JP3569600B2 - Control unit for gas combustion equipment - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for a gas combustion device in which an amount of combustion air corresponding to an amount of gas supplied to a gas burner is supplied by a fan so that an air-fuel ratio is maintained at a predetermined value.
[0002]
[Prior art]
In a gas combustion device such as an instantaneous water heater, a proportional solenoid valve controls the amount of gas supplied to a gas burner provided in a case forming a combustion chamber, and the number of rotations of a fan that supplies combustion air into the case. Is controlled in accordance with a valve drive current to a proportional solenoid valve to control the amount of air blow so that the air-fuel ratio always becomes a predetermined value. In such a gas combustion device, in a basic operating state (for example, a state immediately after installation having a standard shape and size as an exhaust extension pipe), the proportional solenoid valve is adjusted so that the air-fuel ratio becomes a predetermined value. Of the fan with respect to the valve drive current.
[0003]
However, the resistance of the ventilation path composed of the fan, the case, and the exhaust passage depends on the shape and dimensions of the exhaust extension tube, the degree of clogging of the exhaust passage, heat exchanger, fan, etc. due to combustion products, dust, dust, and the like, and the exhaust extension tube. If the fan speed is controlled to be constant for a certain valve drive current, if the resistance of the ventilation path increases, the amount of air blown by the fan, There is a possibility that the amount of air for use may be reduced to deteriorate the combustion state. This will be described with reference to FIG. 7. The characteristic curve of the static pressure P with respect to the blown air amount Q of the fan when the number of rotations of the fan is controlled to be a certain value N1 is FN1, and the characteristic curve of the ventilation path of the gas combustion device is FN1. If the resistance characteristic curve is the characteristic curve R0 in the basic operation state, the operating point of the fan is located at the intersection O1 of the two curves FN1, R0, and the air flow rate Q is Q1. However, if the resistance of the ventilation path of the gas-fired device increases and its characteristic curve becomes like R1, the operating point of the fan moves to the intersection O4 of both curves FN1 and R1, and the static pressure P of the fan slightly increases. The blowing amount Q decreases to Q4.
[0004]
As a means for reducing the amount of decrease in the blown air amount Q, there is a method of controlling the drive current to the fan to be constant with respect to a certain valve drive current, as disclosed in JP-A-62-255723. . That is, FIG. 7 shows a characteristic curve of the static pressure P with respect to the blown air amount Q of the fan when the fan drive current is set to the predetermined value If1 corresponding to the valve drive current by FI1. As in the case of the fixed number, the operating point of the fan is located at the intersection O1 of the curves FI1 and R0, and the air flow rate Q is Q1. However, if the resistance of the ventilation path increases and its characteristic curve becomes like R1, the operating point of the fan 25 moves to the intersection O2 of the two curves FI1 and R1, and the fan 25 moves as compared with the case where the rotation speed is constant. Of the static pressure P increases, and the amount of air flow Q, which becomes Q2, decreases less.
[0005]
[Problems to be solved by the invention]
As described above, according to the method of controlling the drive current to the fan to be constant with respect to the valve drive current to the proportional solenoid valve, the amount of air blown by the increase in the resistance of the ventilation path of the gas combustion device can be reduced. Although it can be reduced, this reduction cannot be made substantially zero. Therefore, the degree of deterioration of the combustion state due to the decrease in the amount of combustion air can be reduced, but the deterioration of the combustion state cannot be prevented.
An object of the present invention is to solve such a problem and to prevent the combustion state from deteriorating by preventing the amount of combustion air from substantially changing even when the resistance of the ventilation path of the gas combustion device changes.
