A secondary heat exchanger for a gas heating furnace

Abstract

The present invention discloses a secondary heat exchanger for a gas heating furnace, comprising an outer shell, an inner water box, a plurality of heat exchange tubes, a water inlet interface, a water outlet interface, and a flue gas rectifying plate. A flue gas inlet and a flue gas outlet are provided on the outer shell, and both the flue gas inlet and the flue gas outlet are connected to the inner cavity of the outer shell. The outer ends of some heat exchange tubes are connected to the water inlet interface, and the inner ends are connected to the inner water box; the outer ends of other heat exchange tubes are connected to the water outlet interface, and the inner ends are connected to the inner water box. A flue gas rectifying plate provided with multiple through holes separates the inner cavity of the outer shell. The aforementioned two parts of heat exchange tubes are both located in the inner cavity of the outer shell, and are located in two different separated chambers, forming a flow channel from the flue gas inlet to the two separated chambers in sequence and then to the flue gas outlet. By providing a flue gas rectifying plate, the flue gas flows through more heat exchange tubes in the secondary heat exchanger cavity, and the flow in the heat exchange area is more uniform, thereby enabling the flue gas to flow smoothly and improve the heat exchange efficiency.

Description

Technical Field

[0001] The present invention belongs to the field of heat exchangers, and in particular relates to a secondary heat exchanger for a gas heating furnace. Background Art

[0002] The secondary heat exchanger of the existing gas heating furnace is affected by factors such as the internal structure and the speed and direction of the flue gas flow. The flow inside the secondary heat exchanger is not uniform, and dead zones are easily formed, resulting in uneven heat exchange in the secondary heat exchanger, the heat exchanger cannot be fully utilized, and the overall heat exchange efficiency is low.

[0003] In view of this, the present invention is proposed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a secondary heat exchanger for a gas heating furnace, so that the flue gas flows through more heat exchange tubes in the secondary heat exchanger cavity, the flow in the heat exchange area is more uniform, and the heat exchange efficiency is improved.

[0005] In order to solve the above technical problems, the basic concept of the technical solution adopted by the present invention is:

[0006] A secondary heat exchanger for a gas heating furnace comprises an outer shell, an inner water box, heat exchange pipes, a water inlet interface, a water outlet interface and a flue gas rectifier plate. The outer shell is provided with a flue gas inlet and a flue gas outlet connected to the inner cavity of the outer shell; the flue gas rectifier plate is provided with a plurality of through holes, and the flue gas rectifier plate divides the inner cavity of the outer shell into a plurality of chambers; the heat exchange pipes comprise a plurality of heat exchange pipes, the outer ends of some heat exchange pipes are connected to the water inlet interface, the outer ends of other heat exchange pipes are connected to the water outlet interface, and the inner ends of all heat exchange pipes are connected to the inner water box; the two parts of heat exchange pipes are respectively located in two different separated chambers.

[0007] Furthermore, it also includes an inlet and outlet water box, which includes an independent water inlet chamber and a water outlet chamber. The water inlet chamber is connected to the water inlet interface, and the water outlet chamber is connected to the water outlet interface. The outer ends of a part of the heat exchange tubes are connected to the water inlet chamber and then connected to the water inlet interface, and the inner ends are connected to the inner water box. The outer ends of another part of the heat exchange tubes are connected to the water outlet chamber and then connected to the water outlet interface, and the inner ends are connected to the inner water box.

[0008] By providing a water inlet and outlet box, and dividing the water inlet and outlet box into a mutually independent water inlet chamber and water outlet chamber, water entering from the water inlet interface first enters the water inlet chamber of the water inlet and outlet box, and then enters the heat exchange tube connected to the water inlet chamber, thereby ensuring that the water entering the heat exchange tube can be evenly distributed, and the problem of poor water flow into the heat exchange tube and insufficient water volume will not occur. Similarly, water exiting the heat exchange tube first enters the water outlet chamber of the water inlet and outlet box, and then flows from the water outlet chamber to the water outlet interface, thus eliminating the problem of poor and uneven water flow from the heat exchange tube due to a small outlet interface causing a small connection surface between the heat exchange tube and the water outlet interface.

[0009] Furthermore, all heat exchange tubes are arranged in parallel to form a heat exchange tube bundle. The heat exchange tube connected to the water inlet cavity is in the upper part of the shell cavity, and the heat exchange tube connected to the water outlet cavity is in the lower part of the shell cavity, and the two parts of the heat exchange tubes are separated by the flue gas rectifier plate.

