Condensation type gas water heating device

Abstract

The utility model belongs to the technical field of gas water heating devices, and discloses a condensation type gas water heating device which is characterized in that when the actual heating return water temperature is lower than the preset lowest allowable heating return water temperature, a spraying switch valve is controlled to be opened, and part of heating return water in a heating return water pipe is conveyed to a nozzle; the nozzle atomizes heating water to form water mist, the water mist is downwards sprayed to the condensation heat exchange pipe, the water molecule density of the water mist is large, the water mist is combined with compounds such as nitrogen and carbon in smoke to form condensation cores, the number of the condensation cores is increased, the smoke rises, water molecules in the smoke are more sufficient, meanwhile, condensation is easier, and more latent heat is released; high-temperature flue gas in the condensation heat exchange shell transfers more heat to heating water in the condensation heat exchange pipe, and the heat exchange efficiency of the condensation type gas water heating device is improved; the temperature difference between the high-temperature smoke in the combustion chamber and the heating water in the main heat exchanger is reduced, the probability that condensate water is formed on the surface of the main heat exchanger is reduced, and the service life of the main heat exchanger is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of gas water heaters, in particular to a condensing gas water heater. Background Art

[0002] A gas-fired hot water boiler is a heating device that burns fuel such as natural gas, coal gas, or liquefied gas, absorbs heat through the main heat exchanger to prepare hot water, and then sends the hot water to the radiator to warm the surrounding environment.

[0003] According to the national standard GB25034-2020 for gas-fired heating water boilers, the thermal efficiency of a condensing furnace with a rated heat load adjustment device at maximum heat load should not be less than 99% when the condensing furnace is at a rated load of 50℃ / 30℃.

[0004] Currently, the experimental conditions for verifying condensate formation in the main heat exchanger of a condensing gas-fired hot water boiler are a heating outlet water temperature of 50°C and a heating return water temperature of 30°C. In actual use, it has been found that during the cold winter months, the heating return water temperature falls far below 30°C. When uneven airflow through the main heat exchanger creates areas of stagnant airflow, the local temperature within the combustion chamber drops to the dew point, causing condensate to form on the surface of the main heat exchanger. This condensate is generally acidic, shortening the service life of the main heat exchanger. Utility Model Content

[0005] The technical problem solved by the utility model is to provide a condensing gas water heater, which can reduce the formation of condensed water on the surface of the main heat exchanger when the heating return water temperature is too low, thereby extending the service life of the main heat exchanger.

[0006] The above technical problems are solved by the following technical solutions:

[0007] Condensing gas water heater, comprising:

[0008] A heating return water pipe and a heating return water temperature detection unit, wherein the heating return water temperature detection unit is used to detect the return water temperature in the heating return water pipe;

[0009] The condensing heat exchanger comprises a condensing heat exchange shell having a smoke inlet and a smoke exhaust port, and a condensing heat exchange pipe arranged in the condensing heat exchange shell and connected to the heating return pipe;

[0010] A nozzle, the inlet of which is connected to the heating return pipe through a spray switch valve. The nozzle is arranged in the condensing heat exchange shell and above the condensing heat exchange pipe, and is used to spray water mist onto the surface of the condensing heat exchange pipe.

[0011] Compared with the background technology, the condensing gas water heater described in the present invention has the following beneficial effects:

[0012] During the operation of the condensing gas water heater, the heating return water in the heating return water pipe continuously enters the condensing heat exchange pipe. The actual heating return water temperature in the heating return water pipe is detected in real time by the heating return water temperature detection unit. When the actual heating return water temperature is lower than the preset minimum allowable heating return water temperature, the spray switch valve is controlled to open, and part of the heating return water in the heating return water pipe is sent to the nozzle. Since the nozzle is located above the condensing heat exchange pipe, the nozzle atomizes the heating water to form water mist and sprays it onto the condensing heat exchange pipe. The water molecules in the water mist have a large density and combine with nitrogen, carbon and other compounds in the flue gas. The high-temperature flue gas in the condensing heat exchange shell transfers more heat to the heating water in the condensing heat exchange tube, thereby improving the heat exchange efficiency of the condensing gas water heater. In addition, the temperature of the heating water entering the main heat exchanger is increased, reducing the temperature difference between the high-temperature flue gas in the combustion chamber and the heating water in the main heat exchanger, which is beneficial to reducing the probability of condensed water forming on the surface of the main heat exchanger and extending the service life of the main heat exchanger.

[0013] In one embodiment, the condensing gas water heater further comprises:

[0014] A smoke exhaust fan, wherein the air outlet of the smoke exhaust fan is connected to the smoke inlet, and the speed of the smoke exhaust fan is adjustable.

[0015] In one embodiment, the condensation heat exchange shell is provided with a condensation drain hole communicating with its inner cavity, and the condensation drain hole is connected to a condensation drain pipe;

[0016] The condensed water in the condensation drain pipe can exchange heat with the heating return water in the heating return water pipe.

