Easily-washed inner pot for electric food warmer

Abstract

The easy-to-wash inner pot for the electric food warmer comprises a stainless steel layer and a micron-sized alloy layer, anti-sticking lines are arranged on the surface, facing the alloy layer, of the stainless steel layer, the alloy layer covers the anti-sticking lines or is embedded into lines of the anti-sticking lines, the thickness of the micron-sized alloy layer is smaller than 10 micrometers, and the thickness of the micron-sized alloy layer is smaller than 10 micrometers. At least more than three metal components of the alloy layer and the stainless steel layer are overlapped, the three overlapped metal components account for 50%-70% of the alloy layer to form a main metal component, the alloy layer further comprises an auxiliary metal component formed by one or more of Zr, Ti, Cu and Nb and a non-metal component, the proportion of the auxiliary metal component is 20%-30%, and the proportion of the non-metal component is 20%-30%. And the non-metal component accounts for 10%-20%. Anti-sticking lines are arranged on the surface, facing the alloy layer, of the stainless steel layer, the alloy layer covers the anti-sticking lines or is embedded into lines of the anti-sticking lines, and the bonding force of the stainless steel layer and the alloy layer can be increased through the arrangement of the anti-sticking lines.

Description

[Technical Field]

[0001] This invention relates to kitchen cooking appliances, and more particularly to an easy-to-wash inner pot for an electric hot pot. [Background Technology]

[0002] In order to achieve non-stick properties, the inner pot of electric hot pots (such as rice cookers and electric pressure cookers) disclosed in the prior art is generally coated with chemical coatings such as Teflon. However, Teflon is prone to peeling off after long-term use, which affects the non-stick effect.

[0003] In order to achieve a non-stick effect for rice in the inner pot, the applicant has researched and invented a cooling device installed inside the pot. This device works when the rice is cooked, causing the rice in the inner pot to cool down and form condensation. This condensation acts as a barrier between the inner pot and the rice, thus preventing the rice from sticking.

[0004] During the applicant's ongoing research into non-stick inner pots, one proposed solution is to create textured surfaces on the inner surface of the pot to form a water-locking space, thereby retaining condensate and achieving a good non-stick effect.

[0005] The applicant's further research revealed that stainless steel inner pots with textured water-locking spaces experience a certain degree of degradation with long-term use. In particular, after repeated cleaning with hard objects such as steel wool, the stainless steel surface is easily damaged, leading to a decrease in non-stick properties.

[0006] To address this, the applicant discovered that setting a metal protective layer on the inner surface of the stainless steel inner pot can achieve protection while improving the non-stick effect. However, when this metal protective layer is bonded to the stainless steel base, insufficient bonding strength occurs, affecting the service life. [Summary of the Invention]

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an easy-to-clean inner pot for electric hot pots. By setting a micron-level alloy layer on a stainless steel layer, and with some metal components of the two overlapping, a good bond is formed, achieving an easy-to-clean effect.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] An easy-to-wash inner pot for an electric hot pot includes a stainless steel layer and a micron-sized alloy layer. The surface of the stainless steel layer facing the alloy layer is provided with an anti-stick texture. The alloy layer covers the anti-stick texture or is embedded in the texture of the anti-stick texture. The thickness of the micron-sized alloy layer is less than 10 microns. The alloy layer and the stainless steel layer have at least three overlapping metal components. The three overlapping metal components account for 55% to 70% of the alloy layer, forming the main metal component. The alloy layer also includes one or more of Zr, Ti, Cu, and Nb to form an auxiliary metal component, as well as a non-metallic component. The auxiliary metal component accounts for 20% to 30%, and the non-metallic component accounts for 10% to 20%.

[0010] Furthermore, the non-metallic component includes N, and the proportion of N in the non-metallic component is 55% to 90%.

[0011] Furthermore, the three overlapping metallic components include Cr, Fe, and Ni, with Cr accounting for 20% to 50% of the metallic components.

[0012] Furthermore, the thickness of the micron-scale alloy layer is 1 micrometer to 5 micrometers.

[0013] Furthermore, the alloy layer is attached to or embedded within the anti-stick texture using a PVD process.

