Electric heating layer insulation structure and preparation method thereof

Abstract

The invention discloses an electric heating layer insulation structure and a preparation method thereof, and relates to the technical field of electric heaters, the electric heating layer insulation structure comprises an aluminum plating layer arranged on the surface of an electric heating sheet, the surface of the aluminum plating layer is oxidized to form an aluminum oxide film, and the surface of the aluminum oxide film is provided with a closed coating layer. Or a hydrated alumina layer is formed on the surface of the aluminum oxide film through a hydration reaction. The preparation method comprises the following steps: performing sand blasting pretreatment on the surface of the electric heating sheet; an aluminum plating layer is formed on the surface of the electric heating sheet by adopting an electric arc spraying method or a metal aluminum plating process; carrying out oxidation treatment on the aluminum plating layer to form an aluminum oxide film on the surface; and sealing the aluminum oxide film by using a sealing coating to form a sealing coating layer, or carrying out hydration reaction on the surface of the aluminum oxide film to form a hydrated aluminum oxide layer on the surface of the aluminum oxide film. The heat transfer effect is improved, the corrosion resistance of the electric heating sheet is improved, a press machine is not used in the preparation process, and mechanical damage in the preparation process is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of electric heaters, and in particular to an electric heating layer insulation structure and a preparation method thereof. Background Art

[0002] Chinese patent publication number CN114909806A discloses a high-pressure fluid microchannel electric heater, including a top plate and a bottom plate, between which metal microchannel heat exchange plates and electric heating plates are alternately stacked in sequence; each layer of the metal microchannel heat exchange plates includes a pair of symmetrically closed flow channel plates, and a fluid channel is arranged inside the flow channel plates; the electric heating plate includes an electric heating plate layer and an insulating layer, and the electric heating plate layer includes a heating resistor composed of a plurality of "J"-shaped metal sheets connected in series, and the "J"-shaped metal sheets are evenly distributed horizontally, and the electric heating plate layer is isolated from the contact surface of the metal microchannel heat exchange plate and both ends in the horizontal direction; both ends of the electric heating plate are provided with a frame; and each layer of the electric heating plate has two connection points. The insulation scheme of the electric heating plate and the body is to weld the upper frame of the electric heating plate into a pressing mold, fill it with insulating powder, and press it repeatedly with a press to compact the blank of the electric heating plate. This solution uses insulating powder to be repeatedly compacted to achieve insulation. Although the process is relatively simple, the actual operation involves repeated use of a press, which poses a high safety risk. In addition, during the compaction of the insulating powder, if the powder is not compacted, complete insulation will not be achieved. In addition, since the powder needs to be compacted to achieve the insulation function, the powder can only achieve this process if it has a certain thickness during continuous filling and compaction, which will result in some heat loss during the subsequent heat transfer process. After continuous filling and compaction, the powder still has a large porosity, and the air can still come into contact with the surface of the electric heating plate. In subsequent use, since the electric heating plate is in a heating state or in an alternating hot and cold cycle for a long time, contact with air will shorten its service life. Summary of the invention

[0003] The purpose of the present invention is to provide an electric heating layer insulation structure and a preparation method thereof to solve the problems existing in the above-mentioned prior art. The insulation layer is thinner, the heat transfer effect is improved, the contact between the metal substrate and the air can be basically isolated, and the corrosion resistance of the electric heating plate is improved. The preparation process does not involve the use of a press, and mechanical damage during the preparation process is eliminated.

[0004] To achieve the above object, the present invention provides the following solutions: The present invention provides an electric heating layer insulation structure, comprising an aluminum coating arranged on the surface of an electric heating plate, wherein the surface of the aluminum coating is oxidized to form an aluminum oxide film on the surface, a closed coating layer is provided on the surface of the aluminum oxide film, or a hydrated aluminum oxide layer is formed on the surface of the aluminum oxide film through a hydration reaction.

[0005] In one embodiment, the aluminum coating has a thickness of 130-170 μm.

[0006] In one embodiment, the aluminum oxide film has a thickness of 50-80 μm.

[0007] In one embodiment, the sealing coating layer has a thickness of 5-10 μm.

[0008] In one embodiment, the aluminum oxide film is formed on the surface of the aluminum coating by anodizing.

