JP2001235144A - Combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combustion device for preventing the temperature of air to be supplied to a combustion chamber from increasing excessively in the combustion device with an air supply/exhaust pipe where air supply and exhaust paths are arranged side by side adjacently inside. SOLUTION: This combustion device is provided with a supply air temperature sensor 17 for detecting the temperature of supply air for combustion that is introduced from an air supply path 11 to the inside of a combustion chamber 2. A control unit 7 that takes care of operation control controls the amount of combustion of a gas burner 3 so that the detection temperature of a supply hot water temperature sensor 29 reaches a target supply hot water temperature when the detection temperature of the supply air temperature sensor 17 increases to a specific overheating temperature or higher, and at the same time decreases the amount of water of a water passage pipe 5 via an amount-of-water control valve 28, thus decreasing the amount of combustion of the gas burner 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion device such as a gas water heater or a gas hot air heater.

[0002]

2. Description of the Related Art As a combustion device such as a gas hot water supply device or a gas hot air heater, a so-called FF type is conventionally known. In the FF type combustion apparatus, a substantially closed combustion chamber containing a combustion section such as a burner is provided in a housing of an apparatus body installed indoors, and combustion air (atmosphere) is supplied to the combustion chamber outdoors. A supply / exhaust pipe in which an air supply passage for introducing air from the outside and an exhaust passage for discharging combustion exhaust gas from the combustion chamber to the outside are juxtaposed inside is connected to the apparatus main body.

[0003] In this case, the supply / exhaust pipe is composed of, for example, an inner pipe that forms an exhaust path inside, and an outer pipe that is inserted into the inner pipe and forms an air supply path between the inner pipe and the inner pipe. What is formed in a double tube structure is generally used.

In this type of combustion apparatus, combustion air flowing through a supply passage of a supply / exhaust pipe toward a combustion chamber is heated by heat exchange with a relatively high temperature exhaust gas flowing through an exhaust passage. In particular, when the supply / exhaust pipe is relatively long due to the location of the apparatus body or the structure of the house, the supply temperature of the combustion air is increased from the supply path to the combustion chamber. May rise to a high temperature of 70 to 80 ° C. or higher in the vicinity of the combustion air inlet.

On the other hand, in this type of combustion apparatus, a combustion fan for introducing the combustion air from the air supply passage to the combustion chamber is provided in the vicinity of the inlet. Also,
For convenience of downsizing of the apparatus main body, in the housing of the apparatus main body, an air supply path portion from the air supply path of the air supply / exhaust pipe to the air inlet of the combustion chamber (the interior of the housing of the apparatus main body is directly supplied with the air supply). In some cases, an electronic circuit unit, a harness, a clamp member of the harness, and the like are arranged at a location that communicates therewith or at a location communicating therewith. Thus, the combustion air introduced into the combustion chamber comes into contact with the above-mentioned various components such as the combustion fan and the electronic circuit unit.

However, when the supply temperature of the combustion air becomes high as described above, the lubricating oil on the rotating shaft of the combustion fan flows out, causing malfunction of the combustion fan or the operation of the electronic circuit unit. Malfunction or clamp member of the harness (this is generally a resin product)
There is a risk of inconvenience such as deformation of

[0007] In order to avoid such inconvenience, for example, it is conceivable to completely separate the air supply passage and the exhaust passage. However, in this case, since the air supply pipe and the exhaust pipe are separately required, the overall configuration of the apparatus is increased, and it is difficult to manage the air supply pipe and the exhaust pipe. Further, since the supply pipe and the exhaust pipe are separately provided, there is a disadvantage that the appearance is not preferable.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of such a background, and is directed to a combustion apparatus having a supply / exhaust pipe in which a supply path and an exhaust path are arranged adjacent to each other and arranged in a combustion chamber. It is possible to prevent the temperature of the supply air to the heater from becoming excessively high, and the air supply passage of the supply / exhaust pipe and the space inside the housing of the device main body communicating therewith can be used as a place for installing various components without any trouble. It is an object to provide a combustion device that can be used.

[0009]

In order to achieve the above object, a combustion apparatus according to the present invention has a combustion chamber containing a combustion section for heating an object to be heated, and an air supply passage and an exhaust passage communicating with the combustion chamber. And a supply / exhaust pipe arranged side by side adjacent to the inside, and supplying fuel to the combustion section while introducing combustion air into the combustion chamber through an air supply passage of the supply / exhaust pipe to perform the combustion. A combustion device that performs a combustion operation of the section and discharges exhaust gas generated by the combustion operation from the combustion chamber through an exhaust path of the supply / exhaust pipe. An air supply temperature sensor provided in the air supply path for detecting the temperature of the supply air, and when the air supply temperature detected by the air supply temperature sensor rises above a predetermined first superheat temperature, the combustion is started. Control over the amount of combustion to reduce the amount of combustion It is characterized in that a prevention means.