[0017] In one embodiment, the condensation drain pipe includes a condensation pipe portion, and the heating return pipe includes a heating pipe portion;

[0018] The condensing pipe portion is sleeved outside the heating pipe portion and forms a condensation heat exchange channel for circulating condensed water between the condensing pipe portion and the heating pipe portion; or, the heating pipe portion is sleeved outside the condensing pipe portion and forms a condensation heat exchange channel for circulating heating return water between the condensing pipe portion and the heating pipe portion; or, the condensing pipe portion is wrapped around the outside of the heating pipe portion; or, the heating pipe portion is wrapped around the outside of the condensing pipe portion.

[0019] In one embodiment, the condensing pipe portion and the heating pipe portion are coaxially arranged.

[0020] In one embodiment, a condensation drain valve is provided on the condensation drain pipe, and along the direction of water flow in the condensation drain pipe, the condensation drain valve is located downstream of the condensation pipe portion; the opening of the condensation drain valve is adjustable.

[0021] In one embodiment, the condensation drain hole is provided at the lowest position of the condensation heat exchange shell, and the condensation drain pipe is provided below the condensation heat exchange shell.

[0022] In one embodiment, the condensing heat exchange tube is a corrugated tube extending from top to bottom, and the two ends of the corrugated tube in the extension direction form a water inlet end and a water outlet end respectively, and the water inlet end is located above the water outlet end.

[0023] In one embodiment, the spray switch valve is arranged outside the condensing heat exchange shell.

[0024] In one embodiment, the condensing gas water heater further comprises:

[0025] Heating water outlet pipe;

[0026] The heating water outlet temperature detection unit is used to detect the heating water outlet temperature in the heating water outlet pipe.

[0027] In one embodiment, the condensing gas water heater further comprises:

[0028] Cold water inlet pipe;

[0029] A water pump, the water pump being arranged on the heating return pipe;

[0030] A pressure detection unit, used to detect the pressure in the heating return pipe;

[0031] A water replenishment switch valve, the inlet of which is connected to the cold water inlet pipe, and the outlet of which is connected to the heating return pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of a condensing gas water heater provided by an embodiment of the present utility model;

[0033] Figure 2 This is the control method flow of the condensing gas water heater provided by the embodiment of the utility model Figure 1 ;

[0034] Figure 3 This is the control method flow of the condensing gas water heater provided by the embodiment of the utility model Figure 2 ;

[0035] Figure 4 This is the control method flow of the condensing gas water heater provided by the embodiment of the utility model Figure 3 ;

[0036] Figure 5This is the control method flow of the condensing gas water heater provided by the embodiment of the utility model Figure 4 .

[0037] In the picture:

[0038] 11. Heating return pipe; 111. Heating pipe section; 12. Heating outlet pipe; 21. Condensing heat exchange shell; 22. Condensing heat exchange pipe; 3. Smoke exhaust fan; 41. Spray on / off valve; 42. Nozzle; 5. Main heat exchanger; 6. Burner; 71. Sanitary hot water outlet pipe; 72. Cold water inlet pipe; 8. Condensate drain pipe; 81. Condensing pipe section; 91. Heating return water temperature detection unit; 92. Heating outlet water temperature detection unit; 10. Water pump; 20. Pressure detection unit; 30. Make-up water on / off valve; 40. Gas proportional valve; 50. Plate heat exchanger;

[0039] 100. Combustion chamber; 200. Condensation heat exchange channel. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0041] In the description of this application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do 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 this application.

[0042] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. Throughout this application, unless otherwise specified, "plurality" means two or more.

[0043] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0044] The present invention provides a condensing gas water heater that prevents condensation from forming on the surface of the main heat exchanger when the heating return water temperature is too low, while also improving the heat exchange efficiency of the condensing gas water heater. The condensing gas water heater is a wall-mounted gas boiler equipped with a rated heat load adjustment device. The rated heat load adjustment device on a wall-mounted gas boiler is conventional in the art and will not be described in detail here.

[0045] like Figure 1 As shown, the condensing gas water heater includes a combustion chamber 100, a burner 6, an igniter, a smoke exhaust fan 3, a main heat exchanger 5 and a condensing heat exchanger, wherein the burner 6 and the main heat exchanger 5 are both arranged in the combustion chamber 100, the main heat exchanger 5 is arranged above the burner 6, the burner 6 is connected to a gas supply pipeline, and a gas proportional valve 40 is provided on the gas supply pipeline. The smoke exhaust fan 3 is arranged above the main heat exchanger 5, and the condensing heat exchanger includes a condensing heat exchange shell 21 with a smoke inlet and a smoke exhaust port, and a condensing heat exchange pipe 22 arranged in the condensing heat exchange shell 21 and connected to the heating return pipe 11; the air outlet of the smoke exhaust fan 3 is connected to the smoke inlet, the inlet end of the condensing heat exchange pipe 22 is connected to the heating return pipe 11, the outlet end of the condensing heat exchange pipe 22 is connected to the inlet of the main heat exchanger 5, and the outlet of the main heat exchanger 5 is connected to the heating outlet pipe 12.

