Control methods for gas water heaters and gas water heaters

Abstract

This invention discloses a control method for a gas water heater and a gas water heater itself. The control method includes: when the blockage level of the gas water heater exceeds a preset blockage level, if it is determined that the current operating load point of the gas water heater is located within the load overlap range between the current load segment and an adjacent smaller load segment, then controlling the gas water heater to switch to the adjacent smaller load segment for operation; wherein, the current load segment is the load segment where the current operating load point is currently located, and the adjacent smaller load segment is a smaller load segment adjacent to the current load segment. This invention solves the technical problem in the prior art where, when a gas water heater is operating at a lower load, encountering strong external winds or partial blockage of the flue, its wind resistance is weakened, potentially triggering the water heater's blockage protection and rendering it unusable.

Description

Technical Field

[0001] This invention relates to the field of gas appliance control technology, and more specifically, to a control method for a gas water heater and a gas water heater. Background Technology

[0002] When a gas water heater is operating, the main controller ignites and controls the fan to operate after the water flow sensor detects a water flow signal. This ensures that the exhaust gases produced during combustion are discharged through the flue, guaranteeing complete and safe combustion. To address poor ventilation caused by external wind pressure or flue blockage, current technology typically monitors the fan's operating current or speed to determine the blockage status. When the fan speed abnormally increases while maintaining a baseline current, the controller determines that there is a blockage and automatically increases the fan drive current to increase the speed, thereby enhancing the ventilation capacity. If the fan speed continues to rise to a preset blockage protection threshold, the controller triggers a protection mechanism, forcibly shutting down the unit to prevent safety hazards such as carbon monoxide leakage.

[0003] When existing gas water heaters encounter flue blockage or excessive external wind pressure, the main controller will increase the fan speed to enhance the smoke extraction capacity. However, when the water heater is operating in the low load segment, due to the small gas flow and poor flame stability, even if the fan speed is increased to the protection threshold, it still cannot effectively resist the wind and is very likely to trigger the blockage protection and shut down.

[0004] There is currently no effective solution to the above problems. Summary of the Invention

[0005] The first technical problem solved by this invention is to provide a control method for a gas water heater that effectively avoids the problem of the gas water heater being unable to operate continuously due to protection shutdown caused by wind pressure blockage during low load periods.

[0006] The second technical problem solved by the present invention is to provide a control device for a gas water heater, which effectively avoids the problem in the prior art where, when the gas water heater is running under low load, strong external winds or partial blockage of the flue can weaken its wind resistance, potentially triggering the water heater's blockage protection and rendering it unusable.

[0007] The first technical problem mentioned above is solved by the following technical solution:

[0008] A method for controlling a gas water heater includes: when the blockage level of the gas water heater is greater than a preset blockage level, if it is determined that the current operating load point of the gas water heater is located within the load overlap range between the current load segment and the adjacent smaller load segment, then controlling the gas water heater to switch to the adjacent smaller load segment for operation; wherein, the current load segment is the load segment where the current operating load point is currently located, and the adjacent smaller load segment is a smaller load segment that is adjacent to the current load segment.

[0009] The control method for a gas water heater described in this invention has the following advantages compared to the prior art:

[0010] The control method for gas water heaters according to this application can determine whether the current operating load point of the gas water heater is located within the load overlap range between the current load segment and the adjacent smaller load segment when it is determined that the gas water heater is blocked but not completely blocked. If so, the gas water heater will be controlled to switch to the adjacent smaller load segment for operation. Since the number of ignition burners in the adjacent larger load segment is greater than that in the adjacent smaller load segment when the current operating load point is within the load overlap range, the firepower of a single burner in the adjacent larger load segment will be less than that in the adjacent smaller load segment. Therefore, the wind pressure resistance of the adjacent larger load segment in the load overlap range is less than that of the adjacent smaller load segment in the load overlap range. This method utilizes the "switchability" of the load overlap range to select the smaller load segment with stronger wind resistance under the same heat output, thereby effectively avoiding unnecessary shutdowns without changing the user's water temperature experience, improving the continuity and reliability of system operation, and solving the technical problem in the prior art where gas water heaters cannot continue to operate due to wind pressure blockage in the small load segment.

[0011] Optionally, the control method further includes: if it is determined that the current operating load point is not located within the load overlap interval between the current load segment and the adjacent smaller load segment, calculating the first actual load point corresponding to the set temperature of the gas water heater being reduced by a first preset temperature; if the first actual load point is located within the load overlap interval, controlling the gas water heater to switch to the first actual load point in the adjacent smaller load segment for operation.

[0012] Optionally, the control method further includes: if it is determined that the current operating load point is not located within the load overlap interval between the current load segment and the adjacent smaller load segment, calculating a first temperature at which the gas water heater needs to be reduced if it drops from the current operating load point to the load overlap interval; if the first temperature does not exceed a first preset temperature, then controlling the gas water heater to switch to the adjacent smaller load segment for operation.

[0013] Optionally, the control method further includes: when it is impossible to improve the wind pressure resistance of the gas water heater by lowering the set temperature, calculating the second actual load point corresponding to the set temperature of the gas water heater being increased by a second preset temperature; determining the target gas proportional valve current of the gas water heater based on the second actual load point, and controlling the gas water heater to operate according to the target gas proportional valve current.

[0014] Optionally, determining the target gas proportional valve current of the gas water heater based on the second actual load point includes: obtaining the maximum load point of the current load segment; if the second actual load point exceeds the maximum load point, then determining the target gas proportional valve current as the gas proportional valve current corresponding to the maximum load point; if the second actual load point does not exceed the maximum load point, then determining the target gas proportional valve current as the gas proportional valve current corresponding to the second actual load point.

