Method and device for protecting a water heater and water heater

Abstract

The application discloses a water heater protection method, a protection device and a water heater, and relates to the technical field of water heaters. The protection method comprises the following steps: obtaining the water inlet temperature, the water outlet temperature and the water flow of the water heater, and calculating the hot water yield of the water heater according to the water inlet temperature, the water outlet temperature and the water flow of the water heater; obtaining the air pressure grade of the fan, calculating the ratio of the hot water yield to the standard hot water yield, and determining the blockage condition of the heat exchange fin according to the air pressure grade and the ratio of the hot water yield to the standard hot water yield; and controlling the water heater to stop running when it is determined that the heat exchange fin is in the blockage condition. The application aims to prevent safety hazards such as overheating and burning caused by poor heat exchange of the water heater, and to improve the safety of users and the reliability of the water heater.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water heaters, and particularly relates to a protection method and device of a water heater and the water heater. BACKGROUND

[0002] A water heater heats cold water by burning gas. In a long-term use process, heat exchange fins are prone to be blocked by impurities such as carbon deposition, oil stains and dust.

[0003] The water heater can still operate normally in the case of blocked heat exchange fins, but the water heating is not hot due to the reduced heat exchange efficiency. In addition, there is a risk of being burned through due to the increased wall surface temperature of the heat exchanger, which affects the user safety. The exhaust gas temperature increases, and the temperature of the smoke pipe also sharply rises. If the user uses a plastic smoke pipe, there is a risk of softening or melting. SUMMARY

[0004] The main purpose of the present application is to provide a protection method and device of a water heater and the water heater, which aims to prevent the safety hazards such as overheating and burning through caused by poor heat exchange of the water heater, and improve the user safety and reliability of the water heater.

[0005] To achieve the above purpose, the present application provides a protection method of a water heater, the water heater comprising a shell assembly formed with a flue gas passage, a heat exchanger arranged in the flue gas passage and a fan for guiding airflow to flow through the flue gas passage, the heat exchanger comprising a heat exchange pipe and heat exchange fins arranged on the heat exchange pipe, the protection method of the water heater comprising:

[0006] obtaining the water inlet temperature, water outlet temperature and water flow of the water heater, and calculating the hot water production rate of the water heater according to the water inlet temperature, water outlet temperature and water flow of the water heater;

[0007] obtaining the wind pressure grade of the fan, calculating the ratio of the hot water production rate to the standard hot water production rate, and determining the blocking condition of the heat exchange fins according to the wind pressure grade and the ratio of the hot water production rate to the standard hot water production rate;

[0008] determining that the heat exchange fins are in the blocking condition, and controlling the water heater to stop operating.

[0009] In an embodiment, the determination of the blocking condition of the heat exchange fins according to the wind pressure grade and the ratio of the hot water production rate to the standard hot water production rate comprises:

[0010] determining that the heat exchange fins are in the blocking condition when the wind pressure grade is not greater than a preset grade and the ratio of the hot water production rate to the standard hot water production rate is less than a first preset ratio;

[0011] determining that the heat exchange fins are in the clogging state in a case where the wind pressure level is greater than a preset level and the ratio of the hot water production rate to the standard hot water production rate is not greater than a second preset ratio, the first preset ratio being greater than the second preset ratio.

[0012] In an embodiment, the determining the clogging state of the heat exchange fins according to the wind pressure level and the ratio of the hot water production rate to the standard hot water production rate comprises:

[0013] acquiring a duration that the ratio of the hot water production rate to the standard hot water production rate is less than the first preset ratio in a case where the wind pressure level is not greater than a preset level and the ratio of the hot water production rate to the standard hot water production rate is less than a first preset ratio;

[0014] determining that the heat exchange fins are in the clogging state in a case where the duration that the ratio of the hot water production rate to the standard hot water production rate is less than the first preset ratio is not less than a first preset duration;

[0015] acquiring a duration that the ratio of the hot water production rate to the standard hot water production rate is not greater than the second preset ratio in a case where the wind pressure level is greater than a preset level and the ratio of the hot water production rate to the standard hot water production rate is not greater than a second preset ratio;

[0016] determining that the heat exchange fins are in the clogging state in a case where the duration that the ratio of the hot water production rate to the standard hot water production rate is not greater than the second preset ratio is not less than a first preset duration.

[0017] In an embodiment, the determining the clogging state of the heat exchange fins according to the wind pressure level and the ratio of the hot water production rate to the standard hot water production rate comprises:

[0018] acquiring a first number of times that the ratio of the hot water production rate to the standard hot water production rate is less than the first preset ratio within a preset time in a case where the wind pressure level is not greater than a preset level and the ratio of the hot water production rate to the standard hot water production rate is less than a first preset ratio;

[0019] determining that the heat exchange fins are in the clogging state in a case where the first number of times is greater than a preset number of times;

[0020] acquiring a second number of times that the ratio of the hot water production rate to the standard hot water production rate is not greater than the second preset ratio within a preset time in a case where the wind pressure level is greater than a preset level and the ratio of the hot water production rate to the standard hot water production rate is not greater than a second preset ratio;

[0021] determining that the heat exchange fins are in the clogging state in a case where the second number of times is greater than a preset number of times.

[0022] In an embodiment, before the obtaining the wind pressure level of the fan, calculating the ratio of the hot water production rate to the standard hot water production rate, and determining the clogging condition of the heat exchange fins according to the wind pressure level and the ratio of the hot water production rate to the standard hot water production rate, the method further comprises:

[0023] obtaining the duty cycle of the PWM signal output to the proportional valve, and determining the standard hot water production rate according to the duty cycle of the PWM signal.

