JP2001289437A - Combustion-controlling device of premixing type combustion burner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the combustion-controlling device of a premixing type combustion burner for maintaining an air ratio in a proper range even if the change ventilation failure in a primary fuel supply pressure occur. SOLUTION: A mixture part T where fuel to be supplied is mixed with air for combustion by the ventilation operation of a ventilating fan 6 for ventilating combustion air to a burner 5 for burning an object to be heated by combustion, a pressure adjustment means 15 that is installed at a fuel supply path 14 being connected to the mixture part T so that suction force is operated by the ventilation operation of the ventilating fan 6 and adjusts fuel supply pressure at the downstream side from the installation position are provided. Also, a pressure detection means 17 for detecting a fuel supply pressure at the downstream of the pressure adjustment means 15 is provided. After a combustion control means H executes combustion control treatment, pressure adjustment treatment is executed so that the fuel supply pressure being adjusted by the pressure adjustment means 15 reaches a target fuel supply pressure in the combustion-controlling device of a premixing type fuel burner.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a premixing type burner for heating an object to be heated by combustion, a ventilation fan for blowing combustion air through the burner, and a supply fan with the ventilation operation of the ventilation fan. A mixing section for mixing the fuel to be mixed with the combustion air, a fuel supply path connected to the mixing section so that suction force acts by a ventilation operation of the ventilation fan, and a fuel supply path for supplying fuel; and a fuel supply path. Pressure control means for adjusting the fuel supply pressure downstream of the installation location, and combustion control means for controlling the combustion of the burner, wherein the combustion control means The present invention relates to a combustion control device for a premixed combustion burner configured to execute a combustion control process for controlling a rotation speed of the ventilation fan so as to have an appropriate ventilation amount corresponding to a supply amount.

[0002]

2. Description of the Related Art A combustion control device for a premixed combustion burner as described above uses, for example, a flow control valve as a pressure control means, and uses the flow control valve to move the flow control valve downstream from the installation position of the flow control valve. By adjusting the flow rate of the fuel, the fuel supply pressure (hereinafter, abbreviated as secondary fuel supply pressure) downstream of the installation position of the flow rate adjustment valve is adjusted, and the adjusted pressure and the operation of the ventilation fan are adjusted. The fuel is supplied to the mixing section by a pressure difference from the negative pressure generated in the mixing section, and the secondary fuel supply pressure is adjusted by the pressure adjusting means so that the combustion amount required for the combustion of the burner is obtained. At the same time, a combustion control process for controlling the rotation speed of the ventilation fan is executed.

However, in the above-described apparatus, when the fuel supply pressure upstream of the pressure adjusting means (hereinafter, abbreviated as primary fuel supply pressure) changes, the secondary fuel supply pressure changes with the change. The fuel supply amount to the mixing section will change, and the ratio of the fuel supply amount to the combustion air supply amount will change, and the ratio of the actual air amount to the theoretical air amount, that is, the air ratio will be out of the appropriate range, There was a risk that good combustion could not be performed.

In order to solve the problem that the air ratio deviates from a predetermined range due to a change in the primary fuel supply pressure, for example, as shown in Japanese Patent Application Laid-Open No. 11-108346, A gas proportional valve that adjusts the fuel flow to the downstream side is provided, and a secondary fuel supply pressure detecting means for detecting the secondary fuel supply pressure is provided, and the detected value of the secondary fuel supply pressure detecting means is an empirical formula. So as to approach the target secondary fuel supply pressure determined in advance by
Some devices adjust the opening of the gas proportional valve. As described in Japanese Patent Application Laid-Open No. H11-108346, as described above, the opening degree of the gas proportional valve is adjusted, and the fuel supply amount is calculated based on the detected value of the secondary fuel supply pressure. The combustion air supply amount capable of maintaining the air ratio in an appropriate range with respect to the fuel supply amount obtained is obtained from the relationship between the rotational speed of the ventilation fan and the fuel air supply amount, which are previously determined,
By controlling the rotation speed of the ventilation fan so as to achieve the determined rotation speed of the ventilation fan, it is possible to obtain the required combustion amount in the burner combustion while maintaining the air ratio in an appropriate range.

[0005]

However, in the above-described conventional apparatus, if a ventilation abnormality occurs in which dust or the like adheres to the blades of the ventilation fan, the relationship between the rotation speed of the ventilation fan and the supply amount of combustion air is determined in advance. Since the relationship deviates from the required relationship, even if the rotation speed of the ventilation fan is controlled based on the relationship previously determined, the combustion air supply amount corresponding to the fuel supply amount cannot be obtained. Was out of the proper range in some cases.

The present invention has been made in view of such a point, and an object of the present invention is to maintain the air ratio in an appropriate range even if a change in the primary fuel supply pressure or a ventilation abnormality occurs. Another object of the present invention is to provide a combustion control device for a premixed combustion burner.

[0007]

According to the first aspect of the present invention, there is provided a premix burner for heating an object to be heated by combustion, and combustion air is supplied to the burner. A ventilation fan that ventilates, a mixing unit that mixes the supplied fuel with the combustion air with the ventilation operation of the ventilation fan, and a mixing unit that applies a suction force to the ventilation unit by the ventilation operation of the ventilation fan. A fuel supply path connected to supply fuel, a pressure adjustment means installed in the fuel supply path to adjust a fuel supply pressure downstream of the installation point, and a combustion control for controlling combustion of the burner Means are provided, and the combustion control means is configured to execute a combustion control process for controlling a rotation speed of the ventilation fan so as to have an appropriate ventilation amount corresponding to a fuel supply amount to the burner. Is A combustion control device for a mixed combustion burner, wherein pressure detection means for detecting a fuel supply pressure downstream of the pressure adjustment means is provided, and after the combustion control means executes the combustion control process, It is configured to execute a pressure adjustment process for controlling the fuel supply pressure adjusted by the pressure adjustment means to be the target fuel supply pressure based on the detection information of the pressure detection means.