According to the present invention, when the supply air temperature detected by the supply air temperature sensor rises above the first superheat temperature, the amount of combustion in the combustion section is reduced by the supply air temperature overheat prevention means. Thus, the temperature of the exhaust gas generated by the combustion operation of the combustion section decreases. For this reason, further excessive temperature rise of the combustion air heated by heat exchange with the exhaust gas in the course of flowing through the air supply passage of the air supply / exhaust pipe is suppressed. As a result, it is possible to prevent the supply temperature of the combustion air from becoming excessively high. As a result, the air supply path of the air supply / exhaust pipe, the space inside the housing of the apparatus main body communicating with the air supply / exhaust pipe, and the like can be used as a place for installing the fan, the electronic circuit unit, the resin parts, and the like.

In the present invention, the means for preventing overheating of the supply air temperature may be such that the supply air temperature detected by the supply air temperature sensor is equal to the first supply temperature.
When the temperature is equal to or higher than the superheat temperature, it is preferable that the combustion amount is controlled in accordance with the supply air temperature so that the degree of decrease in the combustion amount of the combustion section increases as the intake air temperature increases.

With this configuration, when the supply air temperature detected by the supply air temperature sensor rises to a temperature equal to or higher than the first superheat temperature, the higher the supply air temperature, the more the amount of combustion in the combustion section decreases. In addition, it is possible to reliably prevent the supply air temperature from becoming excessively high. Further, the lower the supply air temperature, the smaller the degree of decrease in the amount of combustion in the combustion section, so that the decrease in the amount of combustion in the combustion section can be kept to a minimum.

Further, in the present invention, the supply air temperature overheating prevention means reduces the amount of combustion in the combustion section, and then the supply air temperature detected by the air supply temperature sensor decreases toward the first superheat temperature. Sometimes, the amount of combustion is increased.

Accordingly, if the supply air temperature becomes low,
The combustion amount of the combustion section can be returned to the original combustion amount.

In this case, the supply air temperature overheating prevention means may further include an air supply temperature detected by the air supply temperature sensor.
When the amount of combustion in the combustion section is increased at a temperature equal to or higher than the superheat temperature, the amount of combustion is changed more slowly than when the amount of combustion is decreased.

Thus, when the supply air temperature drops below the first superheat temperature, the amount of combustion in the combustion section increases relatively slowly, so that it is heated by the combustion operation of the combustion section. The temperature of the object to be heated can be prevented from rising rapidly. Further, the supply air temperature is the first
When the temperature rises to the superheat temperature or higher, the amount of combustion in the combustion section decreases relatively quickly, so that a further increase in the supply air temperature can be quickly prevented.

In the present invention, for example, the combustion device uses a fluid flowing through a fluid passage as the object to be heated, and transfers the fluid via a heat exchanger so as to raise the temperature of the fluid to a preset target temperature. And a flow control means for controlling a flow rate of the fluid flowing through the fluid passage. As described above, in the combustion apparatus including the combustion control unit and the flow rate adjustment unit, when the flow rate of the fluid flowing through the fluid passage is reduced through the flow rate adjustment unit, the temperature of the fluid rises to the target temperature. Since the amount of combustion in the combustion section required for the reduction is reduced, the actual amount of combustion in the combustion section controlled by the combustion control means is also reduced as a result.
Conversely, if the flow rate of the fluid is increased, the amount of combustion in the combustion section controlled by the combustion control means will increase.

Therefore, according to the present invention, when the combustion device is a combustion device provided with the combustion control means and the flow rate adjustment means as described above, the supply air temperature overheating prevention means comprises a supply air supply sensor detected by the supply air temperature sensor. When the air temperature rises above the first superheat temperature, the amount of combustion in the combustion section controlled by the combustion control means is reduced by reducing the flow rate of the fluid flowing through the fluid passage via the flow rate adjustment means. Let it decrease.

Further, in the combustion apparatus provided with the combustion control means and the flow rate adjusting means, when the supply air temperature is equal to or higher than the first superheat temperature, the amount of combustion in the combustion section is required. When the air supply temperature is to be increased accordingly, the air supply temperature overheating prevention means, when the air supply temperature detected by the air supply temperature sensor is equal to or higher than the first superheat temperature, opens the fluid passage via the flow rate adjustment means. By controlling the flow rate of the flowing fluid to increase or decrease, the amount of combustion in the combustion section controlled by the combustion control means is controlled.

In this way, when the supply air temperature rises to a temperature equal to or higher than the first superheat temperature, the control of the amount of combustion in the combustion section is performed by controlling the flow rate of the fluid. It is possible to prevent the supply air temperature from becoming excessively high while raising the temperature to the target temperature. That is, it is possible to appropriately prevent the supply air temperature from excessively rising while satisfying the essential function of the combustion device.

As the combustion apparatus having the combustion control means and the flow rate adjustment means as described above, for example, a hot water supply apparatus in which the fluid heated by the combustion operation of the combustion section is water, or the fluid is air in a room or the like. A hot air heating device and the like are included.

In particular, when the combustion device is a hot water supply device in which the fluid is water and the supply air temperature is equal to or higher than the first superheat temperature, the amount of combustion in the combustion section is increased or decreased. In the case of a combustion device that performs heating, preferably, when the supply air temperature detected by the supply air temperature sensor is equal to or higher than the first superheat temperature, the supply air temperature overheat prevention means preferably sets a target of the combustion unit. The maximum combustion amount is set to be lower as the supply air temperature is higher, and the maximum combustion amount is set via the flow rate adjusting means so that the combustion amount of the combustion section controlled by the combustion control means becomes the target maximum combustion amount. By controlling the amount of water flowing through the fluid passage, the amount of combustion in the combustion section is controlled.

