Heat exchange tube, heat exchanger including the same, and gas water heater

Abstract

The present invention discloses a heat exchange tube and a heat exchanger and a gas water heater containing the same, belonging to the technical field of gas water heaters. The heat exchange tube includes an outer tube and an inner tube; the outer tube has a partition section and a mixing section in sequence along the direction of fluid flow, and the partition section is provided with an inner tube along the direction of fluid flow. In the partition section, a first channel is formed between the inner tube and the outer tube, and a second channel is formed inside the inner tube. The first channel and the second channel are connected in the mixing section. Due to the obstruction of the inner tube, a temperature difference can be formed between the fluids in the first channel and the second channel, and fluids with different temperatures are mixed, thereby achieving the purpose of reducing the temperature rise when the water supply is cut off. In addition, only the heat exchange tube itself is optimized and improved, and the structure is simple. There is no need to add additional bypass pipes, the equipment volume is not increased, and the installation space of other components is not occupied.

Description

Technical Field

[0001] The present invention relates to the technical field of gas water heaters, and in particular to a heat exchange tube, a heat exchanger comprising the same, and a gas water heater. Background Art

[0002] Currently, common gas water heaters suffer from the "temperature rise when the water is turned off" problem. This means that if the water is turned off and then back on again shortly after a prolonged period of use, the outlet water temperature can easily become excessively high. This is primarily because the heat in the heat exchange tubes cannot dissipate quickly enough, causing the water inside to continue absorbing heat. When the water is turned back on, the outlet water temperature will exceed the set temperature, potentially scalding the user. Gas water heaters using other fluids also suffer from similar temperature rise issues.

[0003] In order to reduce the temperature rise when the water supply is cut off, the main method used in the existing technology is to set a bypass pipe between the water inlet pipe and the water outlet pipe, so that part of the low-temperature water in the water inlet pipe is mixed with the high-temperature water in the water outlet pipe through the bypass pipe to achieve the purpose of reducing the temperature rise. This method also requires the cooperation of a mixing valve, which leads to a complex equipment structure, increases the volume of the equipment, and squeezes the installation space of other components. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of the existing technology of using bypass pipes to reduce the problem of temperature rise during water outage, which leads to complex and bloated structure, and to provide a heat exchange tube that can reduce the problem of temperature rise during water outage without occupying additional installation space, and a heat exchanger and gas water heater containing the same.

[0005] The present invention solves the above technical problems through the following technical solutions:

[0006] A heat exchange tube, comprising an outer tube and an inner tube; the outer tube has a partition section and a mixing section in sequence along the direction of fluid flow, the inner tube is provided in the partition section along the direction of fluid flow, in the partition section, a first channel is formed between the inner tube and the outer tube, the interior of the inner tube is a second channel, and the first channel and the second channel are connected in the mixing section.

[0007] In this solution, the heat exchange tube has a double-layer structure, with an inner tube nested within an outer tube. The outer tube contacts the heat source, transferring heat. A first channel is formed between the inner and outer tubes, and a second channel is formed within the inner tube. The first and second channels are connected in a mixing section. As a result, the heat exchange tube contains a separation section that separates the fluids and a mixing section that mixes the fluids. In actual use, the outer tube in contact with the heat source has a higher temperature. When fluid flow is shut off, or the heat source is turned off, the fluid in the first channel will continue to absorb heat from the outer tube, raising its temperature. However, the heat transfer between the fluid in the second channel and the fluid in the first channel is blocked by the inner tube, limiting the heat absorption and temperature rise of the fluid in the second channel, thereby lowering the temperature of the fluid in the second channel to that of the fluid in the first channel. When fluid flow is resumed, the fluids of different temperatures in the first and second channels mix in the mixing section. The lower-temperature fluid in the second channel neutralizes the higher-temperature fluid in the first channel, thereby reducing the temperature rise during water outage. Through the above-mentioned structural form, only the interior of the heat exchange tube is optimized and improved, the structure is simple, no additional bypass pipes are required, the volume of the equipment is not increased, and the installation space of other components is not occupied.

[0008] Preferably, along the fluid flow direction, the mixing section is formed between the end of the inner tube and the end of the outer tube.

[0009] In this solution, the inner tube is only located in the partition section of the outer tube. By making the length of the inner tube smaller than the length of the outer tube, a mixing section can be formed between the end of the inner tube and the end of the outer tube, without the need for additional pipe equipment to connect the first channel and the second channel.

