Dual-fan gas water heater

Abstract

The application relates to the field of gas water heaters, in particular to a double-fan gas water heater which comprises a machine shell, a burner, a main fan and a control unit arranged in the machine shell, the control unit being electrically connected with the main fan and the burner; the double-fan gas water heater further comprises an auxiliary fan; the machine shell is provided with an air inlet, the burner is provided with a secondary air inlet; the auxiliary fan is arranged on an air flow path from the air inlet to the secondary air inlet and is electrically connected with the control unit; the control unit is configured to control the auxiliary fan to run a first mode to blow air from the air inlet to the secondary air inlet or run a second mode to draw air from the secondary air inlet to the air inlet according to the current combustion load of the burner, so as to solve the problem that a single-fan gas water heater cannot adapt the secondary air supply according to the combustion load.

Description

Technical Field

[0001] This application relates to the field of gas water heaters, and more particularly to a dual-fan gas water heater. Background Technology

[0002] Gas water heaters employ segmented combustion technology (e.g., equipped with 7 burners, with the combustion sequence corresponding to rows 1-3-5-7 from low to high load), and the gas supply dynamically changes with the load. Combustion in gas water heaters relies on primary and secondary air: primary air is used to fully mix with the gas under high load combustion, while secondary air is used to improve flame stability under low load combustion.

[0003] Current technologies control the total air volume by adjusting the overall airflow, which cannot regulate the primary / secondary air supply under different loads. This results in insufficient air distribution and easy flameout at low loads, and incomplete combustion and poor flue gas emission at high loads. Therefore, developing a technical solution that can balance the stability of low-fire combustion and the completeness of high-fire combustion has become a breakthrough direction for the current technological upgrade of gas water heaters. Utility Model Content

[0004] The purpose of this application is to provide a dual-fan gas water heater to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] 1. A dual-fan gas water heater, comprising a casing, a burner disposed within the casing, a main fan, and a control unit, wherein the control unit is electrically connected to the main fan and the burner; characterized in that:

[0007] It also includes auxiliary fans;

[0008] The housing is provided with an air inlet, and the burner is provided with a secondary air inlet;

[0009] The auxiliary fan is installed in the airflow path from the air inlet to the secondary air inlet and is electrically connected to the control unit;

[0010] The control unit is configured to, based on the current combustion load of the burner, control the auxiliary fan to operate in a first mode to blow air from the air inlet to the secondary air inlet, or to operate in a second mode to draw air from the secondary air inlet to the air inlet.

[0011] Furthermore, the burner is a segmented burner, including multiple rows of flame distributors and multiple gas nozzles;

[0012] Each row of igniters corresponds to at least one gas nozzle;

[0013] The control unit determines the current combustion load level of the segmented burner by controlling the number of gas nozzles opened.

[0014] Furthermore, the multiple rows of fire distributors are arranged in a horizontal direction;

[0015] The secondary air inlet is located at the bottom of the burner and supplies air to the area below the multi-row burner.

[0016] Furthermore, the main fan, heat exchanger, burner, and auxiliary fan are arranged sequentially from top to bottom inside the casing.

[0017] Furthermore, the internal spaces of the main fan, heat exchanger, and burner are interconnected, forming a flue gas exhaust path, with the main fan located upstream of this flue gas exhaust path.

[0018] Furthermore, the burner is fitted with a burner housing, and the burner housing is provided with a primary air inlet and a secondary air inlet.

[0019] Furthermore, the primary air inlet is located on the side of the burner housing, and the secondary air inlet is located at the bottom of the burner housing;

[0020] The auxiliary fan is located below the secondary air inlet.

[0021] Furthermore, the air inlet is located at the top of the housing, and the primary air inlet and the secondary air inlet are located at the bottom of the housing;

[0022] The air inlet is arranged vertically at intervals from the primary air inlet and the secondary air inlet.

