Electric water heater inner tank, its preparation method and application

Abstract

This invention discloses an inner tank for an electric water heater, its preparation method, and its application. The preparation method includes: preparing at least one first shaped tube and at least one second shaped tube; the first shaped tube has an opening arranged along its length on its wall, and the second shaped tube has a plane on its wall, with the orthographic projection of the opening onto the plane located inside the plane; welding the opening of the first shaped tube and the plane of the second shaped tube together to obtain a multi-tube welded assembly connecting two adjacent tubes via a plane tie plate; cutting the multi-tube welded assembly to obtain at least one multi-inner tank body with a desired length; and welding end caps to both ends of the multi-inner tank body to obtain a multi-inner tank product with through-hole ends. This method not only has high production efficiency but also enables the manufacturing of compact and high-precision inner tank bodies. It has strong material applicability and compatibility, higher energy utilization, and can achieve efficient, unmanned, and low-cost manufacturing of shaped multi-inner tanks.

Description

Technical Field

[0001] This invention belongs to the field of water heaters, and more specifically, relates to the inner tank of an electric water heater, its preparation method, and its application. Background Technology

[0002] Existing electric water heaters primarily feature a barrel-shaped inner tank structure. To ensure sufficient water capacity, the tank is quite large, requiring significant installation space. While existing dual-tank products can achieve a flatter appearance, their inner tanks consist of two cylindrical sections connected by a central pipe. This design results in a less compact structure, leading to substantial space waste and low space utilization. Furthermore, the current manufacturing process for dual-tank systems is extremely complex, involving 17 welds, resulting in high manufacturing costs and low efficiency. Production efficiency per unit time is only about 30% of that of existing single-tank products. Therefore, the structure and manufacturing methods of multi-tank electric water heaters still require further improvement. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to provide an electric water heater inner tank, its preparation method, and its application. This method for preparing electric water heaters not only has high production efficiency but also enables the manufacture of compact and high-precision electric water heater inner tanks. It has strong material applicability, is compatible with the manufacture of inner tanks of different material grades and existing metal material composition systems, has higher energy utilization, and can achieve efficient, unmanned, and low-cost manufacturing of irregularly shaped multi-tank systems.

[0004] In one aspect of the invention, a method for preparing the inner tank of an electric water heater is provided. According to an embodiment of the invention, the method includes:

[0005] (1) Prepare at least one first shaped tube and at least one second shaped tube, wherein the first shaped tube has an opening arranged along its length on its tube wall, and the second shaped tube has a plane on its tube wall, wherein the orthographic projection of the opening on the plane is located inside the plane;

[0006] (2) Weld the opening of the first special-shaped tube and the plane of the second special-shaped tube to obtain a multi-tube welded assembly in which two adjacent tubes are connected by a plane pull plate.

[0007] (3) Cut the multi-tube welded assembly to obtain at least one multi-liner barrel body with the expected length;

[0008] (4) Weld end caps to both ends of the multi-liner barrel body to obtain a multi-liner product with through ends.

[0009] The method for preparing the inner tank of an electric water heater according to the above embodiments of the present invention has at least the following advantages: 1. It enables the manufacture of a compact inner tank body, reducing space waste in the external structure; 2. It has high production efficiency, with a maximum speed of 40m long irregular steel pipes per minute. Based on a length of 0.5m per tank body, it can manufacture 40 tank bodies per minute, which is more than 30 times faster than existing tank body manufacturing processes; 3. It allows for material preparation, cleaning, forming, welding, and cutting processes to be carried out on a single production line, achieving one-piece flow for tank body manufacturing; 4. It enables automated production, eliminating the need for manual operation and processing; 5. It has higher energy utilization efficiency; 6. It enables the manufacture of high-precision tank bodies, achieving high dimensions... The dimensional deviation is only 0.5mm, which is only one-tenth of the dimensional tolerance of existing manufacturing processes. The high-precision barrel manufacturing method can effectively ensure the butt welding of the end cap and barrel body; 7. The welding process is carried out on the outside of the barrel body, and the inner surface does not require manual grinding, which is conducive to improving the enamel quality; 8. Using the wall plane of the special-shaped tube as the plane pull plate of the multi-liner barrel body and welding it with the special-shaped tube with openings arranged along the length direction can greatly reduce the welding process and the number of welds, thereby achieving the purpose of reducing production costs and improving production efficiency and product qualification rate; 9. The manufacturing method has strong material adaptability and can be compatible with the manufacturing of inner liners of different material grades and existing metal material composition systems.

[0010] In addition, the method for preparing the inner tank of an electric water heater according to the above embodiments of the present invention may also have the following additional technical features:

[0011] In some embodiments of the present invention, in step (1), the first shaped tube is a C-shaped tube, the second shaped tube includes a D-shaped tube and / or a flat elliptical tube, and the C-shaped tube includes a C-shaped arc tube and / or a C-shaped flat elliptical tube.

[0012] In some embodiments of the present invention, step (1) satisfies at least one of the following conditions: the C-shaped tube, the D-shaped tube, and the flat elliptical tube are respectively formed directly by rolling or rolling; a round tube is prepared in advance, and then the round tube is cut to obtain the C-shaped tube; a round tube is prepared in advance, and then the round tube is extruded to obtain the D-shaped tube or the flat elliptical tube; the C-shaped tube is obtained by cutting the D-shaped tube in a plane, and the C-shaped flat elliptical tube is obtained by cutting one of the planes of the flat elliptical tube.

[0013] In some embodiments of the present invention, the round tube, the D-shaped tube, and the flat elliptical tube are each independently a straight seam steel pipe, and the welds of the D-shaped tube and the flat elliptical tube are each independently located in a non-planar region.

[0014] In some embodiments of the present invention, in step (2), the multi-tube welding assembly includes: one C-shaped tube and one D-shaped tube; or, two C-shaped tubes and one flat elliptical tube; or, one C-shaped arc tube, at least one C-shaped flat elliptical tube and one D-shaped tube; or, two C-shaped arc tubes, one flat elliptical tube and at least one C-shaped flat elliptical tube.

