Condensing heat exchanger and gas water heater

Abstract

The utility model relates to a condensing heat exchanger and a gas water heater. The condensing heat exchanger comprises a shell; the heat exchange tube is arranged in the shell, and the heat exchange tube is provided with a water inlet end; the expansion box body is provided with a water flow expansion cavity, a water inlet and a water outlet, the water inlet and the water outlet are communicated with the water flow expansion cavity, the flow section area of the water flow expansion cavity is larger than that of the water inlet and that of the water outlet, and the water outlet is communicated with the water inlet end. According to the condensing heat exchanger, due to the fact that the water flow expansion cavity is arranged between the water inlet and the water outlet of the expansion box body, and the circulation cross-sectional area of the water flow expansion cavity is larger than that of the water inlet and that of the water outlet, cold water flows into the heat exchange tube after passing through the expansion box body in a pressure reduction mode, and the expansion box body can reduce turbulence intensity of outlet water of a water pump. Water outlet pressure pulsation of the water pump is attenuated, so that vibration amplitude and resonance intensity of the heat exchange tube are reduced, and noise can be effectively reduced.

Description

Technical Field

[0001] The present application relates to the technical field of water heaters, and in particular to a condensing heat exchanger and a gas water heater. Background Art

[0002] The high-temperature flue gas of the gas water heater carries a high amount of heat energy. If it is directly discharged to the outside of the machine, it will lead to energy waste. In the related technology, in order to utilize the heat energy carried by the high-temperature flue gas, a condensing heat exchanger is arranged in series between the cold water inlet pipe of the gas water heater and the heat exchanger. When working, the fan passes the high-temperature flue gas into the shell of the condensing heat exchanger. At the same time, the water pump provides power to send cold water into the heat exchange tube through the cold water inlet pipe. The high-temperature flue gas is in thermal contact with the heat exchange tube of the condensing heat exchanger, and the cold water inside the heat exchange tube is heated to a preset temperature, which plays a preheating role. However, the periodic pressure pulsation generated when the water pump is working makes the turbulence intensity of the water flow out of the water pump large. The pressure pulsation is transmitted to the pipeline of the condensing heat exchanger through the water flow, resonates with the pipeline, and the noise radiation is very obvious. Summary of the invention

[0003] The first technical problem solved by the present application is to provide a condensing heat exchanger which can effectively reduce noise.

[0004] The second technical problem solved by the present application is to provide a gas water heater which can effectively reduce the noise of the condensing heat exchanger.

[0005] The first technical problem mentioned above is solved by the following technical solution:

[0006] A condensing heat exchanger, comprising:

[0007] shell;

[0008] a heat exchange tube, the heat exchange tube being arranged inside the shell and having a water inlet end; and

[0009] An expansion box body is provided with a water flow expansion chamber and a water inlet and a water outlet connected to the water flow expansion chamber. The flow cross-sectional area of ​​the water flow expansion chamber is larger than the flow cross-sectional area of ​​the water inlet and the water outlet. The water outlet is connected to the water inlet end.

[0010] The condensing heat exchanger described in this application has the following beneficial effects compared with the background technology:

[0011] When the above-mentioned condensing heat exchanger is in use, cold water is pressurized by a water pump and flows through the expansion box and the heat exchange tubes in turn. Since a water flow expansion chamber is arranged between the water inlet and the water outlet of the expansion box, and the flow cross-sectional area of ​​the water flow expansion chamber is larger than the flow cross-sectional area of ​​the water inlet and the water outlet, the cold water is decompressed after passing through the expansion box and flows into the heat exchange tubes. The expansion box can reduce the turbulence intensity of the water outlet of the water pump and attenuate the pressure pulsation of the water outlet of the water pump, thereby reducing the vibration amplitude and resonance intensity of the heat exchange tubes, and thus effectively reducing noise.

[0012] In one embodiment, the length L0 of the water flow expansion chamber along the water flow direction is 30 mm to 40 mm.

[0013] In one embodiment, the expansion box includes a box body, the box body is provided with the water flow expansion chamber, and the box body is arranged inside the shell.

[0014] In one embodiment, the box body and the shell are integrally injection molded, fixedly connected by fasteners, welded or adhesively connected.

