Gas water heating equipment and ignition control method thereof

Abstract

The invention provides gas water heating equipment and an ignition control method thereof. The ignition control method comprises the following steps: during primary ignition, acquiring an ignition load, and assigning an ignition power set value as the ignition load; calculating a target load, and comparing the ignition power set value with the target load; and when the ignition power set value is larger than the target load, the ignition power set value is reduced step by step, and operation of the air valve and the draught fan is correspondingly adjusted step by step. In the process of cold ignition and load reduction, the load is reduced step by step in a stepped manner, and the operation of the air valve and the fan is correspondingly adjusted step by step, so that the adjusting speed of the fan can follow the adjusting speed of the air valve, the air amount during ignition can be matched with the gas amount, and then the situations of flameout and equipment shutdown fault reporting are avoided.

Description

Technical Field

[0001] This disclosure relates to the field of gas-fired water heating equipment control, and in particular to a gas-fired water heating equipment and its ignition control method. Background Technology

[0002] Gas-fired water heating systems typically include gas water heaters and gas boilers. Gas water heaters supply hot water for drinking and bathing; while gas boilers, in addition to providing domestic hot water, can be connected to radiators installed indoors to provide central heating. Generally, during initial ignition (cold ignition), the air introduced for combustion is colder and denser. Furthermore, as the ignition load decreases, the gas proportional valve adjusts faster than the fan, causing a mismatch between the air and gas supply at ignition. This often results in an excess of air and a shortage of gas, easily leading to flameout and subsequent equipment shutdown and malfunction. Summary of the Invention

[0003] To overcome the problems existing in the prior art, this disclosure provides a gas-fired water heater and its ignition control method.

[0004] A first aspect of this disclosure provides an ignition control method for a gas-fired water heater, wherein the gas-fired water heater includes a burner, a heat exchanger, a gas valve, a fan, and an ignition device. The method includes: upon initial ignition, acquiring the ignition load and assigning an ignition power setpoint as the ignition load; calculating a target load and comparing the ignition power setpoint with the target load; when the ignition power setpoint is greater than the target load, progressively reducing the ignition power setpoint and correspondingly progressively adjusting the operation of the gas valve and the fan.

[0005] In some embodiments, when the target load is greater than the minimum load of the equipment, the ignition power setting is gradually reduced to the target load; when the target load is less than or equal to the minimum load of the equipment, the ignition power setting is gradually reduced to the minimum load of the equipment.

[0006] In some embodiments, each reduction in the ignition power setting is within the range of 0.1% to 3% of the ignition load.

[0007] In some embodiments, the reduction rate is equal for each level.

[0008] In some embodiments, each decrease in the ignition power setpoint, and the corresponding control of the gas valve and blower, is completed within a fixed time interval.

[0009] In some embodiments, when the ignition power setting value is less than or equal to the target load, the ignition power setting value is directly assigned to the target load, and the operation of the gas valve and the fan is adjusted in one go.

[0010] In some embodiments, the ignition load is obtained by determining the corresponding ignition load based on the model of the current gas-fired water heater.

[0011] In some embodiments, the target load Pt is calculated using the following formula: Pt = c × m × ΔT / η; where c is the specific heat capacity of water, m is the current water flow rate, ΔT is the difference between the set target temperature and the current inlet or outlet water temperature, and η is the equipment efficiency.

[0012] A second aspect of this disclosure provides a computer-readable storage medium having instructions stored thereon that, when executed by a processor, implement the method steps described above.

[0013] A third aspect of this disclosure provides a computer program product including a computer program that, when executed by a processor, implements the method steps described above.

[0014] A fourth aspect of this disclosure provides a gas-fired water heating device, comprising a burner for burning a mixture of gas and air to generate heat, a heat exchanger for heating water flowing through it using the heat generated by the burner, a gas valve for controlling the supply of gas to the burner, a fan for driving the gas flow, an ignition device for igniting the gas-air mixture, and a controller. The controller is configured to: upon initial ignition, acquire the ignition load and assign an ignition power setpoint as the ignition load; calculate a target load and compare the ignition power setpoint with the target load; when the ignition power setpoint is greater than the target load, progressively reduce the ignition power setpoint and accordingly progressively adjust the operation of the gas valve and the fan.