[0009] In one embodiment, the aluminum coating is formed on the surface of the electric heating plate by spraying with an arc spraying method, or the aluminum coating is formed on the surface of the electric heating plate by a metal aluminum plating process.

[0010] In one embodiment, the hydrated aluminum oxide layer is formed on the surface of the aluminum oxide film by a hot water sealing method or a steam sealing method.

[0011] The present invention also provides a method for preparing the above-mentioned electric heating layer insulation structure, comprising the following steps: (1) Pre-treat the surface of the electric heating plate by sandblasting; (2) forming the aluminum coating on the surface of the electric heating plate by an arc spraying method or a metal aluminum plating process; (3) performing oxidation treatment on the aluminum coating to form the aluminum oxide film on the surface; (4) The aluminum oxide film is sealed with a sealing coating to form the sealing coating layer, or the surface of the aluminum oxide film is hydrated to form the hydrated aluminum oxide layer.

[0012] Compared with the prior art, the present invention has achieved the following technical effects: The electric heating layer insulation structure and preparation method provided by the present invention form an aluminum coating on the surface of the electric heating plate, and the surface of the aluminum coating is oxidized to obtain an aluminum oxide film, the aluminum oxide film initially has high temperature resistance and good insulation properties, and a closed coating layer is arranged on the surface of the aluminum oxide film or a hydrated aluminum oxide layer is formed on its surface through a hydration reaction to improve its insulation ability, which can basically isolate the metal substrate from the contact with the air, greatly improve the corrosion resistance of the electric heating plate, the thickness of the insulation layer is thinner, and the thermal conductivity coefficient is slightly different from that of the metal substrate, thereby improving the heat transfer effect, and the preparation process does not involve the use of a press, thereby eliminating mechanical damage during the preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. 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 these drawings without paying creative work.

[0014] Figure 1 It is a schematic diagram of the insulation structure of the electric heating layer in the first embodiment of the present invention.

[0015] In the figure: 1-electric heating plate, 2-aluminum coating, 3-aluminum oxide film, 4-sealing coating layer. DETAILED DESCRIPTION

[0016] 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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0017] The purpose of the present invention is to provide an electric heating layer insulation structure and a preparation method thereof to solve the problems existing in the prior art. The insulation layer is thinner, the heat transfer effect is improved, the contact between the metal substrate and the air can be basically isolated, and the corrosion resistance of the electric heating plate is improved. The preparation process does not involve the use of a press, and mechanical damage during the preparation process is eliminated.

[0018] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] Embodiment 1 like Figure 1 As shown, this embodiment provides an electric heating layer insulation structure, including an aluminum coating 2 arranged on the surface of an electric heating plate 1, the surface of the aluminum coating 2 is oxidized to form an aluminum oxide film 3 on its surface, and a closed coating layer 4 is provided on the surface of the aluminum oxide film 3.

[0020] In this embodiment, the thickness of the aluminum coating 2 is 130-170 μm, preferably 150 μm. After the surface of the aluminum coating 2 is oxidized, part of the aluminum coating 2 is converted into an aluminum oxide film 3 with a thickness of 50-80 μm.

[0021] In this embodiment, the thickness of the sealing coating layer 4 is 5-10 μm.

[0022] In this embodiment, an aluminum oxide film 3 is formed on the surface of the aluminum coating 2 by an anodic oxidation method.

[0023] In this embodiment, an arc spraying method is used to spray the aluminum coating 2 on the surface of the electric heating plate 1, or a metal aluminum plating process is used to form the aluminum coating 2 on the surface of the electric heating plate 1, such as electroplating and hot-dip plating.

[0024] When preparing the electric heating layer insulation structure in this embodiment, the following steps are included: (1) Pre-treat the surface of the electric heating plate 1 by sandblasting; use 120 mesh fine sand, sandblasting pressure 0.4-0.5Mpa, sandblasting distance 200mm, sandblasting angle 70 degrees, and sandblasting to form a relatively rough surface, thereby improving the adhesion of the subsequent aluminum layer; (2) An arc spraying method or a metal aluminum plating process is used to form an aluminum coating 2 on the surface of the electric heating plate 1; the arc spraying method uses an arc aluminum spraying process, and the arc aluminum spraying process is used to form a relatively dense aluminum coating 2 on the surface of the electric heating plate 1 through multiple spraying. The distance between the spray gun and the surface of the electric heating plate 1 is 180±20mm, the spraying voltage is 30±3V, the spraying current is 150±10A, the spraying pressure is 0.4±0.1Mpa, and the spraying angle is 55±5°. During spraying, multiple spraying is performed with opposite reciprocating angles. After spraying, an aluminum coating 2 of about 150μm should be formed; the metal aluminum plating process uses conventional electroplating and hot-dip plating processes.