[0015] In one embodiment, the expansion box also includes a noise reduction tube that penetrates the interior of the box body, and both ends of the noise reduction tube extend to the outside of the box body and respectively form a water inlet and a water outlet, the water inlet is provided with the water inlet, the water outlet is provided with the water outlet, and a through hole connected to the chamber of the box body is formed in the middle portion of the noise reduction tube.

[0016] In one embodiment, the through holes are provided in plurality, and the opening rate of the middle portion of the noise reduction tube is 40% to 60%.

[0017] In one embodiment, the expansion box further includes a first sealing ring disposed between the water inlet and the box body, and a second sealing ring disposed between the water outlet and the box body.

[0018] In one embodiment, the expansion box also includes a first plug and a second plug that are arranged in sequence along the water flow direction. The first plug is provided with a water inlet, and the second plug is provided with a water outlet. The water outlet is connected to the water inlet end; the first plug and the second plug are respectively connected to the box body.

[0019] In one embodiment, the heat exchange tube includes a plurality of sub-heat exchange sections connected in series, and all of the sub-heat exchange sections are arranged in at least two rows arranged in sequence along the direction of the high-temperature air flow, each row has at least two sub-heat exchange sections, and the sub-heat exchange sections of any two adjacent rows are staggered with each other.

[0020] The above second technical problem is solved by the following technical solution:

[0021] A gas water heater, comprising the condensing heat exchanger, a cold water inlet pipe, a water pump and a heat exchanger, wherein the cold water inlet pipe is connected to the water pump, the cold water inlet pipe is also connected to the expansion box, and the water outlet end of the heat exchange pipe is connected to the heat exchanger.

[0022] The gas water heater described in this application has the following beneficial effects compared with the background technology:

[0023] When the above-mentioned gas water heater is in use, the cold water is pressurized by the water pump and flows through the expansion box and the heat exchange tube in turn. Since a water flow expansion chamber is arranged between the water inlet and the water outlet of the expansion box, and the flow cross-sectional area of ​​the water flow expansion chamber is larger than the flow cross-sectional area of ​​the water inlet and the water outlet, the cold water is decompressed after passing through the expansion box and flows into the heat exchange tube. The expansion box can reduce the turbulence intensity of the water outlet of the water pump and attenuate the pressure pulsation of the water outlet of the water pump, thereby reducing the vibration amplitude and resonance intensity of the heat exchange tube, and thus effectively reducing noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application.

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] FIG1 is a schematic structural diagram of a condensing heat exchanger according to an embodiment of the present application.

[0027] FIG. 2 is an enlarged structural diagram of FIG. 1 at point A. FIG.

[0028] FIG. 3 is a structural diagram of the heat exchange tube and the noise reduction tube of the structure shown in FIG. 1 .

[0029] FIG. 4 is a cross-sectional structural diagram of FIG. 3 taken along line BB.

[0030] FIG. 5 is a top view of the structure shown in FIG. 3 .

[0031] Reference numerals:

[0032] 10. Shell; 20. Heat exchange tube; 201. Water inlet; 202. Water outlet; 21. Sub-heat exchange section; 30. Expansion box; 31. Box body; 310. Water flow expansion chamber; 32. Noise reduction tube; 321. First insert; 322. Second insert; 323. Water inlet; 3230. Water inlet; 3231. Limiting part; 324. Water outlet; 3240. Water outlet; 325. Through hole; 33. First sealing ring; 34. Second sealing ring; 35. Fastening nut; 36. Gasket; 37. Bottom plate. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0034] Referring to FIG. 1 and FIG. 2 , FIG. 1 shows a schematic diagram of the structure of a condensing heat exchanger according to an embodiment of the present application. FIG. 2 shows an enlarged structural diagram of FIG. 1 at A. A condensing heat exchanger provided in an embodiment of the present application comprises: a shell 10, a heat exchange tube 20 and an expansion box 30. The heat exchange tube 20 is arranged inside the shell 10, and the heat exchange tube 20 is provided with a water inlet 201. The expansion box 30, the expansion box 30 is provided with a water flow expansion chamber 310 and a water inlet 3230 and a water outlet 3240 connected to the water flow expansion chamber 310, the flow cross-sectional area of ​​the water flow expansion chamber 310 is greater than the flow cross-sectional area of ​​the water inlet 3230 and the water outlet 3240, and the water outlet 3240 is connected to the water inlet 201.