[0015] Optionally, the first preset temperature and the second preset temperature are not greater than 2.5°C.

[0016] Optionally, the control method further includes: when the gas water heater is in a blocked state, obtaining the current actual speed and the current protection speed corresponding to the current operating load point, wherein the current protection speed is the upper limit of the safe speed of the gas water heater's fan at the current operating load point, and the current actual speed is the actual speed of the fan at the current operating load point; if the difference between the current protection speed and the current actual speed is less than or equal to a first preset speed difference, determining that the degree of blockage of the gas water heater is greater than the preset blockage degree.

[0017] Optionally, the control method further includes: collecting the current actual speed and the actual operating current of the fan; obtaining the reference fan speed corresponding to the actual operating current; if the difference between the current actual speed and the reference fan speed is greater than a second preset speed difference, then determining that the gas water heater is in the blocked state.

[0018] Optionally, after determining that the gas water heater is in a blocked state, the control method further includes: if the current actual speed reaches the current protection speed corresponding to the current operating load point, controlling the gas water heater to shut down.

[0019] The second technical problem mentioned above is solved by the following technical solution:

[0020] A gas water heater, wherein the gas water heater uses the control method of any one of the above-described gas water heaters. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0022] Figure 1 This is a flowchart of a control method for a gas water heater according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram illustrating the relationship between fan protection speed and air pressure at different load points in the same load segment of a gas water heater according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram illustrating the relationship between different load segments and wind pressure of a gas water heater according to an embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram illustrating the relationship between the current of the gas proportional valve and the load PSV in the same load segment of a gas water heater according to an embodiment of the present invention.

[0026] Figure 5 This is a schematic diagram illustrating the relationship between the fan current and fan speed of a gas water heater according to an embodiment of the present invention;

[0027] Figure 6 This is a flowchart of an optional control method for a gas water heater according to an embodiment of the present invention;

[0028] Figure 7 This is a schematic diagram of a blockage treatment device for a gas water heater according to an embodiment of the present invention. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0030] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0031] As described in the background section, in the prior art, when a gas water heater is operating under low load and encounters strong external winds or partial blockage of the flue, its wind resistance is weakened, which may trigger the water heater's blockage protection and prevent it from functioning properly. The embodiments of this invention provide a control method and apparatus for a gas water heater, a gas water heater, a computer-readable storage medium, a processor, and a computer program product.

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0033] Example 1

[0034] According to an embodiment of the present invention, a method embodiment for controlling a gas water heater is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0035] Figure 1 This is a flowchart of a control method for a gas water heater according to an embodiment of the present invention, such as... Figure 1 As shown, the method includes the following steps:

[0036] Step S202: When the blockage level of the gas water heater is greater than the preset blockage level, if it is determined that the current operating load point of the gas water heater is located in the load overlap range between the current load segment and the adjacent smaller load segment, then control the gas water heater to switch to the adjacent smaller load segment for operation; wherein, the current load segment is the load segment where the current operating load point is currently located, and the adjacent smaller load segment is the load segment that is adjacent to and smaller than the current load segment.

[0037] Optionally, the preset blockage level can be a threshold value preset by the main controller to determine whether to trigger the blockage compensation mechanism. When the "blockage level" exceeds this threshold, the system initiates load segmentation switching or temperature compensation logic. This threshold corresponds to the difference between the actual fan speed and the protection speed being ≤ a first preset speed difference value (B). The current operating load point can be the current actual output heat load value of the gas water heater, in kilowatts (kW).

[0038] Gas water heaters can calculate the current load based on the inlet water temperature, set temperature, and water flow, and intelligently select to activate different numbers of burners (such as 1 burner, 3 burners, or all burners on). This allows for wide-range adjustment from minimum to maximum load, ensuring that the user's load needs are met. Activating different numbers of burners means that the gas water heater has multiple load segments, and there must be an "overlapping area" between adjacent segments. This is to ensure water temperature stability and equipment durability. This overlapping area means that the maximum heating capacity of the adjacent smaller load segment is slightly higher than the minimum heating capacity of the adjacent larger load segment. Without this overlapping area, when the user's water consumption fluctuates slightly (e.g., a slight fluctuation in water pressure), the water heater may detect that the current heat output is insufficient and must immediately switch to the next load segment; however, after switching, the heat output may momentarily become too high, resulting in excessively high water temperature, forcing the system to revert to a lower heat output. This frequent back-and-forth switching causes the solenoid valve to operate continuously, generating noise, wearing down the equipment, and causing the water temperature to fluctuate. With the overlapping area, within this specific load range, the control system can choose to maintain the current combustion state without switching immediately, thus effectively avoiding frequent start-stop cycles and making water temperature control smoother, more delicate, and more precise.

[0039] It is understandable that when the current operating load point is in the load overlap interval between two adjacent load segments, the number of ignition burners in the adjacent larger load segment is greater than the number of ignition burners in the adjacent smaller load segment. The firepower of a single burner in the adjacent larger load segment will be less than the firepower of a single burner in the adjacent smaller load segment. Therefore, the wind pressure resistance of the adjacent larger load segment in the load overlap interval is less than the wind pressure resistance of the adjacent smaller load segment in the load overlap interval.

[0040] In this embodiment, when the gas water heater is blocked but not completely blocked, the degree of blockage can be obtained. If it is determined that the current degree of blockage of the gas water heater is greater than the preset degree of blockage, it will be further determined whether the current heat load point of the gas water heater is located in the load overlap range between the current load segment and the adjacent smaller load segment. If so, the gas water heater will be controlled to switch to the adjacent smaller load segment.