[0046] When the condensing gas water heater is working, the gas proportional valve 40 is opened to send the gas to the burner 6, the igniter ignites the gas, and the gas burns in the burner 6 to form high-temperature flue gas. The main heat exchanger 5 absorbs the heat in the high-temperature flue gas to heat the heating water in the main heat exchanger 5. The high-temperature heating water is sent to the user's heating equipment through the heating outlet pipe 12. The heating water cools down in the heating equipment to heat the surrounding environment. After that, the heating water enters the heating return pipe 11, and the heating return water in the heating return pipe 11 enters the condensing heat exchange pipe 22 of the condensing heat exchanger; and the high-temperature flue gas in the combustion chamber 100 exchanges heat with the main heat exchanger 5 and is sent into the condensing heat exchange shell 21 by the smoke exhaust fan 3. The heating return water in the condensing heat exchange tube 22 absorbs the heat in the high-temperature flue gas in the condensing heat exchange shell 21 and heats up and then enters the main heat exchanger 5 for secondary heating, and the flue gas in the condensing heat exchange shell 21 is cooled and discharged through the smoke exhaust port.

[0047] Currently, the experimental conditions for testing whether condensate is forming in the main heat exchanger 5 of a condensing gas-fired hot water boiler are a heating outlet water temperature of 50°C and a heating return water temperature of 30°C. In actual use, it has been found that during the cold winter months, the heating return water temperature can fall far below 30°C. When uneven airflow through the main heat exchanger 5 creates areas of stagnant airflow, the local temperature within the combustion chamber 100 drops to the dew point, causing condensate to form on the surface of the main heat exchanger 5. This condensate is generally acidic, shortening the service life of the main heat exchanger 5.

[0048] To this end, the condensing gas water heater also includes a nozzle 42 and a heating return water temperature detection unit 91 for detecting the return water temperature in the heating return water pipe 11. The inlet of the nozzle 42 is connected to the heating return water pipe 11 through a spray switch valve 41. The nozzle 42 is arranged in the condensing heat exchange shell 21 and is located above the condensing heat exchange pipe 22, and is used to spray water mist onto the surface of the condensing heat exchange pipe 22.

[0049] During the operation of the condensing gas water heater, the heating return water in the heating return water pipe 11 continuously enters the condensing heat exchange pipe 22. The actual heating return water temperature in the heating return water pipe 11 is detected in real time by the heating return water temperature detection unit 91. When the actual heating return water temperature is lower than the preset minimum allowable heating return water temperature, the spray switch valve 41 is controlled to open, and part of the heating return water in the heating return water pipe 11 is sent to the nozzle 42. Since the nozzle 42 is located above the condensing heat exchange pipe 22, the nozzle 42 atomizes the heating water to form water mist and sprays it to the condensing heat exchange pipe 22. The water molecule density of the water mist is relatively large, and it reacts with nitrogen and Carbon and other compounds combine to form condensation nuclei, which increases the number of condensation nuclei. During the rising process of the flue gas, the water molecules in the flue gas are more fully and more easily condensed to release more latent heat, that is, the high-temperature flue gas in the condensing heat exchange shell 21 transfers more heat to the heating water in the condensing heat exchange tube 22, thereby improving the heat exchange efficiency of the condensing gas water heater; and increases the temperature of the heating water entering the main heat exchanger 5, reducing the temperature difference between the high-temperature flue gas in the combustion chamber 100 and the heating water in the main heat exchanger 5, which is beneficial to reduce the probability of condensation water forming on the surface of the main heat exchanger 5 and extend the service life of the main heat exchanger 5.

[0050] It should be noted that one or more nozzles 42 may be provided, depending on the size of the condensing heat exchange tube 22 .

[0051] In some embodiments, the speed of the smoke exhaust fan 3 is adjustable. Before, simultaneously with, or after opening the spray on / off valve 41, the speed of the smoke exhaust fan 3 is increased, and the load of the condensing gas water heater is switched to a load corresponding to the speed of the smoke exhaust fan 3. This increases the smoke exhaust speed, shortens the heat exchange time between the high-temperature smoke in the combustion chamber 100 and the main heat exchanger 5, and raises the smoke exhaust temperature. This prevents uneven airflow through the main heat exchanger 5 and the formation of air stagnation areas when the heating return water temperature is low. Furthermore, when the heating return water temperature is low, the combustion chamber 100 does not experience a localized temperature drop to the dew point, thereby preventing the formation of condensed water on the surface of the main heat exchanger 5 and extending the service life of the main heat exchanger 5.

[0052] In some embodiments, as Figure 1 As shown, the condensation heat exchange shell 21 is provided with a condensation drain hole connected to its inner cavity, and the condensation drain hole is connected to a condensation drain pipe 8; the condensed water in the condensation drain pipe 8 can exchange heat with the heating return water in the heating return pipe 11.