[0006]
[Means for Solving the Problems]
As shown in FIG. 1, a control device for a gas combustion apparatus according to the present invention includes a case in which a gas burner in which a gas supply amount is controlled by a proportional solenoid valve is provided, and a fan corresponding to a valve drive current to the proportional solenoid valve. A control device for a gas combustion device, comprising: a fan to which a drive current is applied to supply an amount of combustion air according to a gas supply amount to a gas burner into a case; and a ventilation path including the fan, the case, and an exhaust passage. About
A rotation speed sensor for detecting the rotation speed of the fan,
Rotation speed characteristic storage means for storing a reference rotation speed characteristic of the fan with respect to the fan drive current in the basic operation state;
The amount of change in the number of revolutions of the fan due to the change in the resistance of the ventilation path when the fan drive current is constant, and the change in the resistance of the ventilation path at two points where the valve drive current to the proportional solenoid valve has a minimum value and a maximum value The correction coefficient which is the average value of the ratio to the actually measured value of the amount of change in the number of rotations of the fan required to make the change in the blower amount of the fan substantially zero due to Correction coefficient storage means for storing;
Thereby calculating the rotational speed characteristics storage reference rotational speed N 1 of the fan based on actual fan drive current and the reference rotational speed characteristic stored in the rotation of the fan detected by the rotational speed sensor and the reference rotational speed N 1 based on the correction coefficient K calculated by the number N 2 and the correction coefficient correction coefficient computing equations stored in the stored correction coefficient K or the correction coefficient storage means in the storage means, wherein K · (N 2 -N 1) + N Calculating means for calculating the corrected rotation speed by 1 ;
It is characterized by comprising control means for correcting the drive current to the fan so that the rotation speed of the fan becomes the correction rotation speed .
[0007]
Computing means good to so calculates the compensation rotational speed at predetermined time intervals.
[0008]
Together with the control means of the present invention, when the correction rotation speed calculated by the calculating means exceeds a predetermined value determined in advance is controlled such that the rotational speed of the fan is not increased to the predetermined value or more, the ventilation passage reduce the valve drive current to the proportional solenoid valve in accordance with a change in the fan drive current characteristic with increasing resistance, that this valve drive current to be stop the operation of the device if below a predetermined limit preferable. In this case, a warning may be issued before the valve drive current falls below the predetermined limit and the operation of the device is stopped.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be described below with reference to an embodiment shown in the accompanying drawings.
[0010]
As shown in FIG. 2, a gas burner 20 is provided in a lower portion of the case 10 forming the combustion chamber of the instantaneous water heater, and a source solenoid valve 23 and a proportional solenoid valve 22 arranged in series from the gas supply source side. The fuel gas is supplied by a gas supply passage 21 provided, and the combustion air is supplied by an electric fan 25 provided below the case 10. The proportional solenoid valve 22 changes the degree of gas supply to the gas burner 20 by continuously changing the opening in accordance with the applied valve drive current, and the original solenoid valve 23 is an electromagnetic valve that performs only opening and closing. . In addition, the fan 25 changes the number of revolutions continuously according to the applied fan drive current to change the amount of combustion air supplied to the case 10 (hereinafter simply referred to as the amount of air blow). The fan 25 is provided with a rotation speed sensor 35 for detecting the rotation speed and a current sensor 36 for detecting a fan drive current to the fan motor.
[0011]
A water flow sensor 37 is provided in the water supply pipe 16 connected to the inlet side of the fin tube type heat exchanger 15 provided in the case 10 above the gas burner 20, and a hot water temperature sensor is provided in the water supply pipe 17 connected to the outlet side. 38 and a hot water tap 18 are provided. The water supplied from the water supply pipe 16 is heated by the gas burner 20 when passing through the heat exchanger 15, reaches a predetermined temperature, and is discharged from the hot water tap 18. An exhaust passage formed of an exhaust pipe 12 and an exhaust extension pipe (not shown) connected to the exhaust pipe 12 via a hood 11 is provided at an upper portion of the case 10 above the heat exchanger 15. The combustion gas generated by the combustion of the fuel gas is discharged from the exhaust passage to the outside. The fan 25, the case 10, and the exhaust passage form a ventilation passage through which combustion air and combustion gas pass.