[0023] The technical solutions provided in this application have the following advantages compared with the prior art:

[0024] The dual-fan gas water heater provided in this application embodiment, by adding an auxiliary fan, allows the control unit to flexibly switch between forward air supply (first mode) and reverse air extraction (second mode) of the auxiliary fan according to the current combustion load of the burner, with the cooperation of the auxiliary fan and the air flow path. This can supplement secondary air under low-load combustion to make up for insufficient primary air supply and avoid flameout and unstable combustion. Under high-load combustion, it can also promptly expel excess air from the combustion zone to maintain air-fuel ratio balance and prevent thermal efficiency reduction and excessive emissions of harmful flue gas caused by incomplete combustion of gas. The auxiliary fan is directly set in the air flow path from the air inlet to the secondary air inlet, with a short airflow path, low loss, and rapid control response. It also eliminates the need for complex duct modifications, making the internal structure of the water heater simpler and easier to assemble. The overall design is compatible with the multi-row burner layout of segmented burners, which can adapt to different load requirements, significantly improving the combustion stability, energy efficiency, and environmental performance of the water heater, while enhancing its reliability and adaptability to different scenarios. Attached Figure Description

[0025] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0028] Figure 1 This is an internal structural diagram of a dual-fan gas water heater according to an embodiment of this application;

[0029] Figure 2 This is a diagram showing the airflow direction of the main fan during operation in this application.

[0030] Figure 3 This is a diagram showing the airflow direction of the auxiliary fan in the first mode of this application;

[0031] Figure 4 This is a diagram showing the airflow direction of the auxiliary fan in the second mode of this application;

[0032] Figure 5 This is a schematic diagram of the burner structure of this application;

[0033] Figure 6 This is a schematic diagram of the internal structure of the burner in this application;

[0034] Figure 7 This is a flowchart illustrating the control method for a dual-fan gas water heater.

[0035] Explanation of reference numerals in the attached figures:

[0036] 1. Housing; 2. Burner; 21. Flame distributor; 22. Gas nozzle; 23. Primary air inlet; 24. Secondary air inlet; 3. Main fan; 4. Control unit; 5. Auxiliary fan; 6. Air inlet; 7. Air flow path; 8. Heat exchanger. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0039] For ease of description, spatial relative terms may be used in the text to describe the relative position or movement of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "front," "back," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure undergoes a positional flip, orientation change, or change of motion, these directional indications will change accordingly. For instance, an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0040] To address the technical problems of existing technologies failing to regulate primary / secondary air under different loads, resulting in insufficient air matching and easy flameout at low loads, and incomplete combustion and poor flue gas emission at high loads, this application provides a dual-fan gas water heater, such as... Figures 1 to 4 As shown, this embodiment provides a dual-fan gas water heater. The water heater includes a casing 1 with an air inlet 6. Inside the casing 1, from top to bottom, are arranged a main fan 3, a heat exchanger 8, a burner 2, and an auxiliary fan 5. It can be understood that this arrangement makes the internal space of the dual-fan gas water heater more compact, effectively saving and rationally utilizing the internal space of the water heater.

[0041] Furthermore, the internal spaces of the main fan 3, heat exchanger 8, and burner 2 are interconnected, forming a flue gas discharge path, with the main fan 3 located upstream of this flue gas discharge path.

[0042] When the heat exchanger 8 and burner 2 are working, the heat and flue gas they generate can be drawn away from the main fan 3 located upstream and discharged to the outside through the exhaust path, thus preventing the accumulation of heat and flue gas inside the dual-fan gas water heater and affecting its normal operation.

[0043] The burner 2 is a segmented burner, with a burner housing surrounding it. A primary air inlet 23 is located on the side of the burner housing, and a secondary air inlet 24 is located at the bottom. The auxiliary fan 5 is positioned below the secondary air inlet 24. The main fan 3, heat exchanger 8, and the internal space of the burner 2 are interconnected, forming a flue gas discharge path (e.g., ...). Figure 2As indicated by the arrow (airflow direction when only the main fan is operating), the main fan 3 is located upstream of the flue gas exhaust path and is used to force the exhaust gas generated by combustion to be discharged. The burner 2 includes multiple rows of flame distributors 21, each row of flame distributors 21 corresponding to at least one gas nozzle 22 controlled by a solenoid valve. The control unit 4 is electrically connected to the main fan 3 and the burner 2. Since the burner 2 includes flame distributors 21 and gas nozzles 22, the flame distributors 21 and gas nozzles 22 are also electrically connected to the control unit 4 (not shown in the figure).

[0044] In this embodiment, an air flow path 7 is formed between the air inlet 6 and the secondary air inlet 24 with the cooperation of various components inside the combustion water heater. In other embodiments, a channel can also be specially set to guide the air to flow between the air inlet 6 and the secondary air inlet 24.

[0045] In a preferred embodiment, the air inlet 6 is located at the top of the housing 1, and the primary air inlet and the secondary air inlet are located at the bottom of the housing 1; the air inlet 6 and the primary air inlet and the secondary air inlet are spaced apart in the vertical direction.