[0024] In an embodiment, the water heater further comprises an exhaust pipe, and the protection method of the water heater further comprises:

[0025] obtaining the exhaust temperature of the exhaust pipe;

[0026] controlling the water heater to stop working when the exhaust temperature is greater than a preset temperature.

[0027] In an embodiment, the controlling the water heater to stop working when the exhaust temperature is greater than a preset temperature comprises:

[0028] obtaining a first duration during which the exhaust temperature is greater than the preset temperature;

[0029] controlling the water heater to stop working when the first duration is not less than a second preset duration.

[0030] In an embodiment, the controlling the water heater to stop working when the first duration is not less than a second preset duration comprises:

[0031] when the first duration is not less than the second preset duration, reducing the load of the water heater to a preset load, returning to obtain the exhaust temperature of the exhaust pipe, and obtaining a second duration during which the exhaust temperature is greater than the preset temperature when the exhaust temperature is greater than the preset temperature; when the first duration is less than the second preset duration, returning to obtain the exhaust temperature of the exhaust pipe.

[0032] controlling the water heater to stop working when the second duration is not less than a third preset duration.

[0033] In an embodiment, the protection method of the water heater further comprises:

[0034] controlling the water heater to stop working and outputting a corresponding fault prompt when it is determined that the heat exchange fins are clogged or the exhaust temperature is greater than a preset temperature.

[0035] The application further provides a protection device, which comprises a memory, a processor, and a protection method stored in the memory and executable on the processor, and the protection method comprises the steps of the protection method of any one of the water heaters.

[0036] The application further provides a water heater, which comprises a shell assembly formed with a flue gas passage, a heat exchanger arranged in the flue gas passage, and a fan for guiding airflow to flow through the flue gas passage, and the heat exchanger comprises heat exchange pipes and heat exchange fins arranged on the heat exchange pipes.

[0037] The water heater further comprises the protection device described above, and / or the water heater uses the protection method of any one of the water heaters.

[0038] The protection method of the water heater comprises obtaining the water inlet temperature, the water outlet temperature and the water flow rate of the water heater, and calculating the hot water yield of the water heater according to the water inlet temperature, the water outlet temperature and the water flow rate of the water heater; obtaining the wind pressure grade of the fan, calculating the ratio of the hot water yield to the standard hot water yield, and determining the clogging condition of the heat exchange fins according to the wind pressure grade and the ratio of the hot water yield to the standard hot water yield; and controlling the water heater to stop running when it is determined that the heat exchange fins are in the clogging condition. In this way, in actual application, the water heater can identify the clogging condition of the heat exchange fins when the protection method of the water heater is running, and stop working when the clogging of the heat exchange fins is identified, so as to avoid the accumulation of heat due to the decrease of heat exchange efficiency and the continuous increase of the wall temperature of the heat exchanger, thereby effectively reducing the risk of the heat exchanger being burned through by high temperature. The shutdown effectively controls the decrease of the exhaust gas temperature, and prevents the safety accidents caused by the softening or even melting of the flue due to high temperature. BRIEF DESCRIPTION OF DRAWINGS

[0039] The accompanying drawings, which are incorporated into and form a part of the specification, illustrate an embodiment consistent with the present application and, together with the description, serve to explain the principles of the application.

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, those skilled in the art can obtain other drawings from these drawings without any creative effort.

[0041] Figure 1 The flowchart of an embodiment of the present application;

[0042] Figure 2 The flowchart of another embodiment of the present application;

[0043] Figure 3 The flowchart of still another embodiment of the present application;

[0044] Figure 4 Flowchart of one embodiment of the present application;

[0045] Figure 5 Flowchart of another embodiment of the present application;

[0046] Figure 6 Flowchart of yet another embodiment of the present application;

[0047] Figure 7 Flowchart of still another embodiment of the present application;

[0048] Figure 8 Structure diagram of a water heater according to one embodiment of the present application;

[0049] Figure 9 Structure diagram of a water heater according to yet another embodiment of the present application.

[0050] Reference signs:

[0051] 01, housing assembly; 10, heat exchange pipe; 20, heat exchange fin; 30, exhaust pipe.

[0052] The purposes, functional features and advantages of the present application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0053] It should be understood that the specific embodiments described herein are merely intended to explain the technical solutions of the present application, and are not intended to limit the present application.

[0054] In order to better understand the technical solutions of the present application, the following will be described in detail in conjunction with the accompanying drawings and specific embodiments.

[0055] The water heater is a commonly used hot water supply device in modern families. Its working principle is to generate high-temperature flue gas by burning fuel gas, and to transfer the heat in the flue gas to the cold water flowing through the heat exchanger, so as to realize water heating. In an example, referring to Figure 8 and Figure 9The water heater comprises a shell assembly 01 formed with a flue gas passage, a heat exchanger arranged in the flue gas passage, and a fan for guiding airflow to flow through the flue gas passage. The heat exchanger mainly comprises heat exchange pipes 10 and heat exchange fins 20 arranged on the heat exchange pipes 10. The heat exchange fins 20 can be spiral fins, which are arranged around the heat exchange pipes 10. The heat exchange pipes 10 are connected to the water inlet pipe and the water outlet pipe. During the heat exchange process, the high-temperature flue gas exchanges heat with the heat exchange pipes 10 and the heat exchange fins 20. The heat exchange fins 20 can increase the heat exchange area of the heat exchange pipes 10 and improve the heat exchange efficiency. The flue gas passage can be understood as comprising a combustion chamber, a heat exchange chamber, a flue gas discharge passage, and a flue gas discharge pipe 30. The heat exchange pipes 10 can be arranged in multiple numbers and can be distributed in the combustion chamber and the heat exchange chamber. Here, no limitation is made, and the heat exchange pipes 10 can also be arranged around the outside of the combustion chamber.