[0015] In some embodiments, when the target load is greater than the minimum load of the equipment, the ignition power setting is gradually reduced to the target load; when the target load is less than or equal to the minimum load of the equipment, the ignition power setting is gradually reduced to the minimum load of the equipment.

[0016] In some embodiments, each reduction in the ignition power setting is within the range of 0.1% to 3% of the ignition load.

[0017] In some embodiments, each decrease in the ignition power setpoint, and the corresponding control of the gas valve and blower, is completed within a fixed time interval.

[0018] In some embodiments, the controller is further configured to directly assign the ignition power setpoint to the target load and adjust the operation of the gas valve and fan in one go when the ignition power setpoint is less than or equal to the target load.

[0019] The technical solutions provided by one or more embodiments of this disclosure may include the following beneficial effects: during cold ignition and load reduction, by gradually reducing the load in a stepwise manner and adjusting the operation of the gas valve and fan accordingly, the adjustment speed of the fan can keep up with the adjustment speed of the gas valve, so that the amount of air during ignition can match the amount of gas, thereby avoiding the situation of flameout, equipment shutdown and fault reporting. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic block diagram of a gas-fired water heater according to one embodiment of the present disclosure;

[0022] Figure 2 This is a flowchart of an ignition control method for a gas-fired water heater in one embodiment;

[0023] Figure 3 This is a schematic diagram of the curve showing the ignition power decreasing from the initial ignition load to the target load or the minimum load of the equipment in one embodiment of this disclosure;

[0024] Figure 4 This is a schematic diagram of the curve showing the ignition power increasing from the initial ignition load to the target load in one embodiment of this disclosure. Detailed Implementation

[0025] The embodiments shown will now be described in detail with reference to the accompanying drawings. However, these embodiments do not represent all embodiments consistent with this disclosure, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the scope of protection claimed in the appended claims.

[0026] Gas-fired water heating equipment uses combustible gases as fuel, such as natural gas, city gas, liquefied petroleum gas, and biogas, to provide heat to meet users' living needs. Examples include gas water heaters that provide domestic hot water, or gas boilers that can provide both domestic hot water and heating.

[0027] like Figure 1As shown, the gas-fired water heater 100 includes a housing 10, which houses a burner assembly, a heat exchanger 13, and a flue gas exhaust device 14. The housing 10 may be assembled from several panels to form a storage space within it to accommodate the various components. An inlet pipe 111, an outlet pipe 112, and a gas supply pipe 113 extend from the bottom of the housing 10.

[0028] The burner assembly typically includes a gas distributor (not shown) and a burner 12. A gas valve 15 is provided on the gas supply line 113 for connecting or disconnecting the gas supply passage and controlling the amount of gas supplied to the gas distributor. As is well known to those skilled in the art, this gas valve can be a typical gas proportional valve, such as the SIT 84X (e.g., 840, 843, 845) SIGMA proportional valve, which typically includes a shut-off valve for controlling the opening and closing of the main gas passage and a servo system for adjusting the main gas valve opening to control the proportion and pressure of the output gas; the servo system includes a diaphragm that cooperates with the main gas valve, and the diaphragm is moved by adjusting the pressure on both sides of the diaphragm, thereby adjusting the opening of the main gas valve. In some embodiments, the burner 12 includes a plurality of combustion units arranged side by side along a longitudinal direction. Each combustion unit is flat and plate-shaped, typically upright and fixed in the burner frame, with an air inlet at the bottom, a plurality of flame holes at the top, and a gas-air mixing passage connecting the air inlet and the plurality of flame holes. Gas fuel, via valve 15, is distributed through the gas distributor to the air inlet of each combustion unit, where it mixes with simultaneously entering primary air in the gas-air mixing channel and is then delivered to the burner holes located at the top of the burner plates for combustion, generating hot flue gas. The burner assembly also includes an ignition device 121 for igniting the gas-air mixture and a flame detection device 122 for detecting the presence of a flame. In some embodiments, the ignition device 121 includes a pair of ignition electrodes extending above the burner holes of the combustion unit. The flame detection device 122 includes a flame detection electrode extending above the burner holes of the combustion unit.