[0014] Furthermore, in the PVD process, the target material with the main metal component is activated first, and then the target material with the auxiliary metal component is activated, wherein the non-metallic component is the component that enters the alloy layer during the process.

[0015] Furthermore, in the PVD process, one or two targets in the main metal component are activated first, then the auxiliary metal component targets are activated, and finally the remaining targets in the main metal component are activated.

[0016] Furthermore, in the PVD process, the activation of the main metal component target is carried out throughout the process of activating the auxiliary metal component target.

[0017] Furthermore, the anti-sticking texture includes multiple independent micro-pits or multiple micron-sized protrusions on the surface of the stainless steel layer; the anti-sticking texture includes a textured pattern formed by laser bombardment of the stainless steel layer surface, with randomly distributed ridges and grooves.

[0018] Furthermore, the height difference between the protrusions and the grooves is randomly fluctuating within 15 μm.

[0019] The present invention has the following beneficial effects:

[0020] 1. An anti-adhesion texture is provided on the surface of the stainless steel layer facing the alloy layer. The alloy layer covers the anti-adhesion texture or is embedded within the texture. The anti-adhesion texture increases the bonding strength between the stainless steel layer and the alloy layer. The alloy layer and the stainless steel layer have at least three overlapping metal components, with these three overlapping metal components accounting for 50% to 70% of the main metal components in the alloy layer. This overlap between the main metal components in the alloy layer and the metal components in the stainless steel layer allows for a good bond. The alloy layer also includes one or more auxiliary metal components selected from Zr, Ti, Cu, and Nb, meaning the alloy layer contains at least four metal components, resulting in superior performance. Compared to traditional alloys that typically use one or two metals as the main elements, this application uses four or more metal components. As a thin-film protective layer on the surface of the stainless steel layer, this reduces material costs and achieves ideal performance, making it suitable for various applications. The alloy layer in this application also includes non-metallic components, accounting for 10% to 20%. Due to the disordered structure of the atoms in the metal composition, the internal entropy value is very high, resulting in low surface free energy. This gives the inner pot a low surface energy, achieving a hydrophobic and non-stick effect, making it easy to clean.

[0021] 2. The non-metallic component includes nitrogen (N), and the proportion of N in the non-metallic component is 55% to 90%. Having N accounting for more than 50% of the non-metallic component can reduce production costs and improve the overall strength of the inner pot.

[0022] 3. The three overlapping metallic components include Cr, Fe, and Ni, with Cr accounting for 20% to 50% of the metallic components. Due to the high chromium (Cr) content, it has good corrosion resistance and oxidation resistance, can resist corrosion from the atmosphere, nitric acid, and salt water solutions, and has good high-temperature oxidation resistance and a small coefficient of thermal expansion.

[0023] 4. The alloy layer is attached to or embedded within the anti-sticking texture using a PVD process. This is a surface treatment technology that uses physical vapor deposition (PVD) to vaporize materials into atoms, molecules, or ions under vacuum conditions, and then deposits them on the substrate surface to form a thin film. This method is environmentally friendly, pollution-free, and requires minimal materials.

[0024] These features and advantages of the present invention will be disclosed in detail in the following specific embodiments and accompanying drawings. [Attached Image Description]

[0025] The invention will be further described below with reference to the accompanying drawings:

[0026] Figure 1 This is a cross-sectional view of the rice cooker according to Embodiment 1 of the present invention;

[0027] Figure 2 This is a schematic diagram of the inner pot according to Embodiment 1 of the present invention;

[0028] Figure 3 for Figure 2 Enlarged view of a portion of point A in the middle.

[0029] Icon labels:

[0030] 1. Pot body, 2. Heating device, 3. Inner pot, 31. Stainless steel layer, 32. Alloy layer, 33. Aluminum layer.