[0012]
The electronic control unit 30 for controlling the operation of the instantaneous water heater comprises a central processing unit (CPU), a read-only memory (ROM), a writable memory (RAM), and an interface, via a drive unit (all not shown) and the like. As shown in FIG. 2, each of the solenoid valves 22, 23, the fan 25, the operation device 31, the rotation speed sensor 35, the current sensor 36, the water flow sensor 37, and the hot water temperature sensor 38 are connected. The ROM of the electronic control unit 30 stores a control program necessary for controlling the operation of the instantaneous water heater and the following characteristics, correction coefficients, and the like. The RAM stores the detected values and the like as described later. The fan speed characteristic and the fan drive current characteristic at each point in time that are updated according to the increase of the variable and the resistance of the ventilation path are stored. The operating device 31 is provided with various switches, a hot water temperature setting device, various display lamps, and the like, necessary for operating the instantaneous water heater. The CPU of the electronic control unit 30 inputs predetermined signals from the operating device 31 and the sensors 35 to 38 according to the control program, performs predetermined calculations, and sends the signals to the solenoid valves 22, 23, the fan 25, the operating device 31 and the like. Is output to control the operation of the instantaneous water heater.
[0013]
In a basic operating state (for example, a state immediately after installation having a standard shape and size as an exhaust extension pipe), the characteristic of the air flow rate Q with respect to the rotation speed N of the fan 25 is based on the reference air flow shown in FIG. The characteristics of the rotation speed N with respect to the drive current If applied to the fan 25 are as shown in the reference flow speed characteristics VR0 shown in FIG. 3B, and the valve drive to the proportional solenoid valve 22 is performed. The characteristic of the fan drive current If with respect to the current Iv is as shown in the reference fan drive current characteristic WR0 shown in FIG. Depending on the installation environment, change the exhaust extension pipe of the gas combustion equipment from the standard shape and size, or if the exhaust passage, heat exchanger, fan, etc. are clogged with combustion products, dust, dust etc. If the resistance of the ventilation path changes from the characteristic R0 in the basic operation state to the characteristic R1 (see FIG. 7), the characteristics in FIGS. 3A to 3C are changed to the characteristics UR1 and VR1 in accordance with the degree of the change. , WR1. Among these characteristics, the reference rotation speed characteristic VR0 and the fan reference drive current characteristic WR0 in the basic operation state are stored in the ROM of the electronic control unit 30.
[0014]
The CPU of the electronic control unit 30 controls the fan 25 so that the fan drive current If has a certain valve drive current Iv (in other words, a certain gas supply amount) according to the characteristic shown in FIG. are doing. In the basic operating state, since the characteristics in FIGS. 3A to 3C are UR0, VR0, and WR0, the fan drive current with respect to the valve drive current Iv1 is If1, and the fan rotation speed is N1 (the reference rotation speed). ), And the blowing amount is Q1 (see FIGS. 3A to 3C). This state is indicated by an operating point O1. In this state, the resistance characteristic of the ventilation path changes from R0 to R1 as in the case described above, the fan speed characteristic in FIG. 3B changes from VR0 to VR1, and the air flow rate in FIG. When the characteristic changes from UR0 to UR1, the operating point of the fan 25 in that state moves from O1 to O2 in FIGS. 3A and 3B, the fan speed increases from N1 to N2, and the air flow rate increases. Decreases from Q1 to Q2. This decrease in the blowing amount Q is caused by moving the operating point of the fan 25 to the position O3 where the blowing amount Q1 becomes the original on the changed blowing characteristic UR1 in FIG. It is possible to compensate by setting N3. This may be performed by increasing the fan drive current corresponding to the valve drive current Iv1 from If1 to If2, as indicated by an operating point O3 in FIGS. 3B and 3C. With the increase in the fan drive current, the characteristic curve of the static pressure P with respect to the air flow amount Q of the fan 25 (see FIG. 7) moves from FI1 to FI2.