[0056] However, during the long-term use of the water heater, the heat exchange fins 20 are prone to clogging. This clogging is mainly caused by the following factors: first, impurities such as carbon deposition and oil stains generated during the combustion of gas will gradually adhere to the surface of the fins; second, dust and impurities in the air will also deposit in the fin gaps during the flow of flue gas; in addition, sulfides in the gas may form solid particles such as sulfates in a high-temperature environment, further aggravating the clogging of the fins.

[0057] When the heat exchange fins 20 are clogged, it will seriously affect the normal working performance of the water heater. Specifically, the clogged fins will significantly reduce the heat exchange efficiency of the heat exchanger, causing the heat in the flue gas to be unable to be fully transferred to the cold water, so that the temperature of the heated water cannot meet the set requirements, affecting the normal use of the user.

[0058] More seriously, the reduction of the heat exchange efficiency will cause the wall surface temperature of the heat exchanger to abnormally rise. Under normal working conditions, the wall surface temperature of the heat exchanger should be controlled within a safe range, but when the fins are clogged, the flow of flue gas is blocked, and heat accumulates in the local area, causing the wall surface temperature to rise too high. This abnormal temperature rise not only accelerates the aging of the equipment, but also has the safety hazard of the heat exchanger being burned through, seriously threatening the personal safety of the user.

[0059] At the same time, the decrease in the heat exchange efficiency will also cause the exhaust gas temperature to rise significantly. Since the heat cannot be effectively transferred to the cold water, more heat is discharged with the flue gas, causing the exhaust gas temperature to rise significantly. This phenomenon will further cause the temperature of the smoke pipe to rise sharply. When the user uses a plastic smoke pipe, there is a risk that the smoke pipe will soften or even melt due to high temperature, which may cause safety accidents such as flue gas leakage.

[0060] Therefore, the present application proposes a protection method for a water heater. In an embodiment, with reference to Figure 1 The protection method for the water heater comprises the following steps.

[0061] Step S100: obtaining the water inlet temperature, the water outlet temperature and the water flow rate of the water heater, and calculating the hot water yield of the water heater according to the water inlet temperature, the water outlet temperature and the water flow rate of the water heater;

[0062] Step S200: obtaining the air pressure level of the fan, calculating the ratio of the hot water yield to the standard hot water yield, and determining the blockage condition of the heat exchange fin 20 according to the air pressure level and the ratio of the hot water yield to the standard hot water yield;

[0063] Step S300: controlling the water heater to stop running when it is determined that the heat exchange fin 20 is in the blockage condition.

[0064] It should be noted that the present application can obtain the water inlet temperature and the water outlet temperature by respectively arranging temperature sensors in the water inlet pipeline and the water outlet pipeline. The present application can also obtain the water inlet flow rate and the water outlet flow rate by arranging water flow sensors in the water inlet pipeline and the water outlet pipeline, and take one of them as the above-mentioned water flow rate.

[0065] It should be noted that the hot water yield refers to the amount of water that can be heated to a certain temperature rise per unit time under the current operating condition of the water heater. Specifically, the hot water yield of the water heater is calculated according to the water inlet temperature, the water outlet temperature and the water flow rate of the water heater, which is to calculate the difference between the water outlet temperature and the water inlet temperature, and take the quotient of the difference and the water flow rate as the hot water yield.

[0066] It should be noted that the standard hot water yield refers to the hot water yield that the water heater should theoretically reach under the current gas input power. In an embodiment, since the water heater adjusts the opening degree of the proportional valve by a pulse width modulation (PWM) signal in actual application, the present application can obtain the duty cycle of the PWM signal output to the proportional valve, and determine the standard hot water yield according to the duty cycle of the PWM signal. The higher / lower the PWM duty cycle, the larger / smaller the opening degree of the proportional valve, the larger / smaller the current gas input power, and accordingly, the higher / lower the hot water yield that the water heater should theoretically reach.

[0067] In another embodiment, when the water heater has calibrated the standard hot water yield under each gear before leaving the factory, the present application can also determine the standard hot water yield according to the current working gear of the water heater (such as high fire, medium fire, low fire). For example, the standard hot water yield of the water heater is 10.3 L / MIN at high fire gear, 6.9 L / MIN at medium fire gear, and 4.6 L / MIN at low fire gear.

[0068] It should be noted that the ratio of hot water yield to standard hot water yield is used to reflect the degree of attenuation of the current heat exchange efficiency of the water heater relative to the theoretical performance.

[0069] It should be noted that the existing water heater generally does not have a technical solution to specifically detect the blockage of the heat exchange fin 20. In actual operation, the water heater system mainly monitors the patency of the flue gas passage through the air pressure sensor, and when it detects an increase in exhaust resistance, it is judged that the exhaust is blocked. At this time, the measures usually taken by the water heater system are to increase the fan speed (increase the air pressure level of the fan) to enhance the exhaust capacity of the flue gas duct and supplement sufficient air to the combustion chamber to prevent incomplete combustion of gas due to lack of oxygen.

[0070] Therefore, the air pressure level of the fan can be used as a grading index for quantifying the resistance of the exhaust system in the water heater, which reflects the degree of flue resistance that the fan needs to overcome during operation to maintain normal exhaust. The greater / smaller the air pressure level of the fan, the more / less serious the blockage of the flue passage. In a specific embodiment, when the air pressure level is 1-10, the flue passage is unobstructed and the blockage is basically none. When the air pressure level is 11-17, the flue passage is lightly blocked. When the air pressure level is 18-30, the flue passage is obviously blocked.

[0071] It can be understood that the water heater generally controls the speed of the fan by outputting a PWM signal, so the present application can determine the air pressure level of the fan by obtaining the duty cycle of the PWM signal used to control the fan. The greater / smaller the duty cycle of the PWM signal, the greater / lower the air pressure level of the fan.