[0025] (3) The aluminum coating 2 is oxidized to form an aluminum oxide film 3 on the surface; the oxidation treatment adopts hard anodizing treatment, and after the treatment, a hard oxide film (aluminum oxide film 3) of 50-80 μm can be formed, and the insulation property of 30V / μm is good, and the breakdown voltage can reach 2000V; (4) A sealing coating is used to seal the aluminum oxide film 3 to form a sealing coating layer 4; the oxide film formed by hard anodizing still has small pores, and the oxide film is then sealed with ZS-1021 high temperature resistant sealing coating to isolate the electric heating plate 1 from the air, which can greatly improve the corrosion resistance of the electric heating plate 1 and ensure that the electric heating plate 1 will not rust due to hot and cold cycles under long-term operation.

[0026] Embodiment 2 This embodiment provides an electric heating layer insulation structure, which is different from the first embodiment in that no sealing coating layer 4 is provided on the surface of the aluminum oxide film 3, but a hydrated aluminum oxide layer is formed on the surface of the aluminum oxide film 3 through a hydration reaction.

[0027] In this embodiment, a hydrated aluminum oxide layer is formed on the surface of the aluminum oxide film 3 by using a hot water sealing method or a steam sealing method.

[0028] When preparing the electric heating layer insulation structure in this embodiment, steps (1) to (3) are the same as the preparation steps in Example 1, and step (4) is as follows: The surface of the aluminum oxide film 3 is hydrated to form a hydrated aluminum oxide layer on the surface; specifically, a hot water sealing method or a steam sealing method can be used to utilize the aluminum oxide on the surface of the oxide film and the pore wall to undergo a hydration reaction in hot water to generate hydrated aluminum oxide, thereby increasing the volume of the original oxide film and achieving the purpose of sealing the pores. Distilled water or deionized water should be used for hot water sealing, and tap water should not be used to prevent scale from being adsorbed in the pores of the oxide film and affecting transparency. A good sealing state can be obtained by sealing with slightly acidic distilled water.

[0029] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. An electric heating layer insulation structure, characterized in that: The invention comprises an aluminum coating arranged on the surface of the electric heating plate, wherein the surface of the aluminum coating is oxidized to form an aluminum oxide film on the surface, a closed coating layer is provided on the surface of the aluminum oxide film, or a hydrated aluminum oxide layer is formed on the surface of the aluminum oxide film through a hydration reaction.

2. The electric heating layer insulation structure according to claim 1, characterized in that: The thickness of the aluminum coating is 130-170 μm.

3. The electric heating layer insulation structure according to claim 1, characterized in that: The thickness of the aluminum oxide film is 50-80 μm.

4. The electric heating layer insulation structure according to claim 1, characterized in that: The thickness of the sealing coating layer is 5-10 μm.

5. The electric heating layer insulation structure according to claim 1, characterized in that: The aluminum oxide film is formed on the surface of the aluminum coating by an anodic oxidation method.

6. The electric heating layer insulation structure according to claim 1, characterized in that: The aluminum coating is formed on the surface of the electric heating plate by spraying with an arc spraying method, or the aluminum coating is formed on the surface of the electric heating plate by a metal aluminum plating process.

7. The electric heating layer insulation structure according to claim 1, characterized in that: The hydrated aluminum oxide layer is formed on the surface of the aluminum oxide film by a hot water sealing method or a steam sealing method.

8. A method for preparing an electric heating layer insulation structure according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Pre-treat the surface of the electric heating plate by sandblasting; (2) forming the aluminum coating on the surface of the electric heating plate by an arc spraying method or a metal aluminum plating process; (3) performing oxidation treatment on the aluminum coating to form the aluminum oxide film on the surface; (4) The aluminum oxide film is sealed with a sealing coating to form the sealing coating layer, or the surface of the aluminum oxide film is hydrated to form the hydrated aluminum oxide layer.

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