Heat exchange tube for inner container of water heater

Abstract

The utility model belongs to heat generating device technical field especially relates to fluid heater, concretely relates to a heat exchange pipe for water heater inner bag. The utility model discloses, and heat exchange pipe is configured as at least partial outer wall is embedded in the inner bag, and heat exchange pipe includes input inclined pipe, output inclined pipe and connecting pipe, wherein, input inclined pipe includes input upper port and input lower port and the horizontal position of input upper port is higher than input lower port, output inclined pipe includes output upper port and output lower port and the horizontal position of output upper port is higher than output lower port, and connecting pipe has connecting upper port and connecting lower port, and connecting upper port is configured as connecting input lower port, and connecting lower port is configured as connecting output upper port. The utility model improves the originally U-shaped pipe with horizontal section to the structure that is composed of the inclined input inclined pipe, output inclined pipe and connecting pipe, and the condensed water that produces after shutdown can be automatically, smoothly discharged outside the pipe by the action of gravity.

Description

Technical Field

[0001] This utility model belongs to the technical field of heat generation devices, and particularly relates to fluid heaters, specifically a heat exchange tube for the inner tank of a water heater. Background Technology

[0002] Referring to the applicant's prior patent application, a water heater inner tank with a heat exchange tube is described. The U-shaped heat exchange tube is installed inside the inner tank and consists of an inlet straight pipe (with a heat source inlet), an outlet straight pipe (with a heat source outlet), and an arc-shaped bend connecting the two. The ignition head is located on the inner wall of the heat source inlet. When a flammable material (such as natural gas) is selected as the heat source, the ignition head ignites the flammable material entering from the heat source inlet, causing it to burn inside the U-shaped heat exchange tube, thereby heating the tube and ultimately heating the water in the inner tank.

[0003] However, when the heat exchange tubes are not in operation, their temperature will gradually decrease, resulting in condensation on their inner walls. Since both the inlet and outlet straight pipes are horizontally set, the condensation cannot be discharged in time and will remain in the heat exchange tubes. This condensation will not only affect the ignition process, but will also combine with gas residues (such as nitrogen-containing substances) to form a corrosive solution, which will damage the heat exchange tubes.

[0004] Prior patent application: Chinese utility model patent with publication number CN218821020U and publication date of 2023-04-07. Utility Model Content

[0005] The purpose of this invention is to provide a heat exchange tube for the inner tank of a water heater, which can promptly drain the condensate formed on the inner wall of the heat exchange tube due to cooling.

[0006] The technical solution adopted by this utility model to solve the above problems is: a heat exchange tube for the inner tank of a water heater, wherein the heat exchange tube is configured such that at least part of its outer wall is embedded in the inner tank, and the heat exchange tube includes an input inclined tube, an output inclined tube, and a connecting tube; wherein the input inclined tube includes an input upper port and an input lower port, and the horizontal position of the input upper port is higher than that of the input lower port; the output inclined tube includes an output upper port and an output lower port, and the horizontal position of the output upper port is higher than that of the output lower port; the connecting tube has a connecting upper port and a connecting lower port, wherein the connecting upper port is configured to connect to the input lower port, and the connecting lower port is configured to connect to the output upper port.

[0007] A further preferred technical solution is that the circumferential cross-section of the input inclined tube is circular.

[0008] A further preferred technical solution is that the circumferential cross-section of the output inclined tube is circular.

[0009] A further preferred technical solution is that the port surfaces connecting the upper port and the lower port are located in the same vertical plane.

[0010] A further preferred technical solution is that the connecting pipe has a curved section, and on a radial section taken through the center of curvature of the curved section and along the vertical direction, the cross-sectional profile of the pipe body is composed of an inner semicircle and an outer semicircle.

[0011] A further preferred technical solution is that the inner and outer semicircles are concentrically set.

[0012] A further preferred technical solution is that the inner diameter of the input inclined tube, the output inclined tube, and the connecting tube is φ90-φ100.

[0013] A further preferred technical solution is that the input inclined tube and the output inclined tube are connected to the inner liner by welding.

[0014] A further preferred technical solution is that an ignition head is also provided on the inner wall of the input inclined tube.

[0015] A further preferred technical solution is that a condensate collection component is provided at the lower output port.

[0016] In summary, this utility model has the following advantages: 1. This utility model improves the original U-shaped pipe with a horizontal section into a structure composed of an inclined input pipe, an inclined output pipe and a connecting pipe, so that the condensate generated after the machine stops can be automatically and smoothly discharged outside the pipe by using gravity.

