Electric hot tray, manufacturing method thereof and cooking utensil

Abstract

The invention discloses an electric hot tray, a manufacturing method thereof and a cooking utensil, and relates to the field of electric heating. An electric heating wire comprises a paper substrate, and the two faces of the electric heating wire are covered with inorganic insulating plates and fixed through the clamping force of a metal cover plate and a buckle. The electric hot tray has the advantages of higher working temperature and power density. In order to avoid poor heat dissipation caused by thermal expansion of the heating wire, the length of the continuous line segment of the heating wire does not exceed 30mm, or the product of the length and the power density does not exceed 20. According to the manufacturing method of the electric heating disc, the electric heating disc is heated at a high temperature, and the paper substrate contained in the electric heating wire is carbonized. According to the manufacturing method of the electric heating disc, the metal sheet is placed on the magnet, the electric heating wires are machined through laser cutting, multiple sheets can be cut at a time, and the electric heating wires can also be cut into a female heating wire and a male heating wire. The step of adhering the metal sheet to the mica substrate is omitted, the production efficiency is improved, the production cost is reduced, and materials are saved. The cooking utensil comprises any electric hot tray.

Description

Technical Field

[0001] The present invention relates to the field of electric heating, in particular to the field of household appliances. Background Art

[0002] At present, electric heating plates are generally made by welding or riveting electric heating tubes on metal plates, or by die-casting a metal plate with the electric heating tube as the core. The electric heating tube uses a metal tube as the outer shell, and spiral electric heating wires are evenly distributed along the central axis of the tube. The gaps are filled with compacted magnesium oxide sand with good insulation and thermal conductivity. Limited by factors such as the bending radius of the electric heating tube, the electric heating tube cannot completely cover the metal plate. Therefore, the heat is relatively concentrated, the temperature of the electric heating tube and the area it covers is higher, the temperature of the surrounding area is lower, the metal plate is heated unevenly, and the temperature of the terminal of the electric heating tube is higher. As a result, the heating effect is not ideal, the thermal power density per unit area is not high, and a larger heat dissipation space needs to be left for the terminal, which leads to a series of problems such as a higher overall height of the cooking appliance, an increase in product volume, an impact on user experience, and a waste of production material costs.

[0003] Application 201911244488.1 proposes an electric heating film, which consists of an electric heating film body and a metal wrapping sheet. The electric heating film body is an electric heating wire covered with an insulating film on both sides, and the metal wrapping sheet sandwiches the electric heating film body. The metal wrapping sheet can be formed by folding a metal sheet in half, flattening a metal flat tube, riveting or welding the upper and lower metal sheets. This electric heating film has a good heat dissipation effect and can solve the above-mentioned problems of the electric heating plate. During the application process, it was found that the insulating film of the electric heating film body is generally a plastic film such as a polyimide film. When the power density of the electric heating plate is too high, the temperature of the electric heating wire is too high, causing the insulating film to fail and burn, and causing the electric heating wire to melt.

[0004] However, it is not easy to remove the plastic film. The heating wire of the main body of the electric heating film is etched out of a metal sheet. During the etching process, a plastic film needs to be pasted on the bottom of the metal sheet as a substrate so that the etched heating wire can maintain a flat structure.

[0005] Mica heating plate is made by pasting a metal sheet on a mica substrate, cutting a heating wire through laser, and then covering the heating wire with a second mica plate, and pressing it with adhesives such as resin. Using mica heating plate as the main body of the electric heating film can solve the problem of insulation film failure and burning due to high temperature, but the heating wire of the mica heating plate is made by laser cutting of a metal sheet pasted on the mica substrate, which is not suitable for processing too thin heating wires, and cannot produce small-sized and low-power heating plates. The mica substrate will be damaged during cutting, and the adhesive will produce odor when used at high temperatures.

[0006] Application 202310624395.1 proposes an electric heating plate, including an electric heating film body, a metal cover plate and a buckle, and there is a solder between the electric heating film body and the metal cover plate. The electric heating film body is installed between the metal cover plate and the buckle, and holes can be opened on the electric heating film body to facilitate the connection between the metal cover plate and the buckle. The insulating film of the electric heating film body is made of high-temperature resistant glass fiber cloth, mica paper and other materials. The metal cover plate can be a metal material such as a stainless steel plate, an aluminum plate, or the bottom of a heated appliance such as a pot. The buckle is a metal material that can be welded to the metal cover plate. When welding the metal cover plate and the buckle, the electric heating plate is pressed and heated to melt the solder and flow under capillary action to fill the gap between the electric heating film body and the metal cover plate, so that the electric heating film body and the metal cover plate fit tightly. Since the insulating film of this scheme is made of high-temperature resistant glass fiber cloth, mica paper and other materials, it is not suitable for processing the heating wire using an etching process, so there are problems such as high production costs. Summary of the invention

[0007] The invention provides an electric heating plate, a manufacturing method thereof and a cooking utensil.

