Stainless steel composite inner tank for electric water heater

Abstract

The application relates to a stainless steel composite electric water heater liner, which comprises a barrel body and an end cover welded with the barrel body through a coaxial laser powder feeding welding process; wherein the barrel body and the end cover are prepared from a stainless steel composite plate, and the stainless steel composite plate comprises a stainless steel layer which is an inner layer of the barrel body and the end cover; compared with the prior art, the technical scheme of the application sets the inner measurement of the stainless steel composite electric water heater liner as a stainless steel layer, simultaneously adopts the coaxial laser powder feeding welding to guarantee the welding seam performance, realizes the double promotion of the corrosion resistance and the structural stability of the liner, prolongs the service life and avoids the safety hidden danger.

Description

Technical Field

[0001] This application relates to the field of electric water heater technology, and in particular to a stainless steel composite electric water heater inner tank. Background Technology

[0002] As a commonly used hot water supply device in both residential and commercial sectors, the inner tank of an electric water heater is a core component ensuring the safe and stable operation of the device, directly determining its lifespan and safety. Currently, most mainstream stainless steel composite electric water heaters on the market employ a structural design combining carbon steel plates and enamel coatings for their inner tanks and end caps. The carbon steel plates, with their excellent mechanical strength and pressure-bearing capacity, provide the basic structural support for the inner tank, while the enamel coating covers the inner wall of the carbon steel plates, isolating the water from direct contact with the carbon steel plates to achieve corrosion protection. This structure has become a widely used technical solution in the industry due to its controllable material costs and mature processing technology.

[0003] However, in the manufacturing process of existing stainless steel composite electric water heater inner tanks with carbon steel plates and enamel coatings, the enamel coating on the surface and at the welded joints is prone to quality problems such as missing enamel, micropores, and bubbles due to insufficient coating process precision and improper control of the high-temperature sintering process. Even if the enamel coating has no obvious defects in the initial manufacturing state, during the long-term hot and cold cycle use of the electric water heater, due to the difference in the coefficient of thermal expansion between the carbon steel plate and the enamel coating, the enamel coating may crack or peel off due to repeated thermal expansion and contraction, resulting in the exposure of the inner wall of the carbon steel plate.

[0004] When the enamel coating is missing or peels off, the exposed carbon steel plate forms a corrosion cell with other areas of the inner tank that are still properly coated with enamel. In an aquatic environment, the exposed carbon steel plate acts as the anode, accelerating electrochemical corrosion. As the corrosion intensifies, the carbon steel plate gradually thins, eventually leading to perforation and leakage in the inner tank. This not only shortens the lifespan of the electric water heater but may also cause short circuits, equipment damage, and other safety accidents, threatening user safety and property security. Therefore, it is urgent to improve the structure of the inner tank of existing stainless steel composite electric water heaters to solve the corrosion and leakage problems caused by defects in the enamel coating. Utility Model Content

[0005] This application provides a stainless steel composite electric water heater inner tank, in which the inner side of the inner tank is set as a stainless steel layer, and coaxial laser powder feeding welding is used to ensure the performance of the weld, thereby achieving a dual improvement in the corrosion resistance and structural stability of the inner tank, extending its service life and avoiding safety hazards.

[0006] In a first aspect, this application provides a stainless steel composite electric water heater inner tank, comprising: a tank body, and an end cap welded to the tank body by a coaxial laser powder feeding welding process; wherein the tank body and the end cap are made of stainless steel composite plate, the stainless steel composite plate comprising a stainless steel layer, the stainless steel layer being the inner layer of the tank body and the end cap.

[0007] In one possible implementation, the stainless steel composite plate further includes a carbon steel plate layer, which is the outer layer of the barrel body and the end cap; wherein, when the barrel body is welded to the end cap, the stainless steel layer of the end cap is welded to the barrel body stainless steel layer and the barrel body carbon steel plate layer, respectively.