[0017] 2. This invention avoids the formation of corrosive liquid by the long-term retention of condensate and the combination of gas residue, thereby significantly reducing the risk of localized corrosion and perforation of the heat exchange tube and extending the service life of the heat exchange tube.

[0018] 3. The condensate in the heat exchange tube of this utility model can be discharged in time, ensuring that the input inclined tube remains dry. This eliminates the adverse effects of condensate on the mixing of gas and air and flame stability, and improves the success rate of ignition and the reliability of operation. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the connection between the heat exchange tube and the inner liner of this utility model.

[0020] Figure 2 This is a structural schematic diagram of the vertical cross-section of the connection between the heat exchange tube and the inner liner of this utility model.

[0021] In the attached diagram, the components represented by each number are as follows: Input inclined tube 1, Output inclined tube 2, Connecting tube 3, Input upper port 1.1, Input lower port 1.2, Output upper port 2.1, Output lower port 2.2, Connecting upper port 3.1, Connecting lower port 3.2, Bending part 3.3, Inner semicircle 3.3.1, Outer semicircle 3.3.2, Inner liner 4. Detailed Implementation

[0022] Based on the background description, when the input and output straight pipes are designed to be completely horizontal, there is no downward slope within the pipe. After the heat exchange tubes stop working and the temperature drops, the water vapor produced by internal combustion condenses into liquid water. These water droplets adhere to the pipe wall and collect at the lowest point of the pipe due to gravity. Because the entire pipe is horizontal, every point on the inner wall is at the same height, with no obvious "downstream" direction. The condensate cannot flow automatically to one end due to its own gravity; it can only spread flat at the bottom of the pipe, forming puddles. Water has surface tension, which makes it easy to "adhere" to solid surfaces and depressions inside the pipe. In horizontal pipes, this "adhesion" effect is more pronounced; tiny water droplets converge into a water film, but there is a lack of a concentrated, outlet-oriented "pull" to make it flow out. The condensate remains at the bottom of the horizontal pipe, and when ignition is restarted, this condensate may affect the mixing and flow stability of the fuel gas and air. Furthermore, the condensate combines with residual sulfides and nitrogen oxides in the gas to form an acidic corrosive liquid. This liquid, when soaked in a fixed location in the pipeline for an extended period, often at the bottom of the pipeline, leads to localized corrosion and perforation.

[0023] Based on this, the applicant improved the technical solution by designing the heat exchange tubes with a certain tilt angle, using gravity to achieve self-drainage of condensate, thereby solving the problem of condensate corrosion.

[0024] The present invention will be specifically illustrated below with reference to embodiments: This specific embodiment is merely an explanation of the present utility model and is not intended to limit the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present utility model, they are protected by patent law.

[0025] Example: Reference Figure 1-2A heat exchange tube for a water heater inner tank is configured such that at least a portion of its outer wall is embedded in the inner tank 4. The heat exchange tube includes an input inclined tube 1, an output inclined tube 2, and a connecting tube 3. The input inclined tube 1 includes an input upper port 1.1 and an input lower port 1.2, with the horizontal position of the input upper port 1.1 higher than that of the input lower port 1.2. The output inclined tube 2 includes an output upper port 2.1 and an output lower port 2.2, with the horizontal position of the output upper port 2.1 higher than that of the output lower port 2.2. The connecting tube 3 has a connecting upper port 3.1 and a connecting lower port 3.2, with the connecting upper port 3.1 configured to connect to the input lower port 1.2 and the connecting lower port 3.2 configured to connect to the output upper port 2.1.

[0026] The input inclined pipe 1 is an inclined straight pipe, including an upper input port 1.1 and a lower input port 1.2. The upper input port 1.1 is horizontally higher than the lower input port 1.2, creating a downward-sloping layout throughout the pipe to ensure smooth drainage of condensate. The angle of inclination is typically small, but sufficient to allow condensate to flow under gravity. The input inclined pipe 1 serves as the inlet channel for the heat source, typically natural gas, which enters through the upper input port 1.1 and flows towards the lower input port 1.2. During operation, the heat source burns or flows within the pipe, transferring heat through the pipe wall to the water in the water heater's inner tank.