[0008] An electric heating plate includes an electric heating film body, a metal cover plate and a buckle, wherein the electric heating film body is installed between the metal cover plate and the buckle; the electric heating film body includes an electric heating wire and an inorganic insulating plate, the electric heating wire includes a paper substrate, and the two sides of the electric heating wire are covered with inorganic insulating plates, which are fixed by the clamping force of the metal cover plate and the buckle; the inorganic insulating plate can be made of high-temperature resistant glass fiber cloth, mica paper and other materials. A hole can be opened on the electric heating film body to facilitate the connection between the metal cover plate and the buckle. The metal cover plate and the buckle can be metal materials such as stainless steel plate and aluminum plate, the metal cover plate can also be the bottom of a heated appliance such as a pot, and the buckle can be a thermal insulation material such as ceramic. The buckle is fixed to the metal cover plate by welding, riveting or screws, so that the electric heating film body fits the heat-spreading thin plate and the metal cover plate as closely as possible. The metal cover plate and the buckle can also be formed by flattening a metal flat tube. In order to avoid poor heat dissipation caused by thermal expansion of the heating wire, the length of the continuous segment of the heating wire should not exceed 30 mm, or the product of the length and the power density should not exceed 20. For example, the power density of the area covered by the heating wire is 1w / cm 2 , the length of the continuous segment of the heating wire is 20cm, and the product of the two is 20.

[0009] The beneficial effects of the present invention are:

[0010] An electric heating plate includes an electric heating film body, a metal cover plate and a buckle. The electric heating film body is installed between the metal cover plate and the buckle. The electric heating film body includes an electric heating wire and an inorganic insulating plate. The electric heating wire includes a paper substrate. The electric heating wire can be processed using an etching process and then transferred to paper for easy assembly. The existing mature etching process is used, so it has the advantages of low production cost, high processing efficiency, and high processing precision. The two sides of the electric heating wire are covered with inorganic insulating plates, which are fixed by the clamping force of the metal cover plate and the buckle. Therefore, the electric heating wire is not easy to move after the substrate is carbonized at high temperature. The inorganic insulating plate can be made of glass fiber cloth, mica paper and other materials. This electric heating plate has a low content of organic matter, does not burn at high temperatures, and has no odor, which can improve the working temperature and power density of the electric heating plate.

[0011] Holes can be opened on the main body of the electric heating film to facilitate the connection of the metal cover and the buckle, which can improve the fit between the main body of the electric heating film and the metal cover and improve the heat dissipation efficiency. The metal cover and the buckle can be made of metal materials such as stainless steel plates and aluminum plates. The metal cover can also be the bottom of heated appliances such as pots and kettles. The advantage is that it can reduce thermal resistance, improve heating efficiency, reduce weight and reduce costs. The buckle can be made of thermal insulation materials such as ceramics. The advantage is that it can insulate, reduce the temperature at the bottom of the heating plate, and improve the strength of the buckle. The buckle is fixed to the metal cover by welding, riveting or screws, so that the main body of the electric heating film fits the heat spreader plate and the metal cover as closely as possible. The advantage is that the fixing method is flexible and diverse, which can meet the needs of different products. The metal cover and the buckle can also be formed by flattening a metal flat tube. The advantage is that the structure is simpler and the cost is lower.

[0012] In order to avoid poor heat dissipation caused by thermal expansion of the heating wire, the length of the continuous segment of the heating wire should not exceed 30 mm, or the product of the length and the power density should not exceed 20. This structure can reduce the probability of the heating wire melting due to poor heat dissipation, thereby increasing the power density of the heating plate.

[0013] A method for making an electric hot plate comprises the following steps: 1. Paste the metal sheet on the plastic film and process the heating wire through etching; 2. Paste the heating wire including the plastic film obtained in step 1 onto the paper, and then remove the plastic film; 3. Assemble the heating wire obtained in step 2 with the inorganic insulating plate, the metal cover plate and the buckle into an electric heating plate, wherein the stacking positions are the metal cover plate, the upper inorganic insulating plate, the heating wire, the lower inorganic insulating plate and the buckle in sequence; 4. The electric heating plate obtained in step 3 is heated at high temperature to carbonize the paper contained in the heating wire.