[0041] For example, when the user sets the water temperature to 42℃, the inlet water temperature to 15℃, and the outlet water flow rate to 5L / min, the system calculates the current load to be 10.8kW. At this time, the system is operating in "Segment Two" (setting range 10-16kW). The main controller detects that the actual fan speed is 4200r / min, while the preset protection speed corresponding to this load point is 4300r / min. The difference ΔR = 100r / min ≤ B (B = 100r / min). At the same time, the actual fan current is 1.85A, the reference speed is 3900r / min, and the current speed exceeds the reference by 200r / min (>C = 150r / min), which is judged as "severe blockage".

[0042] At this point, the system queries the load segmentation table: Segment 1: 8-12kW, Segment 2: 9-16kW; Overlapping range: 9-12kW, and the current load of 10.8kW is in the overlapping range. The system calls the wind resistance database and finds that at the 10.8kW load point, the wind pressure resistance of Segment 1 (capable of withstanding wind pressure of 85Pa) is significantly higher than that of Segment 2 (only 68Pa).

[0043] The controller then immediately triggers a switching command: closes the gas proportional valve for load segment two; opens the gas proportional valve for load segment one; the fan PWM is automatically reduced, moving away from the protection threshold; and the outlet water temperature fluctuation is minimal.

[0044] Since wind resistance is related to the combustion structure, lower load sections (such as section one) have fewer burners, larger gas flow per burner, more concentrated flames, higher heat release density per unit area, and stronger flame rigidity, making them less susceptible to external wind disturbance. Furthermore, the system incorporates load overlap zones during the design phase, allowing adjacent sections to serve as backups for each other at the same load point, enabling switching when necessary. Moreover, the load remains unchanged during switching; only the combustion method is altered to improve wind resistance, allowing the system to switch to an adjacent, lower load section without the user noticing.

[0045] As described above, in this embodiment of the invention, when it is determined that the gas water heater is blocked but not completely blocked, it is judged whether the current operating load point of the gas water heater is located within the load overlap range between the current load segment and the adjacent smaller load segment. If so, the gas water heater will be controlled to switch to the adjacent smaller load segment for operation. This method utilizes the switchability of the load overlap area to select the smaller load segment with stronger wind resistance under the same heat output, thereby effectively avoiding unnecessary shutdowns without changing the user's water temperature experience, improving the continuity and reliability of system operation, and solving the technical problem in the prior art where, when the gas water heater is running at a smaller load, strong external wind or partial blockage of the flue leads to weakened wind resistance, which may trigger the water heater's blockage protection and prevent normal use.

[0046] According to the above embodiments of the present invention, the control method further includes: if it is determined that the current operating load point is not located in the load overlap interval between the current load segment and the adjacent smaller load segment, calculating the first actual load point corresponding to the set temperature of the gas water heater being reduced by a first preset temperature; if the first actual load point is located in the load overlap interval, controlling the gas water heater to switch to the first actual load point in the adjacent smaller load segment for operation.

[0047] Optionally, the first preset temperature mentioned above and the second preset temperature below represent the maximum temperature adjustment range allowed by the system in the "cooling compensation" and "heating compensation" strategies, respectively. First preset temperature: the upper limit of the set temperature is lowered; Second preset temperature: the upper limit of the set temperature is increased.

[0048] When the current operating load point is not in the overlapping range, the system will enter the temperature fine-tuning compensation path. That is, when it is determined that the current operating load point is not located in the load overlap range between the current load segment and the adjacent smaller load segment, the system will calculate the first actual load point corresponding to the gas water heater's set temperature being reduced by the first preset temperature; if the first actual load point is located in the load overlap range, the system will control the gas water heater to switch to the first actual load point in the adjacent smaller load segment for operation.

[0049] For example, when the current operating load point is not in the overlapping range, the first actual load point corresponding to a 1°C decrease in the set temperature of the gas water heater can be calculated. If this load point is not in the load overlapping range, the first actual load point corresponding to a 2°C decrease in the set temperature can be calculated. If the first actual load point is in the load overlapping range, the gas water heater can be controlled to switch to the first actual load point in the adjacent smaller load segment. Thus, by reducing the user's set temperature within a certain range, the actual load point of the gas water heater can be placed within the load overlapping range, thereby allowing the gas water heater to switch to the first actual load point in the adjacent smaller load segment.

[0050] By slightly reducing the temperature to shift the load downwards, flexible compensation is achieved using the existing structure without adding hardware. This strategy greatly increases the probability of successfully entering the overlap zone in scenarios where switching would otherwise be impossible, significantly improving the availability of gas water heaters.

[0051] It is understandable that if the first actual load point corresponding to the reduction of the set temperature of the gas water heater to the first preset temperature is still not located in the load overlap range, it means that the wind pressure resistance of the gas water heater cannot be improved by reducing the set temperature.

[0052] According to the above embodiments of the present invention, the control method further includes: if it is determined that the current operating load point is not located in the load overlap interval between the current load segment and the adjacent smaller load segment, calculating the first temperature at which the temperature needs to be reduced if the gas water heater decreases from the current operating load point to the load overlap interval; if the first temperature does not exceed the first preset temperature, controlling the gas water heater to switch to the adjacent smaller load segment for operation.

[0053] In this embodiment, a minimum temperature drop trigger mechanism is set up. That is, the minimum temperature drop required for the gas water heater to decrease from the current operating load point to the load overlap range is calculated to achieve optimal energy control. At the same time, it avoids excessive cooling that may cause user discomfort and maximizes the utilization of resources in the overlap range.

[0054] Understandably, if the first temperature exceeds the first preset temperature, lowering the first temperature would cause discomfort to the user, indicating that the gas water heater's wind pressure resistance cannot be improved by lowering the set temperature.