[0010] Multiple heat exchange tubes are arranged in parallel, allowing flue gas to pass smoothly through the gaps between them, heating the tubes. The multiple heat exchange tubes are divided into two parts: one is the water inlet heat exchange tube connected to the water inlet cavity, and the other is the water outlet heat exchange tube connected to the water outlet cavity. The heat exchange tube connected to the water inlet cavity is located at the upper part of the shell cavity, while the heat exchange tube connected to the water outlet cavity is located at the lower part of the shell cavity. Flue gas entering the shell cavity from the lower flue gas inlet can first heat the outlet heat exchange tube at the lower part of the shell cavity, raising the temperature of the water in the outlet heat exchange tube. The temperature of the flue gas, which has lost some heat, drops, and the flue gas flows further upward, heating the water in the water inlet heat exchange tube at the upper part of the shell cavity, raising the temperature of the water in the water inlet heat exchange tube. Because the two sections of heat exchange tubes are separated by the flue gas rectifying plate, the flue gas can first gather in the lower part of the shell cavity to fully heat the outlet heat exchange tube, raising its temperature. After flowing through the flue gas rectifying plate, it flows upward into the upper part of the shell cavity to heat the inlet heat exchange tube. Because of the presence of the flue gas rectifying plate, the flue gas flow is blocked and can first gather in the lower part of the shell cavity, and then flow upward through the holes of the flue gas rectifying plate, achieving long-term contact and heat exchange with the outlet heat exchange tube.

[0011] Furthermore, an opening is provided on one side of the shell, and the inner water box and the heat exchange tube are pushed into the inner cavity of the shell from the opening on one side of the shell. The inlet and outlet water boxes are detachably fixed on the shell and the inlet and outlet water boxes close the opening on this side of the shell.

[0012] Because the outer shell needs to be sealed to allow smoke to enter the inner cavity of the shell through the smoke inlet and heat the water in the heat exchange tubes before being discharged through the smoke outlet, the inner water box and heat exchange tubes need to have an opening to enter the inner cavity of the shell when they are installed into the inner cavity of the shell, and this opening is then closed after installation. In the present invention, the water inlet and outlet water box is detachably fixed to the outer shell and the water inlet and outlet water box seals the opening on this side of the outer shell, thereby enclosing the inner water box and heat exchange tubes in the inner cavity of the shell. In addition, a sealing ring is provided at the opening to enhance the sealing effect when the water inlet and outlet water box seals the opening on this side of the outer shell.

[0013] Furthermore, the flue gas rectifying plate includes a lower vertical plate, a middle horizontal plate, an upper vertical plate, and an upper inclined plate. One side of the middle horizontal plate is connected to the top end of the lower vertical plate, and the other side of the middle horizontal plate is connected to the bottom end of the upper vertical plate. One end of the upper inclined plate is connected to the top end of the upper vertical plate, and the other end of the upper inclined plate extends away from the flue gas inlet.

[0014] By providing a flue gas rectifying plate and arranging it into a structure connected by a lower vertical plate, a middle horizontal plate, an upper vertical plate, and an upper inclined plate, the upper vertical plate and the lower vertical plate are respectively arranged above and below the middle horizontal plate, and the middle horizontal plate divides the heat exchange tube into upper and lower parts. One end of the upper inclined plate is connected to the top of the upper vertical plate, and the other end of the upper inclined plate extends to the side away from the flue gas inlet. This structure allows the flue gas to enter the space separated by the upper vertical plate and the upper inclined plate when it flows to the rear end of the shell cavity after entering the flue gas inlet and rises. In this way, the flue gas flows to the rear end of the water inlet heat exchange tube and is discharged from the rear end to the flue gas outlet. Therefore, the rear end of the water outlet heat exchange tube and the rear end of the water inlet heat exchange tube can both have flue gas flow for heating, and no local stagnant space is formed to reduce heating efficiency, thereby ensuring smooth flue gas flow and improving heat exchange efficiency.

[0015] Furthermore, a plurality of holes are provided on the lower vertical plate, the middle horizontal plate and the upper vertical plate of the flue gas rectifying plate.

[0016] The exhaust gas of the present invention is cooled by the help of the exhaust fan, and the exhaust gas of the exhaust fan is cooled by the help of the exhaust fan.