[0053] High-temperature water mist is sprayed downward toward the condensation heat exchange tube 22, exchanges heat with the heating water in the condensation heat exchange tube 22, and then cools down to form condensed water. The condensed water gathers at the bottom of the condensation heat exchange shell 21. In actual application, it is found that the temperature of the condensed water gathered at the bottom of the condensation heat exchange shell 21 is still relatively high. After the condensed water in the condensation heat exchange shell 21 enters the condensation drain pipe 8 through the condensation drain hole, it exchanges heat with the heating water in the heating return pipe 11, so that the heating return water in the heating return pipe 11 is heated, which is conducive to further recovery of heat in the condensed water.

[0054] Moreover, since the heating water temperature in the heating return pipe 11 is lower than the condensing water temperature in the condensing heat exchange pipe 22, the heating return water with a lower temperature in the heating return pipe 11 first undergoes heat exchange and heating with the high-temperature condensing water in the condensing heat exchange channel 200, and then undergoes a secondary heat exchange with the high-temperature flue gas in the condensing heat exchange shell 21, thereby increasing the water temperature entering the main heat exchanger 5 and reducing the temperature difference between the high-temperature flue gas in the combustion chamber 100 and the heating water in the main heat exchanger 5, which is beneficial to reducing the probability of condensed water forming on the surface of the main heat exchanger 5 and extending the service life of the main heat exchanger 5.

[0055] In some embodiments, as Figure 1 As shown, the condensation drain pipe 8 includes a condensation pipe portion 81, and the heating return pipe 11 includes a heating pipe portion 111. The condensation pipe portion 81 is sleeved outside the heating pipe portion 111, and a condensation heat exchange channel 200 is formed between the condensation pipe portion 81 and the heating pipe portion 111, through which the condensed water flows. The high-temperature condensed water enters the condensation heat exchange channel 200 between the condensation pipe portion 81 and the heating pipe portion 111. The heating pipe portion 111 is immersed in the high-temperature condensed water in the condensation heat exchange channel 200, which helps improve the heat exchange efficiency between the heating water in the heating return pipe 11 and the high-temperature condensed water in the condensation heat exchange channel 200.

[0056] In some embodiments, as Figure 1 As shown, the condensing pipe portion 81 and the heating pipe portion 111 are coaxially sleeved, which is beneficial to increasing the surface area of the heating pipe portion 111 that can contact the high-temperature condensed water and improving the heat exchange efficiency.

[0057] In other embodiments, the heating pipe portion 111 can be sleeved outside the condensing pipe portion 81 and a condensation heat exchange channel 200 for circulating heating return water can be formed between the heating pipe portion 111 and the condensing pipe portion 81; the condensing pipe portion 81 can also be wrapped around the outside of the heating pipe portion 111; the heating pipe portion 111 can also be wrapped around the outside of the condensing pipe portion 81.

[0058] In some embodiments, as Figure 1 As shown, a condensation drain valve is provided on the condensation drain pipe 8. Along the direction of water flow in the condensation drain pipe 8, the condensation drain valve is located downstream of the condensation pipe portion 81; the opening of the condensation drain valve is adjustable.

[0059] Since the speed at which condensed water is generated at the bottom of the condensation heat exchange shell 21 depends on the flow rate of heating return water sent to the nozzle 42 by the spray switch valve 41, the opening of the condensation drain valve can be adjusted so that the condensation heat exchange channel 200 is filled with condensed water, thereby improving the heat exchange efficiency between the condensed water in the condensation heat exchange channel 200 and the water in the heating return water pipe 11.

[0060] In some embodiments, as Figure 1 As shown, the condensation drain hole is provided at the lowest position of the condensation heat exchange shell 21, and the condensation drain pipe 8 is provided below the condensation heat exchange shell 21. This arrangement allows the condensed water accumulated at the bottom of the condensation heat exchange shell 21 to fall through the condensation drain hole under its own weight and into the condensation heat exchange pipe 22, eliminating the need for a drain pump 10, simplifying the structure of the condensing gas water heater and reducing costs.

[0061] In other embodiments, a condensation drain hole may be provided on the side wall of the condensation heat exchange shell 21, and one end of the condensation drain pipe 8 may extend downward through the condensation drain hole, so that the water inlet end of the condensation drain pipe 8 and the inner bottom wall of the condensation heat exchange shell 21 are spaced apart in the vertical direction. A drainage pump 10 may be provided on the condensation drain pipe 8. By activating the drainage pump 10, condensed water accumulated at the bottom of the condensation heat exchange shell 21 is discharged from the condensation heat exchange shell 21 through the condensation drain pipe 8. To ensure timely discharge of the condensed water, the vertical spacing between the water inlet end of the condensation drain pipe 8 and the inner bottom wall of the condensation heat exchange shell 21 is required to be relatively small, such as greater than 5 mm.