[0015]
In this embodiment, several such sets of N1, N2, N3 are measured in advance by experiment for each model, and (N3-N1) / (N2-N1) is obtained as a correction coefficient K. The value of the correction coefficient K differs depending on the value of the reference rotation speed N1 and the degree of change in the resistance of the ventilation path. According to the results of actual measurement, the value of the correction coefficient K is, for example, about 2 and changes greatly. I will not. Therefore, the increase in the resistance of the ventilation passage is a certain value within the practical limit, and the reference rotation speed N1 is the minimum value Nmin and the maximum value Nmax (the fan drive current characteristic is smaller) corresponding to the minimum value and the maximum value of the valve drive current Iv. the correction coefficient Kmin at two points as the value) when a WR0, determined experimentally Kmax, average of the two correction factors (Kmax + Kmin) / 2 or the two values K min, correction coefficient connecting the K max arithmetic expression {(Kmax-Kmin) (N1 -Nmin) / (Nmax-Nmin)} + Kmin
Is calculated as the correction coefficient K (see FIG. 4). The ROM of the electronic control unit 30 stores the correction coefficient K obtained in this manner or the correction coefficient calculation formula.
[0016]
FIGS. 5 and 6 are flowcharts of a control program for controlling the operation of the instantaneous water heater, and the operation of this embodiment will be described with reference to FIGS.
FIG. 5 is a flowchart of a main program for performing the entire operation. When the power of the electronic control device 30 is turned on, the CPU of the electronic control device 30 resets each variable to 0 or a predetermined initial value and starts the control operation according to the main program. First, in step 100, the CPU detects the presence or absence of a water flow through the water supply pipe 16 by the water flow sensor 37. If the hot water tap 18 is closed and no water flow is detected, the control operation does not proceed. However, if the hot water tap 18 is opened and a predetermined minimum amount of water is detected, the process proceeds to step 101, where the CPU returns to the original solenoid valve. 23, the proportional solenoid valve 22 is set at a predetermined ignition opening, the fan 25 is operated at a predetermined ignition rotation speed, an ignition device (not shown) is operated for a predetermined time, and the gas discharged from the gas burner 20 is ignited. Then, the operation of the instantaneous water heater is started.
[0017]
After the operation of the instantaneous water heater is started, the CPU of the electronic control unit 30 repeats steps 102 and 103 as long as the hot water tap 18 is open. In step 102, the fan drive current characteristic shown in FIG. 6 described later is corrected. In the normal combustion control in step 103, the hot water temperature detected by the hot water temperature sensor 38 is compared with the hot water temperature set by the operation device 31, and the hot water is discharged. The amount of gas supplied to the gas burner 20 is controlled by controlling the valve drive current Iv to the proportional solenoid valve 22 so that the temperature becomes the set temperature, and based on the fan drive current characteristics corrected in step 102, the valve drive current Iv The fan drive current If to the fan 25 is controlled in accordance with the condition (1), and the amount of air blown to the case 10 is controlled so that a predetermined air-fuel ratio is obtained. If the hot water tap 18 is closed and the water flow sensor 37 no longer detects the water flow, the control operation proceeds from step 104 to step 105, in which the proportional solenoid valve 22 and the original solenoid valve 23 are closed according to a predetermined sequence whose description has been omitted, and the fan 25 is stopped to stop the operation of the instantaneous water heater.
[0018]
In the correction of the fan drive current characteristic in step 102, a correction routine shown in FIG. 6 is executed every predetermined time (for example, one minute). This instantaneous water heater has no clogging in each part of the ventilation path immediately after installation, but has an exhaust extension pipe different from the standard shape and size, and the resistance of the ventilation path is lower than the characteristic R0 in the basic operation state. It is assumed that the characteristic R1 is large. Accordingly, the air volume characteristic is UR1, the fan speed characteristic is VR1, and the fan drive current characteristic is WR1. The RAM stores the arithmetic expressions of the reference rotation speed characteristic VR0 and the fan reference drive current characteristic WR0 as the current fan rotation speed characteristics and fan drive current characteristics.