That is, after controlling the rotation speed of the ventilation fan so as to provide a combustion air supply amount corresponding to the combustion amount required in the burner combustion, a fuel supply corresponding to the combustion amount required in the burner combustion is performed. The pressure adjustment processing can be executed so that the secondary fuel supply pressure detected based on the detection value of the pressure detection means becomes the target fuel supply pressure so as to obtain the amount. The fuel supply amount to the mixing section is determined by the pressure difference between the secondary fuel supply pressure and the negative pressure generated in the mixing section by the operation of the ventilation fan, so that the secondary fuel supply pressure becomes the target fuel supply pressure. By performing the pressure adjustment process, even if the primary fuel supply pressure changes, the fuel supply amount to the mixing unit can be maintained at an appropriate amount, and the air ratio can be maintained within an appropriate range.

Further, the negative pressure generated in the mixing section by the operation of the ventilation fan is generated along with the flow of the combustion air by the operation of the ventilation fan. Although the flow rate of the combustion air to the mixing section is reduced due to the decrease in the flow rate of the secondary fuel supply, the secondary fuel supply is performed by executing the pressure adjustment processing so that the secondary fuel supply pressure becomes the target fuel supply pressure. The pressure difference between the pressure and the negative pressure generated in the mixing section by the operation of the ventilation fan is reduced, and the fuel supply amount to the mixing section is also reduced. Therefore, even if the above-described ventilation abnormality occurs, the ratio of the supply amount of combustion air to the supply amount of fuel to the mixing section can be maintained at an appropriate ratio, and the air ratio is maintained in an appropriate range. Becomes possible.

Summarizing the above, according to the first aspect of the present invention, it is possible to maintain the air ratio in an appropriate range even if the primary fuel supply pressure changes and a ventilation abnormality occurs. It has become possible to provide a combustion control device for a mixed combustion burner.

According to the second aspect of the present invention, the relationship between the combustion amount of the burner and the reference rotation speed of the ventilation fan for realizing combustion at the combustion amount is stored as a rotation speed reference relationship. Reference rotation speed storage means, and reference adjustment state storage means for storing the relationship between the combustion amount of the burner and the reference adjustment state of the pressure adjustment means for achieving combustion at the combustion amount as an adjustment state reference relation. Is provided,
The combustion control means obtains, in the combustion control processing, a combustion amount of the burner required to heat the object to be heated to a target heating state from detection information of a heat state of the object to be heated before heating. A reference rotation speed calculation process for obtaining the reference rotation speed for bringing the object to be heated into the target heating state based on the obtained combustion amount of the burner and the reference relationship for rotation speed; The amount of combustion of the burner required to heat the object to the target heating state is obtained from the detection information of the heat state of the object to be heated before heating, and the obtained amount of combustion of the burner and the reference for the adjustment state are obtained. And a reference adjustment state calculation process for obtaining the reference adjustment state for bringing the object to be heated into the target heating state based on the relationship. Performing a reference rotation speed adjustment process for controlling the rotation speed of the ventilation fan to be the determined reference rotation speed, and the reference adjustment state calculated in the reference adjustment state calculation process. It is configured to execute a reference adjustment state adjustment process for controlling the pressure adjustment means.

That is, in the combustion control process, the reference rotational speed calculation process and the reference adjustment state calculation process are performed in parallel, the reference rotation speed adjustment process is performed, and after the reference adjustment state adjustment process is performed. , The pressure adjustment process can be executed. Therefore, in the combustion control process, after controlling the rotation speed of the ventilation fan and the adjustment of the pressure adjusting means in order to realize the combustion of the burner required in the combustion of the burner, the combustion is required in the combustion of the burner. Since the pressure adjustment process can be executed in order to actually realize the combustion of the burner with the combustion amount, it is possible to realize the actual combustion of the burner while maintaining the air ratio in an appropriate range as quickly as possible.

According to the third aspect of the present invention, in the pressure adjustment processing, the combustion control means controls the pressure adjustment means so that a fuel supply pressure adjusted by the pressure adjustment means becomes a target fuel supply pressure. Is configured to be controlled. That is, the configuration according to claim 3 specifies the above-described claim 1, and the secondary state detected based on the detection value of the pressure detection unit by adjusting the adjustment state of the pressure adjustment unit. The pressure adjustment process is performed so that the fuel supply pressure becomes the target fuel supply pressure.

According to a fourth aspect of the present invention, the combustion control means controls the ventilation fan such that the fuel supply pressure adjusted by the pressure adjustment means becomes the target fuel supply pressure in the pressure adjustment processing. It is configured to control the rotation speed. In other words, the configuration according to claim 4 specifies the above-described claim 1, and the secondary fuel detected based on the detection value of the pressure detection means by adjusting the rotation speed of the ventilation fan. The pressure adjustment process is performed so that the supply pressure becomes the target fuel supply pressure.