[0017] Furthermore, a side end of the upper inclined plate facing away from the flue gas inlet extends downward.

[0018] Such a structural design allows the flue gas to flow upwards into the space formed by the upper vertical plate and the upper inclined plate, and then flow smoothly along the oblique angle of the upper inclined plate through the holes of the upper vertical plate and into the shell chamber where the water inlet heat exchange tube is located, thereby utilizing the flow of flue gas without causing local stagnation of flue gas flow.

[0019] Furthermore, the lower vertical plate of the flue gas rectifying plate is adjacent to and faces the flue gas inlet, and multiple rows of holes are arranged on the lower vertical plate. The hole diameter of the middle hole in each row is small, and the hole diameters of the holes on both sides are large.

[0020] Since the lower vertical plate of the flue gas rectifier plate is adjacent to and faces the flue gas inlet, but the area of ​​the lower vertical plate is larger than the diameter of the flue gas inlet, in order to allow the flue gas to flow more evenly into the shell chamber where the outlet water heat exchange tube is located after entering the shell chamber from the flue gas inlet, multiple rows of holes are provided on the lower vertical plate. The aperture of the middle hole in each row of holes is small, and the aperture of the holes on both sides is large. In this way, the flue gas can flow more evenly into the shell chamber where the outlet water heat exchange tube is located, thereby achieving uniform heating.

[0021] Furthermore, there is a certain distance between the lower vertical plate of the flue gas rectifying plate and the flue gas inlet.

[0022] To ensure better flue gas flow into the outer shell chamber where the outlet heat exchange tubes are located, a certain distance is created between the lower vertical plate of the flue gas rectifier and the flue gas inlet. This allows the flue gas to first enter the space between the flue gas inlet and the lower vertical plate and fill this space. The area filled by the flue gas in this space is larger than the diameter of the flue gas inlet, allowing it to more easily enter the outer shell chamber where the outlet heat exchange tubes are located, resulting in optimal flue gas flow and heat exchange.

[0023] Furthermore, there is a flue gas flow duct from the flue gas inlet to the lower vertical plate to the shell chamber where the heat exchange tube connected to the water outlet chamber is located to the middle horizontal plate, the upper vertical plate and then to the shell chamber where the heat exchange tube connected to the water inlet chamber is located to the flue gas outlet.

[0024] The flue gas flow channel formed by the structural setting enables the flue gas flow to better cover the space where the water outlet heat exchange pipe and the water inlet heat exchange pipe are located, heating the water in the heat exchange pipe and achieving a better heat exchange effect.

[0025] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art.

[0026] A secondary heat exchanger for a gas heating furnace comprises an outer shell, an inner water box, a plurality of heat exchange tubes, a water inlet interface, a water outlet interface, and a flue gas rectifier plate. The outer shell is provided with a flue gas inlet and a flue gas outlet, and both the flue gas inlet and the flue gas outlet are connected to the inner cavity of the outer shell. The outer ends of some heat exchange tubes are connected to the water inlet interface, and the inner ends are connected to the inner water box; the outer ends of other heat exchange tubes are connected to the water outlet interface, and the inner ends are connected to the inner water box. A flue gas rectifier plate provided with a plurality of through holes separates the inner cavity of the outer shell. The aforementioned two parts of heat exchange tubes are both located in the inner cavity of the outer shell, and are located in two different separated chambers, forming a flow channel from the flue gas inlet to the flue gas outlet after passing through the two separated chambers in sequence. The present invention provides a secondary heat exchanger for a gas heating furnace, in which flue gas flows from a flue gas inlet into the inner cavity of the shell, and then flows into the shell cavity where the water outlet heat exchange pipe is located through the holes in the lower vertical plate; the flue gas entering the shell cavity where the water outlet heat exchange pipe is located, a part of the flue gas then flows upward through the holes in the middle horizontal plate and enters the shell cavity where the water inlet heat exchange pipe is located, and the other part of the flue gas flows to the rear end of the water outlet heat exchange pipe and then flows upward to enter the space formed by the upper vertical plate and the upper inclined plate, and then enters the shell cavity where the water inlet heat exchange pipe is located through the holes in the upper vertical plate. In this way, the flue gas flows to the rear end of the water inlet heat exchange pipe and is discharged to the flue gas outlet from the rear end, so that flue gas can flow to heat the rear ends of the water outlet heat exchange pipe and the water inlet heat exchange pipe, so that the flue gas can flow through more heat exchange pipes in the secondary heat exchanger cavity, and the flow in the heat exchange area is more uniform, thereby making the flue gas flow smooth and improving the heat exchange efficiency.