[0019]
The CPU of the electronic control unit 30 detects the rotation speed N (= N2) and the driving current If (= If1) of the fan 25 by the rotation speed sensor 35 and the current sensor 36 in step 200, and in subsequent step 201, It is determined whether or not the operating point O1 of the fan 25 is on the current fan speed characteristic (= VR0) stored in the RAM (specifically, whether or not it deviates from VR0 by a predetermined value α to be described later). . In the first control cycle after the start of operation immediately after the installation of the instantaneous water heater as described above, the operating point O1 is determined by the current fan speed characteristic (= VR0) stored in the RAM as shown in FIG. ), The CPU calculates the reference rotation speed N1 in step 202. This calculation is performed based on the reference rotation speed characteristic VR0 of the fan 25 stored in the ROM and the fan drive current If1 detected by the current sensor 36. α is a value larger than the variation width of the fan rotation speed N that occurs when the fan drive current If is constant. Even if the operating point moves within such a variation range, the fan drive current is not corrected. It is provided in order to make.
[0020]
Subsequent to the calculation of the reference rotation speed N1 in step 202, the calculation of the corrected rotation speed N3 is performed in step 203. This calculation is based on the reference rotation speed N1 calculated in step 202, the actual rotation speed N2 of the fan 25 detected by the rotation speed sensor 35, and the correction coefficient K stored in the ROM or the correction coefficient calculation formula stored in the ROM. The calculation is performed by substituting the calculated correction coefficient K into the following equation.
N3 = K · (N2-N1) + N1
As described above, in the basic operating state where the resistance characteristic of the ventilation path is R0, the operating point of the fan 25 when the valve drive current is at a certain value (Iv1) is at O1 in FIGS. If the resistance characteristic increases from R0 to R1, the air volume characteristic changes from UR0 to UR1, the fan speed characteristic changes from VR0 to VR1, the fan drive current characteristic changes from WR0 to WR1, and the operating point of the fan 25 After the resistance is increased, the air moves to O2 on each characteristic, and the air flow decreases from Q1 to Q2. However, by setting the fan rotation speed N to the corrected rotation speed N3 calculated in step 203, the operating point of the fan 25 moves to O3 on each characteristic after the resistance is increased, and the amount of air blown depends on the value of the valve drive current. , The fan driving current corresponding to the valve driving current Iv1 increases from If1 to If2.
[0021]
In response to this, in the subsequent step 204, the CPU changes the fan speed characteristic stored in the RAM from VR0 up to the passing through the operating point O1 to the operating point O2 ((If1, N2) in FIG. 3B). ) Is updated to VR1 passing through the operating points O1 and O2, and the WR1 passing through the operating point O3 (point (Iv1, If2) in FIG. 3 (c)) from the previous WR0 through the operating points O1 and O2. Update to Thereafter, the updated properties are used as the current properties.
[0022]
In the following step 205, the CPU compares the corrected rotation speed N3 calculated in step 203 with the practical maximum rotation speed Nm of the fan 25. Normally, N3> Nm is not satisfied, so the CPU sets the flag F to 0 in step 206 and returns the control operation to step 103 in FIG. In the normal combustion control in step 103, the fan speed N is controlled to be the corrected speed N3, and the fan drive current applied to the fan 25 becomes If2. As a result, the characteristic curve of the static pressure P with respect to the blowing amount Q of the fan 25 becomes FI2 (see FIG. 7).
[0023]
In the case of the second and subsequent control cycles after the start of operation, unless the resistance of the ventilation path changes significantly due to clogging or the like, the operating point O1 does not deviate from the current fan speed characteristic by the predetermined value α or more. The process immediately returns from step 201 to step 103 in FIG. 5, and the fan drive current characteristics are not corrected. In the meantime, if the valve drive current applied to the proportional solenoid valve 22 changes due to a change in the set temperature, the amount of hot water, or the like, the CPU updates the fan drive current and the fan speed in the normal combustion control in step 103 with the updated fan drive current. The control is performed based on the drive current characteristics (= WR1) and the fan rotation speed characteristics (= VR1).