According to the invention described in claim 5, the target fuel supply pressure is set to substantially zero. That is, regardless of the amount of combustion required in the combustion of the burner, the pressure adjustment process can be performed so that the secondary fuel supply pressure detected based on the detection value of the pressure detection means becomes substantially zero. Becomes Therefore, depending on the amount of combustion required in the burner combustion, the control of the pressure adjustment process becomes easier as compared with the case where the target fuel supply pressure is set to a plurality of values. This makes it easy to adapt to a relatively narrow all-primary combustion burner. In addition, when the target fuel supply pressure is set to a plurality of values depending on the amount of combustion required for combustion of the burner, the pressure detected by the pressure detecting means varies depending on the amount of combustion required for combustion of the burner. Therefore, the measurement range of the pressure detection means is widened,
Although the cost must be increased, for example, a wide measurement range must be used, the pressure detected by the pressure detection means can be set to only a pressure close to zero, which reduces costs. It becomes possible to plan.

According to the invention described in claim 6, the combustion control means controls the pressure when the ventilation operation of the ventilation fan is stopped in a non-combustion state in which the burner stops combustion. When the detection value of the detection means is a substantially constant value, a reference value storage process for storing the detection value at that time as a reference value is executed, and the reference value stored in the reference value storage process and the pressure detection means The apparatus is configured to execute a fuel supply pressure detection process of detecting a fuel supply pressure adjusted by the pressure adjusting means from the detected value.

That is, even if the status of the apparatus changes due to a change over time, the reference value of the pressure detecting means taking into account the change over time can be stored by executing the reference value storing process, By executing the supply pressure detection processing, it is possible to detect the fuel supply pressure adjusted by the pressure adjusting means in a state in which a change over time is taken into account. Therefore, the pressure adjustment process can be performed based on the information taking into account the change over time, and even if the change over time occurs, good combustion can be performed while maintaining the air ratio in an appropriate range. Can be performed.

According to the seventh aspect of the present invention, the combustion control means executes the reference value storage processing before starting the ventilation of the ventilation fan to start the combustion of the burner. Have been. That is, by the cooperation with claim 6, it is possible to always execute the reference value storage process before starting the burner combustion, and based on the information immediately before the burner combustion is started,
Since the pressure adjustment process can be performed, it is possible to perform good combustion while maintaining the air ratio more appropriately in the appropriate range.

According to the invention described in claim 8, a mixture ratio detecting means for detecting a mixture ratio of fuel and combustion air in the combustion of the burner is provided, and the combustion control means is provided with the mixture ratio detecting means. And a correction process for correcting the target fuel supply pressure based on the relationship between the mixture ratio and the target mixture ratio detected by the control unit.

That is, if the mixing ratio of fuel and combustion air in the combustion of the burner deviates from the target mixing ratio due to a change over time or a change in gas type, the air ratio will deviate from an appropriate range. By executing the correction process, the target fuel supply pressure is corrected, so that the mixture ratio of fuel and combustion air in the burner combustion can be maintained at the target mixture ratio, and the air ratio is also maintained in an appropriate range. It becomes possible. Therefore, even if a change over time or a change in gas type occurs, it is possible to perform good combustion while maintaining the air ratio in an appropriate range.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] As shown in FIG. 1, this hot water supply apparatus heats supplied water and supplies hot water to a tap water tap 1, and operates the hot water supply unit K. The control unit H is provided with a control unit H as a combustion control unit for controlling, and a remote control operation unit R for instructing the control unit H of operation information.

The hot water supply unit K includes a heat exchanger 4 for water heating provided in a combustion chamber 3 having an exhaust passage 2, and a gas combustion type all-primary premixing type for heating the heat exchanger 4. Burner 5
And a ventilation fan 6 (as a ventilation means) for supplying combustion gas from the upstream side of the burner 5 and mixing and supplying the supplied fuel gas with the combustion air. For example, a turbo fan) is also provided. That is, the water as a heating object is heated by burning the burner 5.

The heat exchanger 4 is connected to a water supply passage 8 to which water is supplied from, for example, a domestic water supply, and a water supply passage 9 for discharging hot and cold water. A water flow rate sensor 10 for detecting the flow rate of water to the heat exchanger 4 and an incoming water temperature thermistor 11 for detecting the temperature of the water supplied through the inlet passage 8 are provided in this order from the upstream side. The tapping path 9 is provided with a tapping temperature thermistor 12 for detecting the temperature of tap water from the tap tap 1.

Along with the ventilation operation of the ventilation fan 6, a mixing chamber 13 as a mixing unit T for mixing the supplied fuel gas with the combustion air is connected to the suction unit 7 of the ventilation fan 6. A fuel supply path 14 that is connected to the mixing chamber 13 and supplies a fuel gas is provided so that a suction force acts by the ventilation operation. The fuel supply path 14 is provided with a flow control valve 15 as a pressure control means for controlling the fuel supply pressure downstream of the installation location, and a supply of fuel gas to the burner 5 upstream of the flow control valve 15. A double solenoid valve 16 composed of a first on-off valve 16a and a second on-off valve 16b, and a pressure for detecting a fuel supply pressure downstream of the flow regulating valve 15 (hereinafter abbreviated as secondary fuel supply pressure). A sensor 17 and a variable nozzle 18 for adjusting a passage resistance downstream of the pressure sensor 17 are provided. And the flow control valve 15
And the pressure difference between the secondary fuel supply pressure and the pressure generated by the ventilation operation of the ventilation fan 6 increases as the ventilation amount of the ventilation fan 6 increases. The amount of fuel gas supplied to the fuel cell 13 is increased.

Incidentally, the variable nozzle 18 is adjusted so as to have a nozzle opening degree corresponding to a gas type, that is, a passage area corresponding to a gas type to be used. For example, 1
When the gas type of 3A is used and the gas type of LP is used, the variable nozzle 18 is adjusted so that the ratio of the passage area at 13A to the passage area at LP is about 1.5: 1.
Is adjusted.

