Inner container of electric cooker

Abstract

The invention provides an electric cooker inner container which comprises a base body, and a metal film is formed on the inner surface of the base body. Wherein the metal film at least comprises a transition layer and a metal surface layer attached to the transition layer, the transition layer is a chromium nitride layer, and the metal surface layer is a chromium metal layer. The adhesive has the advantages of being healthy and environmentally friendly, and has the beneficial effects of being good in anti-sticking effect, high in hardness, good in wear resistance, long in anti-sticking life and the like.

Description

Technical Field

[0001] The invention relates to the technical field of kitchenware, in particular to an inner pot of an electric rice cooker. Background Art

[0002] The non-stick inner pot of the electric rice cooker in the prior art is usually coated with a layer of anti-stick coating on the inner wall of the inner pot. The most commonly used anti-stick coating material is Teflon, whose scientific name is polytetrafluoroethylene, which solves the problem of rice sticking to the pot and brings some convenience to people's lives. However, the anti-stick coating on the inner wall of the inner pot is easy to fall off during use, especially when the inner pot is accidentally burned empty, which is more likely to cause the anti-stick coating to fall off. Although polytetrafluoroethylene itself is non-toxic, when it is burned empty at high temperature, polytetrafluoroethylene will carbonize and crack, releasing trace amounts of toxic gases and substances, which will contaminate the food, thereby causing problems such as rice sticking to the pot and accidental ingestion of chemical coatings.

[0003] On this basis, a non-stick pan has appeared in the prior art, which uses the lotus leaf effect to make an anti-stick structure on the inner wall of the pan. The anti-stick structure is a periodically distributed protrusion or / and pit portion on the inner wall, and the size of the protrusion and pit portion is between a few microns and tens of microns. Since the inner wall surface of the non-stick pan becomes a rough surface with a roughness of micrometer level, the contact surface between the cooked food and the inner wall surface of the non-stick pan becomes a composite contact surface, and the concave area between the protrusions of the anti-stick structure and the concave area of ​​the pit portion are adsorbed with gas to form an air cushion layer, which effectively reduces the contact area between the cooked food and the inner wall surface of the non-stick pan, does not stick to the cooked food, and realizes zero-coating physical anti-sticking. Even if the pan is burned empty, the zero-coating non-stick pan will not release any toxic substances and gases, will not pollute the cooked food and the kitchen environment, and will make cooking safer.

[0004] However, the anti-stick structure in the prior art has poor wear resistance. During long-term use, the contact and friction with food materials such as rice grains and beans, and utensils such as shovels and spoons will damage the anti-stick structure, making it impossible to achieve a long-term non-stick effect. This problem also needs to be solved urgently. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the above-mentioned prior art and provide an electric rice cooker inner pot with high wear resistance and capable of achieving persistent non-stick properties.

[0006] In order to achieve the above object, the present invention provides an electric rice cooker inner pot, comprising a base body; A metal film is formed on the inner surface of the substrate; The metal film at least includes a transition layer and a metal surface layer attached to the transition layer, wherein the transition layer is a chromium nitride layer and the metal surface layer is a chromium metal layer.

[0007] Furthermore, the metal surface layer is a chromium-copper alloy layer, wherein the chromium content is 92-96wt% and the copper content is 4-8wt%.

[0008] Furthermore, the thickness of the chromium nitride layer is 0.1-0.5 μm, and the thickness of the chromium-copper alloy layer is 0.1-0.5 μm.

[0009] Furthermore, the metal film also includes a metal base layer arranged between the inner surface of the substrate and the transition layer, wherein the metal base layer is a chromium metal layer.

[0010] Furthermore, the thickness of the metal base layer is 0.1-0.5 μm.

[0011] Furthermore, the thickness of the metal film is 0.5-1.5 μm.

[0012] Furthermore, the metal film is deposited in sequence by sputtering coating.

[0013] Furthermore, the substrate includes a first substrate layer, a heat-spreading layer and a second substrate layer from the inside to the outside, and the first substrate layer and the second substrate layer are composited into one by the heat-spreading layer so that the first substrate layer is heated evenly.