[0055] For example, if calculations determine that the gas water heater needs to be reduced from its current operating load point to the load overlap range, the user-set temperature needs to be lowered by the following temperature (i.e., the first temperature); further determine whether the required temperature reduction exceeds the first preset temperature (the upper limit of the set temperature reduction); if the reduced temperature does not exceed the first preset temperature, it means that the set temperature can be lowered so that the current operating load point falls into the load overlap range, thereby controlling the gas water heater to switch to an adjacent smaller load segment for operation. This effectively overcomes the defect in the existing solution that when the current load is no longer in the overlap range, it can only operate in the low load segment until the blockage protection triggers a shutdown.

[0056] This method uses the user-set temperature as an adjustable variable, adjusting it within a range that is almost imperceptible to the user. It determines whether lowering the temperature can bring the current load point into the load overlap range. If lowering the set temperature by a certain value can bring the current load point into the load overlap range, the gas water heater is triggered to switch to the adjacent smaller load segment for operation. This not only does not affect the user's water experience but also effectively reduces the number of times the blockage protection triggers shutdown, thus improving the continuity of use of the gas water heater.

[0057] According to the above embodiments of the present invention, the control method further includes: when it is impossible to improve the wind pressure resistance of the gas water heater by lowering the set temperature, calculating the second actual load point corresponding to the set temperature of the gas water heater being increased by a second preset temperature; determining the target gas proportional valve current of the gas water heater based on the second actual load point, and controlling the gas water heater to operate according to the target gas proportional valve current.

[0058] Figure 2This is a schematic diagram illustrating the relationship between fan protection speed and air pressure at different load points within the same load segment of a gas water heater according to an embodiment of the present invention, as shown below. Figure 2 As shown, the fan speed increases linearly with the load. At high load points, the fan speed is higher, the wind pressure is stronger, and the wind resistance is naturally improved.

[0059] Therefore, in this embodiment of the invention, if the gas water heater cannot switch to an adjacent smaller load segment, it can actively increase to a larger load, utilizing methods such as... Figure 2 The physical laws shown enable the improvement of wind resistance.

[0060] That is, when it is impossible to reduce the temperature to a certain level through the above attempts so that the current operating load point falls into the load overlap range, the temperature rise compensation path can be entered.

[0061] It should be noted that in this embodiment of the invention, the increase in the set temperature is not arbitrarily set, but rather pre-calculated to ensure that it is barely perceptible to the user or acceptable to the user. By setting an upper limit for increasing the set temperature, the wind resistance is improved when the user's water temperature does not fluctuate significantly, thereby effectively reducing the frequency of shutdowns due to blockage protection.

[0062] By implementing this approach, unnecessary temperature fluctuations and frequent burner operation caused by segmented switching are effectively avoided. Simultaneously, without relying on hardware upgrades, intelligent temperature control proactively improves the system's wind resistance, significantly enhancing the stability and continuous operation of the gas water heater in scenarios with strong winds or medium to high risk of blockage. Compared to traditional strategies that only reduce load to avoid blockages or shut down directly, this method, by raising the set temperature by a certain degree to improve wind resistance, also reduces the number of times the system shuts down due to blockage protection without affecting the user's water experience.

[0063] Figure 3 This is a schematic diagram illustrating the relationship between load and wind pressure in different segments of a gas water heater according to an embodiment of the present invention, as shown below. Figure 3 As shown, under the same fan control, the wind resistance is stronger in the high-load section. Therefore, the wind resistance is improved by increasing the set temperature to reduce the number of times the fan shuts down due to blockage protection.

[0064] According to the above embodiments of the present invention, determining the target gas proportional valve current of the gas water heater based on the second actual load point includes: obtaining the maximum load point of the current load segment; if the second actual load point exceeds the maximum load point, determining the target gas proportional valve current as the gas proportional valve current corresponding to the maximum load point; if the second actual load point does not exceed the maximum load point, determining the target gas proportional valve current as the gas proportional valve current corresponding to the second actual load point.

[0065] The target gas proportional valve current of the gas water heater can be determined based on the second actual load point in the following way: First, obtain the maximum load point of the current load segment, and then determine whether the second actual load point corresponding to the above-mentioned set temperature plus the second preset temperature exceeds the maximum load point of the current load segment; if it exceeds, then the target gas proportional valve current is determined to be the gas proportional valve current corresponding to the maximum load point of the current load segment; otherwise, the target gas proportional valve current is determined to be the gas proportional valve current corresponding to the second actual load point.

[0066] That is, if the second actual load point corresponding to the increase of the set temperature to the second preset temperature is not in the current load segment, the gas water heater will work according to the maximum value of the current load segment, instead of jumping to a larger load segment, thereby avoiding large fluctuations in the outlet water temperature and affecting the user's water experience.

[0067] In this embodiment, a saturation control strategy is set up to avoid incomplete combustion or overheating caused by load operation. Figure 4 This is a schematic diagram illustrating the relationship between the current of the gas proportional valve in the same load segment and the load PSV of a gas water heater according to an embodiment of the present invention. Figure 4 As shown, the formula for calculating the actual load point is: ,in, The specific heat capacity of water, For water flow rate, This is the difference between the outlet and inlet water temperatures, representing the actual water temperature rise. Based on fundamental thermodynamic principles, this formula quantifies the user-set outlet water temperature, the measured inlet water temperature, and the water flow rate into a true heat load demand (Q). This allows the controller to move beyond relying on vague empirical values ​​or simplified models, dynamically calculating the required heat output based on real physical quantities. Specifically, by combining the calibration curve of the proportional valve current with the load, the system can accurately deduce the corresponding target gas flow rate (i.e., the proportional valve opening), achieving on-demand energy supply and reducing energy waste.