[0029] The heat generated by combustion in burner 12 passes through heat exchanger 13. Heat exchanger 13 is typically positioned above burner 12. In some embodiments, the heat exchanger may be a finned tube heat exchanger, wherein multiple fins are disposed within the heat exchanger housing, and a heat exchange water pipe meanders through these fins, with its two ends connected to an inlet pipe 111 located upstream in the water flow direction and an outlet pipe 112 located downstream in the water flow direction, respectively. The heat generated by combustion of the gas-air mixture is absorbed by the fins and further transferred to the water flowing through the heat exchange water pipe. The heated water is then transferred to the domestic water pipe through outlet pipe 112, thereby providing users with domestic water for drinking, bathing, and other uses.

[0030] In this embodiment, a fan 16 is positioned below the burner 12 to drive airflow, thereby providing the air required for combustion and causing the flue gas generated by combustion to be collected by the smoke hood of the exhaust device 14, and then discharged through the exhaust pipe (not shown) connected to the smoke hood. An inlet water temperature sensing element 181 is positioned at the inlet pipe 111 (e.g., on the outer wall of the inlet pipe), and an outlet water temperature sensing element 182 is positioned at the outlet pipe 112 (e.g., on the outer wall of the outlet pipe). The temperature sensing element can be a thermistor, such as a positive temperature coefficient thermistor (PTC). In some embodiments, the temperature sensing element can also be a negative temperature coefficient (NTC) temperature sensor. A flow detection device 183 is positioned in the water path to detect the water flow rate. In some embodiments, the flow detection device may be installed at the inlet pipe 111 to detect the inlet flow rate. It may include a rotor assembly with a magnet and a Hall element. When water flows through the detection device 183, the rotor assembly is rotated, thereby utilizing the Hall effect of the Hall element to measure magnetic physical quantities.

[0031] A controller 17 is disposed within the housing 10 for detecting and controlling the operation of various circuit components within the gas-fired water heater. In some embodiments, the controller 17 may be a control circuit comprising a processor, a memory, and several electronic components connected in a specific wiring configuration. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0032] The memory can be used to store instructions for any application or method operating on the processor, as well as various types of data. The processor implements the various functions of the gas-fired water heater by running or executing programs or instructions stored in the memory and by calling data stored in the memory. The memory can contain any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (PROM), magnetic storage, flash memory, solid-state memory, magnetic disks, or optical disks, etc.

[0033] In this embodiment, the controller 17 is the control center of the gas water heater, which connects various parts of the equipment through various interfaces and lines. For example, the controller 17 is wired or wirelessly connected to the ignition device 121, the flame detection device 122, the gas valve 15, the fan 16, the inlet and outlet water temperature detection elements 181 and 182, the flow detection device 183, etc.

[0034] Figure 2 The following describes the steps of a method for performing ignition control on a gas-fired water heater in one embodiment. The controller 17 will also describe these steps in detail below.

[0035] Upon entering the ignition procedure, the controller 17 first determines whether it is the first ignition by checking the ignition status bit (step 201). If the ignition status bit is zero, it indicates that this ignition is the first ignition. Only when it is identified as the first ignition will the following steps be executed. Subsequently, the controller 17 acquires the ignition load Pi (step 202). In some embodiments, the memory stores the ignition loads corresponding to different models, so the corresponding ignition load can be determined according to the current model of the gas water heater. For example, if the current model is LNA 11L, its corresponding ignition load can be found to be 11kW (kilowatts) through the index. After acquiring the ignition load, the ignition power setting value is assigned as the ignition load Pi. Next, the target load Pt is calculated (step 202). This target load is the combustion heat load required by the gas water heater to heat the water to the target temperature set by the user. In some embodiments, the target load Pt is calculated using the following formula: Pt = c × m × ΔT / η; where c is the specific heat capacity of water, m is the current water flow rate, ΔT is the difference between the set target temperature and the current inlet or outlet water temperature, and η is the equipment efficiency.