[0014] Furthermore, the substrate is a steel-aluminum-steel composite plate.

[0015] Furthermore, a concave structure is formed on the inner surface of the substrate, and the metal film covers the concave structure.

[0016] Furthermore, the pit structure is formed by etching.

[0017] Furthermore, before forming the metal film on the inner surface of the substrate, the inner surface of the substrate is polished into a mirror surface.

[0018] Furthermore, the metal film is evaluated as Grade II according to the results of the non-stickiness test for cooked rice in the Chinese national standard GB / T32095.2-2015.

[0019] Due to the adoption of the above technical solution, the present invention has the following beneficial effects: The inner pot of the electric rice cooker of the present invention has a chromium nitride layer and a chromium metal layer formed on the inner surface of the base, wherein the chromium metal layer has excellent non-stick properties, and the chromium nitride layer has excellent wear resistance, and the two together realize a metal film with high wear resistance and long-lasting non-stick properties, thereby increasing the service life of the inner pot of the electric rice cooker. In addition, in order to solve the technical problem that the metal film may be damaged due to local overheating of the inner pot during cooking, the base of the inner pot of the present invention also adopts a steel-aluminum-steel composite plate structure, wherein the aluminum layer can act as a heat-averaging layer, so that the inner pot is heated more evenly, further extending the non-stick life of the inner pot. The metal film on the inner pot of the present invention is evaluated as Grade II according to the results of the non-stickiness test for cooking rice in the Chinese national standard GB / T32095.2-2015. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present invention, but are not intended to limit the present invention.

[0021] Figure 1 It is a cross-sectional view of the inner pot of the electric rice cooker in the first embodiment of the present invention.

[0022] Figure 2 yes Figure 1 Magnified view at A in the middle.

[0023] Figure 3 The figure is a schematic diagram of the non-stick structure of the inner pot of the electric rice cooker in the first embodiment of the present invention.

[0024] Figure 4 It is a schematic diagram of each layer of the metal film in the first embodiment of the present invention.

[0025] Description of reference numerals: 100 - rice cooker inner pot; 101 - first base layer; 102 - second base layer; 103 - heat-dissipating layer; 104 - metal film; 1041 - metal base layer; 1042 - transition layer; 1043 - metal surface layer. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. The components of the embodiments of the present invention described and shown in the accompanying drawings can be arranged and designed in various configurations. 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.

[0027] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0028] Unless otherwise defined, the technical terms or scientific terms used in this patent document shall have the usual meanings understood by people with ordinary skills in the field to which the invention belongs. The words "first", "second" and similar words used in the patent specification and claims of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one", "an" or "the" do not indicate a quantity limitation, but indicate the existence of at least one. Words such as "include" or "comprise" mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. "Center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", "far", "near" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the features of the following embodiments can be combined with each other.

[0031] like Figures 1 to 4The inner pot 100 of an electric rice cooker shown in the figure comprises a substrate and a metal film 104 formed on the inner surface of the substrate. The substrate comprises a first substrate layer 101, a heat-averaging layer 103 and a second substrate layer 102. The first substrate layer 101 is configured as an inner layer, and its surface constitutes the inner surface of the substrate. The first substrate layer 101 and the second substrate layer 102 are combined into one by the heat-averaging layer 103. The heat-averaging layer 103 has a higher thermal conductivity than the first substrate layer 101 to prevent the first substrate layer 101 from being locally overheated and damaging the metal film 104. The present invention is described by taking the inner pot of an electric rice cooker as an example. It can be understood that it can also be other pots or utensils, such as a frying pan, a soup pot, etc.