[0062] In some embodiments, as Figure 1 As shown, the condensing heat exchange tube 22 is a corrugated tube extending from top to bottom, with the two ends of the corrugated tube in the extending direction forming a water inlet end and a water outlet end respectively, and the water inlet end is located above the water outlet end.

[0063] Since the water inlet end of the condensing heat exchange tube 22 is located above the water outlet end, the heating water in the condensing heat exchange tube 22 tends to flow downward, and the high-temperature water mist formed by the water mist absorbing the heat in the high-temperature flue gas is sprayed downward. Such a setting is conducive to improving the heat exchange efficiency between the high-temperature water mist and the heating water in the condensing heat exchange tube 22.

[0064] In some embodiments, as Figure 1 As shown, the spray switch valve 41 is disposed outside the condensing heat exchange housing 21. Since the temperature inside the condensing heat exchange housing 21 is relatively high, disposing the spray switch valve 41 outside the condensing heat exchange housing 21 can place the spray switch valve 41 in a relatively low temperature environment, which is beneficial for extending the service life of the spray switch valve 41.

[0065] Exemplarily, the spray switch valve 41 is an electromagnetic switch valve. Setting the spray switch valve 41 outside the condensing heat exchange shell 21 can prevent the spray switch valve 41 from being set in an environment with high humidity and affecting its service life.

[0066] In some embodiments, as Figure 1 As shown, a water pump 10 is provided on the heating return pipe 11, and the condensing gas water heater device also includes a plate heat exchanger 50. The plate heat exchanger 50 has a low-temperature channel and a high-temperature channel. The two ends of the low-temperature channel are respectively connected to the sanitary hot water outlet pipe 71 and the cold water inlet pipe 72, and the two ends of the high-temperature channel are respectively connected to the heating return pipe 11 and the heating outlet pipe 12. The high-temperature channel is connected to the heating return pipe 11 at a preset position of the heating return pipe 11. Along the water flow direction in the heating return pipe 11, the preset position is located downstream of the water pump 10.

[0067] When sanitary hot water needs to be prepared, the heating return pipe 11 sends a portion of the hot water into the high-temperature channel of the plate heat exchanger 50, and at the same time the cold water inlet pipe 72 sends the cold water into the low-temperature channel. The hot water in the high-temperature channel exchanges heat with the hot water circulating in the low-temperature channel. The hot water in the high-temperature channel cools down after heat exchange and returns to the heating return pipe 11. The cold water in the low-temperature channel heats up and is discharged through the sanitary hot water outlet pipe 71 for bathing.

[0068] Along the water flow direction in the heating return pipe 11, the preset position is set downstream of the water pump 10, so that the circulation flow of the heating water and the circulation flow of the hot water in the high-temperature channel can pass through the same water pump 10, reducing the number of parts and reducing costs.

[0069] like Figure 2 As shown, an embodiment of the present invention further provides a control method for a condensing gas-fired water heating device, which is used for the above-mentioned condensing gas-fired water heating device. The condensing gas-fired water heating device comprises the following steps:

[0070] S1. During the operation of the condensing gas water heater, the actual heating return water temperature in the heating return water pipe 11 is obtained;

[0071] S2. When the actual heating return water temperature in the heating return water pipe 11 is lower than the preset minimum allowable heating return water temperature, the spray switch valve 41 is controlled to open, so that the nozzle 42 sprays the heating return water in the heating return water pipe 11 to the condensing heat exchange pipe 22 of the condensing heat exchanger in the form of water mist.

[0072] It should be noted that the preset minimum allowable heating return water temperature is a known value determined through multiple repeated tests, and for example, the preset minimum allowable heating return water temperature is 30° C. The first preset speed is a known value determined through multiple repeated tests and is not specifically limited here.

[0073] During the operation of the condensing gas water heater, the heating return water in the heating return water pipe 11 continuously enters the condensing heat exchange pipe 22. The actual heating return water temperature in the heating return water pipe 11 is detected in real time by the heating return water temperature detection unit 91. When the actual heating return water temperature is lower than the preset minimum allowable heating return water temperature, the spray switch valve 41 is controlled to open, and part of the heating return water in the heating return water pipe 11 is sent to the nozzle 42. Since the nozzle 42 is located above the condensing heat exchange pipe, the nozzle atomizes the heating water to form water mist and sprays it onto the condensing heat exchange pipe. The water molecules in the water mist have a large density and react with nitrogen, carbon and other chemical substances in the flue gas. The compounds combine to form condensation nuclei, which increases the number of condensation nuclei. During the rising process of the flue gas, the water molecules in the flue gas are more fully and more easily condensed to release more latent heat, that is, the high-temperature flue gas in the condensing heat exchange shell 21 transfers more heat to the heating water in the condensing heat exchange tube 22, thereby improving the heat exchange efficiency of the condensing gas water heater; and the temperature of the heating water entering the main heat exchanger 5 is increased, reducing the temperature difference between the high-temperature flue gas in the combustion chamber 100 and the heating water in the main heat exchanger 5, which is beneficial to reducing the probability of condensation water forming on the surface of the main heat exchanger 5 and extending the service life of the main heat exchanger 5.