As described above, when the supply air temperature is equal to or higher than the first superheat temperature, the target maximum combustion amount of the combustion section is set according to the supply air temperature, and is controlled by the combustion control means. By controlling the amount of water so that the amount of combustion in the combustion section becomes the target maximum amount of combustion, it is possible to minimize the degree of decrease in the amount of water when the supply air temperature is equal to or higher than the first superheat temperature. it can. For this reason, it is possible to prevent an excessive rise in the supply air temperature while ensuring a sufficient amount of hot water (water flow) from the hot water supply device.

Further, in the present invention, the supply air temperature overheating prevention means may be arranged so that the supply air temperature detected by the supply air temperature sensor is equal to the first air supply temperature.
A predetermined second predetermined temperature higher than the superheat temperature
Means for stopping the combustion operation of the combustion section when the temperature rises to or above the superheat temperature.

According to this, when the supply air temperature rises above the second superheat temperature, the combustion operation of the combustion section is automatically stopped, so that an excessive increase in the supply air temperature can be reliably prevented. it can. For this reason, it is possible to reliably prevent damage to devices and components installed in the air supply passage and a portion communicating with the air supply passage.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIGS.
This will be described with reference to FIG.

FIG. 1 is a system configuration diagram schematically showing a configuration of a gas water heater as a combustion device in the present embodiment.
FIG. 2 is a block diagram showing a configuration of a main part of the gas water heater.
FIG. 3 is a flowchart for explaining the operation of the gas water heater, and FIG. 4 is a diagram for explaining a partial process of the flowchart of FIG.

Referring to FIG. 1, a gas water heater of the present embodiment has a main body housing 1 installed indoors and a combustion housing 2 (combustion chamber) housed in main body housing 1.
A gas burner 3 (combustion unit) housed in a lower portion of the combustion housing 2, a gas supply pipe 4 for supplying a fuel gas to the gas burner 3, and hot and cold water (fluid) in a kitchen, a bathroom, a washroom, or the like. A water pipe 5 (fluid passage) for supplying air and the combustion air (atmosphere) of the gas burner 3 are guided from outside to the combustion housing 2, and the exhaust gas generated in the combustion housing 2 by the combustion operation of the gas burner 3 is discharged outdoors. And a control unit 7 for controlling the operation of the gas water heater, and a remote controller (remote controller) 8 connected to the control unit 7.

The supply / exhaust pipe 6 includes an inner pipe 10 having an exhaust path 9 formed therein, and an inner pipe 1 which is substantially
0 (space having an annular cross section) and an outer pipe 12 forming an air supply passage 11 for combustion air, and a double pipe structure is provided. It has been extended.

The indoor end of the outer pipe 12 of the supply / exhaust pipe 6 is connected to an opening 13 formed in the upper part of the main body housing 1. Thereby, the air supply passage 1 inside the outer pipe 12
1 communicates with the inside of the main body housing 1 through the opening 13. In this case, in the present embodiment, the main body housing 1 is formed in a substantially hermetic structure, and the inside (outside of the combustion housing 2) is provided at a position of an air supply port 14 formed in a lower portion of the combustion housing 2. Combustion fan 15
It communicates with the inside of the combustion housing 2 via a (fan for supplying combustion air to the gas burner 3 in the combustion housing 2). Therefore, the air supply passage 11 communicates with the inside of the main housing 1 and the inside of the combustion housing 2 via the combustion fan 15.

The combustion fan 15 is not shown in detail, but the combustion air is combusted from inside the main body housing 1 by rotating a rotary fan arranged facing the air supply port 14 by an electric motor. It is supplied into the housing 2.

The indoor end of the inner pipe 10 of the supply / exhaust pipe 6 is introduced into the main body housing 1 from the outer pipe 12,
It is connected to an exhaust port 16 formed in the upper part of the combustion housing 2. Thereby, the exhaust passage 9 inside the inner pipe 10 is formed.
Communicates with the inside of the combustion housing 2 via the exhaust port 16.

The outside ends of the inner pipe 10 and the outer pipe 12 of the supply / exhaust pipe 6 are open to the atmosphere.

In the upper part of the main body housing 1, the temperature of the combustion air introduced into the combustion housing 2 from the air supply passage 11 through the inside of the main body housing 1 (supply temperature).
Is provided.

The gas supply pipe 4 is introduced from the outside of the main body housing 1 into the combustion housing 2 through the inside of the main body housing 1 and is connected to the gas burner 3. The gas supply pipe 4 is provided with a main solenoid valve 18, a gas proportional solenoid valve 19, and a sub solenoid valve 20 in this order from the upstream side.

The main solenoid valve 18 and the sub solenoid valve 20 are solenoid valves for opening and closing the gas supply pipe 4 to supply and shut off fuel to the gas burner 3, respectively, and to supply current to a solenoid (not shown). Opens and closes depending on the presence or absence. The gas proportional solenoid valve 19 is a solenoid valve for controlling the flow rate of the fuel gas supplied to the gas burner 3, and opens at an opening corresponding to the amount of electricity supplied to a solenoid (not shown).