[0036] After calculating the target load Pt, the ignition power setting value is compared with the target load Pt. Since the current ignition power setting value is the ignition load Pi, the comparison is actually between the ignition load Pi and the target load Pt (step 204). (Refer to reference...) Figure 4As shown, when the current ignition power setting value, i.e., the ignition load Pi, is less than or equal to the target load Pt, the ignition power setting value is directly assigned to the target load, that is, the ignition power setting value is increased from the ignition load Pi to the target load Pt in one go (step 204), and the operation of the gas valve 15 and the fan 16 is adjusted accordingly. If the equipment needs to work under the target load Pt, it needs to match the gas quantity and the combustion air quantity according to a certain ratio; in some embodiments, the controller 17 can determine the gas valve opening degree corresponding to the required gas quantity according to the pre-stored power-current curve of the gas valve, and determine the fan speed corresponding to the required combustion air quantity according to the power-current curve of the fan, so as to achieve the desired gas quantity in a short time (e.g., Figure 4 Within the time interval t1 to t3, the air valve is adjusted to the target opening degree and the fan is adjusted to the target speed; then, the controller 17 enters the constant temperature regulation (step 209). In some embodiments, the controller may include a PID (proportional-integral-derivative) controller, which automatically and linearly adjusts the air valve opening degree and / or fan speed by detecting the water flow rate, inlet water and / or outlet water temperature, so that the outlet water temperature quickly reaches and is maintained at the user-set target temperature.

[0037] If the current ignition power setting, i.e., the ignition load Pi, is greater than the target load Pt, in some embodiments, it will be further determined whether the target load Pt is greater than the equipment's minimum load Pmin (step 206). If yes, i.e., the current ignition power setting is greater than the target load, the ignition power setting is gradually reduced from the ignition load Pi to the target load Pt (step 207); if no, the ignition power setting is gradually reduced from the ignition load Pi to the equipment's minimum load Pmin (step 208). (Refer to reference...) Figure 3 As shown, during the gradual reduction of the ignition power setpoint, the controller correspondingly adjusts the operation of the gas valve and fan accordingly. That is, for each level decrease in the ignition power setpoint, the controller determines the required gas and combustion air volume for the current ignition power setpoint and adjusts the gas valve opening and fan speed accordingly. Each level of reduction in the ignition power setpoint, ΔP, falls within the range of 0.1% to 3% of the ignition load Pi. The reduction at each level can be equal or unequal. For example, if each level of reduction is equal and 0.5%, assuming the ignition load Pi = 11kW, the minimum equipment load Pmin = 6kW, and the calculated target load Pt = 7kW, then the ignition power setpoint first decreases to P1 = 11 × (1 - 0.5%) = 10.945kW. Then, the controller adjusts the corresponding gas valve opening and fan speed based on the current ignition power setpoint P1. After adjustment, reduce the ignition power setting P1 by the same amount to P2, and adjust the valve opening and fan speed accordingly; repeat this process until the ignition power setting drops to the target load Pt, i.e., 7kW. (Comparison) Figure 3 and Figure 4 It will be found that the time for step-by-step adjustment (i.e. Figure 3 The time interval from t1 to t2 is relatively long. In some embodiments, each decrease in the ignition power setpoint, and the corresponding control of the gas valve and fan, can be completed within a fixed time interval Δt, such as 100ms. In other embodiments, steps 206 and 208 can be omitted; that is, if the judgment result of step 204 is "yes", then step 207 is executed directly. When the ignition power setpoint drops to the target load Pt or the minimum equipment load Pmin, the equipment then enters the constant temperature regulation (step 209).

[0038] During cold ignition and load reduction, the load is gradually reduced in a step-by-step manner, and the operation of the gas valve and fan is adjusted accordingly. This ensures that the adjustment speed of the fan can keep up with the adjustment speed of the gas valve, so that the amount of air during ignition can match the amount of gas, thereby avoiding situations such as flameout, equipment shutdown and fault reporting.

[0039] All or part of the steps in the methods of the above-disclosed embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or some intermediate form. The readable storage medium can contain any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (PROM), magnetic storage, flash memory, solid-state memory, magnetic disk, or optical disk, etc.

