Figure 1 , Figure 1 The present invention is a schematic structural diagram of an electric heating device provided in a specific embodiment of the present invention.

[0025] A specific embodiment of the present invention provides an electric heating device, which can be applied to precision instruments such as medical analysis instruments, PCR fluorescence quantitative testing, virus detection and vaccine development. The electric heating device includes a substrate 1, on which a metal film resistor heating layer and a temperature sensor 2 are provided, that is, the temperature sensor 2 is also integrated on the substrate 1, which can improve the integration of the electric heating device and reduce its volume so that it can be applied to smaller space scenes. The metal film resistor heating layer is used to transfer heat to the substrate 1. The metal film resistor heating layer can ensure that the temperature field is uniform. In addition, the temperature information of the substrate 1 can be detected by the temperature sensor 2, thereby achieving the purpose of precise temperature control.

[0026] The number of temperature sensors 2 may be determined according to the structure and size of the substrate 1. The multiple temperature sensors 2 are preferably arranged in a uniformly distributed manner, and the average value of the data measured by the multiple temperature sensors 2 is taken to ensure the accuracy of temperature detection.

[0027] Specifically, the substrate 1 is preferably a sheet structure or a curved surface structure, and the specific shape can be set according to the shape of the heating target, for example, it can be a polygonal, circular or special-shaped structure. The substrate 1 is preferably made of aluminum oxide, zirconium oxide, aluminum nitride, silicon nitride ceramics or stainless steel. In addition, the substrate 1 can also be a shell-like structure of a cylindrical or other shape. When stainless steel is used, it is also necessary to perform insulation protection treatment on the stainless steel.

[0028] Specifically, the metal film resistor heating layer includes a first heating layer 3 and a second heating layer 4 symmetrically arranged on the upper surface of the substrate 1, and the first heating layer 3 and the second heating layer 4 are connected to each other. Figure 1The distribution method shown. It should be noted that the symmetrical distribution is only a reasonable design and adaptive distribution method of the metal film resistor heating layer according to the structure of the substrate 1. The main purpose is to achieve a uniform, stable and consistent temperature field for the heating module. Of course, other distribution methods can also be selected. The temperature sensor 2 is preferably arranged between the first heating layer 3 and the second heating layer 4. This position can improve the accuracy of the temperature measurement of the temperature sensor 2. Among them, the temperature sensor 2 is preferably a platinum resistor, and the temperature sensor 2 can be integrated by means of printed thick film or external Pt100 platinum resistor. It is preferred to set the platinum resistor by means of printed thick film. After setting the platinum resistor by means of printed thick film, the steps of laser repairing the resistor and adding a protective layer are also required. When using an external platinum resistor, it is necessary to use thermal conductive silicone grease with a thermal conductivity of not less than 15W / mK.

[0029] In order to ensure the heating accuracy of the heating layer, the metal film resistor heating layer preferably adopts a high power density ruthenium or palladium electronic paste with a temperature coefficient lower than 100ppm / ℃ thick film printed on the upper surface of the substrate 1, which has the advantages of high power density, small temperature coefficient, constant heating temperature and high resistance accuracy. Its heating accuracy is usually not less than + 5%. You can also choose to use laser resistance trimming to appropriately correct the resistance of the metal film resistor to make the resistance accuracy of the heating resistor higher and make the heating temperature of the module more evenly controlled. The use of these materials, designs and process methods can achieve precise temperature control; in addition, other materials of metal film resistor heating layers can also be selected.

[0030] Furthermore, in order to facilitate the connection between the temperature sensor 2 and the metal film resistor heating layer, the upper surface of the substrate 1 is provided with a first pad 5 and a second pad 6, the temperature sensor 2 is connected to the first pad 5, the first pad 5 is arranged in the space between the first heating layer 3 and the second heating layer 4, and the metal film resistor heating layer is connected to the second pad 6. The lead of the temperature sensor 2 can be led out through the first pad 5, or the first pad 5 can be connected to the second pad 6 and led out uniformly by the second pad 6.

[0031] Among them, the first pad 5 is provided with two terminals, and the second pad 6 is provided with four terminals. The two terminals on the first pad 5 are connected to two terminals on the second pad 6. The four terminals on the second pad 6 are connected to the wire 7. The wire 7 is preferably a four-row wire structure. The terminals on both sides are connected to the metal film resistor heating layer, and the middle terminal is connected to the first pad 5. Figure 1 The terminal distribution shown, that is, the lead wires of the temperature sensor 2 and the lead wires of the metal film resistance heating layer are led out through the same wire 7, can further improve the integration of the electric heating device.

[0032] It should be noted that the above description is made by taking one temperature sensor 2 as an example. When multiple temperature sensors 2 are provided, multiple groups of terminals are provided on the first pad 5 accordingly, and the leads can still be uniformly led out from the second pad 6 .

[0033] In addition, the wire 7 is preferably a high-temperature resistant flexible wire 7, for example, a polyimide or polytetrafluoroethylene material can be selected. In order to enhance the reliability of the connection, glue injection treatment can be performed at the connection between the wire 7 and the pad to prevent the problem of falling off after frequent use. The glue is preferably silicone or epoxy glue that is resistant to high temperatures above 200 degrees Celsius.

[0034] Furthermore, the upper surface of the metal film resistance heating layer and / or the lower surface of the substrate 1 is covered with an insulating protective layer with good high temperature resistance and wear resistance to improve the safety of the electric heating device when in use.

[0035] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0036] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An electric heating device, comprising a substrate (1), characterized in that: The substrate (1) is provided with a metal film resistive heating layer and a temperature sensor (2), the metal film resistive heating layer is used to transfer heat to the substrate (1), and the temperature sensor (2) is used to detect the temperature information of the substrate (1), the upper surface of the substrate (1) is provided with a first soldering pad (5) and a second soldering pad (6), the temperature sensor (2) is connected to the first soldering pad (5), the metal film resistive heating layer is connected to the second soldering pad (6), the first soldering pad (5) is provided with two terminals, the second soldering pad (6) is provided with four terminals, the two terminals on the first soldering pad (5) are connected to two of the terminals on the second soldering pad (6), and the four terminals on the second soldering pad (6) are connected to wires (7), and the metal film resistive heating layer is a ruthenium-based or palladium-based electronic paste that is thickly printed on the upper surface of the substrate (1).

2. The electric heating device according to claim 1, characterized in that: The substrate (1) is in the form of a flat sheet or a curved structure.

3. The electric heating device according to claim 2, characterized in that: The metal film resistance heating layer comprises a first heating layer (3) and a second heating layer (4) which are symmetrically arranged on the upper surface of the substrate (1).

4. The electric heating device according to claim 3, characterized in that: The temperature sensor (2) is arranged between the first heat-generating layer (3) and the second heat-generating layer (4).

5. The electric heating device according to claim 1, characterized in that: The conductor (7) is a high temperature resistant polyimide or polytetrafluoroethylene flexible terminal block conductor (7).

6. The electric heating device according to claim 1, characterized in that: The substrate (1) is aluminum oxide, zirconium oxide, aluminum nitride, silicon nitride ceramic or stainless steel.

7. The electric heating device according to any one of claims 1 to 6, characterized in that: The upper surface of the metal film resistance heating layer and / or the lower surface of the substrate (1) are covered with an insulating protective layer.

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