The water pipe 5 includes a water inlet pipe 21 introduced into the main body housing 1 from the outside, a heat exchanger pipe 22 and a bypass pipe 23 branched from the downstream end of the water inlet pipe 21.
And a tapping pipe 24 in which the heat exchanger pipe 22 and the bypass pipe 23 are joined at their downstream ends and led out of the main body housing 1. The downstream end of the tapping pipe 24 is
It is connected to a hot water tap (not shown) such as a kitchen, a bathroom, and a washroom.

In this case, the heat exchanger tube 22 is connected via a heat exchanger 25 formed on the upper part of the combustion housing 2. As a result, the heat exchanger tube 2
The water flowing into the heat exchanger 2 is heated via the heat exchanger 25 in the course of flowing through the heat exchanger tube 22 during the combustion operation of the gas burner 3. Then, the heated water joins the water flowing through the bypass pipe 23 without passing through the heat exchanger 25 and flows through the tapping pipe 24.

In this embodiment, the water inlet pipe 21 has a water temperature sensor 26 for detecting the temperature (water temperature) of water flowing therethrough.
A flow rate sensor 27 for detecting a flow rate of water flowing through the water inlet pipe 21 (= a flow rate of water flowing through the hot water supply pipe 24); and a water amount control valve for controlling the water amount (flow rate of water) flowing through the water inlet pipe 21. 28 (flow rate adjusting means) are mounted in order from the upstream side. The tapping pipe 24 is provided with a tapping temperature sensor 29 for detecting the temperature (tapping temperature) of the water flowing through the tapping pipe 24.

The water amount control valve 28 adjusts the water amount by adjusting the opening degree of the valve body with an electric motor (not shown). Further, in the present embodiment, the ratio of the flow rates of the heat exchanger tube 22 and the bypass tube 23 is constant.

The combustion housing 2 is provided with a frame rod 30 for detecting the combustion flame of the gas burner 3 and an ignition electrode 31 for generating a spark discharge when the gas burner 3 is ignited. Furthermore, in the main body housing 1,
An igniter 32 for energizing the ignition electrode 31 is provided.

The remote controller 8 is installed in a kitchen or the like outside the main body housing 1 in order to perform an operation such as setting a target temperature of tap water (hereinafter, referred to as a target tap temperature) to the control unit 7. , Body housing 1
It is connected via a communication line 33 to the control unit 7 disposed therein. The remote controller 8 has a tapping temperature setting switch 34 for setting the target tapping temperature.
And an indicator 35 for displaying the target hot water temperature, the operation state of the hot water supply device, and the like.

The control unit 7 is an electronic circuit unit constructed using a microcomputer, and includes the main solenoid valve 18, the sub solenoid valve 20, the gas proportional solenoid valve 19, the combustion fan 15, the water amount control valve 28, the igniter Via 32, operation control of the entire apparatus including the combustion operation of the gas burner 3 is performed. As shown in FIG. 2, in order to control the operation of the control unit 7, data and the like of a target hot water temperature are given from the remote controller 8 via the communication line 33, Detection signals from the sensor 26, the tap water temperature sensor 29, the flow rate sensor 27, the supply air temperature sensor 17, and the frame rod 30 are given via signal lines (not shown).

In this case, the control unit 7 mainly includes the main solenoid valve 18, the sub solenoid valve 20,
A combustion control means 36 for controlling the combustion operation of the gas burner 3 via the gas proportional solenoid valve 19, the combustion fan 15, and the igniter 32; and the water amount control valve 28 (more precisely, the valve of the water amount control valve 28 is driven). Water control means 37 for controlling the water flow in the water pipe 5 via an electric motor). Although the detailed processing of the combustion control means 36 and the water amount control means 37 will be described later, the combustion control means 36 and the water amount control means 37
8.

Although not shown in detail, a communication line 33 connecting the control unit 7 and the remote controller 8, various sensors such as the control unit 7 and the water temperature sensor 26, and actuators such as the main solenoid valve 18 are provided. A harness such as a signal line for connecting to the main body is fixed to the main body housing 1 or the like by a resin-made clamp member (not shown) in the main body housing 1.

Next, the operation of the gas hot water supply apparatus of this embodiment will be described together with a more detailed control process of the control unit 7.

In the gas hot water supply apparatus of this embodiment, for example, a user opens a hot water tap (not shown) in a kitchen or the like, and
Is started by the control unit 7 based on the detection signal of the water amount sensor 27. Then, in response to this detection, the combustion control means 36 of the control unit 7 executes an ignition process for the gas burner 3.

In this ignition process, the combustion fan 15 is controlled to rotate at a predetermined speed. At this time, an amount of combustion air corresponding to the number of revolutions of the combustion fan 15 is sucked into the combustion fan 15 from outside through the air supply passage 11 of the supply / exhaust pipe 6 and the inside of the main body housing 2, and the air is drawn into the combustion housing 2. The gas is supplied to the gas burner 3 through an air supply port 14.