[0027] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are part of the present invention and are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but do not constitute an undue limitation of the present invention. Obviously, the drawings described below are only some embodiments. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without inventive effort. In the accompanying drawings:

[0029] Figure 1 This is a schematic diagram of an explosion of a secondary heat exchanger of a gas heating furnace according to the present invention;

[0030] Figure 2 This is a schematic diagram of the interior of a secondary heat exchanger of a gas heating furnace according to the present invention;

[0031] Figure 3 It is a schematic diagram of a secondary heat exchanger of a gas heating furnace according to the present invention;

[0032] Figure 4 This is a schematic diagram of a flue gas rectifier plate of a secondary heat exchanger of a gas heating furnace according to the present invention;

[0033] Figure 5 It is a schematic diagram of the water circuit structure of a secondary heat exchanger of a gas heating furnace of the present invention.

[0034] In the figure: 1, outer shell 2, sealing ring 3, inner water box 4, heat exchange tube 5, flue gas rectifier plate 6, water inlet interface 7, water inlet and outlet water box 8, water outlet interface 9, water inlet chamber 10, water outlet chamber 11, flue gas outlet 12, flue gas inlet 13, condensate outlet 14, rectifying hole 15, lower vertical plate 16, middle horizontal plate 17, upper vertical plate 18, upper inclined plate.

[0035] It should be noted that these drawings and textual descriptions are not intended to limit the conceptual scope of the present invention in any way, but rather to illustrate the concept of the present invention for those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The following embodiments are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0037] In the description of the present invention, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0038] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; and direct or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0039] Combine Figures 1 to 5As shown, a secondary heat exchanger for a gas heating furnace according to the present invention comprises an outer shell 1, an inner water box 3, a plurality of heat exchange tubes 4, a water inlet interface 6, a water outlet interface 8 and a flue gas rectifying plate 5. A flue gas inlet 12 and a flue gas outlet 11 are provided on the outer shell 1, and both the flue gas inlet 12 and the flue gas outlet 11 are connected to the inner cavity of the outer shell 1. The outer ends of a portion of the heat exchange tubes 4 are connected to the water inlet interface 6, and the inner ends are connected to the inner water box 3; the outer ends of the other portion of the heat exchange tubes 4 are connected to the water outlet interface 8, and the inner ends are connected to the inner water box 3. A flue gas rectifying plate 5 provided with a plurality of through holes separates the inner cavity of the outer shell. The aforementioned two portions of heat exchange tubes are both located in the inner cavity of the outer shell, and are located in two different separated chambers; forming a flow channel from the flue gas inlet to the flue gas outlet after passing through the two separated chambers in sequence.

[0040] The present invention provides a secondary heat exchanger for a gas heating furnace, which also includes an inlet and outlet water box 7. The inlet and outlet water box 7 includes an independent water inlet chamber 9 and a water outlet chamber 10. The water inlet chamber 9 is connected to the water inlet interface 6, and the water outlet chamber 10 is connected to the water outlet interface 8. The outer ends of a portion of the heat exchange tubes 4 are connected to the water inlet chamber 9 and then communicated with the water inlet interface 6, and the inner ends are communicated with the inner water box 3. The outer ends of the other portion of the heat exchange tubes 4 are connected to the water outlet chamber 10 and then communicated with the water outlet interface 8, and the inner ends are communicated with the inner water box 3.

[0041] By providing an inlet and outlet water box 7, which is divided into an independent water inlet chamber and a water outlet chamber, water entering from the water inlet interface 6 first enters the water inlet chamber 9 of the inlet and outlet water box 7, and then enters the heat exchange tube 4 connected to the water inlet chamber, thereby ensuring that the water entering the heat exchange tube can be evenly distributed, and the problem of poor water flow and insufficient water volume in the heat exchange tube will not occur. Similarly, water exiting the heat exchange tube 4 first enters the water outlet chamber 10 of the inlet and outlet water box 7, and then flows from the water outlet chamber 10 to the water outlet interface 8. In this way, the problem of poor and uneven water flow from the heat exchange tube due to a small connection surface between the heat exchange tube and the water outlet interface 8 will not occur.