[0074] In some embodiments, as Figure 3 As shown, the control method of the condensing gas water heater also includes the following steps: before controlling the spray switch valve 41 to open, increasing the speed of the smoke exhaust fan 3 so that the actual speed of the smoke exhaust fan 3 reaches a first preset speed and switching the load of the condensing gas water heater to a load corresponding to the first preset speed.

[0075] In this way, the smoke exhaust speed can be increased, the heat exchange time between the high-temperature smoke in the combustion chamber 100 and the main heat exchanger 5 can be shortened, the smoke exhaust temperature can be increased, and the uneven airflow flowing through the main heat exchanger 5 when the heating return water temperature is low can be avoided, thereby avoiding the airflow stagnation area. When the heating return water temperature is low, the local temperature in the combustion chamber 100 will not drop to the dew point, thereby avoiding the formation of condensed water on the surface of the main heat exchanger 5 and extending the service life of the main heat exchanger 5.

[0076] It should be noted that in some other embodiments, after the spray on / off valve 41 is controlled to be opened, the speed of the smoke exhaust fan 3 may be increased so that the actual speed of the smoke exhaust fan 3 reaches the first preset speed, and the load of the condensing gas water heater is switched to the load corresponding to the first preset speed. Alternatively, the speed of the smoke exhaust fan 3 may be increased so that the actual speed of the smoke exhaust fan 3 reaches the first preset speed, and the load of the condensing gas water heater is switched to the load corresponding to the first preset speed, while the spray on / off valve 41 is controlled to be opened.

[0077] It should be noted that the load of the burner 6 and the speed of the smoke exhaust fan 3 correspond one to one. The correspondence between the load of the burner 6 and the speed of the smoke exhaust fan 3 determined through repeated tests, such as a MAP diagram or a data table, is embedded in the controller of the condensing gas water heater in advance.

[0078] In some embodiments, as Figure 4 As shown, the control method of the condensing gas water heater further includes the following steps:

[0079] After the spray switch valve 41 is opened, the target heating water outlet temperature is obtained, and it is determined whether the target heating water outlet temperature is lower than the preset heating water outlet temperature;

[0080] If the target heating water outlet temperature is lower than the preset heating water outlet temperature, the condensing gas water heater will be shut down when the actual heating water outlet temperature reaches the target heating water outlet temperature set by the user;

[0081] If the target heating outlet water temperature is not lower than the preset heating outlet water temperature, the spray switch valve 41 is closed when the actual heating return water temperature reaches the preset minimum allowable heating return water temperature.

[0082] The condensing gas water heater further includes a heating outlet water temperature detection unit 92, which is used to detect the heating outlet water temperature in the heating outlet water pipe 12. For example, the heating outlet water temperature detection unit 92 can be configured as a temperature sensor or a temperature probe, etc., which is not specifically limited here.

[0083] The condensing gas water heater has an operation panel, through which the user can set the target outlet water temperature. After the condensing gas water heater is turned on, the power is automatically adjusted to the target power set by the user, which can be set by the user through the operation panel.

[0084] The preset heating water outlet temperature is greater than the preset minimum allowable heating return water temperature, and the difference between the preset minimum allowable heating return water temperature and the preset minimum allowable heating return water temperature is the preset temperature difference. The preset temperature difference is the minimum temperature drop of the heating water before and after passing through the heating equipment. For example, the preset temperature difference is 5°C to 15°C. For example, the temperature difference can be any value from 5°C, 6°C, 7°C, 8°C, 9°C, 10°C, 11°C, 12°C, 13°C, 14°C, and 15°C.

[0085] Specifically, because the user-set target heating water outlet temperature may be lower than the preset minimum allowable heating return water temperature of the condensing gas water heater, or higher than the preset minimum allowable heating return water temperature but the temperature difference between the temperature and the preset minimum allowable heating return water temperature is no greater than the preset temperature difference, and considering the heat loss of the heating equipment, the actual heating return water temperature may also be difficult to reach the preset minimum allowable heating return water temperature. Therefore, if the target heating water outlet temperature is lower than the preset heating water outlet temperature, the condensing gas water heater is controlled to shut down when the actual heating water outlet temperature reaches the user-set target heating water outlet temperature. Once the condensing gas water heater shuts down, the spray on / off valve 41 automatically closes.

[0086] When the target heating outlet water temperature is not lower than the preset heating outlet water temperature, when the actual heating return water temperature reaches the preset minimum allowable heating return water temperature, the heating return water temperature has risen, and no condensed water will appear on the surface of the main heat exchanger 5, and the spray switch valve 41 can be directly closed.

[0087] In some embodiments, as Figure 1 As shown, the condensing gas water heater also includes a pressure detection unit 20 and a water supply switch valve 30, wherein the pressure detection unit 20 is used to detect the pressure in the heating return pipe 11, the inlet of the water supply switch valve 30 is connected to the cold water inlet pipe 72, and the outlet of the water supply switch valve 30 is connected to the heating return pipe 11.