In parallel with the control of the combustion fan 15, the combustion control means 36 further activates the igniter 32 to energize the ignition electrode 31 to generate a spark discharge. Then, while operating the combustion fan 15 and the ignition electrode 31 in this way, the main electromagnetic valve 18 and the auxiliary electromagnetic valve 20 of the gas supply pipe 4 to the gas burner 3 are energized to open them. . Further, the gas proportional solenoid valve 19 is energized to open the solenoid valve 19 at a predetermined opening.
A predetermined amount of fuel gas is supplied from the gas supply pipe 4 to the gas burner 3. Thereby, the gas burner 3 is ignited.

By the above-described ignition processing, the gas burner 3
Is fired, it is detected by the detection signal of the frame rod 30. Then, when this detection is performed, the combustion control means 36 of the control unit 7 then makes the tapping temperature detected by the tapping temperature sensor 29 match the target tapping temperature set by the tapping temperature setting switch 34 of the remote controller 8. Thus, the process of controlling the combustion amount of the gas burner 3 (hereinafter, referred to as a tapping water temperature adjustment process) is executed.

In the hot water temperature adjusting process, the hot water temperature sensor 2
9. Based on the detection data of the incoming water temperature sensor 26 and the flow rate sensor 27 and the data of the target hot water temperature, the required combustion amount of the gas burner 3 required for setting the hot water temperature to the target hot water temperature is determined by using a predetermined data table or an arithmetic expression It is obtained sequentially using The incoming water temperature can be estimated using detection data from the hot water temperature sensor 29, detection data from the flow rate sensor 27, data on the amount of combustion of the gas burner 3, and the like. It may be omitted.

The combustion control means 36 determines the target number of revolutions of the combustion fan 15 for supplying the required amount of combustion air to the gas burner 3 in accordance with the required combustion amount as described above, based on a data table or the like (not shown). I do. Then, the rotation speed of the combustion fan 15 is controlled according to the target rotation speed.
In this case, in this embodiment, the combustion fan 15 is provided with a rotation speed sensor (not shown) that detects the rotation speed, and the combustion fan 15 performs combustion so that the actual rotation speed detected by the rotation speed sensor becomes the target rotation speed. The rotation speed of the fan 15 is feedback-controlled.

Further, the combustion control means 36 determines the amount of power (opening) of the gas proportional solenoid valve 19 in accordance with the actual rotation speed of the combustion fan 15 detected by the rotation speed sensor. The gas proportional solenoid valve 19 is energized according to the amount. As a result, the combustion air and the fuel gas in an amount corresponding to the required combustion amount are supplied to the gas burner 3, and the combustion amount of the gas burner 3 is controlled to the required combustion amount. That is, the amount of combustion of the gas burner 3 is controlled to the amount of combustion necessary to make the outlet temperature match the target outlet temperature.
As a result, the hot water temperature rises to the target hot water temperature or a temperature close to the target hot water temperature, and hot water at that temperature is supplied to a hot water tap (not shown) in a kitchen or the like.

Since the apparatus according to the present embodiment is a so-called fan-lead type, the amount of energization of the gas proportional solenoid valve 19 is determined according to the actual number of revolutions of the combustion fan 15. Alternatively, the amount of energization of the gas proportional solenoid valve 19 may be determined directly.

When setting the target rotation speed of the combustion fan 15, the supply air temperature detected by the supply air temperature sensor 17 may be taken into consideration. In other words, the higher the supply air temperature, the lower the oxygen concentration in the combustion air, so that an amount of oxygen corresponding to the required combustion amount of the gas burner 3 is supplied to the gas burner 3.
The amount of combustion air that can be supplied to the fuel cell increases. Therefore, for example, when the supply air temperature is higher than the standard temperature,
The correction may be made so that the higher the supply air temperature, the higher the target rotation speed of the combustion fan 17.

On the other hand, while performing the above-described hot water temperature adjustment processing by the combustion control means 36, the control unit 7 controls the supply air temperature detected by the supply air temperature sensor 17 (introduced into the combustion housing 2 from the air supply passage 11). Monitor the temperature of the combustion air). Then, when the supply air temperature rises to a predetermined first superheat temperature Ta (for example, 76 ° C. in the present embodiment) or more, a process shown in the flowchart of FIG. This is executed by the water amount control means 37 in a cycle (for example, one second cycle) to control the amount of water in the water pipe 5.

Further, the supply air temperature is equal to the first superheat temperature Ta.
Higher than the second superheat temperature Tc (for example, 8
0 ° C.) or more.
As a result, the combustion operation of the gas burner 3 is stopped. That is, the combustion control means 36 closes the main solenoid valve 18 and the sub solenoid valve 20 of the gas supply pipe 4, cuts off the supply of the fuel gas to the gas burner 3, and extinguishes the gas burner 3.

The second superheat temperature Tc is determined by the malfunction of the control unit 7 that comes into contact with the combustion air in the main body housing 1, the malfunction of the combustion fan 15, and the aforementioned harness clamp member (not shown). This is a temperature near the upper limit temperature at which no inconvenience such as thermal deformation occurs.

The supply air temperature detected by the supply air temperature sensor 17 is
The control process of the water amount control means 37 when the temperature rises to or above the first superheat temperature Ta (supply air temperature <second superheat temperature Tc) is performed as follows.