[0015] In some embodiments of the present invention, the C-shaped arc tube and the D-shaped tube are symmetrical about the planar structure of the D-shaped tube.

[0016] In some embodiments of the present invention, the chord distance of the D-shaped tube is 30 to 150 degrees; and / or, the opening arc of the C-shaped tube is 30 to 150 degrees.

[0017] In some embodiments of the present invention, in step (1), the orthographic projection area of ​​the opening on the plane is equal to the area of ​​the plane.

[0018] In some embodiments of the invention, before performing step (2), the method further includes cutting at least one hole in the plane.

[0019] In some embodiments of the present invention, in step (2), the length of the multi-liner barrel body is 200-1000 mm.

[0020] In some embodiments of the present invention, the end cap includes a plurality of concave surfaces connected in sequence, and the plurality of concave surfaces correspond one-to-one with the end structures of each irregular tube in the multi-inner-liner barrel.

[0021] In some embodiments of the invention, the edge of the end cap coincides with the end edge of the multi-tube welding assembly.

[0022] In some embodiments of the present invention, the method for preparing an electric water heater inner tank further includes: (5) welding water pipes onto the multi-tank product to obtain an electric water heater inner tank.

[0023] In some embodiments of the invention, the water pipe is welded to the body of the multi-liner barrel and / or the end cap.

[0024] In another aspect, the present invention provides an inner tank for an electric water heater. According to an embodiment of the present invention, the inner tank for the electric water heater comprises:

[0025] The multi-liner barrel body includes at least two shaped tubes of equal length. In two adjacent shaped tubes, one tube wall has an opening extending through its length, and the other tube wall has a plane. The orthographic projection of the opening onto the plane is located inside the plane. The two adjacent shaped tubes are welded together through the opening and the plane.

[0026] Two end caps are independently disposed at both ends of the multi-inner-liner barrel body. The end caps have concave surfaces that match the end structure of the multi-inner-liner barrel body. The edges of the end caps are sealed and welded to the ends of the multi-inner-liner barrel body, and at least a portion of the end of each shaped tube forms a gap space with the concave surface.

[0027] Compared with the prior art, the preparation of the electric water heater inner tank in the above embodiments of the present invention has at least the following advantages: 1. The multi-tank tank structure is compact and has a high space utilization rate; 2. The inner tank body has high precision, with a dimensional deviation of only 0.5mm, which is only one-tenth of the dimensional tolerance of existing processes, and the butt welding effect of the end cap and the tank body is good; 3. The enamel quality of the inner surface of the inner tank body is high; 4. The number of welds is small, the product quality is high and the production cost is low; 5. It can be applied to different material grades and existing metal material composition systems; 6. It has good structural stability, low risk of water pressure pulse deformation, and longer service life.

[0028] In some embodiments of the present invention, the irregular tube with an opening extending through its length on its wall is a C-shaped tube, and the irregular tube with a flat surface on its wall includes a D-shaped tube and / or a flat elliptical tube. The C-shaped tube includes a C-shaped arc tube and / or a C-shaped flat elliptical tube.

[0029] In some embodiments of the present invention, at least one opening is provided on the plane connecting two adjacent shaped tubes.

[0030] In some embodiments of the present invention, the inner tank of the electric water heater further includes a water pipe disposed on the inner tank body and / or the end cap.

[0031] In some embodiments of the present invention, the inner tank of the electric water heater is prepared by the above-described method for preparing the inner tank of the electric water heater.

[0032] In another aspect, the present invention provides an electric water heater. According to an embodiment of the present invention, the inner tank of the electric water heater has the aforementioned inner tank or an inner tank prepared by the aforementioned method for preparing an inner tank. Compared with the prior art, this electric water heater not only has a compact shape and high space utilization, but also high product precision, good quality, better structural stability, and a longer service life.

[0033] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0034] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0035] Figure 1 This is a flowchart of a method for preparing the inner tank of an electric water heater according to an embodiment of the present invention.

[0036] Figure 2 This is a schematic diagram of the structure of a non-circular tube opening / plane according to an embodiment of the present invention (wherein) Figure 2 (a) is a C-shaped tube, (b) is a C-shaped flat elliptical tube, (c) is a D-shaped tube, and (d) is a flat elliptical tube.

[0037] Figure 3 This is a schematic diagram of a uniquely shaped pipe combination method for a double-inner-tank structure of an electric water heater according to an embodiment of the present invention.

[0038] Figure 4 This is a schematic diagram of the combination of irregularly shaped tubes in a three-tank structure of an electric water heater according to an embodiment of the present invention.

[0039] Figure 5 This is a schematic diagram of the combination of irregularly shaped tubes in the three-tank structure of an electric water heater according to another embodiment of the present invention.

[0040] Figure 6 This is a schematic diagram of the combination of irregularly shaped tubes in the four inner tank structure of an electric water heater according to an embodiment of the present invention.

[0041] Figure 7 This is a schematic diagram of the combination of irregularly shaped tubes in the four inner tank structure of an electric water heater according to another embodiment of the present invention.

[0042] Figure 8 This is a schematic diagram of the angle between the center of the plane of a D-shaped tube according to an embodiment of the present invention.

[0043] Figure 9 This is a schematic diagram of cutting a multi-tube welded assembly according to an embodiment of the present invention, and a structural schematic diagram of the multi-inner-liner body after cutting.