[0046] It should be understood that in this preferred embodiment, the air inlet is located at the top of the housing 1, and the primary air inlet and the secondary air inlet are located at the bottom of the housing 1. The vertical spacing between the air inlet 6 and the primary and secondary air inlets provides the necessary flow path length for this section of the airflow path, so as to prevent the air supply from decreasing due to insufficient flow resistance caused by an excessively short path.

[0047] In use, the control unit 4 (not shown in the figure) is configured to: control the auxiliary fan 5 to operate in a first mode to blow air from the air inlet 6 to the secondary air inlet 24, or to operate in a second mode to draw air from the secondary air inlet 24 to the air inlet 6, based on the current combustion load of the burner 2.

[0048] For example, in a specific usage scenario, after the dual-fan gas water heater starts successfully, burner 2 in this dual-fan combustion water heater is a segmented burner, such as... Figure 5 and Figure 6As shown, the system includes multiple rows of burners 21 (such as single-row, triple-row, five-row, and seven-row burners 21), with each row of burners 21 corresponding to at least one gas nozzle 22. The control unit 4 determines the current combustion load level by detecting the number of currently activated gas nozzles 22. This load level includes low-load combustion and high-load combustion. Specifically, when it is determined that the current combustion is low-load, the auxiliary fan 5 is controlled to operate in a first mode to blow air from the air inlet 6 to the secondary air inlet 24. When it is determined that the current combustion is high-load, the auxiliary fan 5 is controlled to operate in a second mode to draw air from the secondary air inlet 24 to the air inlet 6.

[0049] For example Figure 6 As shown, the multi-row burner 21 is arranged horizontally, and the secondary air inlet 24 is located at the bottom of the burner 2, supplying air to the area below the multi-row burner 21. This design shortens the distance between the secondary air and the burner 21, allowing the auxiliary fan located outside the secondary air inlet 24 to promptly replenish or remove secondary air from the vicinity of the burner 21.

[0050] In detail, when one or three rows of burners 21 are activated, two gas nozzles 22 are activated accordingly. The control unit 4 determines the current combustion level as low load based on the two activated gas nozzles 22 (the gas water heater system is set so that one or three rows of burners 21 correspond to a low load combustion level; activating five or seven rows of burners 21 requires activating four gas nozzles 22, corresponding to a high load combustion level). Therefore, if... Figure 3 As shown, the control unit 4 controls the auxiliary fan 5 to operate in the first mode, so as to blow air from the air inlet 6 to the secondary air inlet 24.

[0051] Specifically, the auxiliary fan 5, controlled by the control unit 4, has two operating modes: forward blowing and reverse blowing. In this embodiment, forward blowing corresponds to the first mode, and reverse blowing corresponds to the second mode. In other embodiments, the operating modes corresponding to forward blowing and reverse blowing can be interchanged according to actual needs. This application does not impose a unique limitation on the correspondence between the blowing direction and the operating mode of the auxiliary fan 5.

[0052] When the auxiliary fan 5 blows air in the forward direction, external air enters the water heater through the air inlet 6 of the casing 1, is guided to the secondary air inlet along the air flow path 7, and finally enters the combustion reaction zone of the segmented burner 2 to achieve directional replenishment of secondary air.

[0053] It should be noted that when the gas nozzle 22 is activated, it draws in some air to mix with the gas as primary air. However, under low-fire load combustion, only a small number of burner 21s are activated, and the total air volume provided by the main fan 3 remains constant. This air volume cannot be adjusted synchronously as the number of burner 21s decreases, resulting in insufficient primary air carrying capacity to meet the combustion requirements of the low-fire. In addition, the flame size is small under low-fire combustion, and it is very easy to extinguish when the air supply is insufficient. By using the auxiliary fan 5 to provide targeted secondary air through forward blowing, the air demand of low-fire combustion can be matched, ensuring combustion stability and preventing the flameout problem from the root.