[0072] However, since the exhaust pipe 30 and the heat exchange fin 20 are both located in the flue gas duct, the cause of the blockage of the flue gas duct may be the blockage of the exhaust pipe 30 or the blockage of the heat exchange fin 20, or both. The above control logic based on single air pressure feedback cannot distinguish the specific cause of the increase in exhaust resistance, i.e., it cannot determine whether the flue passage is blocked by the exhaust pipe 30 or the heat exchange fin 20. Although both types of blockage exhibit an increase in air pressure, there are essential differences in their effects on hot water yield:

[0073] If the exhaust pipe 30 is specifically blocked, the main problem is that the exhaust of flue gas is blocked, which may lead to lack of oxygen, incomplete combustion or flameout. At this time, forced exhaust and air supplementation by increasing the fan speed and air pressure level can help restore combustion stability and slow down the decline in heat exchange efficiency due to poor exhaust, which has a positive improvement effect.

[0074] If the heat exchange fins 20 are specifically blocked, the blockage occurs inside the heat exchanger, not only increasing the flue gas flow resistance, but more importantly, severely weakening the heat exchange area and heat transfer capacity, resulting in the inability to effectively transfer heat to the water flow. At this time, even if the fan increases the wind pressure and enhances the exhaust smoke, it cannot improve the heat exchange performance. At the same time, the heat generated by combustion accumulates locally in the heat exchanger, causing the wall temperature to abnormally rise, bringing safety hazards such as heat exchanger burning, exhaust smoke temperature being too high, etc.

[0075] Based on the above, although both the exhaust smoke pipe 30 blockage and the heat exchange fin 20 blockage can cause the wind pressure to rise, there are essential differences in their effects on hot water yield. The heat exchange fin 20 blockage directly destroys the heat exchange capacity, resulting in a significant decrease in hot water yield; while the exhaust smoke pipe 30 blockage mainly affects the combustion stability, and with the fan making up for the wind, the decrease in hot water yield is limited.

[0076] In a specific embodiment, the blockage conditions of the exhaust smoke pipe 30 and the heat exchange fin 20 are the same as those of the flue gas pipe described above, and all include no blockage, slight blockage, and obvious blockage. When the water heater has slight blockage or obvious blockage in the exhaust smoke pipe 30, the ratio of its hot water yield to the standard hot water yield is greater than the minimum value that the ratio of the two should maintain. When the water heater has slight blockage and obvious blockage in the heat exchange fin 20, the ratio of its hot water yield to the standard hot water yield is not greater than the minimum value that the ratio of the two should maintain.

[0077] Therefore, the present application can identify the blockage condition of the heat exchange fin 20 based on the ratio of the hot water yield to the standard hot water yield under different blockage conditions.

[0078] In a feasible embodiment, the determination of the blockage condition of the heat exchange fin 20 according to the wind pressure level and the ratio of the hot water yield to the standard hot water yield comprises:

[0079] In the case where the wind pressure level is not greater than a preset level, and the ratio of the hot water yield to the standard hot water yield is less than a first preset ratio, it is determined that the heat exchange fin 20 is in a blocked state;

[0080] In the case where the wind pressure level is greater than a preset level, and the ratio of the hot water yield to the standard hot water yield is not greater than a second preset ratio, it is determined that the heat exchange fin 20 is in a blocked state; the first preset ratio is greater than the second preset ratio.

[0081] It should be noted that when the wind pressure level is not greater than the preset level, for example, the wind pressure level is not greater than the 18th level in the above embodiment, the blockage of the flue gas duct is no blockage or mild blockage, so that the smoke exhaust resistance of the smoke exhaust pipe 30 increases by a small amplitude. The first preset ratio is the minimum value of the ratio of the hot water yield to the standard hot water yield when the flue gas duct is in the mild blockage state, which can be 35% to 45%, and the specific value is set by the researchers according to the actual situation, which is not limited here.

[0082] Based on the above embodiment, it is known that when the smoke exhaust pipe 30 is in the mild blockage or obvious blockage state, the ratio of the hot water yield to the standard hot water yield of the water heater is greater than the minimum value that the ratio of the two should maintain. When the heat exchange fin 20 is in the mild blockage and obvious blockage state, the ratio of the hot water yield to the standard hot water yield of the water heater is less than the minimum value that the ratio of the two should maintain. Therefore, the present application can determine that the heat exchange fin 20 is not in the blockage state when the wind pressure level is not greater than the preset level and the ratio of the hot water yield to the standard hot water yield is greater than the first preset ratio, which causes the flue gas duct to be in the mild blockage state. The present application can also determine that the heat exchange fin 20 is in the blockage state when the wind pressure level is not greater than the preset level and the ratio of the hot water yield to the standard hot water yield is not greater than the first preset ratio.

[0083] It should be noted that in the case of wind pressure level greater than the preset level, for example, the wind pressure level is greater than the above-mentioned 18 levels of the embodiment, the flue gas pipeline is obviously blocked, so that the smoke exhaust resistance of the smoke exhaust pipe 30 increases by a large margin. In this context, the combustion efficiency of the water heater will decrease due to insufficient oxygen supply or flue gas backflow, and the water production rate will decrease to a certain extent, which is a reasonable degradation of system performance. If the ratio of the water production rate to the standard water production rate still uses the same judgment threshold as the working condition of the wind pressure level not greater than the preset level (the first preset ratio), it is easy to misjudge the normal performance fluctuation as a heat exchange failure, causing false shutdown and affecting user experience. Therefore, in the case of wind pressure level greater than the preset level, a lower judgment threshold "second preset ratio" can be introduced for judgment, and the second preset ratio can be between 25% and 35%, which is set by the R&D personnel according to the actual situation, and is not limited here. Specifically, the present application can determine that the heat exchange fin 20 is not in a blocked state when the wind pressure level is greater than the preset level and the ratio of the water production rate to the standard water production rate is not less than the second preset ratio. In this case, the smoke exhaust pipe 30 is obviously blocked, which causes the flue gas pipeline to be obviously blocked. The present application can also determine that the heat exchange fin 20 is in a blocked state when the wind pressure level is greater than the preset level and the ratio of the water production rate to the standard water production rate is not greater than the second preset ratio. Specifically, it may be that the heat exchange fin 20 is obviously blocked, or that the degree of blockage of the smoke exhaust pipe 30 or the heat exchange fin 20 is above the mild blockage, so that the flue gas pipeline is obviously blocked.