[0044] Figure 10 This is a schematic diagram of the structure of the inner tank of an electric water heater according to an embodiment of the present invention. Detailed Implementation

[0045] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0046] This invention is primarily based on the following problems and findings:

[0047] The existing water heaters and their manufacturing processes have the following main drawbacks: 1. The use of a rolling process for tank forming makes it difficult to guarantee the roundness of the tank, and it is impossible to effectively control the pulse deformation caused by water pressure during the use of the electric water heater, making it difficult to control the pulse fatigue life; 2. The shape is not compact enough, with more than 16mm of space wasted in the middle of the double-tank product; 3. The manufacturing process is complex, with many welding steps. The number of welds in the double-tank product reaches 17, resulting in high manufacturing costs, low product qualification rate, and a large number of parts needing rework; 4. The efficiency is low, with the product production efficiency per unit time being only about 30% of that of the existing single-tank products; 5. The manufacturing process requires a lot of manual operation, making it difficult to achieve automated tank production.

[0048] In view of this, in one aspect of the present invention, a method for preparing the inner tank of an electric water heater is provided. Reference is made below. Figures 1-10 The method for preparing the inner tank of an electric water heater is described in detail below. According to an embodiment of the present invention, the method includes:

[0049] S100: Prepare at least one first shaped tube and at least one second shaped tube, wherein the wall of the first shaped tube has an opening arranged along its length (see reference). Figure 2 (a) and (b) are understood, where 12 is an opening), and the second shaped tube has a flat surface on its wall (see reference). Figure 2 As understood in (c) and (d), where 13 is a plane, the orthographic projection of the opening on the plane is located inside the plane. According to an embodiment of the present invention, making the orthographic projection of the opening of the first shaped tube on the plane of the second shaped tube wall located inside the plane can further ensure the reliability of subsequent welding of the first and second shaped tubes and the water pressure pulse deformation resistance of the flat plate.

[0050] According to some specific embodiments of the present invention, reference is made to Figure 2 As understood in (a) and (b), it is preferable that the openings arranged along the length of the first shaped tube penetrate the entire wall of the shaped tube. Further, the first shaped tube can be a C-shaped tube, and the second shaped tube can be selected from a D-shaped tube and / or a flat elliptical tube. The C-shaped tube can be selected from a C-shaped arc tube (preferably a C-shaped circular tube, i.e., the cross-section of the C-shaped tube perpendicular to its length is an arc, see reference). Figure 3(Understanding) and C-shaped flat elliptical tubes. The C-shaped tube can be directly formed by rolling or forming, or it can be pre-prepared as a round or flat elliptical tube, and then cut to obtain the C-shaped tube. Alternatively, it can be obtained by cutting a plane of a D-shaped tube, or by cutting one plane of a flat elliptical tube. Compared to pre-preparing a round tube and then cutting, direct rolling or forming can save the need for a separate rolling mill for preparing C-shaped tubes. The D-shaped tube refers to a cross-section perpendicular to its length direction consisting of a straight line and an arc (preferably a circular arc; i.e., the D-shaped tube can preferably be a D-shaped round tube, see reference). Figure 3 (Understanding) The D-shaped tube is a special-shaped pipe fitting formed by enclosing two parallel lines. This D-shaped tube can be welded from a C-shaped tube and a flat plate, or it can be obtained by first preparing a round tube and then pressing or extruding it. Preferably, it is obtained by pressing or extruding the round tube. This further reduces the number of welding operations in the entire manufacturing process of the multi-liner barrel, thereby reducing the number of welds and improving the product qualification rate and quality. The flat elliptical tube refers to a special-shaped pipe fitting whose cross-section perpendicular to its length direction is formed by two parallel lines and two arc-shaped segments connected to the ends of these two parallel lines, forming an elliptical shape (see reference). Figure 2 and Figure 4 (Understanding), wherein the two arc segments connected to the two ends of the two parallel lines can preferably be circular arcs; the C-shaped flat elliptical tube can be understood as a special-shaped tube with one plane cut off from a flat elliptical tube, preferably with both ends of the cross-section of the C-shaped flat elliptical tube perpendicular to its length direction also being circular arcs. The flat ellipse can be obtained by pressing or extruding a round tube. The C-shaped flat elliptical tube can be directly rolled or rolled, or it can be obtained by cutting one plane of a flat elliptical tube. The inventors have found that using a C-shaped round tube and / or a C-shaped flat elliptical tube with circular arcs at both ends of the cross-section perpendicular to the length direction as the first special-shaped tube, and using a D-shaped round tube and / or a flat elliptical tube with circular arcs at both ends of the cross-section perpendicular to the length direction as the second special-shaped tube, in order to prepare a multi-tank tank body, it is more conducive to ensuring the roundness of the tank body, thereby further helping to control the pulse deformation caused by water pressure during the use of the electric water heater, and can effectively solve or alleviate the problem of pulse fatigue causing difficulty in controlling the life of the electric water heater.

[0051] According to some specific embodiments of the present invention, in the process of preparing the shaped tube, it is necessary to clean the steel plate to remove the oil stains on its surface. The cleaning can be carried out before tube making. Specifically, it can be cleaned first and then shaped, and then welded. Alternatively, it can be shaped first, welded, and then cleaned. Furthermore, the round tube, D-shaped tube, and flat elliptical tube described in this invention can each be independently made of straight seam steel pipe. Preferably, the C-shaped tube has no weld seam, and the weld seams of the D-shaped tube and flat elliptical tube can each be independently located in a non-planar area. The inventors have discovered that during the use of an electric water heater, the planar pull plate used to connect the multiple inner tank bodies is more susceptible to deformation due to water pressure pulses. Simultaneously, after welding the first and second shaped tubes, internal and external scrapers are required for smoothing. Compared to other parts, the dimensional deformation or fluctuation at the connection between the first and second shaped tubes is relatively greater, making further welding at existing weld seams more difficult. This invention utilizes C-shaped tubes without weld seams or D-shaped tubes and / or flat elliptical tubes with weld seams located in non-planar areas to prepare the multiple inner tank bodies. This reduces welding difficulty and further reduces the weld seams at the connection points of the multiple inner tank bodies, reducing the risk of deformation of the planar pull plate at the connection points due to water pressure pulses, thereby improving the service life of the electric water heater. In addition, during the preparation of special-shaped tubes, high-frequency welding pipe technology can also be used to manufacture straight seam steel pipes. During the raw material forming process, high-efficiency cleaning agents can be used to clean the material to remove oil stains and water can be used as a coolant to clean the steel plate surface. During the high-frequency welding process, the moisture can be dried by the welding heat. The use of high-frequency welding pipe technology is more conducive to the manufacturing of high-precision barrels. The high-precision barrel manufacturing method can effectively ensure the subsequent butt welding of end caps and barrels.