[0068] By implementing this processing method, the target gas proportional valve current of the gas water heater can be accurately determined based on the relationship between the second actual load point and the maximum load point of the current load segment. When the second actual load point exceeds the maximum load point of the current load segment, in order to avoid large fluctuations in the outlet water temperature, the gas proportional valve current of the gas water heater is set to the gas proportional valve current corresponding to the maximum load point of the current load segment.

[0069] That is, in this embodiment, the gas proportional valve current of the gas water heater is determined by the correspondence between the maximum load point of the current load segment and the second actual load point after increasing the set temperature. This method is based on the pre-calibration relationship of "load – proportional valve current" (e.g., Figure 4As shown in the figure, the calculated second actual load point (Q) is used as the target output. The target gas proportional valve current that is precisely matched is obtained by looking up a table or mathematical fitting. The controller outputs the corresponding PWM signal to drive the proportional valve, accurately adjusts the gas flow, and stabilizes the combustion heat output at the target load point.

[0070] By implementing this method, the gas water heater can quickly and smoothly transition to a higher wind-resistant operating point after fine-tuning the temperature, significantly improving the accuracy and stability of the system response. At the same time, this precise control method ensures that water temperature fluctuations are strictly limited to either decreasing the first preset temperature or increasing the second preset temperature, meeting both anti-clogging requirements and ensuring user comfort.

[0071] According to the above embodiments of the present invention, the first preset temperature and the second preset temperature are not greater than 2.5℃.

[0072] In this embodiment, in all temperature control scenarios, the system strictly limits the first preset temperature and the second preset temperature to ≤2.5℃. For example, the maximum temperature drop during cooling is 2.5℃ (e.g., 45℃→42.5℃); the maximum temperature rise during heating is 2.5℃ (e.g., 40℃→42.5℃); the temperature adjustment step size can be set to 0.5℃ each time to achieve a smooth transition.

[0073] This is primarily based on the perception threshold for water temperature changes. 2.5℃ is a relatively optimal balance between comfort and control effectiveness: less than 1℃: load cannot be effectively transferred; greater than 3℃: users clearly perceive cold / heat fluctuations, and the complaint rate increases sharply. By setting the first and second preset temperatures to no more than 2.5℃, a good user experience can be maintained while ensuring improved wind resistance.

[0074] According to the above embodiments of the present invention, the control method further includes: when the gas water heater is in a blocked state, obtaining the current actual speed and the current protection speed corresponding to the current operating load point, wherein the current protection speed is the upper limit of the safe speed of the gas water heater's fan at the current operating load point, and the current actual speed is the actual speed of the fan at the current operating load point; if the difference between the current protection speed and the current actual speed is less than or equal to a first preset speed difference, determining that the degree of blockage of the gas water heater is greater than the preset blockage degree.

[0075] In this embodiment, if Indicates the current protection speed. Indicates the current actual speed. (Indicates the preset speed difference), then it is determined whether the current required load point overlaps with other segments. In order to ensure that the gas water heater can be without load segment interruption from small load to large load, and to ensure that the load can be linearly adjusted throughout the process, and to avoid water temperature fluctuations caused by frequent back-and-forth switching due to unstable switching between burner groups, a large load overlap area is usually set between different burner groups. The so-called overlap area means that there will be a load segment of the same size between the load output of adjacent burner groups.

[0076] As above Figure 2 As shown, the higher the speed of the fan blockage protection, the stronger its wind pressure resistance. This indicates that within the same load segment, the higher the critical speed that the fan needs to reach to overcome external wind pressure or flue resistance, the stronger its ability to withstand external back pressure in order to maintain stable combustion. In other words, by increasing the speed, the fan generates greater exhaust power, which can effectively resist the back pressure increase caused by strong external wind backflow or flue carbon buildup, thereby preventing the flame from being blown out, incomplete combustion, or triggering the blockage protection shutdown.

[0077] As above Figure 3 As shown, when the load point is at the small end of segment two, there is load overlap with the large end of segment one. This indicates that by designing a load overlap interval between adjacent combustion segments, a continuous and smooth transition of fire output is achieved, avoiding the water temperature jump or combustion instability problems caused by segment switching in traditional multi-segment water heaters. Moreover, this load overlap interval provides key operating space for the intelligent anti-clogging control of this embodiment of the invention. That is, under the same heat load point, the system can compare the differences in wind pressure resistance of different load segments (such as segment one and segment two) and prioritize the operation of the segment with stronger wind resistance without changing the actual hot water demand.

[0078] For example, when the system reads in real time: Current load: 11.2kW → looking up the table, the protection speed R = 4350r / min;

[0079] The actual fan speed R1 = 4280 r / min; ΔR = 4350 - 4280 = 70 r / min ≤ B = 100 r / min → judged as "high blockage level". This judgment is triggered before the fan reaches its limit speed, realizing early intervention.

[0080] When the difference between the actual fan speed and the protection speed is less than or equal to a preset threshold (i.e., the system is in a "critical blockage" state), this method further determines whether the current operating load point falls within the overlapping range of two adjacent load segments. If it is within the overlapping range, it means that the load value can be achieved by both segments. At this time, the system actively retrieves and compares the wind pressure resistance of the two segments under the same heat load point. This resistance is usually characterized by the minimum effective wind pressure or the corresponding safe speed required by the fan to maintain stable combustion under this load. This provides a quantitative basis for selecting a better combustion segment in the future, and realizes the use of load redundancy characteristics to find a combustion path with stronger wind resistance without changing the heat output.

[0081] By implementing this method, proactive optimization of wind resistance is achieved through load segment switching by setting load overlap zones, without interrupting heating or increasing energy consumption. This effectively avoids protective shutdowns caused by rigidly maintaining the current segment under critical blockage conditions. When the current operating load falls into the load overlap zone, intelligent switching to an adjacent smaller load segment can significantly improve the system's operational resilience in strong winds or flue resistance environments, ensuring the continuity of hot water supply while avoiding water temperature fluctuations caused by frequent switching.