[0084] In this way, the present application can accurately identify the blockage state of the heat exchange fin 20 by combining the composite judgment mechanism of the wind pressure level and the water production rate ratio. When the fan wind pressure level is low, a higher threshold is used for the judgment of the water production rate ratio to achieve high sensitivity detection, and when the fan wind pressure level is high, a lower threshold is used for the judgment of the water production rate ratio to avoid misjudgment, thereby ensuring user safety while improving the stability of the water heater operation. This method can identify and actively protect against heat exchange failure without increasing hardware costs, effectively preventing overheating and burning of the heat exchanger, excessive exhaust gas temperature, and other safety hazards, and has significant technical progress and practical value.

[0085] In actual application, transient conditions such as water pressure fluctuations, sudden changes in water temperature, and short-term combustion instability may cause the water production rate to decrease for a short time. If it is immediately determined to be a failure and the water heater is controlled to stop working, the user's experience will be reduced. Therefore, in an embodiment, the ratio of the water production rate to the standard water production rate is determined according to the wind pressure level and the ratio of the water production rate to the standard water production rate. Figure 2 , the determination of the blockage of the heat exchange fin 20 according to the wind pressure level and the ratio of the water production rate to the standard water production rate includes:

[0086] Step S210: In the case that the wind pressure level is not greater than the preset level, and the ratio of the hot water yield to the standard hot water yield is less than the first preset ratio, the duration that the ratio of the hot water yield to the standard hot water yield is less than the first preset ratio is obtained.

[0087] Step S211: In the case that the duration that the ratio of the hot water yield to the standard hot water yield is less than the first preset ratio is not less than the first preset duration, it is determined that the heat exchange fin 20 is in the blocked state.

[0088] Step S220: In the case that the wind pressure level is greater than the preset level, and the ratio of the hot water yield to the standard hot water yield is not greater than the second preset ratio, the duration that the ratio of the hot water yield to the standard hot water yield is not greater than the second preset ratio is obtained.

[0089] Step S221: In the case that the duration that the ratio of the hot water yield to the standard hot water yield is not greater than the second preset ratio is not less than the first preset duration, it is determined that the heat exchange fin 20 is in the blocked state.

[0090] It can be understood that the first preset duration is the shortest time that the ratio of the hot water yield to the standard hot water yield is lower than the preset ratio, which can be 20 seconds, 23 seconds or 25 seconds, and is set by the developer according to the actual situation, which is not limited here.

[0091] In this way, on the basis of the original "wind pressure level + yield ratio" composite judgment, the duration judgment mechanism is further introduced, the duration of the abnormal state is detected, the misjudgment caused by instantaneous fluctuation or temporary interference is avoided, and the accuracy and reliability of fault identification are improved.

[0092] In another embodiment, with reference to Figure 3 , the determination of the blocking condition of the heat exchange fin 20 according to the wind pressure level and the ratio of the hot water yield to the standard hot water yield comprises:

[0093] Step S230: In the case that the wind pressure level is not greater than the preset level, and the ratio of the hot water yield to the standard hot water yield is less than the first preset ratio, the first number of times that the ratio of the hot water yield to the standard hot water yield is less than the first preset ratio within a preset time is obtained.

[0094] Step S231: In the case that the first number of times is greater than a preset number of times, it is determined that the heat exchange fin 20 is in the blocked state.

[0095] Step S240: In the case that the wind pressure level is greater than the preset level, and the ratio of the hot water yield to the standard hot water yield is not greater than the second preset ratio, obtaining a second number of times that the ratio of the hot water yield to the standard hot water yield is not greater than the second preset ratio within a preset time;

[0096] Step S241: In the case that the second number of times is greater than a preset number of times, determining that the heat exchange fins 20 are in a blocked state.

[0097] It should be noted that the preset number of times is the maximum cumulative number of times of the event that the ratio of the hot water yield to the standard hot water yield is not greater than the second preset ratio within a preset time. The preset time can be 12 hours or 24 hours, and the preset number of times can be 3 or 4. The preset time and the preset number of times can be set by the developer according to the actual situation, and are not limited herein.

[0098] In this way, the application counts the number of times that the abnormal state of the hot water yield occurs within a preset time, and determines that the heat exchange fins 20 are blocked when the cumulative number of times exceeds a preset threshold, effectively filtering incidental interference, avoiding misjudgment caused by environmental fluctuations, and improving the reliability of the water heater operation and user experience.

[0099] In yet another embodiment, with reference to Figure 4 , the determination of the blocking condition of the heat exchange fins 20 according to the wind pressure level and the ratio of the hot water yield to the standard hot water yield comprises:

[0100] Step S250: In the case that the wind pressure level is not greater than the preset level, and the ratio of the hot water yield to the standard hot water yield is less than the first preset ratio, obtaining a first number of times that the ratio of the hot water yield to the standard hot water yield is less than the first preset ratio within a preset time for a duration not less than a first preset duration;

[0101] Step S251: In the case that the first number of times is greater than a preset number of times, determining that the heat exchange fins 20 are in a blocked state.