[0008] In one possible implementation, a gap space is provided between the barrel body and the end cap, wherein the gap space is filled with alloy powder weld seams; one side of the alloy powder weld seam is connected to the stainless steel layer of the barrel body and the carbon steel plate layer of the barrel body respectively, and the other side of the alloy powder weld seam is connected to the stainless steel layer of the end cap respectively.

[0009] In one possible implementation, the alloy powder weld is formed by melting and solidifying alloy powder fed by a laser coaxial powder feeding process according to preset process parameters.

[0010] In one possible implementation, the alloy powder is a high-entropy alloy powder; the process parameters include laser power, welding rate, powder feeding rate, laser spot size, and protective gas flow rate.

[0011] In one possible implementation, the end cap includes a first end cap and a second end cap; the first end cap is welded to a first side of the barrel body via a coaxial laser powder feeding welding process, and the second end cap is welded to a second side of the barrel body via a coaxial laser powder feeding welding process; the barrel body is a hollow cylindrical structure, and the first end cap and the second end cap are hollow semi-circular arc structures; the interiors of the barrel body, the first end cap, and the second end cap are welded together to form a water storage space.

[0012] In one possible implementation, the length of the water storage space is determined by the stamping depth of the first end cap and the end cap, as well as the length of the barrel body.

[0013] In one possible implementation, the stainless steel composite plate is formed by blanking, stamping, and trimming.

[0014] In one possible implementation, the thickness of the stainless steel layer is 0.2mm-1mm, and the thickness of the carbon steel plate layer is 1mm-2mm.

[0015] In one possible implementation, the stainless steel composite electric water heater inner tank provided in this application further includes a drain outlet, a water outlet nozzle, and a water inlet nozzle; the drain outlet, the water outlet nozzle, and the water inlet nozzle are located below the tank body.

[0016] The technical solutions provided in this application have the following advantages compared with the prior art:

[0017] This application provides a stainless steel composite electric water heater inner tank, comprising: a tank body and an end cap welded to the tank body via a coaxial laser powder welding process; wherein the tank body and the end cap are made of stainless steel composite plates, the stainless steel composite plates comprising a stainless steel layer, the stainless steel layer being the inner layer of the tank body and the end cap; compared with the prior art, the technical solution of this application uses stainless steel composite plates with a stainless steel layer on the inner side for the tank body and the end cap, which ensures that the area inside the inner tank in contact with water is always covered by the stainless steel layer, completely isolating the water from contact with the carbon steel substrate, thus avoiding [the problem] at the source. The absence of exposed carbon steel plates prevents corrosion from forming a galvanic cell effect, solving the core problem of easy corrosion of carbon steel plates after the failure of traditional enamel coatings. Simultaneously, the stainless steel layer has a similar thermal expansion rate to the carbon steel substrate, preventing defects such as peeling and cracking due to thermal expansion and contraction differences, unlike enamel coatings and carbon steel plates. This ensures the structural stability of the inner tank for long-term use. Furthermore, the coaxial laser powder welding process connecting the tank body and end caps reduces coating defects at weld points compared to traditional welding and enamel coating processes, further ensuring the overall sealing and corrosion resistance of the inner tank, effectively improving the service life and safety of the stainless steel composite electric water heater inner tank. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0021] Figure 1 This is a schematic diagram of the structure of the inner tank of a stainless steel composite electric water heater provided in an embodiment of this application;

[0022] Figure 2 This is a schematic diagram of the end cap structure provided in an embodiment of this application;

[0023] Figure 3 Another structural schematic diagram of a stainless steel composite electric water heater inner tank provided for an embodiment of this application;

[0024] Figure 4 This is a schematic diagram of the weld joint structure provided in the embodiments of this application;

[0025] Figure 5 A schematic diagram of the welding process provided in the embodiments of this application;

