Sintering apparatus and sintering method thereof

Abstract

The application relates to the field of heating pipes, in particular to a heating pipe, a sintering device and a sintering method thereof. The heating pipe comprises a fixed part provided with a mounting through hole penetrating along the thickness direction thereof; a heating part provided on one side of the fixed part and formed as a pipe-shaped piece, the heating part being provided with a heating assembly; and an enamel coating layer, at least a part of which is arranged on the outer peripheral surface of the heating pipe; the heating part is fixedly connected with the fixed part through the mounting through hole of the fixed part and forms a fixed connection part, and the surface of the fixed connection part is not provided with the enamel coating layer. According to the technical scheme, the structure of the heating pipe is optimized, the fixed connection part between the fixed part and the heating part is not provided with the enamel coating layer, the phenomenon that the sintered enamel structure accelerates oxidation of the fixed connection part in the actual machining process is reduced, and the corrosion resistance and service life of the heating pipe in the subsequent use process are improved.

Description

Technical Field

[0001] This application relates to the field of heating tubes, and more specifically, to a heating tube, a sintering apparatus, and a sintering method thereof. Background Technology

[0002] Scale buildup and corrosion are currently the main reasons affecting the reliability of electric heating elements in water heaters. Scale buildup leads to poor heat dissipation and increased thermal resistance, which in turn causes the surface temperature of the heating element to rise, promoting the occurrence and development of pitting corrosion. Scale accumulation on the surface of the heating element promotes pitting and stress corrosion, and may even pose a safety hazard of electric shock due to perforation and leakage caused by corrosion.

[0003] To address issues such as tube bursting, corrosion perforation, and electrical leakage caused by corrosion and excessive scaling in electric heating tubes, enamel coating offers excellent scale inhibition. However, enamel coating on metal heating tubes typically requires the entire product to be placed in a high-temperature furnace for sintering.

[0004] Regarding the aforementioned technologies, the inventors believe that during the processing of existing heating tubes with flanges, the surface of the flange and the solder at the brazing point between the flange and the heating tube will oxidize under high temperature conditions, causing the color to turn black. After being installed on a water heater and coming into contact with water, the flange surface and the weld are prone to rust, which reduces the corrosion resistance of the heating tube and affects its service life. Summary of the Invention

[0005] To overcome the shortcomings of existing flanged heating tubes with poor corrosion resistance after enamel processing, this application provides a heating tube, a sintering device, and a sintering method thereof, employing the following technical solution:

[0006] In a first aspect, this application provides a heating element, which adopts the following technical solution:

[0007] A heating element, comprising:

[0008] The fixing part is provided with a first through hole extending along its thickness direction;

[0009] A heating section is provided on one side of the fixing section and is formed as a tubular component, and a heating assembly is provided inside the heating section;

[0010] An enamel coating layer, at least a portion of which is disposed on the outer peripheral surface of the heating tube;

[0011] The heating part is fixedly connected to the fixing part and forms a fixed connection part, and the surface of the fixed connection part is not provided with an enamel coating layer.

[0012] By adopting the above technical solution, the technical solution of this application optimizes the structure of the heating tube. By fixing the fixed part and the heating part without setting the enamel coating layer, the oxidation of the fixed connection part caused by the sintering of the enamel structure during actual processing is reduced, thereby improving the corrosion resistance and service life of the heating tube in subsequent use.

[0013] Furthermore, the heating element includes:

[0014] A transition layer, at least a portion of which is disposed on the outer peripheral surface of the fixed connection portion.

[0015] By adopting the above technical solution, the technical solution of this application processes the connection between the heating part and the fixing part and coats its surface with a transition structure, which effectively improves the phenomenon that the surface of the fixing connection part is susceptible to oxidation due to external environmental influences, and improves the corrosion resistance and service life of the subsequent heating tube.