Detailed Implementation Methods

[0031] This invention proposes an easy-to-wash inner pot for electric hot pots, comprising a stainless steel layer and a micron-sized alloy layer. The surface of the stainless steel layer facing the alloy layer has an anti-stick texture. The alloy layer covers or is embedded within the anti-stick texture. The thickness of the micron-sized alloy layer is less than 10 micrometers. The alloy layer and the stainless steel layer have at least three overlapping metal components, with the overlapping three metal components accounting for 50% to 70% of the alloy layer, forming the main metal component. The alloy layer also includes one or more of Zr, Ti, Cu, and Nb forming auxiliary metal components, as well as non-metallic components. The auxiliary metal components account for 20% to 30%, and the non-metallic components account for 10% to 20%. The anti-stick texture on the surface of the stainless steel layer facing the alloy layer, with the alloy layer covering or embedded within the anti-stick texture, increases the bonding strength between the stainless steel layer and the alloy layer. The alloy layer and the stainless steel layer have at least three overlapping metal components, with these three overlapping metal components accounting for 50% to 70% of the main metal components in the alloy layer. Because the main metal components in the alloy layer overlap with the metal components in the stainless steel layer, they can form a good bond. The alloy layer also includes one or more auxiliary metal components selected from Zr, Ti, Cu, and Nb, meaning the alloy layer contains a total of four or more metal components, resulting in superior performance.

[0032] The technical solutions of the embodiments of the present invention will be explained and described below with reference to the accompanying drawings. However, the following embodiments are only preferred embodiments of the present invention and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments in the implementation methods without creative effort are all within the protection scope of the present invention.

[0033] Example 1

[0034] This embodiment proposes an electric hot pot, which can be a rice cooker or an electric pressure cooker, among other cooking appliances. (Refer to...) Figures 1-3 The invention includes a cooker body 1, a heating device 2, and an inner pot 3 placed inside the cooker body 1. The heating device 2 heats the inner pot 3, and the inner pot 3 has a cavity for accommodating rice. The main improvement of the invention is to the structure of the inner pot 3.

[0035] The inner pot 3 includes a stainless steel layer 31 and a micron-sized alloy layer 32. The stainless steel layer 31 has an anti-stick texture on its surface facing the alloy layer. The alloy layer covers or is embedded within the anti-stick texture. The thickness of the micron-sized alloy layer is less than 10 micrometers. The alloy layer and the stainless steel layer have at least three overlapping metal components. These three overlapping metal components constitute 50% to 70% of the alloy layer, forming the main metal component. The alloy layer also includes one or more auxiliary metal components formed from Zr (zirconium), Ti (titanium), Cu (copper), and Nb (niobium), as well as non-metallic components. The auxiliary metal components constitute 20% to 30%, and the non-metallic components constitute 10% to 20%. It is understood that in this embodiment, the component proportions refer to mass proportions. In this embodiment, the anti-stick texture is primarily understood as an uneven surface, which can reduce the area where food adheres, thus achieving an anti-stick effect to a certain extent.

[0036] An anti-adhesion texture is provided on the surface of the stainless steel layer facing the alloy layer. The alloy layer covers the anti-adhesion texture or is embedded within its lines. This anti-adhesion texture increases the bonding strength between the stainless steel and alloy layers, preventing the alloy layer from detaching from the stainless steel. The alloy layer and stainless steel layer have at least three overlapping metal components, with these three overlapping metal components comprising 50% to 70% of the main metal component in the alloy layer. This overlap between the main metal component in the alloy layer and the metal component in the stainless steel layer allows for a strong bond. The main metal components of stainless steel include iron (Fe), chromium (Cr), nickel (Ni), manganese (Mn), and molybdenum (Mo).

[0037] The two most common types of stainless steel are 304 and 316. The main difference between them in terms of chemical composition is that 316 contains molybdenum (Mo). In other words, whether it is 304 or 316, their metallic composition includes iron (Fe), chromium (Cr), nickel (Ni), and manganese (Mn).

[0038] Different alloy layers were selected and applied to the stainless steel layer for adhesion and hardness testing.

[0039] The adhesion test method is based on the national standard GB / T 8642-2002 "Determination of Tensile Bond Strength of Thermal Spray Coatings". The tensile test method for bond strength involves a substrate disc consisting of two loading blocks and an alloy layer, bonded to the two loading blocks with epoxy resin. A universal tensile testing machine is used to test the bond strength of the samples. The loading speed is 1 mm / min, and each sample is tested three times, with the average value taken. Specific test results are shown in the table below. When there are three or more overlapping metal types, the bond strength is good, and the adhesion test is qualified. When there are only two or one overlapping metal types, the bond strength is poor, and the adhesion test fails.