[0042] Combine Figure 1 、 2 As shown in Figure 5, all heat exchange tubes 4 are arranged in parallel to form a heat exchange tube bundle. The heat exchange tubes 4 connected to the water inlet cavity 9 are in the upper part of the shell cavity, and the heat exchange tubes connected to the water outlet cavity 10 are in the lower part of the shell cavity, and the two parts of the heat exchange tubes 4 are separated by the flue gas rectifier plate 5.

[0043] The multiple heat exchange tubes 4 are arranged in parallel so that the flue gas can pass smoothly through the gaps between the heat exchange tubes, heating the heat exchange tubes. The multiple heat exchange tubes are divided into two parts: one is a water inlet heat exchange tube connected to the water inlet cavity, and the other is a water outlet heat exchange tube connected to the water outlet cavity. The heat exchange tube connected to the water inlet cavity is located at the upper part of the shell cavity, and the heat exchange tube connected to the water outlet cavity is located at the lower part of the shell cavity. The flue gas entering the shell cavity from the lower flue gas inlet can first heat the water outlet heat exchange tube at the lower part of the shell cavity, raising the temperature of the water in the water outlet heat exchange tube. The temperature of the flue gas that has lost some heat drops, and the flue gas further flows upward, heating the water in the water inlet heat exchange tube at the upper part of the shell cavity, thereby heating the water temperature in the water inlet heat exchange tube. Because the two sections of heat exchange tubes are separated by the flue gas rectifying plate, the flue gas can first gather in the lower part of the shell cavity to fully heat the outlet heat exchange tube, raising its temperature. After flowing through the flue gas rectifying plate, it flows upward into the upper part of the shell cavity to heat the inlet heat exchange tube. Because of the presence of the flue gas rectifying plate, the flue gas flow is blocked and can first gather in the lower part of the shell cavity, and then flow upward through the holes of the flue gas rectifying plate, achieving long-term contact and heat exchange with the outlet heat exchange tube.

[0044] Combine Figure 1 、 2 As shown, the housing 1 has an opening on one side. The inner water box 3 and heat exchange tube 4 are pushed into the inner cavity of the housing through the opening on one side of the housing. The inlet and outlet water box 7 is detachably fixed to the housing 1 and seals the opening on this side of the housing 1. The end of the heat exchange tube closest to the opening is the outer end, and the end closest to the inner water box is the inner end.

[0045] Because the outer shell 1 needs to be sealed to allow smoke to enter the inner cavity of the outer shell through the smoke inlet 12 to heat the water in the heat exchange tube 4, and then be discharged through the smoke outlet 11, the inner water box 3 and the heat exchange tube 4 need to have an opening to enter the inner cavity of the outer shell when they are installed into the inner cavity of the outer shell, and this opening is then closed after installation. In the present invention, the water inlet and outlet water box 7 is detachably fixed to the outer shell 1 and the water inlet and outlet water box seals this side opening of the outer shell, thereby enclosing the inner water box and the heat exchange tube in the inner cavity of the outer shell. In addition, for better sealing, a sealing ring 2 is also provided at the opening, thereby achieving a better sealing effect when the water inlet and outlet water box 7 seals this side opening of the outer shell.

[0046] Combine Figure 2 、 4 As shown, the flue gas rectifying plate 5 includes a lower vertical plate 15, a middle horizontal plate 16, an upper vertical plate 17, and an upper inclined plate 18. One side of the middle horizontal plate 16 is connected to the top end of the lower vertical plate 15, and the other side of the middle horizontal plate 16 is connected to the bottom end of the upper vertical plate 17. One end of the upper inclined plate 18 is connected to the top end of the upper vertical plate 17, and the other end of the upper inclined plate 18 extends away from the flue gas inlet 13.

[0047] The flue gas rectifying plate 5 is provided in a structure connected by a lower vertical plate 15, a middle horizontal plate 16, an upper vertical plate 17, and an upper inclined plate 18. The upper and lower vertical plates are respectively provided above and below the middle horizontal plate. The middle horizontal plate divides the heat exchange tubes 4 into upper and lower parts. One end of the upper inclined plate 18 is connected to the top of the upper vertical plate, and the other end of the upper inclined plate 18 extends away from the flue gas inlet 12. The upper inclined plate 18 serves as a guide plate. This structure allows the flue gas, after entering the flue gas inlet and flowing toward the rear end of the shell cavity, to enter the space separated by the upper vertical plate 17 and the upper inclined plate 18. The flue gas then flows to the rear end of the water inlet heat exchange tube and is discharged from the rear end to the flue gas outlet. This allows the flue gas to flow to the rear end of both the water outlet heat exchange tube and the water inlet heat exchange tube for heating, eliminating the formation of local stagnant spaces that would reduce heating efficiency. This ensures smooth flue gas flow and improved heat exchange efficiency.