[0032] In one embodiment, the metal film 104 can be formed on the substrate by physical vapor deposition (PVD) technology. The physical vapor deposition technology refers to a technology that uses physical methods to vaporize the surface of a material source (solid or liquid) into gaseous atoms or molecules, or partially ionizes into ions under vacuum conditions, and deposits a thin film with a special function on the surface of the substrate through low-pressure gas (or plasma). Physical vapor deposition coating technology is mainly divided into three categories: vacuum evaporation coating, vacuum sputtering coating and vacuum ion coating. The corresponding coating equipment includes vacuum evaporation coating machine, vacuum sputtering coating machine and vacuum ion coating machine. According to different uses, physical vapor deposition coating technology can also be divided into tool plating and decorative plating. Tool plating focuses on improving the hardness and wear resistance of the workpiece, and is suitable for fields such as precision parts and molds. The coating characteristics of tool plating are slow deposition speed and single color, but the film thickness is uniform and the thickness can be thicker. It has the characteristics of high hardness, friction resistance, high temperature resistance, and corrosion resistance. Decorative plating focuses on improving the appearance, decorative performance and color of workpieces, and is widely used in the processing and manufacturing of decorative products in the hardware industry. The coating characteristics of decorative plating are fast deposition speed, relatively low hardness, thin film layer, but diversified colors. In order to ensure the thickness of the metal film 104, tool plating is used in this application, so that the thickness of the metal film 104 can reach a thickness with better performance. Preferably, the thickness of the metal film 104 is 0.5 to 1.5 microns, and specifically, the thickness of the metal film 104 is 0.8 microns or 0.9 microns.

[0033] In a preferred embodiment, in order to further improve the service life of the metal film 104, the substrate of the inner pot of the electric rice cooker adopts a steel-aluminum-steel composite plate, that is, the first substrate layer 101 is a stainless steel layer, the heat-absorbing layer 103 is an aluminum layer, and the second substrate layer 102 is a stainless steel layer. The selected stainless steel is preferably food grade, especially the first substrate layer 101, such as SUS304. The second substrate layer 102 mainly has its protective function, and the second substrate layer 102 is directly in contact with the heating plate, preferably a material with better heat resistance, such as SUS430; in addition to stainless steel, other metals, such as titanium alloys, can also be selected. In order to further improve the non-stick effect of the inner surface, a concave point structure can also be formed on the inner surface of the substrate first, and the concave point structure can be etched by an etching process. The concave point structure is arranged in an array or irregularly evenly distributed on the inner surface of the substrate. The array arrangement or irregularly evenly distributed concave point structure can form a lotus leaf structure inside the inner pot of the electric rice cooker 100 to improve the non-stick effect. Before forming the metal film 104 on the inner surface of the substrate, the inner surface of the substrate is polished into a mirror surface. The surface of the substrate after polishing is flatter and smoother, which is conducive to the uniform adhesion and dense growth of the coating layer, thereby improving the quality and performance of the coating; and the polishing process can remove oxides and impurities on the surface of the substrate, increase the bonding force between the substrate and the coating layer, and prevent the coating layer from peeling off or falling off during subsequent use. In one embodiment, after the pit structure is etched and formed, the composite plate is stretched to form an inner tank, and the inner surface of the substrate is polished into a mirror surface. After being cleaned with ultrasonic pure water, the substrate can be placed in a coating machine for sputtering coating to form the metal film 104.

[0034] See also Figure 4 As shown, in one embodiment, the metal film 104 mainly contains chromium and chromium nitride, wherein the chromium element contained therein can reduce surface energy, improve non-stickiness and corrosion resistance, and chromium nitride can enhance wear resistance. Specifically, the metal film 104 at least includes a transition layer 1042 and a metal surface layer 1043 attached to the transition layer 1042, wherein the transition layer 1042 is a chromium nitride layer, and the metal surface layer 1043 is a chromium-containing metal layer. Further, the metal film 104 also includes a metal base layer 1041 disposed between the inner surface of the substrate and the transition layer 1042, wherein the metal base layer 1041 is a chromium metal layer. In the metal base layer 1041 and the metal surface layer 1043, chromium exists in the form of metal. The chromium metal layer as the metal base layer 1041 has the function of improving the adhesion between the metal film 104 and the substrate, and can also prevent the precipitation of heavy metal substances from the first substrate layer 101, which affects human health. The chromium-containing metal layer as the metal surface layer 1043 has the function of preventing adhesion and precipitation of heavy metals.