The flow control valve 15 will be described in more detail. As shown in FIG.
and a valve 15d for adjusting the opening of the gas passage by driving the stepping motor 15c. By driving the valve 15d by driving the stepping motor 15c, the opening degree of the gas passage is adjusted to adjust the secondary fuel supply pressure P2, so that the fuel supply upstream of the flow control valve 15 is controlled. The secondary fuel supply pressure P2 can be adjusted irrespective of a change in pressure (hereinafter, primary fuel supply pressure) P1. Incidentally, P1 in the figure indicates a fuel supply pressure upstream of the flow control valve 15 (hereinafter, primary fuel supply pressure), and the pressure sensor 17 is provided to detect the secondary fuel supply pressure P2. I have.

As shown in FIG. 3, the pressure sensor 17 is provided with silicon on a glass base 17a to form a reference pressure chamber 17b, and a zero governor 15 in the fuel supply passage 14 as shown in FIG. Silicon diaphragm 1 receiving pressure in passage downstream of
7c, a deposition electrode 17d in the reference pressure chamber 17b, an integrated circuit 17e, and the like. When no pressure is applied to the silicon diaphragm 17c, charges determined by the distance between the deposition electrodes 17d, the electrode area, and the dielectric constant are stored between the deposition electrodes 17d. When pressure is applied to the silicon diaphragm 17c, the silicon diaphragm 17c is distorted, the distance between the deposition electrodes 17d is reduced, the charge stored between the deposition electrodes 17d is increased, and the change in the charge stored between the deposition electrodes 17d is changed. Is converted into a sensor signal by the integrated circuit 17e and output. In this way,
The pressure in the fuel supply passage 14 in the passage downstream of the zero governor 15 is detected based on a change in the charge stored between the deposition electrodes 17d. Incidentally, although not described in detail, a temperature sensor for detecting the ambient temperature of the pressure sensor 17 is provided, and the output value is corrected based on the information of the temperature sensor so that the accuracy of the output value of the sensor is improved. ing.

An igniter 19 for executing an ignition operation for the burner 5 and a frame rod 20 for detecting whether or not the burner 5 is ignited are provided near the burner 5, respectively. A rotation speed sensor 6a for detecting a speed is also provided. An oxygen sensor 26 as a mixing ratio detecting means is provided so as to detect the concentration of oxygen gas in the combustion exhaust gas by detecting the combustion exhaust gas of the burner 5.

The oxygen sensor 26 is a zirconia limit current type sensor, and comprises a sensor element 27, a terminal 28, a terminal block 29, and a mesh cover 30, as shown in FIG. As shown in FIG. 5, the sensor element 27 is formed by forming platinum electrodes 27b on both sides of a disk-shaped stabilized zirconia 27a and joining a cap 27d provided with a small hole 27c on one side thereof. .
When a voltage is applied between the two electrodes 27b, a current using oxygen ions as carriers flows by a pumping action. Since the inflow of air into the cap 27d is limited by the small holes 27c, the current becomes substantially constant (limit current) in a predetermined voltage range, and this limit current changes in proportion to the oxygen concentration in the air. Therefore, a constant voltage (monitoring voltage) is applied between both electrodes 27b, and the oxygen concentration can be detected from the current value at that time. Further, since the pumping action occurs at a high temperature (for example, about 500 ° C.), a heater 27e is integrally formed above the cap 27d, and the sensor element 27 is heated by energizing the heater 27e.

The remote control operation unit R includes an operation switch 21 for instructing start / stop of the operation of the hot water supply unit K, a temperature setting switch 22 capable of changing and setting a target temperature for tapping, a tapping temperature and a target temperature for tapping. The display unit 23 includes an operation lamp 24 that indicates that the burner 5 is in a combustion state, an operation lamp 24 that indicates that the burner 5 is in a combustion state, and the like.

The control unit H is provided with a microcomputer, and performs an ignition process for igniting the burner 5 and controls the tapping temperature to reach the tapping target temperature based on an operation command of the remote control operating unit R during tapping. Pressure control processing for controlling the fuel supply pressure adjusted by the flow rate control valve 15 to the target fuel supply pressure based on the detection information of the pressure sensor 17, and the combustion stop processing for stopping the combustion of the burner 5. It is configured to execute each of the processes.

In the ignition process, the operation switch 21 is turned on.
After the operation state is set in accordance with the operation, the operation is executed when the flow rate detected by the flow rate sensor 10 in response to the opening operation of the tap 1 exceeds the set flow rate. In the state where the valve 16 is closed, the pre-purge is performed based on the detection information of the rotation speed sensor 6a to set the pre-purge setting ventilation operation state to the ventilation fan 6 at the pre-purge setting rotation speed for the pre-purge setting time. Execute. After the above-described pre-purge is performed, the dual solenoid valve 16 is opened to adjust the opening of the flow control valve 15 so that the ignition gas amount is obtained, and the rotation speed sensor 6
The rotation speed of the ventilation fan 6 is adjusted based on the detection information a, the igniter 19 ignites the burner 5, and the flame rod 20 confirms the ignition of the burner 5.

In the combustion control process, feedforward control for controlling the opening of the flow control valve 15 and the rotation speed of the ventilation fan 6 is executed based on the detection information of the heat state before the water is heated. The opening degree of the flow rate regulating valve 15 and the ventilation fan 6
It is configured to execute feedback control for controlling the rotation speed of the motor. In addition, based on the detection information of each of the incoming water temperature thermistor 11 and the water flow rate sensor 10 and the information on the target temperature for tapping set by the temperature setting switch 22, the tapping temperature is set to the target temperature for tapping. The feedforward control is performed to adjust the opening of the flow control valve 15 and the rotation speed of the ventilation fan 4 so that the amount of gas required for the hot water supply can be adjusted. Feedback control for finely adjusting the opening degree of the flow control valve 15 and the rotation speed of the ventilation fan 4 according to the deviation is executed.