[0035] In the above-mentioned condensing heat exchanger, since a water flow expansion chamber 310 is arranged between the water inlet 3230 and the water outlet 3240 of the expansion box 30, and the flow cross-sectional area of ​​the water flow expansion chamber 310 is larger than the flow cross-sectional area of ​​the water inlet 3230 and the water outlet 3240, the cold water is decompressed after passing through the expansion box 30 and flows into the heat exchange tube 20. The expansion box 30 can reduce the turbulence intensity of the water outlet of the water pump and attenuate the pressure pulsation of the water outlet of the water pump, thereby reducing the vibration amplitude and resonance intensity of the heat exchange tube 20, and thus effectively reducing the noise.

[0036] It should be noted that the expansion box 30 achieves noise elimination by controlling the size of the acoustic impedance, and utilizes the change in acoustic impedance caused by the sudden change in the cross section of the pipeline to generate reflection, interference, etc. to achieve the purpose of noise elimination.

[0037] Referring to FIG. 1 and FIG. 2 , in one embodiment, the expansion box 30 includes a box body 31, the box body 31 is provided with the water flow expansion chamber 310, and the box body 31 is disposed inside the shell 10. In this way, the box body 31 is located inside the shell 10, will not be exposed to affect the appearance, and can save the internal space of the gas water heater, and the design flexibility is higher. In addition, the shell 10 can also be used to block the noise generated inside the box body 31 from being transmitted to the outside.

[0038] Of course, as some optional solutions, the box body 31 can also be arranged outside the shell 10.

[0039] Referring to Figures 1 and 2, in one embodiment, the box body 31 and the housing 10 are integrally injection molded, fixedly connected by fasteners, welded or bonded. In this way, when the box body 31 and the housing 10 are integrally injection molded, the cost of parts can be reduced, mold molding is convenient, production efficiency is high, and the overall structure is compact.

[0040] The fasteners include but are not limited to pins, rivets, screws, clips, etc.

[0041] It should be noted that the expansion box 30 is used to reduce noise by controlling the size of the acoustic impedance, and uses the change in acoustic impedance of the cross-section mutation in the pipeline to produce reflection, interference, etc. to achieve the purpose of reducing noise. The expansion box 30 is widely used in the field of industrial equipment, but it must strictly comply with the design standards and design a reasonable diameter and length. Among them, the calculation formula for the noise reduction amount △ of the expansion box 30 is:

[0042]

[0043] Where: m is the expansion ratio, m=S2 / S1;

[0044] S1 is the cross-sectional area of ​​the cold water inlet pipe before expansion, which is consistent with the cross-sectional area of ​​the water inlet portion 323; S2 is the cross-sectional area of ​​the box body 31 after expansion, in m²;

[0045] L is the theoretical length of the box body 31 along the water flow direction, in meters;

[0046] k is the wave number, k=2π / λ=2πf / c, unit is m -1 ;

[0047] From the above formula, when sinkL=±1, the sound reduction reaches the maximum, that is, kL=(2n+1)π / 2. From this, the relationship between the maximum sound reduction frequency and the preset length L of the box body 31 can be obtained: , where c is the speed of sound, unit is m / s; n=0,1,2,3…

[0048] When n=0, the first maximum silencing frequency is obtained, which can be rewritten as an expression related to the length L of the box body 31:

[0049] When the gas water heater in the related technology is working, it is measured that there are two single-frequency peaks on the noise spectrum (about 16dB higher than other peaks). The frequencies corresponding to the two single-frequency peaks are 520Hz and 1040Hz respectively. The sound pressure level of the whole machine noise when the water pump is running is 47.2dB(A).

[0050] Taking 1100 Hz as the target frequency, the sound attenuation is △=16dB, the expansion ratio is m=S2 / S1, φ1=11mm, and φ2=39.7mm is calculated. The propagation speed of sound waves in water is c=1500m / s, and the preset length of the box body 31 is calculated to be L=λ / 4=1500 / 1100 / 4=340.9mm.