[0082] According to the above embodiments of the present invention, the control method further includes: collecting the current actual speed and the actual operating current of the fan; obtaining the reference fan speed corresponding to the actual operating current; if the difference between the current actual speed and the reference fan speed is greater than a second preset speed difference, then determining that the gas water heater is in a blocked state.

[0083] Figure 5 This is a schematic diagram illustrating the relationship between the fan current and fan speed of a gas water heater according to an embodiment of the present invention, as shown below. Figure 5 As shown, the controller adjusts the corresponding fan current based on the current congestion speed. This establishes a dynamic closed-loop control relationship between fan speed and fan current, enabling the controller to accurately deduce and adjust the fan input current based on the degree of congestion. This achieves fine-grained, adaptive control of airflow, overcoming the limitations of traditional fans that only use fixed PWM or open-loop control, thus achieving the goal of stopping even when blocked.

[0084] This method constructs a dual-parameter comparison mechanism between the baseline operating condition and the actual operation. Using the baseline fan current and the baseline fan speed when the fan is running normally without blockage as a reference, the current and actual speed are collected in real time. When the difference between the actual current and the baseline current is less than the preset small deviation threshold (indicating that the fan drive power has not increased significantly), if the actual speed is detected to be higher than the baseline speed by a predetermined proportion (e.g., ≥20%), it is determined that the system is in a blocked state because the fan is forced to accelerate to maintain air volume output due to external resistance (e.g., flue blockage or strong wind).

[0085] For example, when the fan is running normally without obstruction, the current is 1.6A, which corresponds to a reference speed of 3900 r / min; the current is 1.6A, but the actual speed is 4120 r / min, which means ΔR = 220 r / min > C = 150 r / min, indicating a blockage.

[0086] By implementing this processing method, the accuracy of blockage detection has been significantly improved. It effectively distinguishes between real blockages and interference factors such as airflow fluctuations, power supply fluctuations, or sensor noise, avoiding the false alarms and missed alarms caused by traditional methods based on a single speed or current threshold.

[0087] According to the above embodiments of the present invention, after determining that the gas water heater is in a blocked state, the control method further includes: if the current actual speed reaches the current protection speed corresponding to the current operating load point, controlling the gas water heater to shut down.

[0088] In this embodiment, if the fan speed still reaches the protection threshold after all compensation strategies have failed (such as switching segments or adjusting the temperature), the system will control the gas water heater to shut down.

[0089] Figure 6 This is a flowchart of an optional control method for a gas water heater according to an embodiment of the present invention, such as... Figure 6 As shown, this example uses a first preset temperature and a second preset temperature of 2℃. First, after the water heater (i.e., the gas water heater) is started, it first determines whether it is currently in a blocked state. If it is not blocked, it continues to operate normally. If it is blocked, it further checks whether the speed difference between the current protection speed (R) and the current actual speed (R1) is less than or equal to the preset speed difference (B). If not, it returns to the blockage judgment step. If it is blocked, it checks whether the load segment where the current operating load point is located overlaps with other load segments. If they do not overlap, it calculates whether the actual load Q1 required for the set temperature (i.e., the set temperature) T-2℃ overlaps with other load segments. Otherwise, it compares whether the wind pressure resistance of other load segments is higher. If the comparison result is that the wind pressure resistance of other load segments is not higher, it calculates the actual load Q2 required for the set temperature T+2℃ and adjusts it to the corresponding proportional valve current. If the comparison result is that the wind pressure resistance of other load segments is higher, the main controller switches to the adjacent smaller load segment. This integrated system achieves load adjustment and segmented load switching under blockage conditions through multi-condition judgment, breaking through the traditional single strategy of dealing with blockages by only increasing the load or shutting down directly. It realizes flexible control that maximizes the continuity of hot water supply and temperature stability while ensuring combustion safety, thus improving the reliability of gas water heaters.

[0090] Furthermore, it should be noted that the aforementioned first and second preset temperatures can be flexibly calculated based on actual conditions. This method yields more accurate first and second preset temperatures, minimizing the impact on user-set temperatures and further improving the user experience. For example, more accurate first and second preset temperatures can be calculated based on factors such as the current protection speed, the current actual speed, and the set temperature. For instance, a network model can be pre-trained, and the aforementioned current protection speed, current actual speed, and set temperature can be input into the network model to calculate a more accurate first and second preset temperature.

[0091] As can be seen from the above, the technical solution provided by the above embodiments of the present invention, when a blockage occurs, determines whether the current load of the gas water heater overlaps with other sections, and selects the load point of the high wind-resistant section based on the comparison of the wind resistance of different sections at the same load point, preventing the water heater from becoming unusable due to blockage protection. This fundamentally breaks through the problem of traditional gas water heaters shutting down as soon as they are blocked due to weak wind resistance under low load conditions. By intelligently identifying the load overlap area and dynamically switching to the adjacent smaller load section with stronger wind resistance, the purpose of imperceptible anti-blockage is achieved without adding hardware or affecting user comfort, significantly improving the reliability and availability of the equipment in harsh environments (such as strong winds and flue dust accumulation).

[0092] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0093] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods of the various embodiments of this application.

[0094] Example 2

[0095] According to an embodiment of the present invention, a blockage treatment device for a gas water heater for implementing the above-described control method for a gas water heater is also provided. Figure 7 This is a schematic diagram of a blockage treatment device for a gas water heater according to an embodiment of the present invention, as shown below. Figure 7 As shown, the device includes a control unit 701. The device will now be described in detail.