[0027] The output inclined tube 2 is also an inclined straight tube, including an upper output port 2.1 and a lower output port 2.2. The upper output port 2.1 is horizontally higher than the lower output port 2.2, similar to the input inclined tube 1, presenting a downward sloping layout. The output inclined tube 2 serves as the outlet channel for exhaust gas or heat medium. The exhaust gas or heat medium after combustion enters through the upper output port 2.1 and flows to the lower output port 2.2 for discharge. When the heat exchange tube stops working, the condensate in the output inclined tube will also flow from the upper output port 2.1 to the lower output port 2.2 due to gravity, eventually being discharged from the heat exchange tube. The output inclined tube 2, like the input inclined tube 1, has an inclined design that ensures condensate does not accumulate inside, avoiding the risk of localized corrosion. After drainage, the output inclined tube can smoothly discharge exhaust gas during the next startup, preventing abnormal pressure or efficiency loss caused by condensate blockage. The inclination of the entire flow channel, from the input inclined tube 1 to the output inclined tube 2, forms a continuous drainage path from input to output, improving the system's durability.

[0028] The upper port 3.1 of connecting pipe 3 is connected to the lower input port 1.2 of the input inclined pipe, and the lower input port 3.2 is connected to the upper output port 2.1 of the output inclined pipe. Typically, connecting pipe 3 is located inside the inner tank of the water heater and is the main area for heat exchange. Connecting pipe 3 connects the input and output inclined pipes, forming a complete V-shaped flow channel, allowing the heat source to flow from the input inclined pipe, then bend through the connecting pipe, and finally enter the output inclined pipe. The connecting pipe can be arc-shaped; by connecting to the inclined input / output pipes, condensate can flow from the connecting pipe to the output inclined pipe, preventing condensate accumulation inside the connecting pipe. In the design, the connecting pipe can also be slightly inclined, or its arc-shaped structure can be used to guide the water flow by gravity. Connecting pipe 3 makes the heat exchange tubes a single unit, achieving efficient heat transfer. Furthermore, as the main heating zone, the well-designed drainage of connecting pipe 3 avoids the negative impact of condensate on heat exchange, maintaining heat exchange efficiency.

[0029] Furthermore, the circumferential cross-section of the input inclined tube 1 is circular. The circumferential cross-section of the output inclined tube 2 is also circular.

[0030] In this design, when condensate forms on the pipe wall, within a circular cross-section, the water film can adhere evenly to the entire lower semicircle and flow smoothly downwards along the inclined pipe wall under gravity. In contrast, non-circular cross-sections, such as square corners, generate additional adhesion forces, such as capillary action, which hinder water film flow and lead to poor drainage. Furthermore, when combustion gas and flue gas flow in a circular pipe, they experience minimal wall friction resistance, resulting in the most uniform flow field distribution and minimizing the formation of eddies or dead zones. Additionally, since combustion flue gas is less dense than air, the inclined design of the inlet inclined pipe 1 and outlet inclined pipe 2 facilitates flue gas discharge.

[0031] Furthermore, the port faces connecting the upper port 3.1 and the lower port 3.2 are located in the same vertical plane.

[0032] The arrangement of the upper port 3.1 and the lower port 3.2 being located in the same vertical plane makes the connecting pipe 3 form a semi-circular structure that bends back, and makes the upper input port 1.1 and the lower output port 2.2 located on the same side. Furthermore, if the lengths of the input inclined pipe 1 and the output inclined pipe 2 are the same, the upper input port 1.1 and the lower output port 2.2 will also be located in the same vertical plane, which facilitates the installation process of the water heater.

[0033] Furthermore, the connecting pipe 3 has a bend 3.3, and on a radial section taken through the center of curvature of the bend 3.3 and along the vertical direction, the cross-sectional profile of the pipe body is composed of an inner semicircle 3.3.1 and an outer semicircle 3.3.2.

[0034] In this context, the bend 3.3 refers to the curved portion of the connecting pipe 3, specifically the V-shaped bend. The inner semicircle 3.3.1 refers to the half-circle closest to the inner side of the bend, and the outer semicircle 3.3.2 refers to the half-circle furthest from the inner side of the bend. In other words, on the vertical section along the bend direction, the cross-sectional shape of the connecting pipe 3 is symmetrical, consisting of two semi-circular profiles: an inner wall and an outer wall. Combined with the overall inclined design of the heat exchange tube and gravity-fed drainage, this smooth, dead-angle-free cross-sectional shape helps condensate flow smoothly downwards by gravity as it passes through the bend, rather than accumulating in corners.

[0035] Furthermore, the inner semicircle 3.3.1 and the outer semicircle 3.3.2 are set concentrically.