The processing in the feedforward control will be described. First, a reference rotation speed calculation process for obtaining a reference rotation speed of the ventilation fan 6 and a flow control valve 15
The reference rotation speed adjustment process for controlling the rotation speed of the ventilation fan 6 so that the reference rotation speed obtained in the reference rotation speed calculation process is performed while performing the reference adjustment state calculation process for obtaining the reference adjustment state of the reference rotation speed calculation process. Run, and
It is configured to execute a reference adjustment state adjustment process for controlling the flow rate adjustment valve 15 so as to be in the reference adjustment state obtained in the reference adjustment state calculation process.

The reference rotational speed calculation processing will be described in further detail. The amount of combustion of the burner 5 required to heat the water to the target temperature for tapping as the target heat state is determined by detecting the heat state before heating the water. Information, namely the incoming water temperature thermistor 11,
The combustion amount of the burner 5 and the rotation stored in the storage means M, which are obtained from the respective detection information of the water flow rate sensor 10 and the information of the tapping target temperature set by the temperature setting switch 22, are obtained. Based on the speed reference relationship, a reference rotation speed for bringing the water to the hot water tapping target temperature is determined. When the reference adjustment state calculation processing is described, the amount of combustion of the burner 5 required to heat water to the target temperature for tapping water is determined by detecting the heat state before heating the water, that is, the input water temperature thermistor 11, The combustion amount of the burner 5 and the adjustment stored in the storage means M are obtained from the detection information of each of the water flow rate sensors 10 and the information of the tapping target temperature set by the temperature setting switch 22. Based on the state reference relationship, a reference adjustment state for bringing water to the hot water tapping target temperature is obtained.

The rotation speed reference relationship indicates the relationship between the combustion amount of the burner 5 and the reference speed of the ventilation fan 6 for realizing combustion at the combustion amount. The relationship indicates the relationship between the combustion amount of the burner 5 and the reference adjustment state of the flow control valve 15 for realizing combustion at the combustion amount. The reference relationship for the rotational speed and the reference relationship for the adjustment state are as follows: It is stored in the storage means M.
That is, the storage unit M is configured to serve as both the reference rotation speed storage unit and the reference adjustment state storage unit.

The pressure adjustment process is configured to be executed after the combustion control process is executed, and the fuel supply pressure (second pressure) adjusted by the flow rate adjustment valve 15 based on the detection information of the pressure sensor 17. Next, the stepping motor 15c is operated to adjust the opening of the flow control valve 15 so that the determined secondary fuel supply pressure becomes substantially zero as the target fuel supply pressure. Have been.

The process for obtaining the secondary fuel supply pressure will be described. In the initial stage of installation of the apparatus, the secondary fuel supply pressure is calculated based on the reference value preset in the pressure sensor 17 and the actual value detected by the pressure sensor 17. The fuel supply pressure is determined. Then, after the initial stage of installation of the apparatus, when the ventilation operation of the ventilation fan 6 is stopped in a non-combustion state in which the burner 5 stops burning, the pressure sensor 1
7 is substantially constant, a reference value storage process for storing the detected value as a reference value is executed, and the reference value stored in the reference value storage process and the detection value of the pressure sensor 17 are used. A fuel supply pressure detection process for detecting the next fuel supply pressure is executed. The reference value storage processing is configured to be executed before the ventilation fan 6 is operated to start the combustion of the burner 5, that is, before the pre-purge is executed, and each time the combustion of the burner 5 is started. To be executed.

The combustion stop process is performed by the water flow sensor 10 when the operation switch 21 is turned off or the tap water tap 1 is closed while the above-described combustion control process and pressure adjustment process are being executed. When the detected flow rate is less than the set flow rate, the dual solenoid valve 16 is closed to stop the burner 5 from burning, and the ventilation fan 6 is rotated at the post-purge set rotation speed for the post-purge set time. Post-purge for ventilation is performed.

The control unit H determines the mixing ratio between fuel and combustion air in the combustion of the burner 5 based on the information detected by the oxygen sensor 26, and determines the relationship between the determined mixing ratio and the target mixing ratio. On the basis of this, a correction process for correcting the target fuel supply pressure in the pressure adjustment process is executed. More specifically, the mixture ratio of fuel and combustion air in the combustion of the burner 5 is detected based on the detection information of the oxygen sensor 26. When the mixture ratio is higher than the target mixture ratio, the target The fuel supply pressure is corrected so as to be smaller by the set amount, and when the mixture ratio is higher than the target mixture ratio of the combustion air, the target fuel supply pressure is corrected so as to be larger by the set amount. I have.

By executing the pressure control process after the execution of the combustion control process in this way, a change in the primary fuel supply pressure or an abnormal ventilation in which dust or the like adheres to the blades of the ventilation fan 6 occurs. However, it is possible to maintain the ratio of the amount of fuel supplied to the mixing section and the ratio to the combustion air at an appropriate ratio, and to set the ratio of the actual air amount to the theoretical air amount, that is, the air ratio, within an appropriate range. It can be maintained.

The air ratio when the above-described pressure adjustment processing is executed will be described based on experimental data when the pressure adjustment processing is actually executed. FIG. 6 is a graph showing a relationship between the flow rate of the fuel gas and the internal pressure of the mixing chamber 13 when the above-described pressure adjustment processing is executed. FIG.
6 shows the relationship between the input of the burner 5 and the air ratio when natural gas (13A-1) flows, using the data of FIG.