[0052] According to some specific embodiments of the present invention, the orthographic projection area of ​​the openings arranged along the length direction on the wall of the first shaped tube on the plane of the second shaped tube can be equal to the area of ​​the plane of the second shaped tube. Preferably, the orthographic projection edge of the openings arranged along the length direction on the wall of the first shaped tube on the plane of the second shaped tube coincides with the edge of the plane of the second shaped tube. For example, on the cross-section of the shaped tube perpendicular to its length direction, the circumferential opening (straight line) distance of the C-shaped tube, the straight edge distance of the D-shaped tube, and the straight edge distance of the flat elliptical tube can be the same. This can further ensure the reliability of the subsequent welding of the first and second shaped tubes and the water pressure pulse deformation resistance of the flat pull plate, and further reduce the space waste between multiple inner tank bodies.

[0053] S200: The opening of the first shaped tube and the plane of the second shaped tube are welded together to obtain a multi-tube welded assembly in which two adjacent tubes are connected by a flat pull plate. For example, at least one C-shaped tube can be welded with at least one D-shaped tube and / or a flat oval tube to obtain a multi-tube welded assembly. The welding process is carried out on the outside of the barrel, and the inner surface does not require manual grinding, which is more conducive to improving the enamel quality. According to an embodiment of the present invention, when manufacturing a multi-liner barrel, it is generally not allowed to weld three components simultaneously. This method is difficult to weld and the welding effect is hard to guarantee. Compared with pre-welding two shaped tubes to the flat plate one after the other, the present invention welds the opening of one shaped tube to the plane of another shaped tube. On the one hand, this reduces the welding difficulty and ensures the welding effect. It is not only easy to operate but also more reliable. On the other hand, it can greatly reduce the welding process and the number of welds at the connection of the multi-liner barrel, and reduce the weld size. This can reduce production costs and improve production efficiency. At the same time, it is also conducive to improving the barrel body precision. This can result in higher product quality and pass rate, and is also conducive to the subsequent butt welding of the end cap and barrel body.

[0054] According to some specific embodiments of the present invention, the multi-tube welding assembly may include various combinations, such as:

[0055] According to a specific example of the invention, when the electric water heater comprises two connected inner tank bodies, such as Figure 3 As shown, the multi-tube welding assembly can be obtained by welding one C-shaped tube and one D-shaped tube. The C-shaped tube and the D-shaped tube can be symmetrical with respect to the planar structure of the D-shaped tube. In this case, the C-shaped tube can preferably be a C-shaped round tube, and the D-shaped tube can preferably be a D-shaped round tube; or, the C-shaped tube can be a C-shaped flat ellipse tube, and the D-shaped tube can be a flat ellipse tube. In this case, both ends of the C-shaped flat ellipse tube and the flat ellipse tube can be arcs in the cross-section perpendicular to the length direction. This can further ensure the roundness of the tank body, reduce the risk of pulse deformation caused by water pressure during the use of the electric water heater, and thus effectively solve or alleviate the problem of pulse fatigue causing difficulty in controlling the life of the electric water heater.

[0056] According to a specific example of the invention, when the electric water heater comprises three interconnected inner tank bodies, reference is made to... Figure 4 Understanding is that a multi-tube welding assembly can preferably be welded from two C-shaped tubes and one flat elliptical tube, in which case the two C-shaped tubes can be symmetrically welded onto two planes of the flat elliptical tube; (Reference) Figure 5It is understood that the multi-tube welding assembly can also be welded from one D-shaped tube, one C-shaped flat elliptical tube, and one C-shaped arc tube. In this case, the plane of the D-shaped tube can be welded to the opening of the C-shaped flat elliptical tube, and the opening of the C-shaped tube can be welded to the plane of the C-shaped flat elliptical tube. In this case, the arc surface structure of the C-shaped tube and the D-shaped tube can be the same. Preferably, the C-shaped (arc) tube can be a C-shaped round tube, and the D-shaped tube can preferably be a D-shaped round tube. The two ends of the (C-shaped) flat elliptical tube in the cross-section perpendicular to the length direction can both be arcs. More preferably, the C-shaped round tube and the D-shaped round tube can be symmetrical with respect to the plane structure of the D-shaped tube (only for the C-shaped round tube and the D-shaped round tube, not for the multi-tank structure after welding). This can further ensure the roundness of the multi-tank body and reduce the risk of pulse deformation caused by water pressure during the use of the electric water heater.

[0057] According to a specific example of the present invention, when the electric water heater comprises four or more connected inner tank bodies, such as Figure 6 As shown, a multi-tube welding assembly can be formed by welding one D-shaped tube, at least two C-shaped flat elliptical tubes, and one C-shaped arc tube. In this case, the plane of the D-shaped tube can be welded to the opening of the C-shaped flat elliptical tube, and the plane of the C-shaped flat elliptical tube can be welded to the opening of another C-shaped flat elliptical tube or the opening of the C-shaped arc tube; or, as... Figure 7 As shown, the multi-tube welding assembly can also be formed by welding one flat elliptical tube, at least one C-shaped flat elliptical tube, and two C-shaped arc tubes. In this case, one plane of the flat elliptical tube can be welded to the opening of one C-shaped arc tube, another plane can be welded to the opening of one C-shaped flat elliptical tube, and the opening of the remaining C-shaped arc tube is welded to the plane of one C-shaped flat elliptical tube. That is, when the electric water heater includes more than four inner tanks, this can be achieved by increasing the number of C-shaped flat elliptical tubes. Preferably, the two C-shaped arc tubes at both ends of the multi-tube welding assembly are symmetrical, or the arc surfaces of the C-shaped arc tubes at both ends of the multi-tube welding assembly are symmetrical with those of the D-shaped tubes. In addition, regardless of the combination method, it is preferable that the C-shaped arc tube is a C-shaped round tube, the D-shaped tube is a D-shaped round tube, and both ends of the (C-shaped) flat elliptical tube are arcs in the cross-section perpendicular to the length direction. This can further ensure the roundness of the multi-tank body and reduce the risk of pulse deformation caused by water pressure during the use of the electric water heater.