That is, referring to the flow chart of FIG. 3, the water amount control means 37 of the control unit 7 first determines the data table determined in advance from the supply air temperature detected by the supply air temperature sensor 17 as shown in FIG. , The target maximum combustion amount of the gas burner 3 is obtained (STEP 1).

In this case, in the data table of FIG. 4, the supply air temperature is equal to or higher than the first superheat temperature Ta, and is a predetermined temperature Tb higher than the first superheat temperature Ta (in the present embodiment, for example, 78 ° C. or lower. , The combustion amount limit end temperature Tb) or less, the target maximum combustion amount is changed from a predetermined maximum value QmaxH to a predetermined minimum value Qma with an increase in the supply air temperature.
It is determined to decrease linearly toward xL.
Further, when the supply air temperature is equal to or higher than the combustion amount limit temperature Tb, the target maximum combustion amount is set to be kept constant at the minimum value QmaxL.

The maximum value QmaxH of the target maximum combustion amount
Is the maximum combustion amount of the gas burner 3 at the original maximum capacity (for example, equivalent to No. 16) of the gas water heater of the present embodiment (this is 2 when the thermal efficiency of the heat exchanger 25 is 0.8, for example).
100 kJ / min (= 500 kcal / min). Also,
The minimum value QmaxL of the target maximum combustion amount is, for example, the maximum combustion amount of the gas burner 3 equivalent to No. 8 (this is 1050 kJ / min (= 250 kcal /, when the heat efficiency of the heat exchanger 25 is 0.8).
Min)).

After the target maximum combustion amount corresponding to the supply air temperature is obtained from the data table shown in FIG.
The water amount control means 37 calculates the current actual combustion amount (actual combustion amount) of the gas burner 3 with the current energization amount of the gas proportional solenoid valve 19 (this defines the flow rate of the fuel gas supplied to the gas burner 3) and the fuel. It is calculated based on the calorific value of the gas (this is determined by the type of the combustion gas) (STEP 2).
The actual combustion amount may be replaced by the required combustion amount obtained by the combustion control means 36 as described above.

Then, the obtained current actual combustion amount (or current required combustion amount) is compared with the target maximum combustion amount (STEP 3).

At this time, if the target maximum combustion amount is smaller than the actual combustion amount, the water amount control means 37 controls the combustion control means 3.
6 is the required combustion amount obtained by the hot water temperature adjustment process,
A predetermined amount ΔQd determined in advance from the current actual combustion amount (for example, 4.2 kJ / min; hereinafter, referred to as a unit reduced combustion amount ΔQd)
Is obtained as a command value of the water amount such that the water amount of the water pipe 5 becomes a value (= actual combustion amount−ΔQd) obtained by subtracting the value (STEP).
4). In this case, the command value of the water amount is
Is calculated from the value of the above (actual combustion amount−ΔQd), the detection data of the tap water temperature sensor 29 and the incoming water temperature sensor 26, and the data of the target tap water temperature by a process that is inversely calculated from the case where the required combustion amount is obtained. . In this manner, the command value of the water amount obtained in STEP 4 is to reduce the required combustion amount by the tapping water temperature adjustment process by the unit reduced combustion amount ΔQd from the current value. Become.

If the target maximum combustion amount is greater than the actual combustion amount in STEP 3, the water amount control means 37 determines that the required combustion amount determined by the combustion control means 36 in the hot water temperature adjustment processing is the current actual combustion amount. To a predetermined amount ΔQ
u (for example, 0.14 kJ / min = ΔQd / 30; hereinafter, referred to as a unit increase combustion amount ΔQu) (= actual combustion amount + Δ
The amount of water in the water pipe 5 that satisfies Qu) is obtained as a command value for the amount of water (STEP 5). In this case, the command value of the water amount is equal to the above (actual combustion amount + ΔQ) as in STEP4.
u), the detection data of the hot water temperature sensor 29 and the incoming water temperature sensor 26, and the data of the target hot water temperature.
In this manner, the command value of the water amount obtained in STEP 5 is for increasing the required combustion amount by the tapping water temperature adjustment process by the unit increase combustion amount ΔQu from the present value, so that the command value of the water amount is larger than the current water amount. Become. In this embodiment, as described above, the unit increase combustion amount ΔQu is smaller than the unit decrease combustion amount ΔQd.

After obtaining the command value of the water amount of the water pipe 5 in this manner, the water amount control means 37 controls the opening of the water amount control valve 28 via an electric motor (not shown) according to the command value. (Step 6). That is, the opening of the water amount control valve 28 is determined according to a predetermined data table or the like so that the amount of water in the water pipe 5 detected by the flow rate sensor 27 becomes the above-described command value, and the water amount control valve 28 is controlled to the opening degree. .

If the target maximum combustion amount is equal to the actual combustion amount in STEP 3, the processing in STEPs 4 to 6 is not performed, and the opening of the water amount control valve 28 is maintained at the current level.

When the supply air temperature detected by the supply air temperature sensor 17 rises above the first superheat temperature Ta, the above-described processing is executed by the water amount control means 37 in a predetermined control cycle (one second cycle). .