[0054] like Figure 4 As shown, when the auxiliary fan 5 blows air in reverse, some of the excess air in the combustion reaction zone is extracted through the secondary air inlet and directed out of the casing 1 through the air inlet 6 along the air flow path 7. Under high-fire-load combustion, the segmented burner 2 starts all or part of the burner 21, and the output of the gas nozzle 22 increases synchronously. At this time, the main fan 3 still maintains a constant total air volume supply, resulting in a relative excess of air in the combustion zone. Excess air will disrupt the air-fuel ratio balance, causing incomplete combustion of gas, which not only reduces thermal efficiency but also leads to poor flue gas emission performance. By directing the excess air out through the reverse blowing of the auxiliary fan 5, the air demand of high-fire combustion can be adapted to ensure that the gas and air are fully mixed and burned, thereby improving the thermal efficiency of high-fire combustion and improving flue gas emission performance.

[0055] It should also be noted that the wind power of the auxiliary fan 5 is preset to be less than that of the main fan 3. Therefore, the operation of the main fan will not be affected by the auxiliary fan 5, and the overall flue gas will still flow upward and be discharged.

[0056] Furthermore, such as Figure 5 and Figure 6 As shown, the burner 2 is fitted with a burner housing, on which a primary air inlet 23 and a secondary air inlet 24 are provided. The primary air inlet 23 is located on the side of the burner 2 housing, and the secondary air inlet 24 is located at the bottom of the burner 2 housing; the auxiliary fan 5 is located below the secondary air inlet 24.

[0057] It should be understood that by installing a burner 2 housing outside the burner 2, and setting the primary air inlet 23 on the side of the burner 2 housing and the secondary air inlet 24 on the bottom of the burner 2 housing, while installing the auxiliary fan 5 below the secondary air inlet 24, the problems of unstable combustion and easy flameout caused by insufficient primary air supply during low fire load in traditional gas water heaters, imbalance of air-fuel ratio, incomplete combustion, poor flue gas emission caused by excess total air during high fire load, and mutual interference between primary and secondary air supply and inability to adapt to different loads are solved.

[0058] In detail, by setting a primary air inlet 23 on the side of the burner 2 housing and a secondary air inlet 24 at the bottom to form a physically separated supply path, the mutual mixing and flow cancellation of the two types of air before entering the combustion reaction zone are effectively avoided. The installation method of the auxiliary fan 5 close to the secondary air inlet 24 greatly shortens the secondary air delivery path, reduces airflow loss, and ensures that the adjustment action of the auxiliary fan 5 can respond quickly.

[0059] For example, under low fire load, with the main fan 3 maintaining a constant total air volume, the side primary air inlet 23 has insufficient air intake due to the limited number of burner 21 activations. At this time, the auxiliary fan 5 blows air in the forward direction and replenishes secondary air to the combustion reaction zone through the bottom secondary air inlet 24 to make up for the primary air shortage and meet the requirements for stable flame under low fire load. Under high fire load, the main fan 3 maintains a constant total air volume and supplies sufficient air through the side primary air inlet 23. The auxiliary fan 5 blows air in the reverse direction and quickly extracts excess air from the combustion zone through the bottom secondary air inlet 24 to avoid exceeding the total air volume and maintain the air-fuel ratio balance.

[0060] In summary, this technical solution not only allows the primary and secondary air supplies to adapt to different loads, ensuring stable combustion and resolving flameout issues under low loads, but also ensures complete combustion of gas under high loads, improving thermal efficiency and flue gas emission performance, thus meeting environmental protection requirements. Furthermore, the dual-fan gas water heater features a simple structure and convenient assembly, requiring no complex duct modifications, offering a short airflow path, high control efficiency, and compatibility with segmented burners 2 with different numbers of rows, making it suitable for a wide range of scenarios and effectively improving the overall performance and reliability of the gas water heater.

[0061] Furthermore, in the case of a single forward or reverse blowing mode, the secondary air supply is a fixed value, which cannot adapt to the needs of different small or large fire subdivision loads (such as the air demand of "micro fire" and "medium fire" in small fire combustion, and "medium fire" and "maximum fire" in large fire combustion). This may lead to problems such as "insufficient air supply still has the risk of flameout" or "excessive exhaust resulting in insufficient air volume".

[0062] In addition to adjusting the flow direction of secondary air supply by operating in the forward (first mode) or reverse (second mode) direction under the control of the control unit 4, the auxiliary fan 5 described above is also configured in another embodiment to control the operating speed of the auxiliary fan 5 in the first mode or the second mode according to the current combustion load.