[0048] like Figure 4 As shown, a plurality of holes serving as rectifying holes 14 are provided on the lower vertical plate 15 , the middle horizontal plate 16 , and the upper vertical plate 17 of the flue gas rectifying plate 5 .

[0049] A plurality of holes are provided on the lower vertical plate 15, the middle horizontal plate 16 and the upper vertical plate 17 of the flue gas rectifier plate, so that the flue gas flows from the flue gas inlet 12 into the inner cavity of the shell, and then flows into the shell cavity where the outlet heat exchange pipe is located through the holes of the lower vertical plate 15; the flue gas entering the shell cavity where the outlet heat exchange pipe is located, part of the flue gas flows upward through the holes on the middle horizontal plate 16 and enters the shell cavity where the inlet heat exchange pipe is located, and the other part of the flue gas flows to the rear end of the outlet heat exchange pipe and then flows upward to enter the upper vertical plate 1 7 and the space formed by the upper inclined plate 18, and then enters the shell chamber where the water inlet heat exchange tube is located through the hole on the upper vertical plate 17, so that the flue gas flows to the rear end of the water inlet heat exchange tube and is discharged to the flue gas outlet 11 from the rear end, so that the rear end of the water outlet heat exchange tube and the rear end of the water inlet heat exchange tube can both have flue gas flow for heating, and no local stagnant space will be formed to cause low heating efficiency. The flue gas flow can be adjusted by adjusting the rectifying hole 14, so that the flue gas flow can be smooth and the heat exchange efficiency can be improved.

[0050] Combine Figure 2 、 4 As shown, the upper inclined plate 18 extends downwardly from one side end thereof facing away from the flue gas inlet 12 .

[0051] Such a structural design allows the flue gas to flow upwards and enter the space formed by the upper vertical plate 17 and the upper inclined plate 18, and then flow smoothly along the oblique angle of the upper inclined plate 18 through the rectifying hole 14 of the upper vertical plate 17 and enter the shell chamber where the water inlet heat exchange tube is located, thereby utilizing the flow of flue gas without causing local stagnation of flue gas.

[0052] Combine Figure 3 、4 As shown, the lower vertical plate 15 of the flue gas rectifying plate is adjacent to and faces the flue gas inlet 12. The lower vertical plate 15 is provided with multiple rows of holes as rectifying holes 14. The hole diameter in the middle of each row of holes is small, and the hole diameters on both sides are large.

[0053] Since the lower vertical plate 15 of the flue gas rectifying plate 5 is adjacent to and faces the flue gas inlet, but the area of ​​the lower vertical plate is larger than the diameter of the flue gas inlet, in order to allow the flue gas to flow more evenly into the shell chamber where the outlet water heat exchange tube is located after entering the shell chamber from the flue gas inlet, multiple rows of holes are provided on the lower vertical plate 15. The aperture of the middle hole in each row of holes is small, and the aperture of the holes on both sides is large. In this way, the flue gas can flow more evenly into the shell chamber where the outlet water heat exchange tube is located, thereby achieving uniform heating.

[0054] Combine Figure 2 、 4 As shown, there is a certain distance between the lower vertical plate 15 of the flue gas rectifying plate 5 and the flue gas inlet 12 .

[0055] To better facilitate the entry of flue gas into the housing chamber housing the outlet heat exchange tubes, a certain distance is maintained between the lower vertical plate 15 of the flue gas rectifying plate 5 and the flue gas inlet 12. This allows the flue gas to first enter the space between the flue gas inlet and the lower vertical plate and fill this space. This allows the flue gas to occupy a larger area than the diameter of the flue gas inlet, allowing it to more effectively enter the housing chamber housing the outlet heat exchange tubes, resulting in optimal flue gas flow and heat exchange.