[0010] Preferably, a fixing device is provided inside the outer tube, and the fixing device is connected to the outer tube and the inner tube respectively, so that the inner tube is suspended in the outer tube.

[0011] In this solution, the inner tube is suspended in the outer tube by a fixing device, which not only helps to form the first channel, but also avoids direct contact between the outer tube and the inner tube for heat exchange, which affects the isolation effect of the inner tube and causes the fluid temperature in the second channel to be too high.

[0012] Preferably, the fixing device includes a radial support and an axial support; the radial support is arranged between the inner tube and the outer tube to limit the radial displacement of the inner tube, and the axial support is arranged at the end of the inner tube to limit the axial displacement of the inner tube.

[0013] In this solution, the inner tube is fixedly suspended in the outer tube by radial supports and axial supports, without radial and axial displacement, thus maintaining the stability of the structure.

[0014] Preferably, the radial support is in a hollow spiral shape and surrounds the outer circumference of the inner tube.

[0015] In this solution, the hollow, spiral radial support member allows the inner tube to be positioned therein, surrounding the inner tube and providing mechanical support. Furthermore, the fluid in the first channel creates a disturbance as it passes over the radial support member, enhancing the heat transfer efficiency of the heat exchange tube during normal use.

[0016] Preferably, the axial support member includes a retaining piece provided at both ends of the inner tube, the retaining piece having a wide portion and a narrow portion, the narrow portion being connected to the end of the inner tube, and the wide portion being engaged with the inner wall of the outer tube.

[0017] In this solution, through the above-mentioned structural form, the inner tube is connected to the outer tube through the retaining piece, so that the inner tube can be suspended in the outer tube; at the same time, the two ends of the inner tube are fixed by the retaining piece, thereby limiting the axial displacement of the inner tube.

[0018] Preferably, it is characterized in that the wall of the inner tube is corrugated.

[0019] In this solution, through the above-mentioned structural form, when the heat exchange tube is in normal use, the fluid passes over the corrugated tube wall of the inner tube, which will destroy the laminar layer at the tube wall of the inner tube, enhance the disturbance, strengthen the heat exchange between the fluid and the tube wall, and ensure the thermal efficiency of the heat exchange tube during normal operation.

[0020] Preferably, the inner tube is made of stainless steel or other materials with a thermal conductivity coefficient lower than that of stainless steel.

[0021] In this solution, stainless steel has excellent corrosion resistance and is a commonly selected material for making heat exchange tubes; using stainless steel or other materials with a thermal conductivity coefficient lower than that of stainless steel to make the inner tube can further reduce the thermal conductivity of the inner tube, thereby better reducing the heat transfer from the fluid in the first channel separated by the inner tube to the fluid in the second channel, thereby improving the effect of reducing the temperature rise when the water supply is cut off.

[0022] A heat exchanger comprises the heat exchange tube as described above.

[0023] A gas water heater comprises the heat exchanger described above.

[0024] The positive progressive effect of the present invention is that: due to the obstruction of the inner tube, the fluid between the first channel and the second channel can form a temperature difference, and the fluids with different temperatures are mixed, thereby achieving the purpose of reducing the temperature rise during water outage. Moreover, only the heat exchange tube itself is optimized and improved, the structure is simple, no additional bypass pipes are required, the equipment volume is not increased, and the installation space of other components is not occupied. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a perspective diagram of the three-dimensional structure of the heat exchange tube according to a preferred embodiment of the present invention.

[0026] Figure 2 This is a schematic diagram of the three-dimensional structure of the heat exchange tube after removing the outer tube of a preferred embodiment of the present invention.

[0027] Figure 3 Schematic cross-sectional view of a heat exchange tube according to a preferred embodiment of the present invention.

[0028] Figure 4 Schematic diagram of the three-dimensional structure of the retaining plate in the heat exchange tube according to a preferred embodiment of the present invention.

[0029] Description of reference numerals:

[0030] Outer tube 100

[0031] Inner tube 200

[0032] Separator 300

[0033] Mixing section 400

[0034] First channel 500

[0035] Second channel 600

[0036] Spring 700

[0037] Card slot 800

[0038] Wide part 801

[0039] Narrow portion 802 DETAILED DESCRIPTION

[0040] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples.