[0088] like Figure 5 As shown, the above-mentioned condensing gas water heater control method further includes the following steps:

[0089] Before controlling the spray switch valve 41 to open, obtain the pressure in the heating return pipe 11; when the pressure in the heating return pipe 11 is lower than the first preset pressure, close the gas proportional valve 40 of the condensing gas water heater, and add water to the heating return pipe 11 until the pressure in the heating return pipe 11 reaches the second preset pressure, then stop adding water to the heating return pipe and restart the condensing gas water heater.

[0090] After the spray switch valve 41 is opened, the nozzle 42 will form water mist with part of the heating return water in the heating return pipe 11 and spray it onto the surface of the condensing heat exchange tube 22. In order to avoid the use of the heating water in the heating return pipe 11 by the nozzle 42 and affect the normal circulation of the heating water in the heating circulation loop, before opening the spray switch valve 41, the pressure detection unit 20 is used to detect whether the pressure in the heating return pipe 11 is lower than the first preset pressure. When the pressure in the heating return pipe 11 is lower than the first preset pressure, it indicates that the nozzle 42 is not used for heating water. The use of heating water in the warm return pipe 11 will affect the normal circulation of heating water in the heating circulation loop. At this time, first close the gas proportional valve 40 of the condensing gas water heater, control the water pump 10 to work and open the water replenishment switch valve 30, and send the cold water in the cold water inlet pipe 72 into the heating return pipe through the water replenishment switch valve 30 to replenish the heating return pipe 11 until the pressure in the heating return pipe 11 reaches the second preset pressure, and then close the water replenishment switch valve 30 to stop replenishing water into the heating return pipe 11 and open the spray switch valve 41.

[0091] Among them, the first preset pressure is less than the second preset pressure. The second preset pressure refers to the maximum pressure allowed by the nozzle 42 for using the heating water in the heating return pipe 11 without affecting the normal circulation of the heating water in the heating circulation loop; and by limiting the second preset pressure, it is also possible to avoid safety hazards caused by excessive pressure in the heating circulation loop.

[0092] It should be noted that the pressure detection unit 20 can be a pressure gauge or a pressure sensor; the water supply switch valve 30 is an electromagnetic switch valve, which is convenient for automatically controlling the opening and closing of the water supply switch valve 30 according to the detection results of the pressure detection unit 20.

[0093] In some embodiments, when the spray on / off valve 41 is not open and the actual heating return water temperature in the heating return water pipe 11 is not lower than the preset minimum allowable heating return water temperature, or after the spray on / off valve 41 is closed, the speed of the smoke exhaust fan 3 is increased so that the actual speed of the smoke exhaust fan 3 reaches a second preset speed, and the load of the condensing gas water heater is switched to the load corresponding to the first preset speed. When the actual heating outlet water temperature reaches the target heating outlet water temperature set by the user, the condensing gas water heater is controlled to shut down. The second preset speed is lower than the first preset speed. It should be noted that the second preset speed is a known value determined through repeated testing.

[0094] When the spray switch valve 41 is not opened and the actual heating return water temperature in the heating return water pipe 11 is not lower than the preset minimum allowable heating return water temperature, or after the spray switch valve 41 is closed, it means that the actual heating return water temperature in the heating return water pipe 11 meets the requirements, and no condensed water will appear on the surface of the main heat exchanger 5. The exhaust fan 3 is controlled to operate at the second preset speed to ensure that the condensing gas water heater can perform normal exhaust.

[0095] The following is combined with Figure 5 , an embodiment of the control method of the condensing gas water heater is specifically introduced.

[0096] S10, during the operation of the condensing gas water heater, obtaining the actual heating return water temperature in the heating return water pipe 11;

[0097] S20, determining whether the actual heating return water temperature in the heating return water pipe 11 is lower than the preset minimum allowable heating return water temperature; if so, executing S30; if not, executing S40;

[0098] S30, increasing the speed of the smoke exhaust fan 3 so that the actual speed of the smoke exhaust fan 3 reaches a first preset speed and switching the load of the condensing gas water heater to a load corresponding to the first preset speed;

[0099] S31, determining whether the pressure in the heating return pipe 11 is lower than a first preset pressure, if so, executing S32; if not, executing S35;

[0100] S32, closing the gas proportional valve 40 of the condensing gas water heater;

[0101] S33, open the water supply switch valve 30 to supply water to the heating return pipe 11, and execute S34;

[0102] S34, determining whether the pressure in the heating return pipe 11 reaches the second preset pressure. If so, start the condensing gas water heater and return to S10; if not, return to S33;

[0103] S35, open the spray switch valve 41, obtain the target heating water outlet temperature, and then execute S36;

[0104] S36, determining whether the target heating water outlet temperature is lower than the preset heating water outlet temperature; if so, executing S37; if not, executing S38;