[0040] The hardness test method is as follows: fix the sample, select a pencil of the corresponding hardness, and break the pencil into a cylindrical shape with the lead exposed about 3mm. Hold the pencil at a 45-degree angle, ensuring that the lead does not break. Press the pencil on the surface at a uniform speed of 1mm / s for about 1cm in front of the tester. After each scratch, the pencil tip should be re-ground. Each sample should have 5 scratches.

[0041] The stainless steel layer in this embodiment takes 304 stainless steel as an example. Its main components are iron, chromium, nickel and manganese. The test data is shown in the table below.

[0042]

[0043]

[0044]

[0045] The above tests show that when the alloy layer has more than three overlapping metal components and the content exceeds 50%, both the adhesion and hardness tests are satisfactory. Impurities or non-metallic components inevitably enter the material during manufacturing; a content exceeding 70% places higher demands on the process. Therefore, the preferred range of 50%-70% for the main metal components, as given in this embodiment, is preferred.

[0046] The applicant tested the stainless steel layer with 316 stainless steel and obtained similar conclusions as shown in the table above.

[0047] The alloy layer also includes one or more auxiliary metal components selected from zirconium (Zr), titanium (Ti), copper (Cu), and niobium (Nb), meaning the alloy layer contains more than four metal components, resulting in superior performance. Compared to traditional alloys that typically use one or two metals as the main elements, this application incorporates four or more metal components. As a thin-film protective layer on the surface of the stainless steel layer, this reduces material costs while achieving ideal performance, making it suitable for various applications. Because the atomic radii of the metal components differ, it increases the disorder of the material's microstructure and reduces free energy, thus giving the inner pot a lower surface energy, achieving a hydrophobic and non-stick effect for easy cleaning.

[0048] The alloy layer of this application also includes non-metallic components, which account for 10% to 20%. Through the synergistic effect of the metallic components and a certain proportion of non-metallic components, the non-stick properties and wear resistance of the inner pot can be enhanced.

[0049] In this embodiment, the non-metallic component includes nitrogen (N), and the proportion of N in the non-metallic component is between 55% and 90%. A proportion of N exceeding 50% in the non-metallic component can reduce production costs and improve the overall strength of the inner pot. Surface nitriding can improve surface yield strength and significantly increase surface hardness.

[0050] In this embodiment, the three overlapping metal components include Cr, Fe, and Ni, with Cr accounting for 20% to 50% of the metal components. Because of the high chromium (Cr) content, the corrosion resistance and oxidation resistance are both good, and it can resist corrosion from the atmosphere, nitric acid, and salt water solutions. It also has the characteristics of good high-temperature oxidation resistance and a small coefficient of thermal expansion.

[0051] During the measurement and experimentation of the alloy layer composition, it was found that when the proportion of auxiliary metal components was 20% to 30% and the proportion of non-metallic components was 10% to 20%, the test requirements could be met, as detailed below. When some proportions were outside this range, the test results often failed. Specifically, when the non-metallic component was less than 10%, the process requirements were higher because a small amount of impurities would inevitably be introduced during manufacturing. When the proportion of non-metallic components exceeded 20%, the hardness test was difficult to pass; when the auxiliary metal component was less than 20%, the adhesion test was difficult to pass; and when the auxiliary metal component was greater than 30%, the hardness test was difficult to pass. Through extensive testing, the applicant summarized the appropriate proportion range of auxiliary metal and non-metallic components, which met the test requirements.

[0052]

[0053] In this embodiment, the thickness of the micron-level alloy layer is between 1 micrometer and 5 micrometers. The purpose of setting the micron-level alloy layer is mainly to change the properties of the inner pot surface. The thickness is set between 1 micrometer and 5 micrometers. When its thickness is less than 1 micrometer, it is easy to break and cause the internal stainless steel to be exposed. When its thickness is greater than 5 micrometers, too much material is consumed.