[0051] The muffler frequency of the muffler depends on the preset length L of the water flow expansion chamber 310. In this embodiment, considering the spatial structure and component costs, the length L0 of the water flow expansion chamber 310 is 1 / 11 to 1 / 9 of the calculated length L, for example, 1 / 10 of L, that is, L0=34.1mm. Although the length L0 has greatly deviated from the preset length L of the theoretical design, it can buffer and avoid vibration of the periodic pressure pulsation generated by the water pump, effectively reduce noise, and meet the use of gas water heaters.

[0052] 1 and 2 , in one embodiment, the length L0 of the water flow expansion chamber 310 along the water flow direction is 30 mm to 40 mm. Thus, after research, it is found that the length L0 is set to be more appropriate and can effectively reduce noise.

[0053] Please refer to FIG. 1 and FIG. 2. In one embodiment, the expansion box 30 further includes a first plug 321 and a second plug 322 which are arranged in sequence along the water flow direction. The first plug 321 is provided with a water inlet, and the second plug 322 is provided with a water outlet, the water outlet is connected to the water inlet 201 end, the first plug 321 is connected to the box body 31, and the second plug 322 is connected to the box body 31. In this way, the cold water of the cold water inlet pipe enters the first plug 321, enters the interior of the box body 31 through the first plug 321, then enters the interior of the second plug 322, and is discharged outward through the water outlet of the box body 31. It can be seen from the test that the sound reduction can be improved compared with the case where the first plug 321 and the second plug 322 are not provided.

[0054] It should be noted that the “water inlet portion 323 of the box body 31” can be “a part of the first plug 321”, that is, the “water inlet portion 323 of the box body 31” and the “other parts of the first plug 321” can be manufactured as one piece; it can also be an independent component that can be separated from the “other parts of the first plug 321”, that is, the “water inlet portion 323 of the box body 31” can be manufactured independently and then combined with the “other parts of the first plug 321” into a whole.

[0055] It should be noted that the "water outlet portion of the box body 31" can be "a part of the second plug 322", that is, the "water outlet portion 324 of the box body 31" and the "other parts of the second plug 322" are manufactured as one piece; it can also be an independent component that can be separated from the "other parts of the second plug 322", that is, the "water outlet portion of the box body 31" can be manufactured independently and then combined with the "other parts of the second plug 322" into a whole.

[0056] Referring to Figures 1 and 2, in some embodiments, the length of the first insert pipe 321 includes but is not limited to L0 / 2, and the length of the second insert pipe 322 includes but is not limited to L0 / 4. In this way, the sound reduction can be improved, and a better vibration reduction effect on the water flow can be achieved.

[0057] Please refer to FIG. 1 and FIG. 2. In one embodiment, the expansion box 30 further includes a noise reduction pipe 32 which is arranged inside the box body 31. The two ends of the noise reduction pipe 32 extend out of the box body 31 and form a water inlet 323 and a water outlet 324 respectively. The water inlet 323 is provided with the water inlet 3230, and the water outlet 324 is provided with the water outlet 3240. The middle part of the noise reduction pipe 32 is formed with a through hole 325 which is connected with the chamber of the box body 31. In this way, the cold water of the cold water inlet pipe enters the noise reduction pipe 32 through the water inlet 323, enters the inside of the box body 31 through the through hole 325 of the noise reduction pipe 32, and is discharged outward through the water outlet 324. It can be seen from the test that the sound reduction amount can be improved compared with the case where the noise reduction pipe 32 is not provided. In addition, the role played by the noise reduction tube 32 with a through hole 325 formed in the middle portion is equivalent to the role played by the first insert tube 321 and the second insert tube 322 in the above embodiment. However, compared with the first insert tube 321 and the second insert tube 322, since the noise reduction tube 32 is configured as one tube, it is not only convenient for parts processing, but also easy to install on the box body 31, and the assembly efficiency is higher.

[0058] Specifically, the through hole 325 is formed at a position where the first inserting tube 321 and the second inserting tube 322 are connected.

[0059] In one embodiment, a plurality of through holes 325 are provided, and the opening rate of the middle portion of the noise reduction tube 32 is 40% to 60%. In this way, the opening rate is large enough to improve the noise reduction effect, but not too large to weaken the noise reduction strength of the middle portion of the noise reduction tube 32.