[0102] Step S260: In the case that the wind pressure level is greater than the preset level, and the ratio of the hot water yield to the standard hot water yield is not greater than the second preset ratio, obtaining a second number of times that the ratio of the hot water yield to the standard hot water yield is not greater than the second preset ratio within a preset time for a duration not less than a first preset duration;

[0103] Step S261: In the case that the second number of times is greater than a preset number of times, determining that the heat exchange fins 20 are in a blocked state.

[0104] It should be noted that the preset number of times is the maximum cumulative number of times of the event of "the ratio of the hot water yield to the standard hot water yield being not greater than the second preset ratio" occurring within a preset time, the preset time can be 12 hours or 24 hours, the preset number of times can be 3 or 4, and the specific value is set by the R&D personnel according to the actual situation, which is not limited here.

[0105] In this way, the duration judgment mechanism and the cumulative number judgment mechanism of the above-mentioned embodiments are introduced at the same time, which can more effectively filter incidental interference, avoid misjudgment caused by environmental fluctuations, and improve the reliability of the water heater operation and user experience.

[0106] Through the above setting, in actual application, the water heater can identify the blockage of the heat exchange fin 20 when the protection method of the water heater is running, and stop working when the heat exchange fin 20 is blocked, thereby avoiding the accumulation of heat due to the decrease of heat exchange efficiency, and the continuous rise of the wall temperature of the heat exchanger, thereby effectively reducing the risk of the heat exchanger being burned by high temperature. And shutdown can effectively control the temperature drop of the exhaust pipe, prevent the safety accident of the exhaust pipe softening or even melting due to high temperature.

[0107] In an embodiment of the present application, with reference to Figure 5 , the water heater further comprises an exhaust pipe 30, and the protection method of the water heater further comprises:

[0108] Step S500: acquiring the exhaust temperature of the exhaust pipe 30;

[0109] Step S600: controlling the water heater to stop working in the case that the exhaust temperature is greater than a preset temperature.

[0110] It should be noted that the preset temperature is the maximum temperature that the exhaust pipe 30 can withstand, which can be between 65-75℃, and the specific value is set by the R&D personnel according to the actual situation, which is not limited here.

[0111] In this embodiment, the present application can set a temperature sensing device on the exhaust pipe 30 to detect the exhaust temperature of the exhaust pipe 30. In order to improve the accuracy of detecting the exhaust temperature, the temperature sensing device can be arranged at the middle axis position of the outlet of the exhaust pipe 30, and at a position about 30mm away from the outlet, so that the temperature sensing device can detect the exhaust temperature of the main flow area of the flue gas, avoid the heat dissipation interference of the wall surface of the exhaust pipe 30, and thus obtain more accurate core flue gas temperature.

[0112] Through the above setting, in actual application, the water heater can control the water heater to stop working in the case that the exhaust temperature is greater than a preset temperature when the protection method of the water heater is running, thereby avoiding the exhaust pipe 30 being burned by the too high exhaust temperature.

[0113] In actual operation of the water heater, the exhaust gas temperature may be temporarily increased in the working conditions of unstable combustion at the initial ignition, gas pressure fluctuation leading to instantaneous high load combustion, etc. These working conditions will cause the exhaust gas temperature to be temporarily over-standard, but are not real faults. In an embodiment, the control of stopping the water heater from working when the exhaust gas temperature is greater than the preset temperature and the corresponding fault prompt are made according to Figure 6 , which include:

[0114] Step S610: acquiring a first duration that the exhaust gas temperature is greater than the preset temperature;

[0115] Step S620: controlling the water heater to stop working when the first duration is not less than a second preset duration.

[0116] It should be noted that the second preset duration is a minimum duration threshold required for judging whether to reduce the load of the water heater to a preset load, which can be valued within 25-35 seconds, and is specifically set by the R&D personnel according to the actual situation, which is not limited here.

[0117] Through the above setting, the water heater is controlled to stop working only when the exhaust gas temperature is continuously too high, which effectively avoids the false action caused by the temporary temperature increase due to the transient working conditions such as ignition and temperature adjustment, and improves the reliability and accuracy of the over-temperature protection of the water heater.

[0118] In another embodiment, reference is made to Figure 7 , which includes:

[0119] Step S621: reducing the load of the water heater to a preset load when the first duration is not less than the second preset duration, and returning to acquire the exhaust gas temperature of the exhaust gas pipe 30 and acquire a second duration that the exhaust gas temperature is greater than the preset temperature; returning to acquire the exhaust gas temperature of the exhaust gas pipe 30 when the first duration is less than the second preset duration.

[0120] Step S622: controlling the water heater to stop working when the second duration is not less than a third preset duration.

[0121] It should be noted that the third preset duration is a minimum duration threshold for the exhaust gas temperature still being over-standard after the load reduction operation, which can be valued within 12-17 seconds, and is specifically set by the R&D personnel according to the actual situation, which is not limited here.

[0122] The preset load is an operation power used for temporary adjustment of the water heater in the above protection method, and is used for tentative operation or fault mitigation of the water heater. The preset load can be 85% to 95% of the rated power of the water heater, and is set by the R&D personnel according to the actual situation, which is not limited herein.

[0123] It should be noted that in actual application, the temperature sensing device may output a higher temperature signal due to reasons such as carbon deposition, aging or circuit noise, which is easy to cause the water heater system to misjudge and stop, or temporary working condition fluctuations such as strong wind backflow into the exhaust pipe 30, sudden change of gas pressure or ignition fluctuation, etc., which may also cause the exhaust temperature to be temporarily too high, causing the water heater system to misjudge and stop, thereby affecting the user's experience. In view of this, the present application first controls the load of the water heater to decrease to the preset load when the first-identified duration of the exhaust temperature being too high is too long, rather than directly stopping, giving the temperature sensing device or temporary working condition fluctuations a recovery and stabilization time window, avoiding the water heater from stopping due to signal abnormalities or temporary working condition fluctuations, and improving the user's experience.