[0054] In this embodiment, the alloy layer is attached to or embedded within the anti-sticking texture using a PVD process. Physical Vapor Deposition (PVD) is a method that uses physical methods (such as evaporation, sputtering, etc.) to vaporize the coating material and deposit it onto the substrate surface to form a film.

[0055] This embodiment employs physical vapor deposition (PVD), which involves bombarding the target material (chromium, nickel, iron, etc.) with plasma-enhanced argon (Ar+) ions and electrons, sputtering small molecular clusters of the target material onto the surface of the inner pot substrate (stainless steel layer). Due to the high bonding between the substrate surface and the molecular clusters, approaching metallic bond energies, this metallic protective layer is difficult to detach. Its surface Vickers hardness is higher than that of the substrate, exhibiting excellent surface density, enhancing non-stick properties and providing superior wear and scratch resistance. Furthermore, the metallic protective film exhibits excellent chemical stability, remaining unreacted at high temperatures and rarely discoloring. This surface treatment technology, which vaporizes materials into atoms, molecules, or ions through physical methods and deposits them on the substrate surface to form a thin film, is environmentally friendly, pollution-free, and requires minimal materials.

[0056] In this embodiment, multiple metals similar to the metal substrate on the inner pot surface are deposited and polymerized during the PVD process to form an alloy layer on the inner pot surface. This method is more reliable than directly bonding the alloy material to the pot body, and the alloy itself has higher hardness and stability. Those skilled in the art often face cost and process complexity when directly applying alloy materials to the inner pot surface, and there is a risk of changes in alloy properties during the process. This application, by forming the alloy through the PVD process, ensures alloy stability, has a relatively simple process, and offers very high product consistency and controllability.

[0057] In one embodiment, the PVD process first activates the target material of the main metal component (such as chromium, nickel, iron, etc.), and then activates the target material of the auxiliary metal component (such as zirconium, titanium, copper, niobium, etc.), wherein the non-metallic component is the component that enters the alloy layer during the process.

[0058] In this embodiment, the target material is a columnar target or a planar target. Because the alloy layer and the stainless steel layer have at least three overlapping metal components, and these three overlapping metal components account for 50% to 70% of the main metal component in the alloy layer, the target material with the main metal component is activated first. The overlap between the main metal component and the stainless steel layer allows for better bonding. This results in strong adhesion between the alloy layer and the substrate, and a dense and uniform alloy layer. In other words, a key to ensuring adhesion is activating the target material with the main metal component before bonding it to the substrate.

[0059] In other embodiments, the PVD process first activates one or two targets (such as chromium, nickel, or iron) in the main metal component, then activates the auxiliary metal component targets (such as zirconium, titanium, copper, niobium, etc.), and finally activates the remaining targets in the main metal component.

[0060] Alternatively, in other embodiments, the activation of the main metal component target in the PVD process is carried out throughout the activation of the auxiliary metal component target.

[0061] The PVD process allows for the thorough mixing of primary and secondary metal elements, resulting in a uniformly distributed cross-section after deposition and enhancing the overall bonding strength.

[0062] In this embodiment, the anti-sticking texture includes multiple independent micro-pits or multiple micron-sized protrusions on the surface of the stainless steel layer; the anti-sticking texture includes a textured pattern formed by laser bombardment of the stainless steel layer surface, with randomly distributed ridges and grooves.

[0063] When the surface of a stainless steel substrate is laser-impacted to form a textured pattern with randomly distributed ridges and grooves, the roughness increases, which can improve the adhesion of the micron-level alloy layer.

[0064] In this embodiment, the height difference between the ridges and grooves is randomly undulating within 15 μm. Since the thickness of the micron-level alloy layer is 1 to 5 microns, which is significantly smaller than the height difference of 15 μm between the ridges and grooves, the setting of the micron-level alloy layer does not significantly change the morphology of the ridges and grooves. The randomly distributed ridges and grooves can change the contact pattern of droplets on the surface, making it difficult for the starch liquid to spread on the stainless steel substrate surface. Therefore, the starch paste formed is in an uneven state, which improves the non-stickiness of the rice. In addition, the random distribution can increase the heating area of ​​the rice, making it easier to form a staggered heat flow at the bottom, thereby stirring the rice and ensuring that the rice is fully heated, thus improving the cooking effect of the rice.