[0026] Figure 6 This is another structural schematic diagram of a stainless steel composite electric water heater inner tank provided in an embodiment of this application. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0029] For ease of description, spatial relative terms may be used in the text to describe the relative position or movement of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "front," "back," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure undergoes a positional flip, orientation change, or change of motion, these directional indications will change accordingly. For instance, an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0030] Figure 1 This application provides a schematic diagram of the structure of a stainless steel composite electric water heater inner tank; as shown in the embodiment. Figure 1 As shown, the inner tank of the stainless steel composite electric water heater includes a tank body 1 and an end cap 2 welded to the tank body 1 by a coaxial laser powder feeding welding process; wherein, the tank body 1 and the end cap 2 are made of stainless steel composite plate, the stainless steel composite plate includes a stainless steel layer 3, the stainless steel layer 3 being the inner layer of the tank body 1 and the end cap 2.

[0031] In one embodiment, the stainless steel composite plate further includes a carbon steel plate layer 4, which is the outer layer of the barrel body 1 and the end cap 2; wherein, when the barrel body 1 is welded to the end cap 2, the end cap carbon steel plate layer 202 of the end cap 2 is attached to the end cap stainless steel layer 201 of the end cap 2; the end cap stainless steel layer 201 of the end cap 2 is welded to the barrel body stainless steel layer 101 and the barrel body carbon steel plate layer 102 of the barrel body 1 respectively; as Figure 2 As shown, Figure 2 This is a schematic diagram of the end cap structure provided in an embodiment of this application.

[0032] Specifically, the carbon steel plate layer 4 is made of low carbon steel such as SPCC or SPHC, with a thickness of 1mm-2mm. This material is low in cost and has excellent mechanical properties. It can withstand the water pressure inside the inner tank, prevent the inner tank from undergoing excessive deformation, and play a core pressure-bearing role.

[0033] Specifically, the stainless steel layer 3 is made of stainless steel such as SUS304, SUS316 or SUS201, with a thickness of 0.2mm-1mm. This material has strong resistance to water corrosion and its coefficient of thermal expansion is close to that of the outer carbon steel, which can avoid interlayer separation or detachment caused by thermal expansion and contraction.

[0034] Specifically, the stainless steel composite plate is formed by blanking, stamping and trimming.

[0035] Specifically, the processing steps of the stainless steel composite plate are as follows: For the tank body 1: After the stainless steel composite plate is cut to the preset size, it is made into a hollow cylindrical structure by rolling process. The length of the tank body 1 is designed according to the specifications of the water heater. After rolling, it is welded longitudinally. This process also uses laser coaxial powder feeding process to generate a sealed joint to ensure the overall sealing of the tank body 1; For the end cap 2: The end cap 2 includes a first end cap 21 and a second end cap 22, both of which are formed by the stainless steel composite plate through three steps of "blanking-stamping-edge trimming"; Among them, blanking: according to the outer diameter of the end cap 2, the stainless steel composite plate is cut to obtain a plate that meets the blank specifications of the end cap 2; stamping: the blank is stamped into a hollow semi-circular arc structure using an arc mold to form the end cap 2 prototype with an arc-shaped cavity, wherein the cavity is the core component of the subsequent water storage space; edge trimming: the edge of the stamped end cap 2 prototype is trimmed to remove burrs and ensure that the stainless steel layer 3 of the edge of the end cap 2 is fully exposed to prepare for subsequent welding.

[0036] In one embodiment, the end cap 2 includes a first end cap 21 and a second end cap 22; specifically, the first end cap 21 is the left end cap, and the second end cap 22 is the right end cap; as shown Figure 3 As shown, Figure 3 This is another structural schematic diagram of a stainless steel composite electric water heater inner tank provided in an embodiment of this application.