[0035] In the transition layer 1042, chromium exists in the form of nitride (i.e., CrN). Chromium nitride has good corrosion resistance and can reduce the friction coefficient of the PVD film, making it have excellent wear resistance. Chromium nitride can significantly reduce the surface energy of the metal film 104, and at the same time significantly improve the hardness and wear resistance of the metal film 104. Its hardness can reach HV1000-5000, and its surface energy can reach below 40 dynes, so that the metal film 104 has excellent non-stick effect and wear resistance. The setting of the chromium nitride layer strengthens the problem of poor hardness and wear resistance of the metal chromium layer alone.

[0036] In one embodiment, the metal surface layer 1043 is a chromium metal layer. Chromium is a metal element with stable chemical properties. It can form a dense oxide film (i.e., a passivation layer) on the surface of the cookware. This oxide film can effectively isolate the metal from contact with the external medium, thereby preventing the cookware from chemical corrosion and oxidation reaction. This is of great significance for maintaining the beauty of the cookware and extending its service life. At the same time, the surface of the chromium metal layer is smooth and not easy to adhere to food residues and grease, making the cookware easy to clean. Users can more easily remove stains on the surface of the cookware to keep the cookware hygienic and beautiful. Moreover, the chromium metal layer also has good thermal conductivity, which can evenly distribute heat on the surface of the cookware, which helps to improve the cooking effect, make the food more evenly heated, and taste more delicious. In the manufacture of cookware, the use of chromium metal layers meets food safety standards. Compared with some toxic and harmful coating materials, chromium metal layers are safer and more stable, and will not pollute food or harm human health.

[0037] In another embodiment, the metal surface layer 1043 is a chromium-copper alloy layer. In addition to having similar beneficial effects as the above-mentioned chromium metal layer, the copper element contained in the chromium-copper alloy layer also has an antibacterial effect, which can reduce bacterial growth and further improve the anti-sticking effect. Specifically, in this embodiment, the chromium content in the chromium-copper alloy layer is 92-96wt%, and the copper content is 4-8wt%.

[0038] Furthermore, in this embodiment, the thickness of the transition layer 1042, i.e., the chromium nitride layer, is 0.1-0.5 μm, preferably 0.3 μm; the thickness of the metal surface layer 1043, i.e., the chromium metal layer or the chromium-copper alloy layer, is 0.1-0.5 μm, preferably 0.3 μm; the thickness of the chromium metal layer of the metal base layer 1041 is 0.1-0.5 μm, preferably 0.3 μm. The overall thickness of the metal film 104 formed by the metal base layer 1041, the transition layer 1042 and the metal surface layer 1043 is 0.5-1.5 μm, preferably 0.8-1.2 μm. The layers of the metal film 104 are deposited in sequence by sputtering. After testing, the metal film 104 formed by the technical solution of the present invention is evaluated as Grade II for the non-stick test results of cooking rice in accordance with the Chinese national standard "GB / T32095.2-2015 Non-stick Surface Performance and Test Specifications for Metal Cooking Utensils for Household Food Part 2: Non-stick and Abrasion Resistance Test Specifications", that is, after testing according to the test requirements in the standard, the cooking utensil is gently shaken and there is still rice stuck to the coating, with a weight of 50 g of rice.

[0039] After testing, the hardness range of the metal film 104 on the rice cooker inner pot 100 of the present invention is HV1500-3500, and its hardness and wear resistance are good; and the metal film 104 has a low surface energy, so that the present invention has the beneficial effects of good anti-sticking effect, high hardness, good wear resistance and long service life.

[0040] The manufacturing process of an embodiment of the rice cooker inner pot 100 provided by the present invention is as follows: a steel-aluminum-steel three-layer composite plate is selected as a substrate, and a concave point structure is formed on the steel layer as the inner surface of the rice cooker inner pot 100; the base of the rice cooker inner pot 100 is formed by stretching, and the inner surface of the rice cooker inner pot 100 is polished to form a mirror surface; after cleaning, it is placed in an ion plating machine for sputtering coating, and a chromium metal layer, a chromium nitride layer and a chromium-copper alloy layer are formed on the inner surface of the rice cooker inner pot 100 in sequence; after the metal film 104 is deposited and formed, it is cleaned and other subsequent treatments are performed to complete the manufacturing of the rice cooker inner pot 100.