By such processing, the required combustion amount of the gas burner 3 and the actual combustion amount determined by the combustion control means 36 so that the tapping temperature detected by the tapping temperature sensor 29 becomes the target tapping temperature are shown in FIG. As shown, the control is performed such that the target maximum combustion amount is set according to the supply air temperature. More specifically, in a state where the actual combustion amount is larger than the target maximum combustion amount according to the supply air temperature, the water amount in the water pipe 5 is gradually reduced, and as a result, the combustion amount of the gas burner 3 becomes a predetermined amount. In each control cycle (every second), the amount is reduced by the unit reduced combustion amount ΔQd. Further, when the actual combustion amount is smaller than the target maximum combustion amount, the water amount in the water pipe 5 is gradually increased. As a result, the combustion amount of the gas burner 3 is increased every time the control cycle is performed.
u is incremented by one.

In the gas hot water supply apparatus of this embodiment, the situation in which the supply air temperature rises above the first superheat temperature Ta (76 ° C.) basically depends on the gas burner at the maximum capacity of the gas hot water supply apparatus. This occurs when the combustion operation of the gas burner 3 is being performed with a maximum combustion amount of 3 (this is the maximum value QmaxH of the target maximum combustion amount) or a combustion amount near the maximum combustion amount. Until the supply air temperature rises from the first superheat temperature Ta to the combustion amount restriction end temperature Tb, the target maximum combustion amount decreases as the supply air temperature rises as described above. Therefore, the supply air temperature becomes the first superheat temperature Ta.
Immediately after the rise, the combustion amount (actual combustion amount) of the gas burner 3 decreases along with the water amount of the water pipe 5.

The temperature of the exhaust gas discharged from the combustion housing 2 to the exhaust passage 9 of the supply / exhaust pipe 6 decreases due to the decrease in the amount of combustion of the gas burner 3. As a result, the temperature of the combustion air heated by the heat exchange with the exhaust gas in the hot water supply passage 11, that is, the supply air temperature is suppressed from further increasing, and basically lowers.

This prevents the supply air temperature from becoming excessively high, and consequently causes the control unit 7, the combustion fan 15, and the clamp member (not shown) of the harness to come into contact with the combustion air. Exposure to a natural atmosphere is prevented.

When the supply air temperature is reduced due to the decrease in the combustion of the gas burner 3 as described above, the target maximum combustion amount increases according to the data table of FIG. 4, so that the combustion amount of the gas burner 3 also increases. . At this time, the increase in the combustion amount is performed by the unit increase combustion amount ΔQu for each predetermined control cycle. In this case, the unit increase combustion amount ΔQu is smaller than the unit decrease combustion amount ΔQd when decreasing the combustion amount. For this reason, the combustion amount is increased relatively slowly. As a result, it is possible to avoid a situation in which the tapping temperature temporarily rises significantly (overshoots) above the target tapping temperature. On the other hand, since the amount of combustion decreases relatively quickly,
The increase in the supply air temperature can be suppressed quickly.

Further, when the supply air temperature is equal to or higher than the first superheat temperature Ta, the above-described increase or decrease in the combustion amount of the gas burner 3 is performed as a result of the increase or decrease in the amount of water in the water pipe 5. In addition, the control of the combustion amount of the gas burner 3 for preventing the rise of the supply air temperature can be performed while performing the tapping temperature adjustment processing, in other words, while controlling the tapping temperature to the target tapping temperature. Therefore, it is possible to prevent the supply air temperature from rising while satisfying the essential function of the gas water heater.

Further, when the supply air temperature is higher than the first superheat temperature Ta, the combustion amount of the gas burner 3 is controlled to the target maximum combustion amount set according to the supply air temperature. That is, the combustion operation of the gas burner 3 is performed with the maximum possible combustion amount. For this reason, the degree of reduction in the amount of water in the water pipe 5 for reducing the amount of combustion of the gas burner 3 can be minimized. As a result, the amount of combustion of the gas burner 3 can be reduced without excessively restricting the amount of hot water (= the amount of water in the water pipe 5), and an excessive increase in the supply air temperature can be prevented.

If the supply air temperature rises to the second superheat temperature Tc (80 ° C.), the combustion operation of the gas burner 3 is stopped (since the gas burner 3 is extinguished).
Further increase in the supply air temperature is completely prevented, whereby it is possible to reliably prevent malfunction of the control unit 7, malfunction of the combustion fan 15, and the like.

In the embodiment described above, the gas hot water supply device is described as an example. However, the present invention is also applied to an FF type gas hot air heating device having a supply / exhaust pipe having the same structure as the supply / exhaust pipe 6, for example. Can be applied. in this case,
In the case of controlling a combustion amount of a gas burner in a combustion chamber so that a blast air or the like blows warm air as a fluid from a main body housing into a room and keeps a blast temperature (room temperature) at a target temperature, for example, combustion in a combustion chamber is performed. When the supply air temperature of the service air rises above the predetermined first superheat temperature, the amount of hot air from the convection fan etc. is reduced, resulting in a reduction in the combustion amount of the gas burner and a decrease in the exhaust gas temperature. Thus, it is possible to lower the supply air temperature.