[0065] Reference Figure 2 and Figure 3 In this embodiment, the inner pot is composed of two composite layers of aluminum and steel. The aluminum layer 33 improves thermal conductivity, and the innermost steel layer is the stainless steel layer 31 described in this embodiment. Of course, in other embodiments, the inner pot can also be a three-layer composite of steel, aluminum, and steel, with a protective coating of silicone or other materials applied to the outside; in this case, the inner steel layer is the stainless steel layer of this embodiment. The inner pot can also be a single layer of stainless steel.

[0066] The inner pot of this embodiment is made of stainless steel on both the inner and outer surfaces and has a micron-level alloy layer, so it does not need to be coated with chemical coatings such as Teflon. Therefore, it is easy to clean the inner pot, and it can even be scrubbed with a steel wool pad.

[0067] In other embodiments, the inner surface of the inner pot can also be an iron base layer, with a micron-sized alloy layer then applied, achieving a similar effect. The inner pot can have multiple layers with an iron base layer on its inner surface, or it can have only one iron base layer. In specific manufacturing, the iron base layer is nitrided, and then the alloy layer is deposited onto the iron base using a PVD process. In this case, the main component of the PVD target is iron, and the main metal component of the alloy layer is also iron.

[0068] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of the present invention will be included within the scope of the claims.

Claims

1. A non-stick inner pot for electric food warmer, comprising a stainless steel layer, a micron alloy layer, the surface of the stainless steel layer toward the alloy layer is provided with anti-sticking lines, the alloy layer covers on the anti-sticking lines, or is embedded in the lines of the anti-sticking lines, the thickness of the micron alloy layer is less than 10 microns, characterized in that, The metal components of the alloy layer and the stainless steel layer overlap at least 3 kinds, the 3 kinds of overlapping metal components account for 50% to 70% of the main metal components in the alloy layer, and the alloy layer also includes one kind of metal component or multiple formed auxiliary metal components of Zr, Ti, Cu, Nb, and non-metal components, the auxiliary metal components account for 20% to 30%, and the non-metal components account for 10% to 20%.

2. The easy-to-clean inner pot for electric food warmer according to claim 1, wherein The non-metal component includes N, and the N accounts for 55% to 90% of the non-metal component.

3. The easy-to-clean inner pot for electric food warmer according to claim 1, wherein The 3 kinds of overlapping metal components include Cr, Fe, and Ni, and the Cr accounts for 25% to 50% of the metal components.

4. The easy-to-clean inner pot for electric food warmer according to claim 1, wherein The thickness of the micron-level alloy layer is 1 micron to 5 microns.

5. The easy-to-clean inner pot for electric food warmer according to claim 1, wherein The alloy layer is attached to or embedded in the anti-sticking pattern through a PVD process.

6. An easy-to-clean inner pot for an electric food warmer according to claim 5, wherein In the PVD process, the target material of the main metal component is activated first, and then the auxiliary metal component target material is activated, and the non-metal component is the component entering the alloy layer in the process.

7. The easy-to-clean inner pot for electric food warmer according to claim 5, wherein In the PVD process, one kind of target material or two kinds of target materials of the main metal component are activated first, then the auxiliary metal component target material is activated, and finally the remaining target material of the main metal component is activated.

8. The easy-to-clean inner pot for electric food warmer according to claim 5, wherein In the PVD process, the target material of the main metal component is activated throughout the process of activating the target material of the auxiliary metal component.

9. An easy-to-clean inner pot for electric food warmer according to any one of claims 1 to 8, characterized in that, The anti-sticking pattern includes a plurality of independent micro-pits or a plurality of micron-level protrusions on the surface of the stainless steel layer; the anti-sticking pattern includes a bite pattern formed by randomly distributing ridges and ravines on the surface of the stainless steel layer through laser bombardment.

10. The easy-to-clean inner pot for electric food warmer according to claim 9, wherein The height difference of the ridges and ravines is randomly fluctuated within 15 microns.

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