[0056] In this embodiment, the flue gas rectifying plate 5 is mounted on the inner side of the housing through a slot. In other embodiments, the flue gas rectifying plate 5 can be fixed to the inlet and outlet water box 7 and the inner water box 3 by welding. The flue gas rectifying plate 5 can be integral as a whole or the parts can be separable.

[0057] The flue gas rectifying plate 5 is designed with rectifying holes 14, which can be adjusted to adjust the flue gas flow by adjusting the position, number, and size of the holes. The central horizontal plate 16 of the flue gas rectifying plate 5 divides the interior of the secondary heat exchanger into a lower convection heat exchange zone and an upper condensation zone. These zones are the lower region of the shell cavity where the heat exchange tubes connected to the water outlet chamber are located, and the upper region of the shell cavity where the heat exchange tubes 4 connected to the water inlet chamber are located. After entering the secondary heat exchanger, the flue gas is rectified by the flue gas rectifying plate 5 and then passes through the convection heat exchange zone. The water in the heat exchange tubes in this convection heat exchange zone is at a higher temperature than that in the condensation zone, and absorbs heat from the flue gas primarily through convection heat transfer. After being rectified by the rectifying holes 14 of the flue gas rectifying plate 5, the flue gas enters the condensation zone. After passing through the convection heat exchange zone, the flue gas's temperature decreases. When the flue gas flows through the cooler water surfaces of the heat exchange tubes 4 in the condensation zone, water vapor in the flue gas is more likely to condense. Therefore, a condensation water outlet 13 is provided at the bottom of the shell. The heat released by condensation is absorbed by water, further improving the heat exchange efficiency.

[0058] The secondary heat exchanger of a gas heating furnace according to the present invention has a flue gas flow passage extending from a flue gas inlet 12 to a lower vertical plate 15, to the outer shell chamber containing the heat exchange tubes connected to the water outlet chamber 10, to a middle horizontal plate 16, to an upper vertical plate 17, and then to the outer shell chamber containing the heat exchange tubes connected to the water inlet chamber 9, to a flue gas outlet 11. The flue gas flow passage formed by the structural arrangement allows the flue gas flow to better cover the space where the water outlet and water inlet heat exchange tubes are located, heating the water in the heat exchange tubes 4 and achieving a better heat exchange effect.

[0059] The present invention provides a secondary heat exchanger for a gas heating furnace, comprising an outer shell, an inner water box, a plurality of heat exchange tubes, a water inlet interface, a water outlet interface, and a flue gas rectifier plate. A flue gas inlet and a flue gas outlet are provided on the outer shell, and both the flue gas inlet and the flue gas outlet are connected to the inner cavity of the outer shell. The outer ends of one portion of the heat exchange tubes are connected to the water inlet interface, and the inner ends are connected to the inner water box; the outer ends of another portion of the heat exchange tubes are connected to the water outlet interface, and the inner ends are connected to the inner water box. A flue gas rectifier plate provided with a plurality of through holes separates the inner cavity of the outer shell. The aforementioned two portions of heat exchange tubes are both located in the inner cavity of the outer shell, and are located in two different separated chambers, forming a flow channel from the flue gas inlet to the flue gas outlet after passing through the two separated chambers in sequence. The present invention provides a secondary heat exchanger for a gas heating furnace, in which flue gas flows from a flue gas inlet into the inner cavity of the shell, and then flows into the shell cavity where the water outlet heat exchange pipe is located through the holes in the lower vertical plate; the flue gas entering the shell cavity where the water outlet heat exchange pipe is located, a part of the flue gas then flows upward through the holes in the middle horizontal plate and enters the shell cavity where the water inlet heat exchange pipe is located, and the other part of the flue gas flows to the rear end of the water outlet heat exchange pipe and then flows upward to enter the space formed by the upper vertical plate and the upper inclined plate, and then enters the shell cavity where the water inlet heat exchange pipe is located through the holes in the upper vertical plate. In this way, the flue gas flows to the rear end of the water inlet heat exchange pipe and is discharged to the flue gas outlet from the rear end, so that flue gas can flow to heat the rear ends of the water outlet heat exchange pipe and the water inlet heat exchange pipe, so that the flue gas can flow through more heat exchange pipes in the secondary heat exchanger cavity, and the flow in the heat exchange area is more uniform, thereby making the flue gas flow smooth and improving the heat exchange efficiency.