[0016] Meanwhile, due to the difference between the cooling rate and heating rate during the actual sintering and cooling process of enamel structure and metal structure, the heating tube is prone to deformation near the fixed connection after the ambient temperature changes, which can lead to cracking of the heating tube structure. Therefore, this application further improves the structural strength and service life of the heating tube by covering it with a transition layer.

[0017] Secondly, this application provides an apparatus for sintering heating tubes, which adopts the following technical solution:

[0018] An apparatus for sintering heating tubes includes a sintering furnace, the sintering furnace comprising:

[0019] A high-temperature sintering cavity is provided along the length of the sintering furnace, and multiple sets of heating components are provided on the inner walls of both sides of the high-temperature sintering cavity.

[0020] A low-temperature isolation chamber is provided, which is spaced apart from and connected to the high-temperature sintering chamber. The inner wall of the low-temperature isolation chamber is provided with a heat insulation layer in the circumferential direction.

[0021] By adopting the above technical solution, the technical solution of this application distinguishes between the high-temperature sintering chamber and the low-temperature isolation chamber, corresponding to the fixing part and the heating part of the product to be sintered. By selecting a suitable processing temperature, the fixing part is processed in a relatively low-temperature environment, thereby improving the defect that the fixing part of the heating tube is prone to oxidation at high temperatures, and improving the corrosion resistance and service life of the heating tube.

[0022] Furthermore, the sintering furnace also includes:

[0023] A transition cavity is provided between the high-temperature sintering cavity and the low-temperature isolation cavity so that the low-temperature isolation cavity and the high-temperature sintering cavity are connected;

[0024] The transmission cavity is located on the side of the low-temperature isolation cavity away from the high-temperature sintering cavity, and the transmission cavity is connected to the low-temperature isolation cavity.

[0025] By adopting the above technical solution, the technical solution of this application further optimizes the structure of the sintering furnace. The transmission cavity enables the process area of ​​the sintering heating tube to be automated and integrated, effectively improving the production and processing efficiency of the heating tube.

[0026] Based on this, this application forms an effective transition between the high-temperature sintering cavity and the low-temperature isolation cavity through a transition cavity, corresponding to the transition layer on the surface of the fixed connection part on the heating tube, further reducing the heating temperature of the fixed part during the sintering process, and preventing the heating tube from being oxidized by high-temperature radiation in the high-temperature sintering cavity, thus reducing the corrosion resistance of the heating tube.

[0027] Furthermore, multiple electromagnetic heating coils are spaced apart on the inner wall surfaces of both sides of the transition cavity.

[0028] By adopting the above technical solution, the technical solution of this application uses electromagnetic heating to treat the transition layer area based on the transition layer structure set on the heating tube. Compared with traditional hot sintering, electromagnetic heating is easier to control and has lower heat radiation, which can reduce the heat radiation of the sintering area to the low-temperature isolation cavity, thereby protecting the flange structure. While effectively improving the corrosion resistance of the fixed connection part, it also improves the corrosion resistance and service life of the fixed part structure.

[0029] Furthermore, the inner wall surfaces of the transition cavity that are oppositely arranged are formed as concave surfaces.

[0030] By adopting the above technical solution, the technical solution of this application optimizes the internal structure of the transition cavity and sets up a concave structure, which enables the temperature formed by electromagnetic heating to accumulate, prevents temperature loss, and increases the heating temperature in the transition cavity, thereby improving the forming rate of the transition layer.

[0031] Furthermore, the heating assembly is provided in three groups, which are spaced apart along the length of the high-temperature sintering cavity and heated independently to adjust the high-temperature sintering cavity into a preheating surface drying zone, a high-temperature sintering zone, and a slow cooling zone.

[0032] By adopting the above technical solution, this application's technical solution uses a high-temperature sintering chamber with a multi-temperature zone structure to sinter the heating tube. Due to the design of the multi-temperature zone high-temperature sintering chamber, the impact of enamel on the deformation of the heating tube structure during heating is reduced. The setting of multiple temperature zones further adjusts the structural performance at the junction of the fixing part and the heating part, thereby improving the corrosion resistance and service life of the sintered heating tube.