[0058] According to some further embodiments of the present invention, reference is made to Figure 8As shown, the chord distance of the D-shaped tube can be 30–150 degrees, for example, 30, 45, 60, 75, 90, 105, 120, or 135 degrees; and the opening radius of the C-shaped tube can be 30–150 degrees, for example, 30, 45, 60, 75, 90, 105, 120, or 135 degrees. The inventors have found that if the angle of the chord distance of the D-shaped tube and / or the opening radius of the C-shaped tube are too small, the resulting multi-tube weld will be unsatisfactory. The current design is not compact enough, with significant space wastage between adjacent inner tanks. Furthermore, if the angle of the D-shaped tube's chord distance and / or the opening curvature of the C-shaped tube are too large, such as 180 degrees each, the internal capacity of the multiple inner tanks will be small, resulting in limited water storage capacity and impacting the product's cost-effectiveness and practicality. This invention, by controlling the D-shaped and C-shaped tubes to the aforementioned structure, better balances the internal capacity and external space utilization of the multiple inner tanks, resulting in a compact electric water heater with high water storage capacity. It should be noted that the D-shaped tube can be obtained by pressing and / or drawing a round tube. When the arc surface of the D-shaped tube is not circular, the chord distance is referenced to the center of the round tube that was pressed into the D-shape.

[0059] According to some specific embodiments of the present invention, before welding the first shaped tube and the second shaped tube, at least one hole can be pre-cut on the plane of the second shaped tube, that is, the planes of two adjacent inner liner bodies (such as...) can be... Figure 2 As shown in Figure 13, one or more holes are formed on the pull plate. When there are multiple holes, the holes can be evenly distributed on the plane of the second shaped tube. At the same time, it is also necessary to avoid the absence of holes at the welding joint of the first and second shaped tubes. This can ensure the welding effect and connection strength. Furthermore, based on the end connection of the final multi-liner product, the holes on the plane pull plate connecting the two adjacent multi-liner barrels can be used to improve the water flow in the multi-liner barrel and ensure the water flow effect in the multi-liner barrel.

[0060] According to some specific embodiments of the present invention, the welding process used when welding the first and second shaped tubes is not particularly limited. Those skilled in the art can choose according to actual needs. For example, welding processes such as gas metal arc welding (MAG), gas metal arc welding (MIG), or plasma welding (PAW) can be used to weld the two long straight steel tubes to form a shaped steel tube with a tie plate in the middle. Preferably, except at the connection between the first and second shaped tubes, there are preferably no weld seams on the flat tie plate connecting two adjacent multi-tank tanks. This further ensures the flat tie plate's resistance to water pressure pulse deformation, thereby improving the quality and service life of the multi-tank electric water heater.

[0061] S300: The multi-tube welded assembly is cut to obtain at least one multi-liner body with a desired length. According to an embodiment of the invention, refer to... Figure 9 It is understood that when preparing the first or second shaped tube, the shaped tube is usually quite long. The longer first and second shaped tubes can be pre-welded and then the multi-tube welded assembly can be cut to the expected length, thereby further improving production efficiency. Specifically, the preparation process of the present invention can achieve a maximum speed of 40m in length of shaped steel tube per minute. Based on the length of each barrel body of 0.5m, 40 barrel bodies can be manufactured per minute, which is more than 30 times that of the existing barrel body manufacturing process.

[0062] According to some specific embodiments of the present invention, the length of the multi-liner barrel is not particularly limited. Those skilled in the art can select it according to actual needs. For example, the length of the multi-liner barrel can be 200-1000mm, specifically 200mm, 300mm, 400mm, 500mm, 600mm, 700mm, 800mm, 900mm or 1000mm, etc.

[0063] S400: End caps (matching their end structures) are welded to both ends of the multi-liner body to obtain a multi-liner product with through-hole ends. According to an embodiment of the invention, refer to... Figure 10 It is understood that the edge area of ​​the end cap matches the outer edge structure of both ends of the multi-liner barrel, and the end of the multi-liner barrel can be sealed by welding. At the same time, the non-welded part of the end cap can allow the flow of water between the multi-liner barrels.

[0064] According to some specific embodiments of the present invention, reference is made to Figure 10 It is understood that the end cap may include multiple concave surfaces connected in sequence. These concave surfaces can correspond one-to-one with the end structures of the various irregular tubes in the multi-tank body. Furthermore, after the end cap is welded to both ends of the multi-tank body, at least a portion of the connection between any two adjacent concave surfaces does not contact the end of the multi-tank body, thus forming a gap. This further ensures the flow of water between the multi-tank bodies. Preferably, the concave surface can also be a near-spherical surface or a part of a spherical or near-spherical surface, thereby ensuring the flow of water between the multi-tank bodies and further increasing the water storage capacity of the electric water heater's inner tank.

[0065] According to some specific embodiments of the present invention, the end cap can be sleeved on the end of the multi-inner-liner barrel and welded thereto, or preferably the edge of the end cap can be directly overlapped with the end edge of the multi-tube welding assembly for welding, thereby ensuring the welding effect and reducing the cost of raw materials.