[0041] This embodiment provides a gas water heater, which contains a heat exchanger. The heat exchanger includes multiple heat exchange tubes. High-temperature flue gas is outside the heat exchange tubes, and fluid passes through the heat exchange tubes. The heat of the high-temperature flue gas is transferred to the fluid through the heat exchange tubes, thereby heating the fluid.

[0042] like Figures 1-4 As shown, the heat exchange tube includes an outer tube 100 , an inner tube 200 and a fixing device for suspending the inner tube 200 in the outer tube 100 .

[0043] In the outer tube 100, along the fluid flow direction (such as Figure 3The heat exchange tube has a separating section 300 and a mixing section 400 (in the X direction shown). The separating section 300 is connected to the inner tube 200 by a fixing device along the direction of fluid flow. In the separating section 300, a first channel 500 is formed between the inner tube 200 and the outer tube 100, and a second channel 600 is formed inside the inner tube 200. The ends of the inner tube 200 and the outer tube 100 form a mixing section 400, and the first channel 500 and the second channel 600 are connected in the mixing section 400. Thus, the heat exchange tube has a double-layer structure, with the separating section 300 separating the fluids and the mixing section 400 mixing the fluids. The heat source is the flue gas outside the heat exchange tubes, and heat is transferred from the outside to the inside. While the gas water heater continues to operate, heat continues to transfer from the outside to the inside, keeping the temperatures of the fluids in the inner and outer tubes essentially constant. When the user turns off the faucet, halting fluid flow, the fluid in the first channel 500 continues to absorb heat from the outer tube 100 and the remaining flue gas in the heat exchanger, raising its temperature to a value higher than its original value. However, heat transfer between the fluid in the second channel 600 and the fluid in the first channel 500 is blocked by the inner tube 200, limiting the heat absorption and temperature rise of the fluid in the second channel 600 and, consequently, lowering the temperature of the fluid in the second channel 600 than that of the fluid in the first channel 500. If the faucet is turned on again within a short period of time, the fluids in the heat exchange tubes begin to flow again. The fluids of different temperatures in the first and second channels 500 and 600 mix in the mixing section 400. The lower-temperature fluid in the second channel 600 neutralizes the higher-temperature fluid in the first channel 500, thereby reducing the temperature rise during water shut-off.

[0044] The fixing device is connected to the outer tube 100 and the inner tube 200 respectively, so that the inner tube 200 is suspended in the outer tube 100, which not only helps to form the first channel 500, but also avoids the outer tube 100 and the inner tube 200 from directly contacting each other for heat exchange, thereby affecting the isolation effect of the inner tube 200 and causing the fluid temperature in the second channel 600 to be too high.

[0045] Specifically, the fixing device includes a radial support and an axial support. The radial support is arranged between the inner tube 200 and the outer tube 100 to limit the radial displacement of the inner tube 200. The axial support is arranged at the end of the inner tube 200 to limit the axial displacement of the inner tube 200.

[0046] The axial support member includes retaining plates 800 disposed at both ends of the inner tube 200. The retaining plates 800 have a wide portion 801 and a narrow portion 802. The narrow portion 802 is connected to the end of the inner tube 200, while the wide portion 801 is engaged with the inner wall of the outer tube 100. In this embodiment, the narrow portion 802 is welded to the end of the inner tube 200, and the wide portion 801 is welded to the inner wall of the outer tube 100. Thus, the inner tube 200 is fixedly connected to the outer tube 100 via the retaining plates 800, allowing the ends of the inner tube 200 to be suspended within the outer tube 100. Simultaneously, the ends of the inner tube 200 are secured by the narrow portions 802 of the retaining plates 800, thereby limiting axial displacement of the inner tube 200. In other alternative embodiments, the narrow portion 802 can be bonded to the ends of the inner tube 200, and the wide portion 801 can be engaged with the inner wall of the outer tube 100 to secure the retaining plates 800.

[0047] The radial support member is hollow and spiral, surrounding the outer circumference of the inner tube 200. In this embodiment, the radial support member is a spring 700. The hollow spiral spring 700 allows the inner tube 200 to be positioned therein. The spring 700 surrounds the inner tube 200, providing force support for the inner tube 200 and preventing radial displacement of the inner tube 200. In addition, the fluid in the first channel 500 is disturbed when flowing through the spring 700, enhancing the heat exchange effect of the heat exchange tube during normal use.