[0040] It should be understood that the methods and apparatus disclosed above can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. The division of units in the controller is only a logical functional division; in actual implementation, there may be other division methods. For example, multiple units may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the connections between the components, parts, and units discussed above can be electrical, mechanical, or other forms of connection; they can be direct connections or indirect connections through interfaces, etc.; they can be wired connections or wireless connections.

[0041] Furthermore, the units described above as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; some or all of the units can be selected to achieve the purpose of the disclosed embodiments according to actual needs. Additionally, the functional units in the above embodiments 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 units described above can be implemented in hardware or in a combination of hardware and software functional units.

[0042] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. An ignition control method for a gas-fired water heater, the gas-fired water heater comprising a burner, a heat exchanger, a gas valve, a fan, and an ignition device; characterized in that, The method includes: Upon initial ignition, the ignition load is acquired, and the ignition power setting value is assigned as the ignition load. Calculate the target load and compare the ignition power setpoint with the target load; When the ignition power setting value is greater than the target load, the ignition power setting value is reduced step by step, and the operation of the gas valve and fan is adjusted accordingly.

2. The method according to claim 1, characterized in that: When the target load is greater than the minimum load of the equipment, the ignition power setting is gradually reduced to the target load; when the target load is less than or equal to the minimum load of the equipment, the ignition power setting is gradually reduced to the minimum load of the equipment.

3. The method according to claim 1 or 2, characterized in that: Each reduction in the ignition power setting value is within the range of 0.1% to 3% of the ignition load.

4. The method according to claim 3, characterized in that: The reduction at each level is equal.

5. The method according to claim 1, characterized in that: Each decrease in the ignition power setting, and the corresponding control of the gas valve and blower, is completed within a fixed time interval.

6. The method according to claim 1, characterized in that: When the ignition power setting is less than or equal to the target load, the ignition power setting is directly assigned to the target load, and the operation of the gas valve and fan is adjusted in one go.

7. The method according to claim 1, characterized in that: The ignition load is obtained by determining the corresponding ignition load based on the current model of the gas-fired water heater.

8. The method according to claim 1, characterized in that: The target load Pt is calculated using the following formula: Pt = c × m × ΔT / η; where c is the specific heat capacity of water, m is the current water flow rate, ΔT is the difference between the set target temperature and the current inlet or outlet water temperature, and η is the equipment efficiency.

9. A computer-readable storage medium having instructions stored thereon, characterized in that: When the instructions are executed by the processor, they implement the steps of the method as described in any one of claims 1-8.

10. A computer program product comprising a computer program, characterized in that: When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1-8.

11. A gas-fired hot water device, comprising a burner for burning a mixture of gas and air to generate heat, a heat exchanger for using the heat generated by the burner to heat water flowing through it, a gas valve for controlling the supply of gas to the burner, a fan for driving the gas flow, an ignition device for igniting the gas-air mixture, and a controller; characterized in that, The controller is configured to, Upon initial ignition, the ignition load is acquired, and the ignition power setting value is assigned as the ignition load. Calculate the target load and compare the ignition power setpoint with the target load; When the ignition power setting value is greater than the target load, the ignition power setting value is reduced step by step, and the operation of the gas valve and fan is adjusted accordingly.

12. The gas-fired water heater according to claim 11, characterized in that: When the target load is greater than the minimum load of the equipment, the ignition power setting is gradually reduced to the target load; when the target load is less than or equal to the minimum load of the equipment, the ignition power setting is gradually reduced to the minimum load of the equipment.

13. The gas-fired hot water equipment according to claim 11 or 12, characterized in that: Each reduction in the ignition power setting value is within the range of 0.1% to 3% of the ignition load.

14. The gas-fired water heater according to claim 11, characterized in that: Each decrease in the ignition power setting, and the corresponding control of the gas valve and blower, is completed within a fixed time interval.

15. The gas-fired hot water equipment according to claim 11, characterized in that: The controller is also configured to directly assign the ignition power setpoint to the target load when the ignition power setpoint is less than or equal to the target load, and to adjust the operation of the gas valve and the fan in one go.

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