[0066] According to some specific embodiments of the present invention, when manufacturing the inner tank of an electric water heater, water pipes can also be welded onto the multi-tank product (see reference). Figure 10 (See section 30 for clarification). The water pipe can include an inlet pipe and an outlet pipe, thus forming a complete inner tank for the electric water heater. Furthermore, it should be noted that the location of the water pipe is not particularly limited; those skilled in the art can choose according to actual needs. For example, the water pipe can be welded to the inner tank body or to the end cap. Additionally, the relative positions of the inlet and outlet pipes are not particularly limited; those skilled in the art can choose according to actual needs. Moreover, the water pipe can be a metal pipe. Furthermore, it should be noted that in addition to the water pipe, flanges and other components can be further welded on. After welding, a water test can be performed.

[0067] According to some specific embodiments of the present invention, the present invention does not have special requirements for the material of the shaped tube when preparing the shaped tube. Those skilled in the art can choose according to actual needs. In fact, the preparation method of the present invention has strong material adaptability, can be compatible with the manufacture of inner liner of different material grades, and can be compatible with existing metal material composition systems.

[0068] In summary, the method for preparing the inner tank of an electric water heater according to the above embodiments of the present invention has at least the following advantages: 1. It enables the manufacture of a compact inner tank body, reducing space waste in the external structure; 2. It has high production efficiency, achieving a maximum speed of 40m in length for the manufacture of irregularly shaped steel pipes per minute. Based on a length of 0.5m per tank body, it can manufacture 40 tank bodies per minute, which is more than 30 times faster than existing tank body manufacturing processes; 3. It allows for material preparation, cleaning, forming, welding, and cutting processes to be carried out on a single production line, achieving one-piece flow for tank body manufacturing; 4. It enables automated production, eliminating the need for manual operation and processing; 5. It has higher energy utilization efficiency; 6. It enables the manufacture of high-precision tank bodies. The dimensional deviation is only 0.5mm, which is only one-tenth of the dimensional tolerance of existing manufacturing processes. The high-precision barrel manufacturing method can effectively ensure the butt welding of the end cap and barrel body; 7. The welding process is carried out on the outside of the barrel body, and the inner surface does not require manual grinding, which is conducive to improving the enamel quality; 8. Using the wall plane of the special-shaped tube as the plane pull plate of the multi-liner barrel body and welding it with the special-shaped tube with openings arranged along the length direction can greatly reduce the welding process and the number of welds, thereby achieving the purpose of reducing production costs and improving production efficiency and product qualification rate; 9. The manufacturing method has strong material adaptability and can be compatible with the manufacturing of inner liners of different material grades and existing metal material composition systems.

[0069] Based on the same inventive concept, in another aspect of the present invention, an inner tank for an electric water heater is also provided. According to an embodiment of the present invention, see... Figure 2 and Figures 8-10The electric water heater inner tank includes a multi-tank body 10 and two end caps 20. The multi-tank body 10 may include at least two shaped tubes 11 of equal length. One of the adjacent shaped tubes 11 has an opening 12 extending along its length on its wall, and the other has a plane 13 on its wall. The orthographic projection of the opening 12 onto the plane 13 is located inside the plane 13. The adjacent shaped tubes 11 are welded together via the opening 12 and the plane 13. The two end caps 20 are independently located at both ends of the multi-tank body 10. Each end cap 20 has a concave surface 21 that matches the end structure of the multi-tank body. The edges of the end caps 20 are sealed and welded to the ends of the multi-tank body 10, and at least a portion of the end of each shaped tube 11 forms a space between itself and the concave surface 21. Compared with existing technologies, this electric water heater inner tank not only has a compact structure and high precision, but also fewer welds, better structural stability, higher product quality, and longer service life, giving it better market competitiveness.

[0070] According to some specific embodiments of the present invention, a shaped tube (which can be regarded as a first shaped tube, see reference) has an opening extending through its length on its wall. Figure 2 (Understanding in (a) and (b)) 11 can be a C-shaped tube with a flat, irregularly shaped tube on its wall (which can be considered a second irregularly shaped tube, see reference). Figure 2 (c) and (d) (understood) 11 may include D-shaped tubes and / or flat elliptical tubes, wherein the C-shaped tube may be selected from C-shaped arc tubes (preferably C-shaped circular tubes, i.e., the cross-section of the C-shaped tube perpendicular to its length direction is an arc, see reference). Figure 3 (Understanding) and C-shaped flat elliptical tubes. The C-shaped tube can be directly formed by rolling or forming, or it can be pre-prepared as a round or flat elliptical tube, and then cut to obtain the C-shaped tube. Alternatively, it can be obtained by cutting a plane of a D-shaped tube, or by cutting one plane of a flat elliptical tube. Compared to pre-preparing a round tube and then cutting, direct rolling or forming can save the need for a separate rolling mill for preparing C-shaped tubes. The D-shaped tube refers to a cross-section perpendicular to its length direction consisting of a straight line and an arc (preferably a circular arc; i.e., the D-shaped tube can preferably be a D-shaped round tube, see reference). Figure 3 (Understanding) The D-shaped tube is a special-shaped pipe fitting formed by enclosing two parallel lines. This D-shaped tube can be welded from a C-shaped tube and a flat plate, or it can be obtained by first preparing a round tube and then pressing or extruding it. Preferably, it is obtained by pressing or extruding the round tube. This further reduces the number of welding operations in the entire manufacturing process of the multi-liner barrel, thereby reducing the number of welds and improving the product qualification rate and quality. The flat elliptical tube refers to a special-shaped pipe fitting whose cross-section perpendicular to its length direction is formed by two parallel lines and two arc-shaped segments connected to the ends of these two parallel lines, forming an elliptical shape (see reference). Figure 4(Understanding), wherein the two arc segments connected to the two ends of the two parallel lines can preferably be circular arcs; the C-shaped flat elliptical tube can be understood as a special-shaped tube with one of its planes cut off from a flat elliptical tube, preferably with both ends of the cross-section of the C-shaped flat elliptical tube perpendicular to its length direction also being circular arcs, the flat ellipse can be obtained by pressing or extruding a round tube, the C-shaped flat elliptical tube can be directly rolled or rolled, or it can be obtained by cutting one of the planes of the flat elliptical tube.