[0063] Specifically, the control unit 4 first determines the core load level (small fire / large fire) based on the number of burners 21 starting, determines the forward / reverse working mode of the auxiliary fan 5, and then dynamically adjusts the speed according to the load subdivision level (such as "tiny fire" and "medium fire" under small fire combustion, and "medium fire" and "maximum fire" under large fire combustion): low speed forward air supply during small fire, medium speed forward air supply during medium fire combustion, to ensure that the secondary air supply matches the flame size under small fire combustion; low speed reverse air supply during medium fire combustion, and high speed reverse air supply during maximum fire combustion, to ensure that the total air volume in the combustion area is within the optimal range under large fire combustion.

[0064] This dual control design of "mode + speed" firstly solves the problem of fixed wind speed in a single forward or reverse blowing mode, which cannot adapt to the needs of detailed loads. It avoids situations where "insufficient air supply still poses a risk of flameout" or "excessive air extraction leads to insufficient air volume," further improving combustion stability and completeness. Secondly, through dynamic speed adjustment, it can effectively offset the interference of external factors such as gas pressure fluctuations and changes in ambient gas pressure on air supply, ensuring that the air-fuel ratio is always maintained at a suitable state. This reduces problems such as flameout and incomplete combustion caused by changes in external conditions, improving the environmental adaptability and operational reliability of the water heater. At the same time, speed control can avoid "excessive or insufficient" secondary air supply, allowing for more complete gas combustion, which reduces energy waste, improves thermal efficiency, and reduces harmful flue gas emissions.

[0065] The control unit 4 in the dual-fan gas water heater described above operates according to the control method of the dual-fan gas water heater. The hardware on which the control method depends includes: a casing 1 (with an air inlet 6), a main fan 3 arranged from top to bottom, a heat exchanger 8, a segmented burner 2 (with an external burner casing, a primary air inlet 23 on the side, and a secondary air inlet 24 at the bottom), an auxiliary fan 5 (located below the secondary air inlet 24), a multi-row burner 21 (each row corresponds to at least one gas nozzle 22 controlled by a solenoid valve), a control unit 4, and a water flow sensor for detecting water flow signals (outputting a square wave pulse signal to the control unit 4 when water flows through).

[0066] The control unit 4 is electrically connected to the solenoid valves and water flow sensor of the main fan 3, auxiliary fan 5, and gas nozzle 22, and can receive sensor signals and output control commands. An air flow path 7 is formed between the air inlet 6 and the secondary air inlet 24. The auxiliary fan 5 can achieve forward blowing (first mode, air is blown from the air inlet 6 to the secondary air inlet 24) or reverse blowing (second mode, air is drawn from the secondary air inlet 24 to the air inlet 6) under the control of the control unit 4.

[0067] Detailed, such as Figure 7 As shown, the control method includes the following steps:

[0068] S1: Detect water flow signal; After the gas water heater is powered on, it is in standby mode. The control unit 4 continuously sends detection commands to the water flow sensor, either in real time or at preset intervals, such as every 5 seconds, to collect the signal output by the water flow sensor. The water flow sensor outputs a square wave pulse signal based on the water flow rate. The control unit 4 identifies the frequency or amplitude of this pulse signal and calculates the current actual water flow signal value Q1 (unit: L / min).

[0069] In this embodiment, the preset water flow signal setting value is Q0 = 3L / min (this setting value can be pre-configured in the control unit 4 according to parameters such as the water heater model and rated power, and the user can also fine-tune it through the operation panel). The control unit 4 compares the real-time collected water flow signal value Q1 with the set value Q0 in real time. That is, step S2 is executed: if the water flow signal is greater than the set value, the gas water heater is started; in detail, if the real-time water flow signal Q1 ≤ the set value Q0 (such as the user has not turned on the hot water tap, or the water flow is too small after turning it on): the control unit 4 determines that there is no effective water demand, the water heater remains in standby mode, the main fan 3, burner 2, and auxiliary fan 5 are not started, and only the water flow sensor continues to detect.

[0070] If the real-time water flow signal Q1 > the set value Q0 (e.g., when the user turns on the hot water tap and the water flow meets the combustion start-up conditions): the control unit 4 immediately outputs a start command, and the water heater enters the working process; first, it controls the main fan 3 to start, and pre-exhausts the exhaust gas through the flue gas exhaust path for 3-5 seconds to exhaust the residual exhaust gas in the casing 1; then it controls the main electromagnetic opening of the gas pipeline to supply gas to the gas nozzle 22, and at the same time completes the preheating preparation of the ignition device.