[0096] The control unit 701 is configured to, when the blockage level of the gas water heater is greater than a preset blockage level, if it is determined that the current operating load point of the gas water heater is located within the load overlap range between the current load segment and the adjacent smaller load segment, control the gas water heater to switch to the adjacent smaller load segment for operation; wherein, the current load segment is the load segment where the current operating load point is currently located, and the adjacent smaller load segment is the load segment that is adjacent to and smaller than the current load segment.

[0097] It should be noted that the control unit 701 mentioned above corresponds to step S202 in the above embodiments. The instances and application scenarios implemented by the unit and the corresponding steps are the same, but are not limited to the content disclosed in the above embodiments.

[0098] As can be seen from the above, in the solution described in the above embodiments of the present invention, when the blockage degree of the gas water heater is greater than a preset blockage degree, if it is determined that the current operating load point of the gas water heater is located within the load overlap interval between the current load segment and the adjacent smaller load segment, the control unit can control the gas water heater to switch to the adjacent smaller load segment for operation. Here, the current load segment is the load segment where the current operating load point is currently located, and the adjacent smaller load segment is a smaller load segment adjacent to the current load segment. That is, when it is determined that the gas water heater is blocked but not completely blocked, it is determined whether the current operating load point of the gas water heater is located within the load overlap interval between the current load segment and the adjacent smaller load segment. If so, the control unit will switch the gas water heater to the adjacent smaller load segment for operation. This method utilizes the "switchability" of the load overlap area to select smaller load segments with stronger wind resistance under the same heat output. This effectively avoids unnecessary shutdowns without changing the user's water temperature experience, improves the continuity and reliability of system operation, and solves the technical problems of "weak wind resistance in small load segments and easy triggering of blockage protection shutdowns" in existing technologies.

[0099] Optionally, the control device further includes: a first calculation unit, configured to calculate the first actual load point corresponding to the reduction of the set temperature of the gas water heater by a first preset temperature if it is determined that the current operating load point is not located in the load overlap interval between the current load segment and the adjacent smaller load segment; and a control unit, configured to control the gas water heater to switch to the first actual load point in the adjacent smaller load segment for operation if the first actual load point is located in the load overlap interval.

[0100] Optionally, the control device further includes: a second calculation unit, configured to calculate a first temperature at which the set temperature needs to be reduced if the current operating load point is determined not to be located within the load overlap range between the current load segment and the adjacent smaller load segment; and a control unit, configured to control the gas water heater to switch to the adjacent smaller load segment for operation if the first temperature does not exceed the first preset temperature.

[0101] Optionally, the control device further includes: a third calculation unit, used to calculate the second actual load point corresponding to the increase of the set temperature of the gas water heater by the second preset temperature when the wind pressure resistance of the gas water heater cannot be improved by lowering the set temperature; and a control unit, used to determine the target gas proportional valve current of the gas water heater according to the second actual load point, and control the gas water heater to operate according to the target gas proportional valve current.

[0102] Optionally, the control unit includes: an acquisition module for acquiring the maximum load point of the current load segment; a first determination module for determining the target gas proportional valve current as the gas proportional valve current corresponding to the maximum load point if the second actual load point exceeds the maximum load point; and a second determination module for determining the target gas proportional valve current as the gas proportional valve current corresponding to the second actual load point if the second actual load point does not exceed the maximum load point.

[0103] Optionally, the first preset temperature and the second preset temperature are no greater than 2.5℃.

[0104] Optionally, the control device further includes: a first acquisition unit, configured to acquire the current actual speed and the current protection speed corresponding to the current operating load point when the gas water heater is in a blocked state, wherein the current protection speed is the upper limit of the safe speed of the gas water heater's fan at the current operating load point, and the current actual speed is the actual speed of the fan at the current operating load point; and a first determination unit, configured to determine that the degree of blockage of the gas water heater is greater than the preset blockage degree if the difference between the current protection speed and the current actual speed is less than or equal to a first preset speed difference.

[0105] Optionally, the control device further includes: a data acquisition unit for acquiring the current actual speed and the actual operating current of the fan; a second acquisition unit for acquiring the reference fan speed corresponding to the actual operating current; and a second determination unit for determining that the gas water heater is in a blocked state if the difference between the current actual speed and the reference fan speed is greater than a second preset speed difference.

[0106] Optionally, the control device further includes a control unit, which is also used to control the gas water heater to shut down when the actual current speed reaches the current protection speed corresponding to the current operating load point after determining that the gas water heater is in a blocked state.

[0107] According to one aspect of the present invention, a gas water heater is provided, wherein the gas water heater uses the control method of any of the above-described gas water heaters.

[0108] According to one aspect of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium including a stored program, wherein the program executes the control method for a gas water heater described above.

[0109] According to one aspect of the present invention, a processor is provided for running a program, wherein the program executes the control method for a gas water heater described above.

[0110] According to one aspect of the present invention, a computer program product is provided, including computer instructions, which, when executed by a processor, perform a control method for a gas water heater that executes any of the above-described methods.

[0111] Optionally, in this embodiment, the computer-readable storage medium may be located in any computer terminal in a group of computer terminals in a computer network, or in any communication device in a group of communication devices.

[0112] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: when the blockage level of the gas water heater is greater than a preset blockage level, if it is determined that the current operating load point of the gas water heater is located within the load overlap interval between the current load segment and the adjacent smaller load segment, then the gas water heater is controlled to switch to the adjacent smaller load segment for operation; wherein, the current load segment is the load segment where the current operating load point is currently located, and the adjacent smaller load segment is the load segment that is adjacent to and smaller than the current load segment.

[0113] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: if it is determined that the current operating load point is not located within the load overlap interval between the current load segment and the adjacent smaller load segment, calculate the first actual load point corresponding to the set temperature of the gas water heater being reduced by a first preset temperature; if the first actual load point is located within the load overlap interval, control the gas water heater to switch to the first actual load point in the adjacent smaller load segment for operation.