The air ratio when the pressure adjustment process is actually executed is approximately 1.3 to 1.3 based on the experimental results shown in FIG.
Since it can be said that the air ratio is within the range of 1.4, it can be said that the air ratio can be maintained within the appropriate range. That is, the burner 5 in this embodiment uses an all-primary premixed combustion burner, and the appropriate range of the air ratio of this burner is 1.3 to 1.4. Since the air ratio is within the range of approximately 1.3 to 1.4, it can be said that the air ratio can be maintained within the appropriate range.

The control operation of the control unit H is shown in FIGS.
0 will be described. First, in a state where the operation switch 21 of the remote control operation unit R is turned on and set to the operation state, the water flow detected by the water flow sensor 10 with the opening operation of the hot water tap 1 exceeds the set water flow. When the water flow rate is detected, a reference value storage process is executed, and an ignition process is executed (steps 1 to 3). Then, after performing the reference rotation speed calculation processing and the reference adjustment state calculation processing, the reference rotation speed adjustment processing and the reference adjustment state adjustment processing adjustment processing, and the feedback control, the pressure adjustment processing and the correction processing are sequentially performed. (Steps 4 to 7).

In this manner, the water flow detected by the water flow sensor 10 in accordance with the closing operation of the hot water tap 1 becomes equal to or less than the set water flow and the water flow is turned off, or the operation switch 21 is turned off. In the combustion state in which the burner 5 is burned up to, the arithmetic processing, the adjusting processing, the pressure adjusting processing, and the correcting processing are sequentially executed. Then, when the flow rate detected by the flow rate sensor 10 becomes equal to or less than the set flow rate and the water flow rate is turned off with the closing operation of the tap water tap 1 or the operation switch 21 is turned off, the combustion stop processing is performed. Execute (steps 8 to 10).

The pressure adjustment process will be described with reference to the flowchart of FIG. By executing the above-described fuel supply pressure detection processing and the like, the secondary fuel supply pressure P2 is calculated, and the obtained secondary fuel supply pressure P2 is calculated.
Is determined between the target fuel supply pressure minimum value PL and the target fuel supply pressure maximum value PH, and the secondary fuel supply pressure P
It is determined whether or not 2 is substantially zero as the target fuel supply pressure (steps 11 and 12).

When the secondary fuel supply pressure P2 is smaller than the target fuel supply pressure minimum value PL, if the opening of the flow control valve 15 is not the maximum, the opening of the flow control valve 15 is opened by a set amount. Execute operation (steps 13-1)
5). Even if the secondary fuel supply pressure P2 is smaller than the target fuel supply pressure minimum value PL, when the opening degree of the flow control valve 15 is the maximum, the above-described combustion stop processing is executed, and the operation lamp 24 and the combustion lamp 25 are turned off. It blinks and interlocks so as not to start the combustion of the burner 5 thereafter and abnormally stops. Incidentally, in this case, an abnormality in the primary fuel supply pressure, an abnormality in ventilation, an abnormality in the flow control valve, and the like may be considered, and the abnormality may be displayed on the display unit 23.

When the secondary fuel supply pressure P2 is higher than the target fuel supply pressure maximum value PH, the flow control valve 1
If the opening of Step 5 is not the minimum, a closing operation of closing the opening of the flow regulating valve 15 by a set amount is executed (Steps 16 and 1).
7). Even if the secondary fuel supply pressure P2 is higher than the target fuel supply pressure maximum value PH, when the opening degree of the flow control valve 15 is minimum, the abnormal stop is performed as described above.

The correction processing will be described with reference to the flowchart of FIG. Calculating the oxygen concentration O ₂ in the combustion exhaust gas based on the value detected by the oxygen sensor 26, and determining whether or not the obtained O ₂ is between the target minimum value O ₂ L and the target maximum value O ₂ H. Thus, it is determined whether or not the mixture ratio of fuel and combustion air in the combustion of the burner 5 has reached the target mixture ratio (steps 21 and 22).

Then, the oxygen concentration O ₂ becomes the target minimum value O ₂ L
If the target fuel supply pressure minimum value PL is not the minimum, the target fuel supply pressure maximum value PH
Is reduced by the set amount ΔPH, and the target fuel supply pressure minimum value PL is reduced by the set amount ΔPL to correct the target fuel supply pressure (steps 23 to 25). Even if the oxygen concentration O ₂ is smaller than the target minimum value O ₂ L, if the target fuel supply pressure minimum value PL is the minimum, the above-described combustion stop process is executed, and the operation lamp 24 and the combustion lamp 2
5 is blinked, and the burner 5 is interlocked so as not to start burning thereafter and abnormally stopped. Incidentally, in this case, an abnormality of the gas type is considered, and the fact that the gas type is abnormal may be displayed on the display unit 23.

When the oxygen concentration O ₂ is higher than the target maximum value O ₂ H, the target fuel supply pressure maximum value PH is increased by the set amount ΔPH if the target fuel supply pressure maximum value PH is not the maximum. At the same time, the target fuel supply pressure minimum value PL is increased by the set amount ΔPL to correct the target fuel supply pressure (steps 26 and 27). Note that, even if the oxygen concentration O ₂ is higher than the target maximum value O ₂ H, if the target fuel supply pressure maximum value PH is at the maximum, an abnormal stop occurs as described above.