[0036] The concentric design ensures that the cross-sectional area of ​​the flow channel remains relatively uniform in the bend, without sudden expansion or contraction. This better guides the fluid smoothly through the bend, reducing the generation of eddies and dead zones. The more uniform flow velocity distribution reduces the likelihood of condensate deposition on the inside of the bend, thus indirectly reducing the risk of exacerbated localized corrosion due to impurity retention.

[0037] Furthermore, the inner diameters of the input inclined tube 1, the output inclined tube 2, and the connecting tube 3 are φ90-φ100, preferably φ96.

[0038] Furthermore, the input inclined tube 1, output inclined tube 2, and inner liner 4 are connected by welding. The input inclined tube 1, output inclined tube 2, and inner liner 4 do not require separate disassembly during maintenance; the welding process makes them a single unit, providing robust support at the connection and ensuring the structural integrity and reliability of the product under long-term use and various operating conditions.

[0039] Furthermore, an ignition head is also provided on the inner wall of the input inclined tube 1. Since the input inclined tube 1 is at the top of the entire heat exchange tube system, the condensate residue is minimal. Placing the ignition head here can ensure dryness to the greatest extent and improve the ignition success rate.

[0040] Furthermore, a condensate collection assembly is installed at the lower output port 2.2. The function of this assembly is to provide final treatment for the condensate collected from the inclined pipe. This assembly can be a short metal or heat-resistant plastic drain nozzle, welded vertically or obliquely downwards or threadedly connected below or to the side of the lower output port 2.2. The condensate flows down the inclined output pipe and is collected and discharged at the lower output port 2.2 by the drain nozzle. A small amount of condensate may drip slowly as droplets or be instantly evaporated and carried away by the high-temperature exhaust gas. Alternatively, a small container can be installed, connected to the lower output port 2.2, with the collection cup positioned below the airflow to collect the condensate and treat it periodically.

[0041] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Furthermore, the terms "vertical," "horizontal," "front," and "rear," etc., mentioned in the embodiments of this utility model indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are only for the convenience of describing this utility model 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 utility model. It should be further noted that, unless otherwise explicitly specified and limited, terms such as "install," "connect," "join," and "fix" in the description should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

Claims

1. A heat exchange tube for a water heater inner tank, said heat exchange tube being configured such that at least a portion of its outer wall is embedded in the inner tank (4), characterized in that, The heat exchange tube includes an input inclined tube (1), an output inclined tube (2), and a connecting tube (3); wherein, the input inclined tube (1) includes an input upper port (1.1) and an input lower port (1.2), and the horizontal position of the input upper port (1.1) is higher than that of the input lower port (1.2); the output inclined tube (2) includes an output upper port (2.1) and an output lower port (2.2), and the horizontal position of the output upper port (2.1) is higher than that of the output lower port (2.2); the connecting tube (3) has a connection upper port (3.1) and a connection lower port (3.2), the connection upper port (3.1) is configured to connect to the input lower port (1.2), and the connection lower port (3.2) is configured to connect to the output upper port (2.1).

2. The heat exchange tube for the inner tank of a water heater according to claim 1, characterized in that, The circumferential cross-section of the input inclined tube (1) is circular.

3. The heat exchange tube for the inner tank of a water heater according to claim 1, characterized in that, The circumferential cross-section of the output inclined tube (2) is circular.

4. The heat exchange tube for the inner tank of a water heater according to claim 1, characterized in that, The port faces of the upper connection port (3.1) and the lower connection port (3.2) are located in the same vertical plane.

5. The heat exchange tube for the inner tank of a water heater according to claim 1, characterized in that, The connecting pipe (3) has a bend (3.3), and on a radial section taken through the center of curvature of the bend (3.3) and along the vertical direction, the cross-sectional profile of the bend pipe body is composed of an inner semicircle (3.3.1) and an outer semicircle (3.3.2).

6. The heat exchange tube for the inner tank of a water heater according to claim 5, characterized in that, The inner semicircle (3.3.1) and the outer semicircle (3.3.2) are concentrically arranged.

7. The heat exchange tube for the inner tank of a water heater according to claim 1, characterized in that, The inner diameters of the input inclined tube (1), the output inclined tube (2), and the connecting tube (3) are φ90-φ100.

8. The heat exchange tube for the inner tank of a water heater according to claim 1, characterized in that, The input inclined tube (1), output inclined tube (2) and inner liner (4) are connected by welding.

9. The heat exchange tube for the inner tank of a water heater according to claim 1, characterized in that, The inner wall of the input inclined tube (1) is also provided with an ignition head.

10. The heat exchange tube for the inner tank of a water heater according to claim 1, characterized in that, A condensate collection component is provided at the lower output port (2.2).

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