[0124] The present application also acquires the exhaust temperature of the exhaust pipe 30 again after the load of the water heater is reduced to the preset load, thereby verifying whether the temperature sensing device fails. When the exhaust temperature is greater than the preset temperature, and the second duration is not less than the third preset duration, it indicates that the actual exhaust temperature of the exhaust pipe 30 is too high, and it is not that the detection of the temperature sensing device deviates, or that the temporary working condition fluctuation causes the exhaust temperature to be too high. Therefore, the water heater can be controlled to stop under this condition to avoid damage to the exhaust pipe 30 due to high temperature.

[0125] In this way, the present application realizes a hierarchical protection mechanism, which can try to restore the normal operation of the water heater by reducing the load after confirming the high temperature risk, thereby avoiding direct stop caused by reversible abnormalities. Only in the case of invalid load reduction and persistent high temperature, the final stop is executed, which not only ensures the use safety, but also improves the stability of the water heater operation and the user experience.

[0126] It should be noted that the present application also returns to acquire the exhaust temperature of the exhaust pipe 30 in the case that the first duration is less than the second preset duration, or the second duration is less than the third preset duration, thereby maintaining the continuous dynamic monitoring of the exhaust temperature.

[0127] In an embodiment of the present application, the protection method of the water heater further comprises:

[0128] In the case that the heat exchange fins 20 are blocked or the exhaust temperature is greater than the preset temperature, the water heater is controlled to stop working, and a corresponding fault prompt is output.

[0129] In the embodiment, the fault prompt can include a fault code, text information, an audible and visual alarm, or a remote notification, etc., for indicating the abnormal type. The setting not only can terminate the dangerous operation in time to ensure the safety of the user, but also can provide clear fault guidance to facilitate the user or the maintenance personnel to understand and subsequent maintenance. For example, when it is determined that the heat exchange fin 20 is in a clogging state, a fault prompt that the heat exchange fin 20 is clogged can be output to an external terminal through wireless communication, so that the maintenance personnel can know the position of the water heater where the fault occurs and take corresponding solution measures. Alternatively, when the exhaust gas temperature is greater than the preset temperature, the water heater control alarm light flashes to prompt the user to move away from the water heater, so as to avoid the situation that the user still approaches the water heater when the exhaust gas temperature is too high.

[0130] The application provides a protection device, comprising: at least one processor; and a memory connected with the at least one processor in communication; wherein the memory stores a protection method executable on the processor, and the protection method comprises the steps of the protection method of the water heater according to any one of the above embodiments.

[0131] The protection device provided by the application adopts the protection method of the water heater according to the above embodiments. Compared with the prior art, the protection device provided by the application has the same beneficial effects as the protection method of the water heater provided by the above embodiments, and other technical features in the protection device are the same as the features disclosed in the previous embodiment method, which will not be repeated here.

[0132] It should be understood that parts of the application disclosed herein can be realized by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0133] The above is merely specific implementation of the application, but the protection scope of the application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the application, which should be covered by the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

[0134] The application also provides a water heater, which comprises a shell assembly 01 formed with a flue gas passage, a heat exchanger arranged in the flue gas passage, and a fan for guiding airflow to flow through the flue gas passage, the heat exchanger comprising heat exchange pipes 10 and heat exchange fins 20 arranged on the heat exchange pipes 10.

[0135] The water heater also comprises the protection device as described above; and / or, the water heater uses the protection method of the water heater according to any one of the above embodiments.

[0136] It should be noted that the water heater comprises the protection device described above, and / or uses the protection method of the water heater described above. The specific embodiments of the protection device and the specific embodiments of the protection method of the water heater are referred to the above embodiments, and since the water heater adopts all the technical solutions of the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0137] The above is only part of the embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation made by using the content of the present application specification and drawings, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.

Claims

1. A method of protecting a water heater, the water heater including a housing assembly formed with a flue passage, a heat exchanger disposed in the flue passage, and a fan for directing an airflow through the flue passage, the heat exchanger including heat exchange tubes and heat exchange fins disposed on the heat exchange tubes, the method comprising: The protection method of the water heater comprises: ​ obtaining the water inlet temperature, the water outlet temperature and the water flow of the water heater, and calculating the hot water yield of the water heater according to the water inlet temperature, the water outlet temperature and the water flow of the water heater; obtaining the wind pressure grade of the fan, calculating the ratio of the hot water yield to the standard hot water yield, and determining the clogging condition of the heat exchange fins according to the wind pressure grade and the ratio of the hot water yield to the standard hot water yield; determining that the heat exchange fins are in the clogging condition, and controlling the water heater to stop running.

2. The method of protecting a water heater as defined in claim 1, wherein, The determination of the clogging condition of the heat exchange fins according to the wind pressure grade and the ratio of the hot water yield to the standard hot water yield comprises: in the case that the wind pressure grade is not greater than a preset grade and the ratio of the hot water yield to the standard hot water yield is less than a first preset ratio, determining that the heat exchange fins are in the clogging condition; in the case that the wind pressure grade is greater than the preset grade and the ratio of the hot water yield to the standard hot water yield is not greater than a second preset ratio, determining that the heat exchange fins are in the clogging condition; the first preset ratio is greater than the second preset ratio.