[0024]
If the blockage of the ventilation passage progresses gradually and the resistance increases, the fan speed N increases, and the deviation of the operating point of the fan 25 from the current fan speed characteristics gradually increases. When the difference becomes equal to or larger than the predetermined value α, the control operations in steps 202 to 206 are performed again, and the fan speed characteristic and the fan drive current characteristic are updated to new current characteristics in the same manner as described above. This update is repeated, and each time, the fan speed characteristic VR1 in FIG. 3B is leftward from the reference speed characteristic VR0, and the fan drive current characteristic WR1 in FIG. 3C is based on the fan reference drive current characteristic WR0. Moving away to the right, the corrected rotation speed N3 gradually increases. If N3> Nm, the CPU proceeds from step 205 to step 207.
[0025]
Then, the CPU sets the flag F to 1 in step 207, sets N3 = Nm in step 208, compares the valve drive current Iv applied to the proportional solenoid valve 22 with a predetermined limit value β in step 209, and if Iv <β is not satisfied. The control operation returns to step 103 in FIG. In this case, in the normal combustion control in step 103, the fan speed N is controlled so as to be the practical maximum speed Nm of the fan 25. The fan rotation speed N increases as the resistance increases due to the blockage of the ventilation passage. However, if this rotation speed exceeds the practical maximum rotation speed Nm of the fan 25, noise increases, overheating occurs, and the life of the fan 25 increases. Inconveniences such as shrinking are caused. However, in this embodiment, since the rotation speed of the fan 25 is limited so as not to exceed the maximum rotation speed Nm, such inconvenience is avoided.
[0026]
When the fan speed N is limited to the practical maximum speed Nm as described above, the fan drive current If decreases as the resistance increases due to the blockage of the ventilation passage, and the air-fuel ratio becomes a predetermined value. In order to maintain this, the valve drive current Iv must be controlled to decrease accordingly. Therefore, when the flag F is 1, in the normal combustion control in step 103, a fan drive current is applied to the fan 25 so that the rotation speed N becomes the maximum rotation speed Nm. The valve drive current reduced in accordance with the fan drive current characteristic of FIG.
[0027]
The valve drive current decreases in this way as the ventilation passage becomes more and more blocked. If γ <Iv <β, the CPU issues a warning by an abnormality display lamp or the like in step 210, and then performs the normal combustion control in step 103 as in step 209. If Iv <β, the CPU advances the control operation to step 212 to close the proportional solenoid valve 22 and the original solenoid valve 23, stops the fan 25, and stops the operation of the instantaneous water heater. The limit value γ is smaller than the limit value β, and is such a value that if the valve drive current is lower than the limit value, the efficiency of the device decreases and the device becomes unsuitable for use. Note that the limit values β and γ are not fixed values, and the fan drive current characteristic WR0 in the basic operation state shown in FIG. 3C is moved downward (WR1 side) by a predetermined amount in the valve drive current axis direction. And changes in accordance with the fan drive current If.
[0028]
In a gas combustion device such as an instantaneous water heater, when the degree of clogging of the ventilation passage is low, it is preferable to increase the rotation speed of the fan 25 so that the use can be continued. If the combustion products are clogged in the meantime, it is not preferable because heat transfer is deteriorated, thermal efficiency is reduced, and local overheating is caused to reduce durability of the device. In this embodiment, the fan speed is automatically increased until the resistance of the ventilation path exceeds a certain limit, so that the air-fuel ratio can be maintained at a predetermined value and the use can be continued. If a certain limit is exceeded, a warning is displayed and the equipment stops, so it is possible to know that the degree of clogging has become so bad that it is necessary to clean the ventilation path and prevent inconvenience due to excessive clogging. .
[0029]
【The invention's effect】
As described above, according to the present invention, the calculating means calculates the corrected rotation speed such that the amount of change in the blown air amount due to the change in the resistance of the ventilation path of the gas combustion apparatus becomes substantially close to 0, and the control means Since the drive current to the fan is controlled so that the fan rotation speed becomes the corrected rotation speed, even if the resistance of the ventilation path changes, the air flow will be a value corresponding to the fan drive current, and this fan drive current will be proportional Since the value is in accordance with the valve drive current to the solenoid valve, the supply amount of combustion air is a predetermined value in accordance with the gas supply amount. Therefore, even if the resistance of the ventilation passage changes, the air-fuel ratio is maintained at a predetermined value, and the deterioration of the combustion state is reduced.