[0071] According to further embodiments of the present invention, the orthographic projection area of ​​the opening 12 arranged along the length direction of the first shaped tube on the tube wall plane 13 of the second shaped tube can be equal to the area of ​​the tube wall plane 13 of the second shaped tube. Preferably, the orthographic projection edge of the opening arranged along the length direction of the first shaped tube on the tube wall plane of the second shaped tube coincides with the edge of the tube wall plane of the second shaped tube. Furthermore, the number of inner liner units in the multi-liner barrel 10 is not particularly limited, and those skilled in the art can select according to actual needs. For example, the multi-liner barrel 10 can be a double-liner structure, a 3-liner structure, or a 4-liner structure, etc.

[0072] According to some specific embodiments of the present invention, such as Figure 8 As shown, the chord distance of the D-shaped tube can be 30–150 degrees, for example, 30, 45, 60, 75, 90, 105, 120, or 135 degrees; and the opening curvature of the C-shaped tube can be 30–150 degrees, for example, 30, 45, 60, 75, 90, 105, 120, or 135 degrees. The inventors have found that if the angle of the chord distance of the D-shaped tube and / or the opening curvature of the C-shaped tube are too small, the shape of the inner liner of the barrel will be affected. The design is still not compact enough, with significant space wastage between adjacent inner tanks. Furthermore, if the angle of the D-shaped tube's chord distance and / or the opening arc of the C-shaped tube are too large, such as 180 degrees each, the internal capacity of the multi-tank water heater will be small, resulting in limited water storage capacity and impacting the product's cost-effectiveness and practicality. This invention, by controlling the D-shaped and C-shaped tubes to the aforementioned structure, better balances the internal capacity and external space utilization of the multi-tank water heater, resulting in a compact design with high water storage capacity. Additionally, the length of the multi-tank water heater 10 is not particularly limited; those skilled in the art can select it according to actual needs. For example, the length of the multi-tank water heater can be 200–1000 mm, specifically 200 mm, 300 mm, 400 mm, 500 mm, 600 mm, 700 mm, 800 mm, 900 mm, or 1000 mm, etc.

[0073] According to some specific embodiments of the present invention, at least one opening (not shown) may be provided on the plane 13 connecting two adjacent shaped tubes 11, that is, one or more holes may be formed on the plane pull plate of two adjacent multi-liner barrels. When there are multiple holes, the multiple holes can be evenly distributed on the plane 13 of the shaped tube. At the same time, it should be avoided that there are no holes at the weld joint of the two shaped tubes. Thus, the welding effect and connection strength can be guaranteed. On the basis of the end penetration of the finally manufactured multi-liner product, the holes on the plane pull plate connecting two adjacent multi-liner barrels can be further used to improve the water flow in the multi-liner barrel and ensure the water flow effect in the multi-liner barrel.

[0074] According to further embodiments of the present invention, the end cap 20 may include a plurality of sequentially connected concave surfaces 21. These concave surfaces 21 may correspond one-to-one with the end structures of each shaped tube in the multi-tank body 10. Furthermore, after the end cap is welded to both ends of the multi-tank body, at least a portion of the connection between any two adjacent concave surfaces does not contact the end of the multi-tank body, thus forming a gap. This further improves the flow of water between the multi-tank bodies. Preferably, the concave surface may also be a near-spherical surface or a part of a spherical or near-spherical surface, thereby ensuring the flow of water between the multi-tank bodies and further increasing the water storage capacity of the electric water heater's inner tank. Additionally, the end cap may be fitted onto the end of the multi-tank body and welded thereto, or preferably, the edge of the end cap may be directly welded to the end edge of the multi-tube welding assembly. This ensures welding effectiveness and reduces raw material costs.

[0075] According to further embodiments of the present invention, the inner tank of the electric water heater may further include a water pipe 30, wherein the water pipe 30 may include an inlet pipe and an outlet pipe, thereby obtaining a complete inner tank of the electric water heater. Furthermore, it should be noted that the location of the water pipe is not particularly limited, and those skilled in the art can choose according to actual needs. For example, the water pipe can be welded to the inner tank body or to the end cap. Additionally, the relative positions of the inlet and outlet pipes are not particularly limited, and those skilled in the art can choose according to actual needs. Moreover, the water pipe can be a metal water pipe. Furthermore, it should be noted that in addition to the water pipe, flanges and other components can be further welded in, and a water test can be performed after welding.

[0076] According to some specific embodiments of the present invention, the inner tank of an electric water heater can preferably be prepared by the above-described method for preparing an inner tank of an electric water heater. This not only makes it easier to manufacture a compact inner tank body and reduce the space waste of the external structure, but also improves production efficiency. The material cutting, cleaning, forming, welding and cutting processes can be carried out on a single production line to achieve one-piece flow of tank body manufacturing. At the same time, it can also realize automated production without manual operation and processing, enabling the manufacturing of high-precision tank bodies, reducing the number of welds, improving product quality and pass rate, and improving energy utilization.

[0077] It should be noted that the above-mentioned method for preparing the inner tank of an electric water heater and the above-mentioned inner tank of an electric water heater are based on the same inventive concept. The features and effects described in the above-mentioned method for preparing the inner tank of an electric water heater are also applicable to the inner tank of the electric water heater, and will not be repeated here.

[0078] In summary, compared with the prior art, the preparation of the electric water heater inner tank of the above embodiments of the present invention has at least the following advantages: 1. The multi-tank tank structure is compact and has high space utilization; 2. The inner tank body has high precision, with a dimensional deviation of only 0.5mm, which is only one-tenth of the dimensional tolerance of existing processes, and the butt welding effect of the end cap and the tank body is good; 3. The enamel quality of the inner surface of the inner tank body is high; 4. The number of welds is small, the product quality is high and the production cost is low; 5. It can be applied to different material grades and existing metal material composition systems; 6. It has good structural stability, low risk of water pressure pulse deformation, and longer service life.