[0105] S37, when the actual heating water outlet temperature reaches the target heating water outlet temperature set by the user, controlling the condensing gas water heater to shut down;

[0106] S38. When the actual heating return water temperature reaches the preset minimum allowable heating return water temperature, the spray switch valve 41 is closed; and then S40 is executed;

[0107] S40, adjusting the speed of the smoke exhaust fan 3 so that the actual speed of the smoke exhaust fan 3 reaches a second preset speed and switching the load of the condensing gas water heater to a load corresponding to the second preset speed;

[0108] S41. Determine whether the actual heating water outlet temperature reaches the target heating water outlet temperature; if so, control the condensing gas water heater to shut down; if not, return to S41.

[0109] In the embodiment of the present invention, the load regulation of the condensing hot gas water heater is a prior art in the art and will not be described in detail here.

[0110] In the specific contents of the above-mentioned specific implementation methods, the various technical features can be combined in any non-contradictory manner. In order to make the description concise, not all possible combinations of the above-mentioned technical features 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.

[0111] The specific contents of the above-mentioned specific embodiments only express several embodiments of the present invention. Although the description is relatively specific and detailed, it should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be based on the appended claims.

Claims

1. Condensing gas water heater, characterized in that: include: A heating return water pipe (11) and a heating return water temperature detection unit (91), wherein the heating return water temperature detection unit (91) is used to detect the return water temperature in the heating return water pipe (11); A condensing heat exchanger comprising a condensing heat exchange shell (21) having a smoke inlet and a smoke exhaust port, and a condensing heat exchange pipe (22) disposed in the condensing heat exchange shell (21) and connected to the heating return pipe (11); A nozzle (42), the inlet of which is connected to the heating return water pipe (11) via a spray switch valve (41), and the nozzle (42) is arranged in the condensing heat exchange shell (21) and above the condensing heat exchange pipe (22), for spraying water mist onto the surface of the condensing heat exchange pipe (22).

2. The condensing gas water heater according to claim 1, characterized in that: The condensing gas water heater further comprises: A smoke exhaust fan (3), wherein the air outlet of the smoke exhaust fan (3) is connected to the smoke inlet, and the rotation speed of the smoke exhaust fan (3) is adjustable.

3. The condensing gas water heater according to claim 1, characterized in that: The condensation heat exchange shell (21) is provided with a condensation drain hole communicating with its inner cavity, and the condensation drain hole is connected to a condensation drain pipe (8); The condensed water in the condensation drain pipe (8) can exchange heat with the heating return water in the heating return water pipe (11).

4. The condensing gas water heater according to claim 3, characterized in that: The condensation drain pipe (8) includes a condensation pipe portion (81), and the heating return water pipe (11) includes a heating pipe portion (111); The condensing pipe portion (81) is sleeved outside the heating pipe portion (111) and forms a condensation heat exchange channel (200) for circulating condensed water between the condensing pipe portion (81) and the heating pipe portion (111); or, the heating pipe portion (111) is sleeved outside the condensing pipe portion (81) and forms a condensation heat exchange channel (200) for circulating heating return water between the condensing pipe portion (81); or, the condensing pipe portion (81) is wrapped around the outside of the heating pipe portion (111); or, the heating pipe portion (111) is wrapped around the outside of the condensing pipe portion (81).

5. The condensing gas water heater according to claim 4, characterized in that: The condensing pipe portion (81) and the heating pipe portion (111) are coaxially sleeved.

6. The condensing gas water heater according to claim 3, characterized in that: The condensation drain hole is arranged at the lowest position of the condensation heat exchange shell (21), and the condensation drain pipe (8) is arranged below the condensation heat exchange shell (21).

7. The condensing gas water heater according to any one of claims 1 to 6, characterized in that: The condensing heat exchange tube (22) is a corrugated tube extending from top to bottom, and the two ends of the corrugated tube in the extending direction respectively form a water inlet end and a water outlet end, and the water inlet end is located above the water outlet end.

8. The condensing gas water heater according to any one of claims 1 to 6, characterized in that: The spray switch valve (41) is arranged outside the condensation heat exchange shell (21).

9. The condensing gas water heater according to any one of claims 1 to 6, characterized in that: The condensing gas water heater further comprises: Heating water outlet pipe (12); The heating water outlet temperature detection unit (92) is used to detect the heating water outlet temperature in the heating water outlet pipe (12).

10. The condensing gas water heater according to any one of claims 1 to 6, characterized in that: The condensing gas water heater further comprises: Cold water inlet pipe (72); A water pump (10), wherein the water pump (10) is arranged on the heating return pipe (11); A pressure detection unit (20) for detecting the pressure in the heating water return pipe (11); A water replenishment switch valve (30), wherein the inlet of the water replenishment switch valve (30) is communicated with the cold water inlet pipe (72), and the outlet of the water replenishment switch valve (30) is connected to the heating return water pipe (11).

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