[0114] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: if it is determined that the current operating load point is not located within the load overlap interval between the current load segment and the adjacent smaller load segment, calculate the first temperature at which the gas water heater needs to be reduced if it drops from the current operating load point to the load overlap interval; if the first temperature does not exceed the first preset temperature, control the gas water heater to switch to the adjacent smaller load segment for operation.

[0115] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: when it is impossible to improve the wind pressure resistance of the gas water heater by lowering the set temperature, calculate the second actual load point corresponding to the increase of the set temperature of the gas water heater by a second preset temperature; determine the target gas proportional valve current of the gas water heater according to the second actual load point, and control the gas water heater to operate according to the target gas proportional valve current.

[0116] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: obtaining the maximum load point of the current load segment; if the second actual load point exceeds the maximum load point, determining the target gas proportional valve current as the gas proportional valve current corresponding to the maximum load point; if the second actual load point does not exceed the maximum load point, determining the target gas proportional valve current as the gas proportional valve current corresponding to the second actual load point.

[0117] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: when the gas water heater is in a blocked state, obtaining the current actual speed and the current protection speed corresponding to the current operating load point, wherein the current protection speed is the upper limit of the safe speed of the gas water heater's fan at the current operating load point, and the current actual speed is the actual speed of the fan at the current operating load point; if the difference between the current protection speed and the current actual speed is less than or equal to a first preset speed difference, determining that the degree of blockage of the gas water heater is greater than the preset blockage degree.

[0118] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: collecting the current actual speed and the actual operating current of the fan; obtaining the reference fan speed corresponding to the actual operating current; if the difference between the current actual speed and the reference fan speed is greater than a second preset speed difference, then determining that the gas water heater is in a blocked state.

[0119] Optionally, in this embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: after determining that the gas water heater is in a blocked state, if the current actual speed reaches the current protection speed corresponding to the current operating load point, control the gas water heater to shut down.

[0120] In the above embodiments of the present invention, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0121] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual couplings, direct couplings, or communication connections may be through some interfaces; indirect couplings or communication connections between units or modules may be electrical or other forms.

[0122] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0123] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0124] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0125] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0126] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A control method of a gas water heater, characterized by, include: When the blockage level of the gas water heater is greater than the preset blockage level, if it is determined that the current operating load point of the gas water heater is located in the load overlap range between the current load segment and the adjacent smaller load segment, then the gas water heater is controlled to switch to the adjacent smaller load segment for operation; wherein, the current load segment is the load segment where the current operating load point is currently located, and the adjacent smaller load segment is the load segment that is adjacent to and smaller than the current load segment.

2. The control method of the gas water heater according to claim 1, characterized by, The control method further includes: If it is determined that the current operating load point is not located within the load overlap interval between the current load segment and the adjacent smaller load segment, calculate the first actual load point corresponding to the gas water heater after the set temperature is reduced by the first preset temperature; If the first actual load point is located in the load overlap interval, the gas water heater is controlled to switch to the first actual load point in the adjacent smaller load segment for operation.

3. The control method of the gas water heater according to claim 1, characterized by, The control method further includes: If it is determined that the current operating load point is not located within the load overlap interval between the current load segment and the adjacent smaller load segment, calculate the first temperature at which the gas water heater needs to be reduced if the current operating load point is reduced to the load overlap interval; If the first temperature does not exceed the first preset temperature, the gas water heater is controlled to switch to the adjacent smaller load segment for operation.

4. The control method of the gas water heater according to claim 2 or 3, characterized in that, The control method further includes: When it is impossible to improve the wind pressure resistance of the gas water heater by lowering the set temperature, calculate the second actual load point corresponding to the set temperature of the gas water heater after increasing the set temperature by the second preset temperature; The target gas proportional valve current of the gas water heater is determined based on the second actual load point, and the gas water heater is controlled to operate according to the target gas proportional valve current.

5. The control method of the gas water heater according to claim 4, characterized in that, Determining the target gas proportional valve current of the gas water heater based on the second actual load point includes: Get the maximum load point of the current load segment; If the second actual load point exceeds the maximum load point, then the target gas proportional valve current is determined to be the gas proportional valve current corresponding to the maximum load point; If the second actual load point does not exceed the maximum load point, then the target gas proportional valve current is determined to be the gas proportional valve current corresponding to the second actual load point.

6. The control method of the gas water heater according to claim 5, characterized in that, The first preset temperature and the second preset temperature are not greater than 2.5℃.

7. The control method of the gas water heater according to claim 1, characterized by, The control method further includes: When the gas water heater is in a blocked state, the current actual speed and the current protection speed corresponding to the current operating load point are obtained, wherein the current protection speed is the upper limit of the safe speed of the gas water heater's fan at the current operating load point, and the current actual speed is the actual speed of the fan at the current operating load point; If the difference between the current protected speed and the current actual speed is less than or equal to the first preset speed difference, it is determined that the degree of blockage of the gas water heater is greater than the preset blockage degree.

8. The control method of the gas water heater according to claim 7, characterized by, The control method further includes: Collect the current actual rotational speed and the actual operating current of the fan; Obtain the reference fan speed corresponding to the actual operating current; If the difference between the current actual speed and the reference fan speed is greater than the second preset speed difference, then the gas water heater is determined to be in the blocked state.

9. The control method of the gas water heater according to claim 7, characterized by, After determining that the gas water heater is blocked, the control method further includes: If the current actual speed reaches the current protection speed corresponding to the current operating load point, the gas water heater will be shut off.

10. A gas water heater, characterized by, The gas water heater uses the control method for the gas water heater described in any one of claims 1 to 9.

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