[0037] In one embodiment, the first end cap 21 is welded to the first side of the barrel body 1 by a coaxial laser powder feeding welding process, and the second end cap 22 is welded to the second side of the barrel body 1 by a coaxial laser powder feeding welding process. The three together form a closed water storage space 11, and this connection relationship forms a seal around the barrel body 1, which together can form a complete inner liner structure. At the same time, the inner wall of the water storage space 11 is completely covered by a stainless steel layer 3. When in use, the water only comes into contact with the stainless steel layer 3 and does not come into direct contact with the carbon steel plate layer 4, which fundamentally avoids carbon steel corrosion.

[0038] In one embodiment, the barrel body 1 is a hollow cylindrical structure, and the first end cap 21 and the second end cap 22 are hollow semi-circular arc structures; the interiors of the barrel body 1, the first end cap 21 and the second end cap 22 are welded together to form a water storage space 11.

[0039] Specifically, the length of the water storage space 11 is determined by the stamping depth of the first end cap 21 and the second end cap 22, as well as the length of the barrel body 1.

[0040] In one embodiment, a gap space is provided between the barrel body 1 and the end cap 2, wherein the gap space is filled with alloy powder weld 10; one side of the alloy powder weld 10 is connected to the stainless steel layer of the barrel body 1 and the carbon steel plate layer of the barrel body, respectively, and the other side of the alloy powder weld 10 is connected to the stainless steel layer of the end cap 2, respectively. Figure 4 As shown, Figure 4 This is a schematic diagram of the weld joint structure provided in the embodiments of this application.

[0041] Specifically, the alloy powder weld 10 is formed by melting and solidifying alloy powder based on a laser coaxial powder feeding process according to preset process parameters.

[0042] Specifically, the alloy powder is a high-entropy alloy powder; preferably, the high-entropy alloy powder is CrNi2MnTi. 0.5 Ti0.5Al 0.5 alloy powder.

[0043] Specifically, the process parameters include laser power, welding rate, powder feeding rate, laser spot size, and protective gas flow rate.

[0044] Specifically, to address the issues of easy corrosion and cracking in traditional welding methods (such as argon arc welding and ordinary laser welding), this embodiment employs a coaxial laser powder feeding welding process to connect the barrel body 1 and the end caps. During welding, both ends of the barrel body 1 are aligned with the first end cap 21 and the second end cap 22, leaving a gap for filling with alloy powder. Argon gas is used to pre-protect the welding area, eliminating air and preventing oxidation. The process parameters are adjusted according to the thickness of the composite plate. During welding, the laser beam is emitted from the coaxial laser powder feeding welding nozzle 12, simultaneously applying CrNi2MnTi... 0.5 Ti0.5Al 0.5 High-entropy alloy powder is transported to the interstitial space along with argon gas; the powder melts under high laser temperature and fully fuses with the stainless steel layer of barrel body 1, the carbon steel plate layer of barrel body 1, and the stainless steel layer of end cap 2. After cooling and solidification, a high-entropy alloy powder weld is formed; one side of the weld is tightly connected to the stainless steel layer of barrel body 1 and the carbon steel plate layer of barrel body 1, and the other side is tightly connected to the stainless steel layer of end cap 2, without gaps or micropores, completely solving the potential for weld leakage. Figure 5 As shown, Figure 5 A schematic diagram of the welding process provided in the embodiments of this application.

[0045] In one embodiment, the stainless steel composite electric water heater inner tank provided in this application embodiment further includes a drain outlet 5, a water outlet 6, and a water inlet 7; the drain outlet 5, the water outlet 6, and the water inlet 7 are located below the tank body 1, as shown below. Figure 6 As shown, Figure 6 This is another structural schematic diagram of a stainless steel composite electric water heater inner tank provided in an embodiment of this application.

[0046] Specifically, the water inlet nozzle 7 is located on the lower side of the tank body 1. When water is introduced, the water flows from below into the water storage space 11, avoiding disturbance to the upper hot water and ensuring a stable water temperature.

[0047] Specifically, the water outlet 6 is located on the other side below the tank body 1, and is connected to the upper area of ​​the water storage space, prioritizing the output of heated hot water.