[0033] Thirdly, this application provides a method for sintering a heating tube using an apparatus for sintering heating tubes, comprising the following preparation steps:

[0034] S1. Coat the heating part of the heating tube with the coating slurry and place it on the transmission track of the transmission mechanism, and let it air dry naturally;

[0035] S2. Place the dried heating tube heating part in the high-temperature sintering chamber and the fixing part in the low-temperature isolation chamber. Suspend it to the transmission track of the transmission mechanism through the suspension fixture and send it into the sintering furnace.

[0036] S3. Adjust the operating frequency of the transmission track and perform sintering treatment. After the product is sintered, place it in a heat preservation mechanism for heat preservation treatment, and let it cool to room temperature to obtain the heating tube.

[0037] Furthermore, the operating frequency of the transmission track is 3 to 10 Hz.

[0038] By adopting the above technical solution, the sintering process of this application is further optimized. By using a suitable sintering device in combination with the sintering process, not only is the structural strength, corrosion resistance and service life of the heating tube improved, but the optimized sintering process also has good processing efficiency.

[0039] In summary, this application includes at least one of the following beneficial technical effects:

[0040] First, the technical solution of this application improves the oxidation phenomenon of the fixed connection surface, which is easily affected by the external environment, by processing the connection between the heating part and the fixing part and covering its surface with a transition structure, thereby improving the corrosion resistance and service life of the subsequent heating tube.

[0041] Meanwhile, due to the difference between the cooling rate and heating rate during the actual sintering and cooling process of enamel structure and metal structure, the heating tube is prone to deformation near the fixed connection after the ambient temperature changes, which can lead to cracking of the heating tube structure. Therefore, this application further improves the structural strength and service life of the heating tube by covering it with a transition layer.

[0042] Secondly, the technical solution of this application distinguishes between the high-temperature sintering chamber and the low-temperature isolation chamber, corresponding to the fixing part and the heating part of the product to be sintered. By selecting a suitable processing temperature, the fixing part is processed in a low-temperature environment, thereby improving the defect that the fixing part of the heating tube is prone to oxidation at high temperatures, and improving the corrosion resistance and service life of the heating tube.

[0043] Third, the technical solution of this application uses electromagnetic heating to treat the transition layer area based on the transition layer structure set on the heating tube. Compared with traditional thermal sintering, electromagnetic heating is easier to control and has lower heat radiation, which can reduce the heat radiation of the sintering area to the low-temperature isolation cavity, thereby protecting the flange structure. It can effectively improve the corrosion resistance of the fixed connection part and improve the corrosion resistance and service life of the fixed part structure. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of heating tube 1 in an embodiment of this application;

[0045] Figure 2 This is a schematic diagram of the structure of the heating tube 2 in an embodiment of this application;

[0046] Figure 3 This is a schematic diagram of the sintering heating tube apparatus according to an embodiment of this application;

[0047] Figure 4 This is a schematic diagram of the sintering furnace in an apparatus for sintering heating tubes according to an embodiment of this application;

[0048] Figure 5 This is a schematic diagram of the sintering furnace in an apparatus for sintering heating tubes according to another embodiment of this application;

[0049] Figure 6 This is a front view of the sintering furnace in an apparatus for sintering heating tubes according to an embodiment of this application;

[0050] Figure 7 This is a front view of the sintering furnace in an apparatus for sintering heating tubes according to another embodiment of this application;

[0051] Figure 8 This is a cross-sectional view of the sintering furnace in the apparatus for sintering heating tubes according to an embodiment of this application;

[0052] In the diagram: 1. Fixing part; 2. Heating part; 21. Transition layer; 3. Enamel coating layer; 4. Sintering furnace; 41. High-temperature sintering chamber; 411. Preheating and surface drying zone; 412. High-temperature sintering zone; 413. Slow cooling zone; 42. Low-temperature isolation chamber; 43. Transition chamber; 431. Electromagnetic heating coil; 44. Transmission chamber; 45. Transmission mechanism; 46. Heat preservation mechanism; 47. Workbench; 5. Tooling bracket. Detailed Implementation

[0053] The technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0054] In the description of this invention patent, 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 only for the convenience of describing this invention patent and simplifying the description, and do not indicate or imply that the device or component 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 invention patent.