[0041] Through the above description of the specific embodiments, it can be seen that the present invention has the following beneficial effects: The electric cooker liner 100 of the present invention has good non-stick performance and wear resistance due to the deposition of chromium nitride layer and chromium-containing metal layer on the inner surface of the substrate. Further, since the local overheating generated at the bottom of the electric cooker liner 100 during use easily destroys the metal film 104, causing the electric cooker liner 100 to lose its non-stick performance, in order to solve this technical problem, the electric cooker liner 100 of the present invention adopts a heat-saturating layer 103 of aluminum material between two layers of metal, and the heat-saturating layer 103 of aluminum material can make the bottom of the electric cooker liner 100 heated more evenly, thereby protecting the metal film 104 and extending the non-stick life of the electric cooker liner 100. The chromium plating layer in the metal film 104 of the electric cooker liner 100 of the present invention has good chemical stability, does not act in alkali, sulfide, nitric acid and most organic acids, and after multiple cleanings after plating, the amount of chromium salt that may remain is actually very small, and the metal chromium has almost no harmful effect on the human body. The materials used in the present invention meet the requirements of food hygiene indicators, do not contain heavy metal elements harmful to the human body, and are safe and healthy.

[0042] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An electric rice cooker liner, comprising a base body; characterized in that: A metal film is formed on the inner surface of the substrate; Wherein, the metal film at least includes a transition layer and a metal surface layer attached to the transition layer, the transition layer is a chromium nitride layer, and the metal surface layer is a chromium metal layer.

2. The inner pot of the rice cooker according to claim 1, characterized in that: The metal surface layer is a chromium-copper alloy layer, wherein the chromium content is 92-96wt% and the copper content is 4-8wt%.

3. The inner pot of the electric rice cooker according to claim 2, characterized in that: The thickness of the chromium nitride layer is 0.1-0.5 μm, and the thickness of the chromium metal layer or the chromium-copper alloy layer is 0.1-0.5 μm.

4. The inner pot of the electric rice cooker according to claim 1, characterized in that: The metal film further comprises a metal base layer arranged between the inner surface of the substrate and the transition layer, wherein the metal base layer is a chromium metal layer.

5. The inner pot of the electric rice cooker according to claim 4, characterized in that: The thickness of the metal base layer is 0.1-0.5 μm.

6. The inner pot of the electric rice cooker according to claim 5, characterized in that: The thickness of the metal film is 0.5-1.5 μm.

7. The inner pot of the rice cooker according to any one of claims 1 to 6, characterized in that: The metal films are deposited in sequence by sputtering coating.

8. The inner pot of the electric rice cooker according to claim 1, characterized in that: The substrate includes a first substrate layer, a heat-spreading layer and a second substrate layer in sequence from the inside to the outside. The first substrate layer and the second substrate layer are composited into one by the heat-spreading layer, so that the first substrate layer is heated uniformly.

9. The inner pot of the electric rice cooker according to claim 8, characterized in that: The substrate is a steel-aluminum-steel composite plate.

10. The inner pot of the electric rice cooker according to claim 9, characterized in that: A concave structure is formed on the inner surface of the substrate, and the metal film covers the concave structure.

11. The inner pot of the electric rice cooker according to claim 10, characterized in that: The pit structure is formed by etching.

12. The inner pot of an electric rice cooker according to any one of claims 1 to 6, characterized in that: Before forming the metal film on the inner surface of the substrate, the inner surface of the substrate is polished to a mirror surface.

13. The inner pot of the electric rice cooker according to claim 1, characterized in that: The metal film is evaluated as Grade II according to the results of the non-stickiness test for cooked rice in the Chinese national standard GB / T32095.2-2015.

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