[0071] After step S2, step S3 is executed: determine the current combustion load type of the burner;

[0072] Step S3, which involves determining the current combustion load type of the burner 2, includes:

[0073] S31: Get the number of currently active gas nozzles;

[0074] S32: Determine whether the current combustion load type is low-load combustion or high-load combustion based on the number of gas nozzles.

[0075] In detail, the control unit 4 sends a status query command to the solenoid valve of each gas nozzle 22 to obtain the on / off status of each solenoid valve (energized means open, de-energized means closed), and then counts the total number N of currently open gas nozzles 22.

[0076] The combustion load type is determined based on the preset correspondence between the number of nozzles and the load type:

[0077] For example, in this embodiment, the system presets "opening 2 gas nozzles 22" to correspond to low-load combustion (at this time, the burner 21 is activated in 3 rows); "opening 4 gas nozzles 22" to correspond to high-load combustion (at this time, the burner 21 is activated in 7 rows).

[0078] If the statistics show N=2, control unit 4 determines that the current combustion is under low load; if the statistics show N=4, the current combustion is determined to be under high load.

[0079] After the control unit 4 determines the combustion load type, it outputs the corresponding mode control command to the auxiliary fan 5. That is, after executing step S3, step S4 is executed: determine the current combustion load type of the burner 2; if it is low-load combustion, control the auxiliary fan 5 to operate in the first mode; if it is high-load combustion, control the auxiliary fan 5 to operate in the second mode.

[0080] That is, if the combustion is determined to be under low load: the control unit 4 outputs a forward blowing command, and the auxiliary fan 5 operates in the first mode. At this time, the control unit 4 controls the ignition device corresponding to one or three rows of burners 21 to start, igniting the mixture of gas and primary air; at the same time, the auxiliary fan 5 rotates forward, and external air enters the water heater through the air inlet 6 of the casing 1, and is quickly guided to the secondary air inlet 24 along the air flow path 7, and finally enters the combustion reaction zone of the burner 2 to supplement the secondary air. Since only a few burners 21 are started under low load, the constant total air volume provided by the main fan 3 is insufficient to meet the primary air demand. The supplementation of secondary air can prevent the flame from going out due to insufficient air and ensure stable combustion.

[0081] If high-load combustion is detected: Control unit 4 outputs a reverse blowing command, and auxiliary fan 5 operates in the second mode. At this time, control unit 4 controls the ignition device corresponding to the five-row or seven-row burner 21 to start, and the output of gas nozzle 22 increases synchronously; the constant total air volume provided by main fan 3 is supplied in sufficient quantity through primary air inlet 23 on the side of burner housing 2. Excess air is easily generated in the combustion reaction zone. Auxiliary fan 5 rotates in reverse to extract the excess air in the combustion zone through secondary air inlet 24 and guide it in reverse along air flow path 7 to the outside of housing 1, avoiding air-fuel ratio imbalance and ensuring complete combustion of gas.

[0082] Furthermore, once the water heater enters a stable combustion state, the control unit 4 continuously detects the water flow signal through the water flow sensor.

[0083] When the detected water flow signal is less than or equal to the set value, the gas water heater is controlled to stop working, that is, step S5 is executed: During operation, if the detected current water flow signal is less than or equal to the set value, the gas water heater is controlled to stop working.

[0084] In detail, if the current water flow signal Q1 ≤ the set value Q0 (e.g., the user turns off the hot water tap, or the water flow suddenly decreases): the control unit 4 determines that the water demand has terminated and immediately outputs a shutdown command. In a specific usage scenario, it works as follows: First, the solenoid valve of the gas nozzle 22 and the main solenoid valve are closed to cut off the gas supply; then, the auxiliary fan 5 is controlled to continue running for 2-3 seconds (in forward mode, it purges residual air; in reverse mode, it purges residual exhaust gas); finally, the main fan 3 and the auxiliary fan 5 are turned off, and the water heater returns to standby mode.

[0085] In another embodiment, when executing step S4, the control unit 4 further determines the load subdivision level based on the number of gas nozzles 22 that are turned on, and synchronously controls the operating speed of the auxiliary fan 5:

[0086] For example, when one gas nozzle 22 is turned on to correspond to one row of burners 21, it is determined to be a "small flame", and the auxiliary fan 5 provides positive air supply at a low speed (e.g., 1500 r / min); when two gas nozzles 22 are turned on to correspond to three rows of burners 21, it is determined to be a "medium-small flame", and the auxiliary fan 5 provides positive air supply at a medium speed (e.g., 2500 r / min).