[0055] In the description of this patent, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection or setting, a detachable connection or setting, or an integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this patent according to the specific circumstances.

[0056] 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 invention patent, "a plurality of" means two or more, unless otherwise explicitly specified.

[0057] Please see Figures 1 to 8 As shown, this invention patent provides a heating tube and a sintering apparatus used for the sintering heating tube:

[0058] First, combined Figure 1 and Figure 2This application discloses a heating tube, including a fixing part 1, which is a flange, and a heating part 2, which is a heating coil. The flange has two through mounting holes. On the right side of the flange, one end of the heating part 2 is first passed through one mounting hole, then bent back to the other mounting hole, and then fixedly connected to the heating part 2 by welding. This fixed connection portion forms a fixed connection part to fix the heating part 2 and the fixing part 1 into a whole. Simultaneously, a receiving chamber for placing a heating resistance wire is provided inside the heating coil, and the environment on the right side of the flange is heated by the heating resistance wire.

[0059] like Figure 1 As shown, an enamel coating layer 3 is wrapped around the heating coil. The enamel coating layer 3 does not completely cover the heating coil. Near the fixed connection part, the enamel coating layer 3 is not provided. This is because the coating of the enamel coating layer 3 needs to be sintered at high temperature. Therefore, the high temperature will accelerate the oxidation of the fixed connection part, which will cause cracking and other phenomena during subsequent use, thereby reducing the service life of the heating tube.

[0060] like Figure 2 As shown, a transition layer 21 is provided at the connection between the heating coil and the flange (fixed connection part). This transition layer 21 is mainly formed by plasma spraying of Ni / Al powder followed by high-temperature sintering. By covering the fixed connection part with the transition layer 21, the oxidation phenomenon that is easily affected by the external environment on the surface of the fixed connection part is effectively improved, thereby improving the corrosion resistance and service life of the subsequent heating tube.

[0061] like Figures 3-8 As shown, this application also discloses a sintering apparatus for sintering heating tubes. This sintering apparatus mainly includes a sintering furnace 4. Inside the sintering furnace 4, along its length, there are multiple receiving chambers with open ends. At the bottom of the sintering furnace 4, two high-temperature sintering chambers 41 are symmetrically arranged. On the inner walls of both sides of each high-temperature sintering chamber 41, along its length, three heating pipes are sequentially installed. Combined with... Figure 8 By setting the number of bends in the heating pipes, the installation area of ​​the heating pipes per unit area is adjusted, thereby dividing each high-temperature sintering chamber 41 into three regions along its length. These three regions are respectively the preheating surface drying zone 411, the high-temperature sintering zone 412, and the slow cooling zone 413 according to their heating area.

[0062] By implementing a zoned design, the impact of enamel on the deformation of the heating tube structure during heating is reduced. Furthermore, this application optimizes the heating temperatures of different zones: 600–700℃ for the preheating and drying zone 411, 800–850℃ for the high-temperature sintering zone 412, and 400–450℃ for the slow cooling zone 413. This results in a heating tube enamel coating 3 with excellent strength and corrosion resistance.