[0014] The beneficial effects of the present invention are: Processing the heating wire by etching in step 1 is an existing mature process with the advantages of low production cost, high processing efficiency and high processing precision; Using paper instead of plastic film to fix the heating wire in step 2 can make carbonization in step 4 easier and will not produce toxic gases, which is more environmentally friendly; In step 3, the electric heating plate is assembled so that the heating wire is fixed by the clamping force of the metal cover plate and the buckle, and it is not easy to move after the paper is carbonized in step 4; In step 4, the paper contained in the electric heating wire is carbonized so that the electric heating plate will not burn or produce odor during operation, thereby improving the operating temperature and power density of the electric heating plate.

[0015] A method for making an electric hot plate comprises the following steps: 1. Place the metal sheet on the magnet, and then use laser cutting to process the heating wire. In order to protect the metal sheet and the magnet, a protective layer of paper or rubber can be placed between the metal sheet and the magnet. Multiple metal sheets can be cut at one time. In order to protect the metal sheets and avoid mutual adhesion, the metal sheets are separated by paper or other materials. 2. Cover the heating wire obtained in step 1 with another magnet to separate the cut metal sheet into two groups of positive and negative heating wires. In order to facilitate the separation of the heating wires, the shape of the magnet can be processed into the shape of the heating wire; 3. Paste the metal sheet on the plastic film and process the heating wire through etching; 4. Place the heating wire including the plastic film obtained in step 3 on the magnet, and then remove the plastic film; 5. Assemble the heating wire obtained in step 1, 2 or 4 with the inorganic insulating plate, the metal cover plate and the fastener into an electric heating plate, wherein the stacking positions are the metal cover plate, the upper inorganic insulating plate, the heating wire, the lower inorganic insulating plate and the fastener in sequence; during the assembly process, the heating wire is fixed by a magnet.

[0016] The beneficial effects of the present invention are: In step 1, the metal sheet is placed on the magnet and fixed by magnetic force, thereby eliminating the step of pasting the metal sheet to the mica substrate of the mica heating plate, reducing production costs, improving production efficiency, reducing the use of adhesives, and reducing odor generated at high temperatures; placing a protective layer of rubber or other materials between the metal sheet and the magnet can reduce vibration and noise during operation, avoid scratching the metal sheet and the magnet, avoid laser cutting of the magnet, prevent harmful shavings, and facilitate cutting through the metal sheet; cutting multiple metal sheets at one time can increase production efficiency; separating the metal sheets with paper or other materials can avoid scratching the metal sheet, avoid melting and bonding of the metal during cutting, and facilitate separation of the heating wires of each layer.

[0017] In step 2, the cut metal sheet is separated into two groups of positive and negative heating wires by using a magnet, such as a mosquito coil structure, which solves the material waste problem existing in the existing etching and laser cutting, reduces the production cost, and improves the production efficiency; the shape of the magnet is processed into the shape of the heating wire, which is more conducive to separating the two groups of positive and negative heating wires and improves the production efficiency; In step 3, etching is used to process the heating wire, which is a mature process with the advantages of low production cost, high processing efficiency and high processing precision. It does not have the limitation of the laser cutting process that is not suitable for processing too thin heating wires. In step 4, fix the heating wire with magnets and remove the plastic film to avoid failure and burning due to the high temperature of the heating wire; In step 5, the electric heating plate is assembled so that the heating wire is fixed by the clamping force of the metal cover plate and the buckle, eliminating the step of fixing the second mica plate with adhesive of the mica heating plate, saving costs, improving production efficiency, and reducing the use of adhesive, resulting in less odor at high temperatures; fixing the heating wire with a magnet during the assembly process can prevent the heating wire from being easily displaced.

[0018] The present invention provides a cooking utensil comprising any one of the above electric heating plates.

[0019] The beneficial effects of the present invention are: This cooking utensil has all the advantages of any of the above-mentioned electric hot plates, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of the electric heating plate according to the present invention.

[0021] Figure 2 Schematic diagram of the circuit of the electric heating film according to the present invention.