[Second Embodiment] This second embodiment shows another embodiment of the mixing section T of the first embodiment, and will be described with reference to the drawings. In addition, about the structure similar to the said 1st Embodiment, such as the control operation | movement of the control part H, the detailed description is abbreviate | omitted by attaching the same code | symbol etc.

That is, as shown in FIG. 11, a ventilation path 27 for supplying combustion air to the burner 5 by the ventilation operation of the ventilation fan 6 is provided, and the fuel gas supplied along with the ventilation operation of the ventilation fan 6 is provided. A fuel supply path 14 for supplying a fuel gas is provided, which is connected to a ventilation path 27 as a mixing section T for mixing the fuel gas with the combustion air. The pressure generated in the ventilation path 27 increases as the ventilation amount of the ventilation fan 6 increases.

[Another Embodiment] (1) In the first and second embodiments, an example in which the opening of the flow control valve 15 is controlled in the pressure adjustment processing so that the secondary fuel supply pressure becomes the target fuel supply pressure. However, in the pressure adjustment processing, the rotation speed of the ventilation fan 6 may be controlled so that the secondary fuel supply pressure becomes the target fuel supply pressure.

Hereinafter, an example of controlling the rotation speed of the ventilation fan 6 in the pressure adjustment processing will be described with reference to the flowchart of FIG. By executing the above-described fuel supply pressure detection processing and the like, the secondary fuel supply pressure P2 is calculated, and the obtained secondary fuel supply pressure P2 is used as the target fuel supply pressure minimum value PL and the target fuel supply pressure maximum value PH. Between the secondary fuel supply pressure P2
Is determined to be substantially zero as the target fuel supply pressure (steps 31 and 32).

When the secondary fuel supply pressure P2 is smaller than the target fuel supply pressure minimum value PL, the rotation speed of the ventilation fan 6 is reduced by a predetermined amount unless the rotation speed of the ventilation fan 6 is not the minimum. A reduction operation is performed (steps 33 to 35). Even if the secondary fuel supply pressure P2 is smaller than the target fuel supply pressure minimum value PL, if the rotation speed of the ventilation fan 6 is the minimum, the above-described combustion stop processing is executed, and the operation lamp 24 and the combustion lamp 25 blink. Then, the burner 5 is interlocked and stopped abnormally so as not to start the combustion of the burner 5 thereafter. Incidentally, in this case, an abnormality in the primary fuel supply pressure, an abnormality in ventilation, an abnormality in the flow control valve, and the like may be considered, and the abnormality may be displayed on the display unit 23.

When the secondary fuel supply pressure P2 is higher than the target fuel supply pressure maximum value PH, the ventilation fan 6
If the rotation speed is not the maximum, a rotation speed increasing operation for increasing the rotation speed of the ventilation fan 6 by a set amount is executed (steps 36 and 37). The secondary fuel supply pressure P2 is set to the target fuel supply pressure maximum value PH. If the rotation speed of the ventilation fan 6 is the maximum even if the rotation speed is larger than the above, the operation is abnormally stopped as described above. Incidentally, the rotation speed of the ventilation fan 6 in the above operation is detected based on the detection information of the rotation speed sensor 6a.

(2) In the first and second embodiments, the rotation speed of the ventilation fan 6 and the opening of the flow control valve 15 are adjusted in the combustion control processing, and the opening of the flow control valve 15 is controlled in the pressure control processing. Although an example of performing the adjustment is shown, it is also possible to adjust the rotation speed of the ventilation fan 6 only in the combustion control process and to adjust the opening of the flow control valve 15 in the pressure adjustment process. is there. That is, after performing a combustion control process of operating the ventilation fan 6 so as to provide a combustion air supply amount for realizing the combustion amount of the burner 5, the secondary fuel supply is performed based on the detection information of the pressure sensor 17. The opening of the flow control valve 15 is adjusted so that the pressure becomes the target fuel supply pressure.

(3) In the first and second embodiments, the feed-forward control and the feedback control are executed in the combustion control process. However, only the feed-forward control is executed in the combustion control process. It is also possible to execute and execute, or to execute and execute only feedback control.

(4) In the first and second embodiments, the target fuel supply pressure which is the target of the secondary fuel supply pressure in the pressure adjustment processing is set to substantially zero. It is not limited to substantially zero, and can be set arbitrarily in accordance with the combustion amount of the burner 5.

(5) In the first and second embodiments, each of the reference value storage processing, the fuel supply pressure detection processing, and the correction processing is executed. Execute only the pressure detection process,
It is not necessary to execute only the correction processing, or to execute all of the reference value storage processing, the fuel supply pressure detection processing, and the correction processing. Further, the execution timing of the reference value storage processing is not limited to the time before the ventilation fan 6 is operated to start the combustion of the burner 5 as in the first and second embodiments, and the ventilation fan is not operated in the non-combustion state. It may be any time as long as the ventilation operation of 6 is stopped.

(6) In the first and second embodiments, the storage means M is configured to serve as both the reference rotation speed storage means and the reference adjustment state storage means. It is also possible to provide and implement storage means separately.

(7) In the first and second embodiments, the example in which the oxygen sensor 26 is used as the mixing ratio detecting means has been described. However, the present invention is not limited to this, and the carbon dioxide concentration in the combustion exhaust gas is detected. Various sensors such as a carbon sensor can be applied.

(8) In the first and second embodiments, an example is shown in which the combustion control device of the all-primary combustion burner according to the present invention is applied to a hot water supply device. However, the present invention is applicable to various other devices such as a heating device. It is adaptable, for example, when it is adapted to a heating device, the heating object is air.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a hot water supply device according to a first embodiment.

FIG. 2 is a schematic configuration diagram of a flow control valve.