[0063] like Figure 4 and Figure 6 Referring to Embodiment 1, this application further optimizes the longitudinal structure of the sintering furnace 4. At the upper end of each high-temperature sintering chamber 41, a low-temperature isolation chamber 42 is provided, allowing the flange to pass laterally. Each low-temperature isolation chamber 42 is surrounded by insulating material for heat exchange with the external environment. Between the low-temperature isolation chamber 42 and the high-temperature sintering chamber 41, a channel only wide enough for the heating tube diameter to pass through is provided. This ensures that when the low-temperature isolation chamber 42 is heated within the high-temperature sintering chamber 41, a large amount of high-temperature air cannot enter, thus maintaining a lower temperature. When the fixing part 1 is conveyed within the low-temperature isolation chamber 42, it is protected from high-temperature heating, thereby preventing oxidation due to high temperatures.

[0064] Will Figure 5 and Figure 7 In conjunction with Embodiment 2, this application adjusts the structure on both sides of the channel between the low-temperature isolation chamber 42 and the high-temperature sintering chamber 41. The channel is set as a transition chamber 43 according to the height of the channel between the low-temperature isolation chamber 42 and the high-temperature sintering chamber 41, so that the height of the transition chamber 43 is not less than the length of the transition layer 21.

[0065] Combination Figure 7 and Figure 8 Multiple electromagnetic heating coils 431 are installed at equal intervals on the inner wall surfaces on both sides of the transition cavity 43. When the heating tube covered with the transition layer 21 is passed in the sintering furnace 4, the transition layer 21 is electromagnetically heated by the multiple electromagnetic heating coils 431. Since the heating tube is made of metal material, mostly stainless steel, it is effectively heated under the action of electromagnetic induction and forms an effective sintering effect on the Ni / Al powder covering its surface, so that the transition layer 21 is effectively covered to the fixed connection part. Thus, through the transition structure covering its surface, the phenomenon of oxidation of the surface of the fixed connection part is easily affected by the external environment is effectively improved, and the corrosion resistance and service life of the subsequent heating tube are improved.

[0066] Combination Figures 4-8 The structure of the inner walls on both sides of the transition cavity 43 has been further optimized by setting the inner walls on both sides as concave structures, which can concentrate the temperature formed by electromagnetic heating, prevent the temperature from dissipating, and increase the heating temperature inside the transition cavity 43, effectively sintering and forming a transition layer 21 on the surface of the heating tube.

[0067] Combination Figures 4-7 This application further optimizes the structure of the sintering furnace 4. By further optimizing the longitudinal structure of the sintering furnace 4, the upper end of the sintering furnace 4 is set as a transmission cavity 44 through which the transmission structure can pass. The transmission cavity 44 also runs through the length of the sintering furnace 4, ensuring that after the tooling bracket 5 is installed, the transmission mechanism 45 can transmit the heating tube to be sintered from one end to the other end in the sintering furnace 4 along the transmission cavity 44.

[0068] Combination Figure 3 This application optimizes the sintering apparatus by connecting insulation covers to both ends of the sintering furnace 4. Both insulation covers are semi-circular, and a processing worktable 47 is placed between the insulation covers, forming a ring structure for the entire sintering apparatus. This structure creates a streamlined sintering process for the heating tubes, effectively improving sintering efficiency. Furthermore, the insulation covers effectively mitigate the environmental impact on the heating tubes before and after sintering, thus enhancing product quality stability.

[0069] Combination Figures 3-8 The present application also provides a method for sintering heating tubes using a sintering heating tube sintering device, the specific steps of which are as follows:

[0070] S1. Coat the heating part 2 of the heating tube with the coating slurry and place it on the transmission track of the transmission mechanism 45, and let it air dry naturally.

[0071] S2. Place the dried heating tube heating part 2 in the high temperature sintering chamber 41, and the fixing part 1 in the low temperature isolation chamber 42. Suspend it to the transmission track of the transmission mechanism 45 through the suspension fixture and send it into the sintering furnace 4.

[0072] S3. Adjust the operating frequency of the transmission track and perform sintering treatment. After the product is sintered, place it in the heat preservation mechanism 46 for heat preservation treatment, and let it cool to room temperature to obtain the heating tube.