[0060] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with this patent can make slight changes or modifications to equivalent embodiments of equivalent changes using the above-mentioned technical contents without departing from the scope of the technical solution of the present invention. The implementation schemes in the above-mentioned embodiments can also be further combined or replaced. However, any simple modifications, equivalent changes and modifications made to the above-mentioned embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A secondary heat exchanger for a gas heating furnace, characterized by: It includes the outer shell, inner water box, heat exchange tube, water inlet interface, water outlet interface and flue gas rectifier plate. The shell is provided with a smoke inlet and a smoke outlet communicating with the inner cavity of the shell; A flue gas rectifying plate is provided with a plurality of through holes, and the flue gas rectifying plate divides the inner cavity of the shell into a plurality of chambers; The heat exchange tubes include a plurality of heat exchange tubes, the outer ends of some heat exchange tubes are connected to the water inlet interface, the outer ends of other heat exchange tubes are connected to the water outlet interface, and the inner ends of all heat exchange tubes are connected to the inner water box; The two parts of heat exchange tubes are respectively located in two different separation chambers and the two parts of heat exchange tubes are separated by the middle horizontal plate, upper vertical plate and upper inclined plate of the flue gas rectifier plate; multiple holes are set on the middle horizontal plate and the upper vertical plate; The middle horizontal plate is located between the two parts of the heat exchange tubes. One side of the middle horizontal plate is connected to the bottom end of the upper vertical plate. The upper vertical plate is located between the entire heat exchange tube in the upper chamber and the vertical wall of the shell away from the flue gas inlet. There is a gap between the upper vertical plate and the vertical wall of the shell to form a flue gas channel. One end of the upper inclined plate is connected to the top end of the upper vertical plate, and the other end of the upper inclined plate extends downward to the side away from the smoke inlet and is connected to the aforementioned vertical wall of the shell.

2. A secondary heat exchanger for a gas heating furnace according to claim 1, characterized in that: It also includes a water inlet and outlet box, which includes an independent water inlet cavity and a water outlet cavity. The water inlet cavity is connected to the water inlet interface, and the water outlet cavity is connected to the water outlet interface. The outer ends of some heat exchange tubes are connected to the water inlet cavity and then communicated with the water inlet interface, and the inner ends are communicated with the inner water box. The outer ends of the other part of the heat exchange tubes are connected to the water outlet cavity and further communicated with the water outlet interface, and the inner ends are communicated with the inner water box.

3. A secondary heat exchanger for a gas heating furnace according to claim 2, characterized in that: All heat exchange tubes are arranged in parallel to form a heat exchange tube bundle. The heat exchange pipe connected with the water inlet cavity is located at the upper part of the inner cavity of the shell, and the heat exchange pipe connected with the water outlet cavity is located at the lower part of the inner cavity of the shell.

4. A secondary heat exchanger for a gas heating furnace according to claim 2, characterized in that: An opening is provided on one side of the shell, and the inner water box and the heat exchange tube are pushed into the inner cavity of the shell from the opening on one side of the shell. The inlet and outlet water boxes are detachably fixed on the shell and the inlet and outlet water boxes close the opening on this side of the shell.

5. The secondary heat exchanger for a gas heating furnace according to claim 1, characterized in that: The flue gas straightening plate also includes a lower vertical plate, The other side of the middle horizontal board is connected to the top of the lower vertical board.

6. A secondary heat exchanger for a gas heating furnace according to claim 2, characterized in that: The lower vertical plate of the flue gas rectifying plate is provided with a plurality of holes.

7. A secondary heat exchanger for a gas heating furnace according to claim 6, characterized in that: The lower vertical plate of the flue gas rectifying plate is adjacent to and faces the flue gas inlet. A plurality of rows of holes are arranged on the lower vertical plate. The aperture of the middle hole in each row is small, and the apertures of the holes on both sides are large.

8. The secondary heat exchanger for a gas heating furnace according to claim 6, characterized in that: There is a certain distance between the lower vertical plate of the flue gas rectifier and the flue gas inlet.

9. The secondary heat exchanger for a gas heating furnace according to claim 6, characterized in that: It has a flue gas flow channel from the flue gas inlet to the lower vertical plate to the shell chamber where the heat exchange tube connected to the water outlet chamber is located to the middle horizontal plate, the upper vertical plate, and then to the shell chamber where the heat exchange tube connected to the water inlet chamber is located to the flue gas outlet.

Images