[0087] For example, when three gas nozzles 22 are turned on to correspond to the five-row burner 21, it is determined to be "medium to high fire", and the auxiliary fan 5 draws air in the opposite direction at a low speed (e.g., 1500 r / min); when four gas nozzles 22 are turned on to correspond to the seven-row burner 21, it is determined to be "maximum fire", and the auxiliary fan 5 draws air in the opposite direction at a high speed (e.g., 3000 r / min).

[0088] Control unit 4 adjusts the speed of auxiliary fan 5 through PWM signal. Different speeds correspond to different wind speeds and airflow rates, ensuring that the secondary air supply matches the subdivided load, and further improving combustion stability and thermal efficiency.

[0089] In summary, this control method uses whether the water flow signal exceeds a set value as the core basis for starting and stopping the machine. Combined with continuous monitoring of the water flow signal during operation, and steps such as pre-extraction by the main fan 3 and forward or reverse blowing by the auxiliary fan 5, it avoids the risks of dry burning without water and the safety hazards of gas leakage and exhaust gas accumulation from the source, ensuring safe and reliable use. By statistically analyzing the number of activated gas nozzles 22, it intuitively and quickly determines the type of low or high load, and selectively controls the auxiliary fan 5 to operate in either the first mode of forward air supply or the second mode of reverse air extraction, compensating for the insufficient primary air supply during low-load combustion. It removes excess air during high-load combustion, solving the pain points of traditional water heaters such as "easy flameout at low flames and incomplete combustion at high flames," and improving combustion stability under different loads. By matching the secondary air supply with the gas combustion demand, it avoids "excessive or insufficient" air supply, reducing energy waste, improving thermal efficiency to lower operating costs, and reducing emissions of harmful flue gases such as carbon monoxide and nitrogen oxides, thus balancing energy efficiency and environmental protection requirements. At the same time, it is compatible with segmented burners with different numbers of rows and water heaters of different specifications, and can also adapt to specific load demands through dual control of "mode + speed," improving the adaptability to various usage scenarios.

[0090] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0091] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used 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, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0092] Furthermore, 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0093] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0094] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0095] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0096] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Since these modifications and variations fall within the scope of the claims and their equivalents, this application also intends to include these modifications and variations.

[0097] The above description describes specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A dual-fan gas water heater, comprising a casing, a burner disposed within the casing, a main fan, and a control unit, wherein the control unit is electrically connected to the main fan and the burner; characterized in that: It also includes auxiliary fans; The housing is provided with an air inlet, and the burner is provided with a secondary air inlet; The auxiliary fan is installed in the airflow path from the air inlet to the secondary air inlet and is electrically connected to the control unit; The control unit is configured to, based on the current combustion load of the burner, control the auxiliary fan to operate in a first mode to blow air from the air inlet to the secondary air inlet, or to operate in a second mode to draw air from the secondary air inlet to the air inlet.

2. The dual-fan gas water heater according to claim 1, characterized in that: The burner is a segmented burner, including multiple rows of flame distributors and multiple gas nozzles; Each row of igniters corresponds to at least one gas nozzle; The control unit determines the current combustion load level of the segmented burner by controlling the number of times the gas nozzles are opened.

3. The dual-fan gas water heater according to claim 2, characterized in that: The multiple rows of fire distributors are arranged horizontally. The secondary air inlet is located at the bottom of the burner and supplies air to the area below the multi-row burner.

4. The dual-fan gas water heater according to claim 1, characterized in that: The main fan, heat exchanger, burner, and auxiliary fan are arranged sequentially from top to bottom inside the casing.

5. The dual-fan gas water heater according to claim 4, characterized in that: The internal spaces of the main fan, heat exchanger, and burner are interconnected, forming a flue gas exhaust path, with the main fan located upstream of this flue gas exhaust path.

6. The dual-fan gas water heater according to claim 1, characterized in that: The burner is fitted with a burner housing, which has a primary air inlet and a secondary air inlet.

7. The dual-fan gas water heater according to claim 6, characterized in that: The primary air inlet is located on the side of the burner housing, and the secondary air inlet is located at the bottom of the burner housing; The auxiliary fan is located below the secondary air inlet.

8. The dual-fan gas water heater according to claim 1, characterized in that: The air inlet is located at the top of the housing, and the primary air inlet and the secondary air inlet are located at the bottom of the housing. The air inlet is arranged vertically at intervals from the primary air inlet and the secondary air inlet.

Images