[0060] It should be noted that the opening ratio refers to the ratio of the total opening area of ​​each through hole 325 to the area of ​​the middle part of the noise reduction tube 32 in the circumferential direction.

[0061] Specifically, in this embodiment, the length of the pipe body in the middle portion of the noise reduction pipe 32 is one half of the length of the pipe body of the noise reduction pipe 32 located inside the box body 31 along the water flow direction.

[0062] In some embodiments, the open porosity includes, but is not limited to, various values ​​such as 40%, 45%, 50%, 55% or 60%.

[0063] In some embodiments, the shape of the through hole 325 includes but is not limited to regular-shaped holes such as circular holes, elliptical holes, polygonal holes, and other irregular-shaped holes, and can be flexibly adjusted and set according to actual needs.

[0064] 1 and 2, in one embodiment, the expansion box 30 further includes a first sealing ring 33 disposed between the water inlet 323 and the box body 31, and a second sealing ring 34 disposed between the water outlet 324 and the box body 31. In this way, under the respective sealing effects of the first sealing ring 33 and the second sealing ring 34, the sealing performance of the box body 31 can be improved.

[0065] Please refer to FIG. 1 and FIG. 2 , in one embodiment, a limiting portion 3231 is provided around the outer wall of the water inlet portion 323, a first opening is provided on the box body 31, the water inlet portion 323 is passed through the first opening and is tightly abutted against the wall of the first opening through the first sealing ring 33. In addition, a step is provided around the circumference of the first opening on the box body 31, and the limiting portion 3231 abuts against the step.

[0066] In addition, the expansion box 30 further includes a fastening nut 35, and the water inlet 323 is provided with a thread adapted to the fastening nut 35, and the fastening nut 35 is installed on the water inlet 323 and is tightly abutted against the box body 31. Specifically, a gasket 36 is provided between the fastening nut 35 and the box body 31 and is sleeved on the water inlet 323. The gasket 36 includes but is not limited to a washer.

[0067] Please refer to Figures 1 and 2. In one embodiment, a bottom plate 37 is circumferentially provided on the outer wall of the water outlet portion 324. A second opening adapted to the bottom plate 37 is provided on the box body 31. The bottom plate 37 is disposed in the second opening and is tightly abutted against the mouth wall of the second opening through a second sealing ring 34.

[0068] Please refer to Figures 3 to 5. Figure 3 shows a structural diagram of the heat exchange tube 20 and the noise reduction tube 32 of the structure shown in Figure 1. Figure 4 shows a cross-sectional structural diagram of Figure 3 at BB. Figure 5 shows a top view of the structure shown in Figure 3. In one embodiment, the heat exchange tube 20 includes a plurality of sub-heat exchange sections 21 connected in series in sequence. Cold water from the cold water inlet pipe enters through the water inlet end 201 and flows through each sub-heat exchange section 21 in sequence. The flow direction is, for example, as shown in Figure 5. After being preheated by the high-temperature flue gas, it is discharged outward through the water outlet end 202 and enters the heat exchanger. In addition, all the sub-heat exchange sections 21 are arranged in at least two rows arranged in sequence along the direction of the high-temperature air flow. Each row C has at least two sub-heat exchange sections 21. The sub-heat exchange sections 21 of any two adjacent rows are arranged in a staggered manner, as shown in Figure 4. In this way, the flushing conditions of high-temperature flue gas received by each row of C sub-heat exchange sections 21 are roughly the same, the speed and direction of the fluid flowing between the tubes often change, and the mixing of each part of the fluid is better than when arranged in sequence, which can improve the heat exchange efficiency. While ensuring the same heat exchange efficiency, the amount of heat exchange tubes 20 can be reduced, reducing the cost of parts.

[0069] The mutually staggered arrangement of the sub-heat exchange segments 21 in two adjacent rows means that, along the direction of the high-temperature airflow, the sub-heat exchange segments 21 in one row are positioned opposite to the interval areas between two adjacent sub-heat exchange segments 21 in the other row, as shown in FIG. 4 .

[0070] In one embodiment, a gas water heater includes a condensing heat exchanger of any of the above embodiments, and also includes a cold water inlet pipe, a water pump and a heat exchanger. The cold water inlet pipe is connected to the water pump, and the cold water inlet pipe is also connected to the expansion box 30. The water outlet end 202 of the heat exchange tube 20 is connected to the heat exchanger.