FIG. 3 is a schematic configuration diagram of a pressure sensor.

FIG. 4 is a schematic configuration diagram of an oxygen sensor.

FIG. 5 is a diagram showing a main part of the oxygen sensor.

FIG. 6 is a graph showing the relationship between the internal pressure of the mixing chamber and the flow rate of the fuel gas in the first embodiment.

FIG. 7 is a graph showing a relationship between a burner input and an air ratio in the first embodiment.

FIG. 8 is a flowchart illustrating an operation of a control unit according to the first embodiment.

FIG. 9 is a flowchart illustrating an operation of a pressure adjustment process of a control unit according to the first embodiment.

FIG. 10 is a flowchart illustrating an operation of a correction process of a control unit according to the first embodiment.

FIG. 11 is a schematic configuration diagram of a hot water supply device according to a second embodiment.

FIG. 12 is a flowchart illustrating an operation of a pressure adjustment process of a control unit according to another embodiment.

[Explanation of symbols]

5 Burner 6 Ventilation fan 14 Fuel supply path 15 Pressure adjusting means 17 Pressure detecting means 26 Mixing ratio detecting means H Combustion controlling means M Reference rotating speed storing means and reference adjusting state storing means T Mixing unit

Claims (8)

[Claims] 1. A premix burner for heating an object to be heated by combustion, a ventilation fan for passing combustion air through the burner, and a fuel supplied by the ventilation operation of the ventilation fan. A mixing section that mixes with the air for use, a fuel supply path connected to the mixing section so that suction force acts by the ventilation operation of the ventilation fan, a fuel supply path for supplying fuel, and a fuel supply path, Pressure adjustment means for adjusting the fuel supply pressure downstream of the installation location, and combustion control means for controlling the combustion of the burner are provided, and the combustion control means adjusts the fuel supply amount corresponding to the fuel supply amount to the burner. A combustion control device for a premixed-type combustion burner configured to execute a combustion control process for controlling a rotation speed of the ventilation fan so that a ventilation amount is obtained, and a downstream side of the pressure adjustment unit. Pressure detection means for detecting a fuel supply pressure is provided, and after the combustion control means executes the combustion control processing, the fuel supply pressure adjusted by the pressure adjustment means based on the detection information of the pressure detection means A combustion control device for a premixed combustion burner configured to execute a pressure adjustment process for controlling the fuel supply pressure to a target fuel supply pressure. 2. A reference rotation speed storage means for storing, as a rotation speed reference relationship, a relationship between a combustion amount of the burner and a reference rotation speed of the ventilation fan for realizing combustion at the combustion amount; Reference adjustment state storage means for storing, as an adjustment state reference relation, a relationship between a combustion amount of the pressure adjustment means and a reference adjustment state of the pressure adjustment means for realizing combustion at the combustion amount. In the combustion control process, the amount of combustion of the burner required to heat the object to be heated to the target heating state is obtained from detection information of the heat state of the object to be heated before heating, and the obtained amount is obtained. A reference rotation speed calculation process for obtaining the reference rotation speed for setting the heating target to the target heating state based on the burner combustion amount and the rotation speed reference relationship; The combustion amount of the burner required to heat to the target heating state is obtained from the detection information of the heat state of the heating target before heating, and the obtained combustion amount of the burner and the reference relation for the adjustment state are obtained. And a reference adjustment state calculation process for obtaining the reference adjustment state for bringing the object to be heated into the target heating state, and the reference rotation speed calculated in the reference rotation speed calculation process. A reference rotation speed adjustment process for controlling the rotation speed of the ventilation fan to be at a speed is performed, and the pressure adjustment unit is controlled to be in the reference adjustment state obtained in the reference adjustment state calculation process. The combustion control device for a premixed combustion burner according to claim 1, wherein the combustion control device is configured to execute a reference adjustment state adjustment process. 3. The combustion control unit is configured to control the pressure adjustment unit in the pressure adjustment process so that the fuel supply pressure adjusted by the pressure adjustment unit becomes a target fuel supply pressure. The combustion control device for a premixed combustion burner according to claim 1 or 2. 4. The combustion control means is configured to control the rotation speed of the ventilation fan so that the fuel supply pressure adjusted by the pressure adjustment means becomes the target fuel supply pressure in the pressure adjustment processing. 3. The combustion control device for a premixed combustion burner according to claim 2, wherein: 5. The combustion control device for a premixed combustion burner according to claim 1, wherein the target fuel supply pressure is set to substantially zero. 6. The non-combustion state in which the burner has stopped burning, wherein the combustion control means keeps the detection value of the pressure detecting means substantially constant when the ventilation operation of the ventilation fan is stopped. Then, a reference value storage process for storing the detected value at that time as a reference value is executed, and the pressure adjustment unit uses the reference value stored in the reference value storage process and the detection value of the pressure detection unit. The combustion control device for a premixed combustion burner according to any one of claims 1 to 5, configured to execute a fuel supply pressure detection process of detecting a fuel supply pressure to be adjusted. 7. The combustion engine according to claim 6, wherein the combustion control means is configured to execute the reference value storage processing before starting the ventilation of the ventilation fan to start combustion of the burner. Combustion control device for premixed combustion burner. 8. A mixing ratio detecting means for detecting a mixing ratio between fuel and combustion air in combustion of the burner, wherein the combustion controlling means detects a mixing ratio and a target mixing ratio detected by the mixing ratio detecting means. The combustion control device for a premixed combustion burner according to any one of claims 1 to 7, wherein a correction process for correcting the target fuel supply pressure is performed based on the relationship.