[0073] It should be noted that the operating frequency of the transmission track in this application is 3 to 10 Hz. In other words, by adjusting the operating frequency of the transmission track, this application can control the sintering rate and effectively improve the sintering quality of the heating tube.

[0074] The foregoing has shown and described the basic principles, main features, and advantages of this invention. Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made without departing from the spirit and scope of this invention, and all such changes and modifications fall within the scope of the claims. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. An apparatus for sintering heating tubes, comprising a sintering furnace (4), characterized in that, The sintering furnace (4) includes: A high-temperature sintering cavity (41) is provided along the length of the sintering furnace (4), and multiple sets of heating components are provided on the inner walls of both sides of the high-temperature sintering cavity (41). A low-temperature isolation cavity (42) is provided at intervals and connected to the high-temperature sintering cavity (41). A heat insulation layer is provided circumferentially on the inner wall surface of the low-temperature isolation cavity (42). The heating element includes: The fixing part (1) is provided with a mounting through hole extending along its thickness direction; Heating part (2), the heating part (2) is provided on one side of the fixing part (1) and is formed as a tubular part, and a heating assembly is provided inside the heating part (2); Enamel coating layer (3), at least a portion of which is provided on the outer peripheral surface of the heating tube; The heating part (2) passes through the mounting through hole of the fixing part (1) and is fixedly connected to the fixing part (1) to form a fixed connection part. The surface of the fixed connection part is not provided with an enamel coating layer (3). The heating element (2) includes: A transition layer (21) is provided at least in part on the outer peripheral surface of the fixed connection portion.

2. The apparatus for a sintering heating tube according to claim 1, characterized in that, The sintering furnace (4) also includes: A transition cavity (43) is provided between the high-temperature sintering cavity (41) and the low-temperature isolation cavity (42) so that the low-temperature isolation cavity (42) and the high-temperature sintering cavity (41) are connected; The transmission cavity (44) is located on the side of the low-temperature isolation cavity (42) away from the high-temperature sintering cavity (41), and the transmission cavity (44) is connected to the low-temperature isolation cavity (42).

3. The apparatus for a sintering heating tube according to claim 2, characterized in that, Multiple electromagnetic heating coils (431) are spaced apart on the inner wall surfaces of both sides of the transition cavity (43).

4. The apparatus for a sintering heating tube according to claim 3, characterized in that, The inner wall surfaces of the transition cavity (43) are concave.

5. The apparatus for a sintering heating tube according to claim 1, characterized in that, The heating assembly is provided in three groups. The three groups of heating assemblies are spaced apart along the length of the high-temperature sintering cavity (41) and are heated independently to adjust the high-temperature sintering cavity (41) into a preheating surface drying zone (411), a high-temperature sintering zone (412), and a slow cooling zone (413).

6. The apparatus for a sintering heating tube according to claim 2, characterized in that, Also includes: The transmission mechanism (45) is provided with a transmission track extending along its length direction, and at least a portion of the transmission track is provided inside the transmission cavity (44) along the length direction of the sintering furnace (4). The heat preservation mechanism (46) is located at both ends of the sintering furnace (4) and forms a heat preservation cover.

7. A method of using the apparatus for a sintering heating tube as described in claim 6, characterized in that, The preparation steps include the following: S1. Coat the heating part (2) of the heating tube with coating slurry and place it on the transmission track of the transmission mechanism (45) and let it air dry naturally. S2. Place the dried heating tube heating part (2) in the high temperature sintering chamber (41), and the fixing part (1) in the low temperature isolation chamber (42). Suspend it to the transmission track of the transmission mechanism (45) through the suspension fixture and send it into the sintering furnace (4). S3. Adjust the operating frequency of the transmission track and sinter it. After the product is sintered, place it in the heat preservation mechanism (46) for heat preservation treatment and let it cool to room temperature to obtain the heating tube.

8. The method of using the sintering heating tube apparatus according to claim 7, characterized in that, The operating frequency of the transmission track is 3 to 10 Hz.

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