3. The method of protecting a water heater as defined in claim 1, wherein, The determination of the clogging condition of the heat exchange fins according to the wind pressure grade and the ratio of the hot water yield to the standard hot water yield comprises: in the case that the wind pressure grade is not greater than a preset grade and the ratio of the hot water yield to the standard hot water yield is less than a first preset ratio, obtaining the duration that the ratio of the hot water yield to the standard hot water yield is less than the first preset ratio; in the case that the duration that the ratio of the hot water yield to the standard hot water yield is less than the first preset ratio is not less than a first preset duration, determining that the heat exchange fins are in the clogging condition; in the case that the wind pressure grade is greater than the preset grade and the ratio of the hot water yield to the standard hot water yield is not greater than a second preset ratio, obtaining the duration that the ratio of the hot water yield to the standard hot water yield is not greater than the second preset ratio; in the case that the duration that the ratio of the hot water yield to the standard hot water yield is not greater than the second preset ratio is not less than the first preset duration, determining that the heat exchange fins are in the clogging condition.

4. The water heater protection method of claim 1, wherein, The determination of the clogging condition of the heat exchange fins according to the wind pressure grade and the ratio of the hot water yield to the standard hot water yield comprises: in the case that the wind pressure grade is not greater than a preset grade and the ratio of the hot water yield to the standard hot water yield is less than a first preset ratio, obtaining the first number of times that the ratio of the hot water yield to the standard hot water yield is less than the first preset ratio within a preset time; in the case that the first number of times is greater than a preset number of times, determining that the heat exchange fins are in the clogging condition; in the case that the wind pressure grade is greater than the preset grade and the ratio of the hot water yield to the standard hot water yield is not greater than a second preset ratio, obtaining the second number of times that the ratio of the hot water yield to the standard hot water yield is not greater than the second preset ratio within the preset time; in the case that the second number of times is greater than the preset number of times, determining that the heat exchange fins are in the clogging condition.

5. The method of protecting a water heater as defined in claim 1, wherein, The determination of the clogging condition of the heat exchange fins according to the wind pressure grade and the ratio of the hot water yield to the standard hot water yield comprises: in a case where the wind pressure level is not greater than the preset level and the ratio of the hot water production rate to the standard hot water production rate is less than a first preset ratio, obtaining a first number of times that a duration for which the ratio of the hot water production rate to the standard hot water production rate is less than the first preset ratio within a preset time is not less than a first preset duration; in a case where the first number of times is greater than a preset number of times, determining that the heat exchange fins are in the clogging state; in a case where the wind pressure level is greater than the preset level and the ratio of the hot water production rate to the standard hot water production rate is not greater than a second preset ratio, obtaining a second number of times that a duration for which the ratio of the hot water production rate to the standard hot water production rate is not greater than the second preset ratio within the preset time is not less than the first preset duration; in a case where the second number of times is greater than the preset number of times, determining that the heat exchange fins are in the clogging state.

6. The method of protecting a water heater as defined in claim 1, wherein, The method further comprises, before obtaining the wind pressure level of the fan, calculating the ratio of the hot water production rate to the standard hot water production rate, and determining the clogging state of the heat exchange fins according to the wind pressure level and the ratio of the hot water production rate to the standard hot water production rate, the method further comprises: obtaining a duty cycle of a PWM signal output to the proportional valve, and determining the standard hot water production rate according to the duty cycle of the PWM signal.

7. The method of protecting a water heater as defined in claim 1, wherein, The water heater further comprises an exhaust pipe, and the protection method of the water heater further comprises: obtaining an exhaust temperature of the exhaust pipe; in a case where the exhaust temperature is greater than a preset temperature, controlling the water heater to stop working.

8. The method of protecting a water heater as defined in claim 7, wherein, The method further comprises, before obtaining the wind pressure level of the fan, calculating the ratio of the hot water production rate to the standard hot water production rate, and determining the clogging state of the heat exchange fins according to the wind pressure level and the ratio of the hot water production rate to the standard hot water production rate, the method further comprises: obtaining a first duration for which the exhaust temperature is greater than the preset temperature; in a case where the first duration is not less than a second preset duration, controlling the water heater to stop working.

9. The method of claim 8, wherein the step of determining the temperature of the water in the tank comprises the steps of: determining the temperature of the water in the tank by measuring the temperature of the water in the tank. The method further comprises, before obtaining the wind pressure level of the fan, calculating the ratio of the hot water production rate to the standard hot water production rate, and determining the clogging state of the heat exchange fins according to the wind pressure level and the ratio of the hot water production rate to the standard hot water production rate, the method further comprises: in a case where the first duration is not less than the second preset duration, reducing a load of the water heater to a preset load, returning to obtain the exhaust temperature of the exhaust pipe, and in a case where the exhaust temperature is greater than the preset temperature, obtaining a second duration for which the exhaust temperature is greater than the preset temperature; in a case where the first duration is less than the second preset duration, returning to obtain the exhaust temperature of the exhaust pipe; in a case where the second duration is not less than a third preset duration, controlling the water heater to stop working.

10. The method of protecting a water heater as defined in claim 1 or 7, wherein, The protection method of the water heater further comprises: in a case where it is determined that the heat exchange fins are in the clogging state / the exhaust temperature is greater than the preset temperature, controlling the water heater to stop working, and outputting a corresponding fault prompt.

11. A protection device, characterized in that The protection device comprises a memory, a processor, and a protection method stored on the memory and executable on the processor, the protection method comprising the steps of the protection method of the water heater according to any one of claims 1 to 10.

12. A water heater, characterized by The water heater comprises a housing assembly formed with a flue passage, a heat exchanger arranged in the flue passage, and a fan for guiding airflow to flow through the flue passage, the heat exchanger comprising heat exchange pipes and heat exchange fins arranged on the heat exchange pipes; The water heater further comprises the protection device according to claim 11; and / or, the water heater uses the protection method of the water heater according to any one of claims 1 to 10.

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