[0048] In other optional embodiments, the ends of the spring 700 may be welded to the inner wall of the outer tube 100, and the inner tube 200 may be placed inside the spring 700, so that the spring 700 provides force support for the inner tube 200, allowing the inner tube 200 to be suspended in the outer tube 100. Although the inner tube 200 is radially supported by the spring 700, it is possible for the inner tube 200 to slide out of the spring 700 in the direction of the fluid flow under the action of fluid flow. The retaining plates 800 are welded to the outer periphery of the two ends of the inner tube 200. Specifically, the narrow portion 802 of the retaining plate 800 is welded to the end of the inner tube 200. The end of the spring 700 surrounds the narrow portion 802 of the retaining plate 800 and the end of the inner tube 200 from above, while the wide portion 801 connected to the narrow portion 802 of the retaining plate 800 extends out of the spring 700 and is locked to the outside of the spring 700. When the inner tube 200 has a tendency to slide in a certain direction within the spring 700, the wide portion 801 of the retaining piece 800 located in the opposite direction is stuck on the outside of the spring 700, thereby preventing the inner tube 200 from sliding. The retaining pieces 800 are welded at both ends of the inner tube 200, so that the inner tube 200 is stuck in the spring 700, preventing the inner tube 200 from axial displacement.

[0049] The inner tube 200 may have a corrugated wall. During normal operation, fluid flowing over the corrugated wall of the inner tube 200 disrupts the laminar flow layer at the inner tube 200, increasing the disturbance and enhancing heat transfer between the fluid and the wall, thereby improving the thermal efficiency of the heat exchange tube during normal operation.

[0050] In this embodiment, inner tube 200 is made of stainless steel, which has excellent corrosion resistance and is a commonly used material for heat exchange tubes. In other optional embodiments, inner tube 200 can also be made of other materials with a lower thermal conductivity than stainless steel, thereby further reducing the thermal conductivity of inner tube 200, thereby further reducing heat transfer from the fluid in the first channel 500 separated by inner tube 200 to the fluid in the second channel 600, thereby improving the effect of reducing the temperature rise during water outage.

[0051] By installing the inner tube 200 in the outer tube 100, the water outage temperature rise can be reduced by optimizing and improving the interior of the heat exchange tube. The structure is simple, no additional bypass pipes are required, the volume of the equipment is not increased, and the installation space of other components is not occupied.

[0052] The "fluid" described in this embodiment is not limited to water. When other types of fluids need to be heated, the gas water heater, or heat exchanger, or heat exchange tube provided in this embodiment is also applicable and can also solve the same problem of temperature rise due to water outage.

[0053] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0054] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A heat exchange tube, characterized in that: The heat exchange tube includes an outer tube and an inner tube; The outer tube has a separation section and a mixing section in sequence along the fluid flow direction, and the inner tube is provided in the separation section along the fluid flow direction. In the separation section, a first channel is formed between the inner tube and the outer tube, the interior of the inner tube is a second channel, and the first channel and the second channel are connected in the mixing section; Along the fluid flow direction, the mixing section is formed between the end of the inner tube and the end of the outer tube; A fixing device is provided inside the outer tube, and the fixing device is connected to the outer tube and the inner tube respectively, so that the inner tube is suspended in the outer tube; The fixing device includes a radial support member and an axial support member; the radial support member is arranged between the inner tube and the outer tube to limit the radial displacement of the inner tube, and the axial support member is arranged at the end of the inner tube to limit the axial displacement of the inner tube.

2. The heat exchange tube according to claim 1, characterized in that The radial support is in a hollow spiral shape and surrounds the outer circumference of the inner tube.

3. The heat exchange tube according to claim 1, wherein: The axial support member includes a retaining piece provided at both ends of the inner tube, the retaining piece having a wide portion and a narrow portion, the narrow portion being connected to the end of the inner tube, and the wide portion being engaged with the inner wall of the outer tube.

4. The heat exchange tube according to claim 1, wherein The tube wall of the inner tube is corrugated.

5. The heat exchange tube according to claim 1, wherein The inner tube is made of stainless steel or other materials with a thermal conductivity coefficient lower than that of stainless steel.

6. A heat exchanger, characterized in that: The heat exchanger comprises the heat exchange tube according to any one of claims 1 to 5.

7. A gas water heater, characterized in that: The gas water heater includes the heat exchanger according to claim 6.

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