In the above-described embodiment, the supply / exhaust pipe 6 has a double pipe structure. However, the supply / exhaust pipe may have another structure as long as the supply path and the exhaust path are adjacent to each other. (For example, a structure in which a partition plate that crosses in the diametric direction is provided in a pipe to form an air supply passage and an exhaust passage having a semicircular cross section).

[Brief description of the drawings]

FIG. 1 is an overall system configuration diagram of a gas water heater as one embodiment of a combustion device of the present invention.

FIG. 2 is a block diagram showing a configuration of a main part of the apparatus shown in FIG.

FIG. 3 is a flowchart for explaining the operation of the apparatus of FIG. 1;

FIG. 4 is a diagram for explaining a partial process of the flowchart in FIG. 3;

[Explanation of symbols]

2 ... combustion housing (combustion chamber), 3 ... gas burner (combustion section), 5 ... water pipe (fluid passage), 6 ... supply / exhaust pipe, 9 ... exhaust path, 11 ... air supply path, 17 ... supply air temperature sensor, 25 ... heat exchanger, 28 ... water amount control valve (flow rate adjusting means), 36 ... combustion control means, 38 ... means for preventing overheating of supply air temperature.

Claims (8)

[Claims] A combustion chamber accommodating a combustion section for heating an object to be heated, and a supply / exhaust pipe in which an air supply passage and an exhaust passage communicating with the combustion chamber are arranged adjacent to each other and arranged in parallel. While introducing combustion air into the combustion chamber through the air supply passage of the supply / exhaust pipe, fuel is supplied to the combustion section to perform the combustion operation of the combustion section, and the exhaust gas generated by the combustion operation is discharged to the combustion chamber. In a combustion device for discharging air from a combustion chamber through an exhaust path of the supply / exhaust pipe, an air supply temperature provided in the air supply path for detecting a temperature of combustion air introduced into the combustion chamber from the air supply path. Sensors and
When the supply air temperature detected by the supply air temperature sensor rises above a predetermined first superheat temperature, the supply air temperature overheat prevention means for controlling the amount of combustion so as to reduce the amount of combustion in the combustion section. A combustion device comprising: 2. The overheating prevention means according to claim 1, wherein when the supply air temperature detected by the supply air temperature sensor is equal to or higher than the first overheating temperature, the higher the supply air temperature is, the more the combustion of the combustion section is performed. 2. The combustion apparatus according to claim 1, wherein the combustion amount is controlled according to the supply air temperature so as to increase the degree of decrease in the amount. 3. The overheating prevention means according to claim 1, wherein, after reducing the amount of combustion in said combustion section, when the air supply temperature detected by said air supply temperature sensor decreases toward said first superheated temperature, said combustion is stopped. 3. The combustion device according to claim 1, wherein the amount is increased. 4. The system according to claim 1, wherein said supply air temperature overheating prevention means includes means for, when the air supply temperature detected by said air supply temperature sensor is equal to or higher than said first superheat temperature, increasing the amount of combustion in said combustion section, 4. The combustion apparatus according to claim 3, wherein the combustion amount is changed more slowly than when the amount is reduced. 5. The combustion device uses a fluid flowing through a fluid passage as the object to be heated, and heats the fluid via a heat exchanger so as to raise the temperature of the fluid to a preset target temperature. A combustion device comprising: combustion control means for controlling the amount of combustion in the combustion part; and flow rate adjusting means for adjusting the flow rate of the fluid flowing through the fluid passage. When the supply air temperature detected by the sensor rises above the first superheat temperature, the flow rate of the fluid flowing through the fluid passage is reduced through the flow rate adjusting means, whereby the combustion controlled by the combustion control means is reduced. The combustion device according to any one of claims 1 to 4, wherein the combustion amount of the section is reduced. 6. The combustion device uses a fluid flowing through a fluid passage as the object to be heated, and heats the fluid via a heat exchanger so as to raise the temperature of the fluid to a preset target temperature. A combustion device comprising: a combustion control unit that controls a combustion amount of the combustion unit; and a flow rate adjustment unit that adjusts a flow rate of a fluid flowing through the fluid passage. When the temperature is equal to or higher than the first superheat temperature, the flow rate of the fluid flowing through the fluid passage is controlled to increase or decrease via the flow rate control means, thereby controlling the combustion amount of the combustion unit controlled by the combustion control means. The combustion device according to claim 3, wherein the combustion is performed. 7. The combustion device is a hot water supply device in which the fluid is water, and the supply air temperature overheating prevention means is such that an air supply temperature detected by the air supply temperature sensor is equal to or higher than the first superheat temperature. At this time, the target maximum combustion amount of the combustion section is set to be lower as the supply air temperature is higher, so that the combustion amount of the combustion section controlled by the combustion control means becomes the target maximum combustion amount. 7. The combustion apparatus according to claim 6, wherein the amount of water flowing through the fluid passage is controlled via the flow rate adjusting means to control the amount of combustion in the combustion section. 8. The supply air temperature overheating prevention means, when the supply air temperature detected by the air supply temperature sensor rises to a temperature higher than the first superheat temperature and equal to or higher than a predetermined second superheat temperature. The combustion device according to any one of claims 1 to 7, further comprising means for stopping a combustion operation of the combustion unit.