[0030]
According to the fan rotation speed is prevented from increasing above a predetermined value, and if the valve drive current falls below a predetermined limit, the operation of the device is stopped in advance without issuing a warning or issuing a warning. Inconvenience due to overcapacity of the air conditioner or excessive clogging of the ventilation path does not occur.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a control device of a gas combustion device according to the present invention.
FIG. 2 is an overall configuration diagram showing an embodiment of a control device for a gas combustion device according to the present invention.
FIG. 3 is a characteristic diagram illustrating the operation of the embodiment shown in FIG. 2;
FIG. 4 is an explanatory diagram of a correction coefficient of the embodiment shown in FIG.
FIG. 5 is a flowchart of a main program used in the embodiment shown in FIG.
FIG. 6 is a flowchart of a fan drive current characteristic correction routine that forms part of the main program shown in FIG. 5;
FIG. 7 is a characteristic diagram illustrating the operation of the gas combustion device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Rotation speed characteristic storage means, 2 ... Correction coefficient storage means, 3 ... Calculation means, 4 ... Control means, 10 ... Case, 20 ... Gas burner, 22 ... Proportional solenoid valve, 25 ... Fan, 35 ... Rotation speed sensor.

Claims (4)

A case in which a gas burner in which a gas supply amount is controlled by a proportional solenoid valve is provided, and a fan drive current corresponding to a valve drive current to the proportional solenoid valve is applied so that a gas supply amount to the gas burner is increased. A fan for supplying combustion air into the case, and a control device for a gas combustion device including a ventilation path including the fan, the case, and an exhaust passage.
A rotation speed sensor for detecting the rotation speed of the fan,
Rotation speed characteristic storage means for storing a reference rotation speed characteristic of the fan with respect to the fan drive current in a basic operating state;
The amount of change in the number of revolutions of the fan due to a change in the resistance of the ventilation path when the fan drive current is constant, and the ventilation at two locations where the valve drive current to the proportional solenoid valve has a minimum value and a maximum value. the average value of the ratio is the correction coefficient or the two locations between the measured value of the rotational speed of the change amount of the fan required to substantially zero a change in the air volume of the fan due to the change in resistance of the road Correction coefficient storage means for storing a correction coefficient calculation formula that connects the ratios in
Thereby calculating a reference rotational speed N 1 of the fan based on actual the fan driving current to the reference rotational speed characteristics stored in the rotational speed characteristic storage means is detected the reference rotational speed N 1 and by the rotational speed sensor wherein based on the rotation speed N 2 and the correction coefficient storage means stored correction coefficient K or the correction coefficient K calculated by the correction coefficient calculation equations stored in the correction coefficient storage means fans, formula K · (N the 2 -N 1) + N 1 and calculating means for calculating a correction rotational speed,
A control device for a gas combustion device, comprising control means for correcting a drive current to the fan so that the rotation speed of the fan becomes the correction rotation speed. It said calculating means control device for a gas combustion apparatus according to claim 1 is for calculating the pre-Symbol correction rotation speed every predetermined time. Wherein, with the case where the calculated correction rotation speed exceeds a predetermined rotational speed set in advance is controlled such that the rotational speed of the fan is not increased to the predetermined value or more by the calculating means, wherein in response to changes in the fan drive current characteristic with increasing air passage in resistance reduces the valve drive current to the proportional solenoid valve, that this valve driving current stops operation of the device if below a predetermined limit The control device for a gas-fired appliance according to claim 1 or 2, wherein The control device for a gas-fired device according to claim 3, wherein a warning is issued before the valve drive current to the proportional solenoid valve falls below the predetermined limit and the operation of the device is stopped.

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