[0022] In the figure, 1. Heating film body, 2. Metal cover plate, 3. Fastener, 4. Heating wire, 4-1. Paper substrate, 4-2. Heating wire covering area, 4-3. Heating wire continuous line segment, 5-1. Upper inorganic insulating plate, 5-2. Lower inorganic insulating plate, 6. Opening. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0024] Embodiment 1 An embodiment of the present invention is an electric hot plate; like Figure 1As shown: an electric heating plate, including an electric heating film body 1, a metal cover plate 2 and a buckle 3, the electric heating film body 1 is installed between the metal cover plate 2 and the buckle 3; the electric heating film body 1 includes an electric heating wire 4 and an upper inorganic insulating plate 5-1 and a lower inorganic insulating plate 5-2, the electric heating wire 4 includes a paper substrate 4-1, and both sides of the electric heating wire 4 are covered with an upper inorganic insulating plate 5-1 and a lower inorganic insulating plate 5-2, and are fixed by the clamping force of the metal cover plate 2 and the buckle 3. The upper inorganic insulating plate 5-1 and the lower inorganic insulating plate 5-2 are made of mica paper material, and a hole 6 is opened on the electric heating film body 1 to facilitate the connection between the metal cover plate 2 and the buckle 3. The metal cover plate 2 and the buckle 3 are made of aluminum alloy material, and the buckle 3 is fixed to the metal cover plate 2 by riveting; like Figure 2 As shown in the figure: In order to avoid poor heat dissipation caused by thermal expansion of the heating wire 4, the heating wire 4 is arranged in an S shape, the length of the continuous line segment 4-3 of the heating wire is 5 cm, and the power density of the heating wire coverage area 4-2 is 3w / cm 2 , the product of the two is 15.

Claims

1. An electric heating plate, comprising an electric heating film body, a metal cover plate and a buckle, wherein the electric heating film body is installed between the metal cover plate and the buckle, the electric heating film body comprises an electric heating wire and an inorganic insulating plate, and both sides of the electric heating wire are covered with an inorganic insulating plate, wherein: The heating wire comprises a paper substrate.

2. An electric heating plate, comprising an electric heating film body, a metal cover plate and a buckle, wherein the electric heating film body is installed between the metal cover plate and the buckle, the electric heating film body comprises an electric heating wire and an inorganic insulating plate, and both sides of the electric heating wire are covered with an inorganic insulating plate, wherein: In order to avoid poor heat dissipation caused by thermal expansion of the heating wire, the length of the continuous line segment of the heating wire does not exceed 30 mm, or the product of the length of the continuous line segment of the heating wire and the power density of the area covered by the heating wire does not exceed 20.

3. The electric hot plate according to claim 1 or 2, characterized in that: The metal cover plate is the bottom of the heated device.

4. A method for making a hot plate, comprising the following steps:

1. Paste the metal sheet on the plastic film and process the heating wire through etching; 2. Paste the heating wire including the plastic film obtained in step 1 onto the paper, and then remove the plastic film; 3. Assemble the heating wire obtained in step 2 with the inorganic insulating plate, the metal cover plate and the buckle into an electric heating plate, wherein the stacking positions are the metal cover plate, the upper inorganic insulating plate, the heating wire, the lower inorganic insulating plate and the buckle in sequence; 4. The electric heating plate obtained in step 3 is heated at high temperature to carbonize the paper contained in the heating wire.

5. A method for making an electric hot plate, characterized in that: The following steps are involved:

1. Place the metal sheet on the magnet and then cut the heating wire by laser.

2. Cover the heating wire obtained in step 1 with another magnet to separate the cut metal sheet into two groups of positive and negative heating wires; 3. Paste the metal sheet on the plastic film and process the heating wire through etching; 4. Place the heating wire including the plastic film obtained in step 3 on the magnet, and then remove the plastic film; 5. Assemble the heating wire obtained in step 1, 2 or 4 with the inorganic insulating plate, the metal cover plate and the fastener into an electric heating plate, wherein the stacking positions are metal cover plate, upper inorganic insulating plate, heating wire, lower inorganic insulating plate and fastener.

6. The method according to claim 5, characterized in that: In the step 1, a plurality of the metal sheets may be cut at one time.

7. The method according to claim 5, characterized in that: In the step 1, 2 or 4, in order to protect the metal sheet and the magnet, a protective layer may be placed between the metal sheet and the magnet.

8. The method according to claim 5, characterized in that: In the step 2, in order to facilitate the separation of the heating wire, the shape of the magnet can be processed into the shape of the heating wire.

9. The method according to claim 5, characterized in that: In step 5, the heating wire is fixed by a magnet during the assembly process.

10. A cooking utensil, characterized in that: The invention comprises an electric heating plate according to any one of claims 1 to 9.

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