[0079] In another aspect, the present invention provides an electric water heater. According to an embodiment of the present invention, the inner tank of this electric water heater has the aforementioned inner tank or an inner tank prepared by the aforementioned method for preparing an inner tank. Compared with the prior art, this electric water heater not only has a compact structure and high space utilization, but also high product precision, good quality, good structural stability, and a longer service life. It should be noted that the features and effects described above regarding the inner tank and the method for preparing the inner tank also apply to this electric water heater, and will not be repeated here.

[0080] In the description of this invention, it should be understood that the terms "center," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention 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, and therefore should not be construed as a limitation of the invention. 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 indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0081] In this invention, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed 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, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "on top" can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0082] 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 the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer 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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0083] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing the inner tank of an electric water heater, characterized in that, include: (1) Prepare at least one first shaped tube and at least one second shaped tube, wherein the first shaped tube has an opening arranged along its length on its tube wall, and the second shaped tube has a plane on its tube wall, wherein the orthographic projection of the opening on the plane is located inside the plane; (2) Weld the opening of the first special-shaped tube and the plane of the second special-shaped tube to obtain a multi-tube welded assembly in which two adjacent tubes are connected by a plane pull plate; (3) Cut the multi-tube welded assembly to obtain at least one multi-liner barrel body with the expected length; (4) Weld end caps to both ends of the multi-liner barrel body to obtain a multi-liner product with through ends; In step (1), the first shaped tube is a C-shaped tube, the second shaped tube includes a D-shaped tube and / or a flat elliptical tube, and the C-shaped tube includes a C-shaped arc tube and / or a C-shaped flat elliptical tube; The multi-tube welding assembly includes: two of the aforementioned C-shaped tubes and one of the aforementioned flat elliptical tubes; or, One of the C-shaped arc tubes, at least one of the C-shaped flat elliptical tubes, and one of the D-shaped tubes; or, Two of the aforementioned C-shaped arc tubes, one of the aforementioned flat elliptical tubes, and at least one of the aforementioned C-shaped flat elliptical tubes; The chord distance of the D-shaped tube is 30 to 150 degrees; and / or, the opening arc of the C-shaped tube is 30 to 150 degrees.

2. The method according to claim 1, characterized in that, Step (1) satisfies at least one of the following conditions: The C-shaped tube, the D-shaped tube, and the flat elliptical tube are each formed directly by rolling or twisting independently. A circular tube is pre-prepared, and then the circular tube is cut to obtain the C-shaped tube; A circular tube is pre-prepared, and then the circular tube is extruded to obtain the D-shaped tube or the flat elliptical tube; The C-shaped tube is obtained by cutting the D-shaped tube with a plane, and the C-shaped flat elliptical tube is obtained by cutting one of the planes of the flat elliptical tube.

3. The method according to claim 2, characterized in that, The round tube, the D-shaped tube, and the flat elliptical tube are each independently straight seam steel pipes, and the welds of the D-shaped tube and the flat elliptical tube are each independently located in a non-planar area.

4. The method according to any one of claims 1 to 3, characterized in that, In step (2), the multi-tube welding assembly further includes: One C-shaped tube and one D-shaped tube.

5. The method according to claim 4, characterized in that, The C-shaped arc tube and the D-shaped tube are symmetrical in planar structure with respect to the D-shaped tube.

6. The method according to any one of claims 1 to 3, characterized in that, In step (1), the orthographic projection area of ​​the opening on the plane is equal to the area of ​​the plane.

7. The method according to any one of claims 1 to 3, characterized in that, Before proceeding to step (2), the procedure further includes cutting at least one hole in the plane.

8. The method according to any one of claims 1 to 3, characterized in that, In step (3), the length of the multi-liner barrel is 200~1000mm.

9. The method according to any one of claims 1 to 3, characterized in that, The end cap includes multiple concave surfaces connected in sequence, and each of the multiple concave surfaces corresponds one-to-one with the end structure of each irregular tube in the multi-inner-liner barrel.

10. The method according to claim 9, characterized in that, The edge of the end cap coincides with the end edge of the multi-tube welding assembly.

11. The method according to claim 1 or 10, characterized in that, Further includes: (5) Weld water pipes onto the multi-tank product to obtain the inner tank of the electric water heater.

12. The method according to claim 11, characterized in that, The water pipe is welded to the body of the multi-liner barrel and / or the end cap.

13. An inner tank for an electric water heater, prepared by the method according to any one of claims 1 to 12, characterized in that, include: The multi-liner barrel body includes at least two shaped tubes of equal length. In two adjacent shaped tubes, one tube wall has an opening extending through its length, and the other tube wall has a plane. The orthographic projection of the opening onto the plane is located inside the plane. The two adjacent shaped tubes are welded together through the opening and the plane. Two end caps are independently disposed at both ends of the multi-inner-liner barrel body. The end caps have concave surfaces that match the end structure of the multi-inner-liner barrel body. The edges of the end caps are sealed and welded to the ends of the multi-inner-liner barrel body, and at least a portion of the end of each shaped tube forms a gap space with the concave surface.

14. The inner tank of the electric water heater according to claim 13, characterized in that, A C-shaped tube is a special-shaped tube with an opening extending through its length on its wall. A D-shaped tube and / or a flat elliptical tube are special-shaped tubes with a flat surface on their wall. The C-shaped tube includes a C-shaped arc tube and / or a C-shaped flat elliptical tube.

15. The inner tank of the electric water heater according to claim 13, characterized in that, At least one opening is provided on the plane connecting two adjacent irregular tubes.

16. The inner tank of the electric water heater according to claim 13, characterized in that, Further includes: A water pipe, which is disposed on the body of the multiple inner tanks and / or the end caps.

17. An electric water heater, characterized in that, An electric water heater inner tank having any one of claims 13 to 16, or an electric water heater inner tank prepared by any one of claims 1 to 12.

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