[0071] The above-mentioned gas water heater has an expansion box 30 arranged between the cold water inlet pipe and the water inlet end 201 of the heat exchange tube 20. The expansion box 30 can reduce the turbulence intensity of the water discharged by the water pump and attenuate the pressure pulsation, thereby reducing the resonance intensity of the heat exchange tube 20, and thus effectively reducing the noise.

[0072] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0073] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0074] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0075] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0076] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0077] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0078] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A condensing heat exchanger, characterized in that: The condensing heat exchanger comprises: Housing (10); a heat exchange tube (20), the heat exchange tube (20) being arranged inside the shell (10), the heat exchange tube (20) being provided with a water inlet end (201); and An expansion box (30), wherein the expansion box (30) is provided with a water flow expansion chamber (310) and a water inlet (3230) and a water outlet (3240) connected to the water flow expansion chamber (310), the flow cross-sectional area of ​​the water flow expansion chamber (310) is greater than the flow cross-sectional area of ​​the water inlet (3230) and the water outlet (3240), and the water outlet (3240) is connected to the water inlet end (201).

2. The condensing heat exchanger according to claim 1, characterized in that: The length L0 of the water flow expansion chamber (310) along the water flow direction is 30 mm to 40 mm.

3. The condensing heat exchanger according to claim 1, characterized in that: The expansion box (30) comprises a box body (31), the box body (31) is provided with the water flow expansion chamber (310), and the box body (31) is arranged inside the outer shell (10).

4. The condensing heat exchanger according to claim 3, characterized in that: The box body (31) and the outer shell (10) are integrally injection molded and are fixedly connected by fasteners, welded, or bonded.

5. The condensing heat exchanger according to claim 3, characterized in that: The expansion box (30) also includes a noise reduction pipe (32) that is arranged to penetrate the interior of the box body (31), and the two ends of the noise reduction pipe (32) respectively extend to the outside of the box body (31) and respectively form a water inlet (323) and a water outlet (324), the water inlet (323) is provided with the water inlet (3230), and the water outlet (324) is provided with the water outlet (3240), and the middle part of the noise reduction pipe (32) is formed with a through hole (325) that is connected to the chamber of the box body (31).

6. The condensing heat exchanger according to claim 5, characterized in that: The through holes (325) are arranged in plurality, and the opening rate of the middle portion of the noise reduction tube (32) is 40% to 60%.

7. The condensing heat exchanger according to claim 5, characterized in that: A limiting portion (3231) is provided around the outer wall of the water inlet portion (323); a first opening is provided on the box body (31); the water inlet portion (323) is inserted into the first opening and is in close contact with the wall of the first opening via a first sealing ring (33); and a bottom plate (37) is provided around the outer wall of the water outlet portion (324); a second opening adapted to the bottom plate (37) is provided on the box body (31); the bottom plate (37) is provided in the second opening and is in close contact with the wall of the second opening via a second sealing ring (34).

8. The condensing heat exchanger according to claim 3, characterized in that: The expansion box (30) further comprises a first insert pipe and a second insert pipe which are arranged in sequence at intervals along the water flow direction, the first insert pipe is provided with a water inlet, the second insert pipe is provided with a water outlet, the water outlet is connected to the water inlet end (201); the first insert pipe and the second insert pipe are respectively connected to the box body (31).

9. The condensing heat exchanger according to claim 1, characterized in that: The heat exchange tube (20) comprises a plurality of sub-heat exchange sections (21) connected in series, wherein all the sub-heat exchange sections (21) are arranged in at least two rows arranged in series along the direction of the high-temperature airflow, each row having at least two sub-heat exchange sections (21), and the sub-heat exchange sections (21) in any two adjacent rows are arranged in a staggered manner.

10. A gas water heater, characterized in that: The gas water heater comprises a condensing heat exchanger as described in any one of claims 1 to 9, and also comprises a cold water inlet pipe, a water pump and a heat exchanger, wherein the cold water inlet pipe is connected to the water pump, and the cold water inlet pipe is also connected to the expansion box (30), and the water outlet end (202) of the heat exchange tube (20) is connected to the heat exchanger.

Images