[0048] Specifically, the drain outlet 5 is located in the middle of the lower part of the tank body 1 and is equipped with a sealing cover. Regularly opening it can drain the scale and impurities at the bottom of the water storage space, extending the service life of the inner tank.

[0049] Specifically, since sediments and impurities usually accumulate at the bottom of the inner tank of a stainless steel composite electric water heater due to gravity, placing the drain outlet 5 below the tank body 1 can effectively remove these impurities and dirt, ensuring the cleanliness of the inner tank, reducing corrosion and other damage caused by the accumulation of impurities, extending the service life of the inner tank, and also improving the quality of hot water.

[0050] Specifically, placing the water outlet 6 at the bottom allows for the drainage of hot water from the inner tank as much as possible. This avoids the situation where some hot water remains at the bottom of the inner tank due to the high position of the water outlet 6, which could potentially breed bacteria and other harmful substances over time, affecting the quality of hot water used subsequently.

[0051] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0052] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0053] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0054] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0055] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0056] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0057] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Since these modifications and variations fall within the scope of the claims and their equivalents, this application also intends to include these modifications and variations.

[0058] The above description describes specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A stainless steel composite electric water heater inner tank, characterized in that, include: The barrel body, and the end caps welded to the barrel body via a coaxial laser powder feeding welding process; The barrel body and the end cap are made of stainless steel composite plate, wherein the stainless steel composite plate includes a stainless steel layer, which is the inner layer of the barrel body and the end cap.

2. The stainless steel composite electric water heater inner tank according to claim 1, characterized in that, The stainless steel composite plate also includes a carbon steel plate layer, which is the outer layer of the barrel body and the end cap; When the barrel body is welded to the end cap, the stainless steel layer of the end cap is welded to the stainless steel layer of the barrel body and the carbon steel plate layer of the barrel body, respectively.

3. The stainless steel composite electric water heater inner tank according to claim 2, characterized in that, A gap space is provided between the barrel body and the end cap, wherein the gap space is filled with alloy powder weld seams; One side of the alloy powder weld is connected to the stainless steel layer of the barrel body and the carbon steel plate layer of the barrel body, respectively, and the other side of the alloy powder weld is connected to the stainless steel layer of the end cap.

4. The stainless steel composite electric water heater inner tank according to claim 3, characterized in that, The alloy powder weld is formed by melting and solidifying alloy powder according to preset process parameters based on laser coaxial powder feeding technology.

5. The stainless steel composite electric water heater inner tank according to claim 4, characterized in that, The alloy powder is a high-entropy alloy powder; The process parameters include laser power, welding rate, powder feeding rate, laser spot size, and protective gas flow rate.

6. The stainless steel composite electric water heater inner tank according to claim 1, characterized in that, The end cap includes a first end cap and a second end cap; The first end cap is welded to the first side of the barrel body by a coaxial laser powder feeding welding process, and the second end cap is welded to the second side of the barrel body by a coaxial laser powder feeding welding process. The barrel body is a hollow cylindrical structure, and the first end cap and the second end cap are hollow semi-circular arc structures; The interiors of the barrel body, the first end cap, and the second end cap are welded together to form a water storage space.

7. The stainless steel composite electric water heater inner tank according to claim 6, characterized in that, The length of the water storage space is determined by the stamping depth of the first end cap and the end cap, as well as the length of the barrel body.

8. The stainless steel composite electric water heater inner tank according to claim 1, characterized in that, The stainless steel composite plate is formed by blanking, stamping and trimming.

9. The stainless steel composite electric water heater inner tank according to claim 2, characterized in that, The thickness of the stainless steel layer is 0.2mm-1mm, and the thickness of the carbon steel plate layer is 1mm-2mm.

10. The stainless steel composite electric water heater inner tank according to claim 1, characterized in that, It also includes drain outlets, water outlet nozzles, and water inlet nozzles; The drain outlet, the water outlet nozzle, and the water inlet nozzle are located at the bottom of the barrel.

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