JP2002364838A - Open type gas combustion appliance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly discriminate whether the cause of incomplete combustion is due to oxygen deficiency or the blocking of fins, and prevent incomplete combustion with high reliability. SOLUTION: A secondary electromotive force V2 is compared with a determining electromotive force Vr2 (S13). If it is the determining electromotive force Vr2 or below (|V2 |>=|Vr2 |), it is determined that the blocking of fins is caused. Then, a non-combustion preventing lamp 43 is blinked (S14), and a solenoid valve 16 is closed (S15). Moreover, a composite electromotive force V0 is monitored at the same time on this occasion. If the composite electromotive force V0 is the determining electromotive force Vr0 or below (S20: NO), it is determined that incomplete combustion is caused. Then, the solenoid valve 16 is closed (S15).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an open-type gas burner, such as a water heater, which takes combustion air from a room and discharges combustion gas into the room as it is.

[0002]

2. Description of the Related Art In an open-type gas burning appliance, for example, a main-stop type water heater installed in a kitchen or the like, when the indoor ventilation is insufficient or when the fins of a heat exchanger adhere to combustion products and the like. If blockage is caused by the combustion air, it becomes difficult to take in the combustion air, which may cause incomplete combustion.
An incomplete combustion prevention device (hereinafter abbreviated as a non-combustion prevention device) that detects these in advance and shuts off gas supply is provided. Specifically, a primary thermocouple installed near the burner of the water heater, and a secondary thermocouple facing the combustion chamber window opened on the side wall of the combustion chamber between the burner and the heat exchanger , Connected in series so that the polarities are reversed, and the combined electromotive force obtained here is used directly for holding the magnet solenoid valve provided in the gas flow path, or monitored by a controller that controls the opening and closing of the magnet solenoid valve It is a configuration to make it. As a result, when the oxygen concentration in the room decreases, the electromotive force (primary electromotive force) of the primary thermocouple decreases due to the lift or extinguishment of the burner flame, and the fin clogging of the heat exchanger due to long-term use. Progresses, the electromotive force (secondary electromotive force) of the secondary thermocouple, which acts to cancel the primary electromotive force by being heated by the combustion gas overflowing from the combustion chamber window, becomes higher, so that both are synthesized. Since the electromotive force decreases, the magnet solenoid valve is closed directly or via the controller, and the supply of gas is shut off.

[0003] Generally, the causes of incomplete combustion include oxygen deficiency and fin blockage. In the case of lack of oxygen, the cause of the abnormal combustion can be easily eliminated by ventilating the room. On the other hand, in the case of fin clogging, if the fin is continuously used without performing maintenance, the fin may be clogged, damaging the heat exchanger or the like, or the flame may overflow into the outside of the combustion chamber. For this reason, different treatments are required depending on whether the fin is clogged or oxygen is insufficient.When incomplete combustion occurs, the supply of gas to the burner is stopped and the cause of incomplete combustion is determined. It is desirable to turn on a notification lamp or the like in order to inform the user whether the fin is due to the fin blockage or the lack of oxygen. However, in the conventional non-combustible protection device as described above, since both the lack of oxygen in the room and the blockage of the fin are detected by the same decrease in the combined electromotive force, the two cannot be distinguished.

[0004] The applicant of the present invention has reported that the cause of incomplete combustion is fumes.
Is it due to blockage of oxygen or lack of oxygen?
Two open-type gas fuels that can distinguish between
Proposes baking utensils. The first open type gas burning appliance
Is disclosed in JP-A-11-304144.
In the case of oxygen deficiency and fin blockage,
Focusing on the difference in the rise characteristics of the generated electromotive force,
By detecting this difference, the cause of incomplete combustion can be distinguished.
Things. Specifically, as shown in FIG.
In the case of starting use in a state of lack of oxygen, the normal operation shown in FIG.
Primary electromotive force V₁The rise was slow
The combined electromotive force V₀Is the first judgment because it rises slowly
Time T '₁At the combined electromotive force V ₀Is the determination electromotive force Vr₀
If not reached, it is determined that the cause is insufficient oxygen.
Can be different. On the other hand, as shown in FIG.
In the closed state, the primary electromotive force V ₁With the secondary electromotive force V
₂Rises greatly, and the primary electromotive force V₁Than the secondary electromotive force V
₂Takes longer to stabilize, so that the combined electromotive force V
₀Changes to descend after reaching a peak on the way
You. Therefore, the first determination time T '₁In the synthetic electromotive
Force V₀Is the determination electromotive force Vr₀, But the second format
Fixed time T '₂At the combined electromotive force V₀Is the determination electromotive force Vr
₀If not, it is due to fin blockage
Can be determined. The rise characteristics of the electromotive force of the thermocouple here
As for the sex, we started using the equipment when it was cold,
The description is for a so-called cold start. Two
An open-type gas-burning apparatus is disclosed in Japanese Patent Application Laid-Open No. H11-311412.
And the primary and secondary thermocouples
By monitoring the electromotive force of each
This is to detect fin blockage.

[0005]

[SUMMARY OF THE INVENTION However, in the former case, if the fin blockage occurs, the resultant electromotive force V ₀ which after the end of the peak at a certain time (second determination time T _'2) Since it has to be compared with the judgment electromotive force Vr ₀ , there is a disadvantage that it takes time to detect a change in the combined electromotive force due to the fin blockage. Therefore, even though the non-combustion prevention device works to stop the combustion, the appliance can be used for a predetermined period from the start of ignition to the detection of incomplete combustion. The desired hot water can be obtained if the ignition operation is repeated many times continuously using the above method. Then, when such unreasonable usage is performed, the concentration of carbon monoxide in the room may be rapidly increased, resulting in carbon monoxide poisoning. In the latter case, in the case of incomplete combustion due to a combined factor of fin blockage and oxygen deficiency, in which the primary electromotive force and the secondary electromotive force change only slightly with respect to the normal value, a small change amount is obtained. Therefore, there is a problem that an error in the detection level is apt to occur due to a variation in the electromotive force.
In addition, if an attempt is made to detect incomplete combustion by calculating a combined electromotive force from the detected primary electromotive force and secondary electromotive force, an additional operation circuit is required as compared with the case where the combined electromotive force is directly detected. In order to ensure the safety against incomplete combustion, redundant design must be performed in consideration of the case where the arithmetic circuit has failed, which is costly. The open-type gas-burning apparatus of the present invention solves the above-described problems, and quickly determines whether the cause of incomplete combustion is due to lack of oxygen or clogged fins, and prevents incomplete combustion with high reliability. With the goal.

[0006]

According to a first aspect of the present invention, there is provided an open-type gas combustion apparatus, comprising: a burner for burning fuel gas; and a burner gas provided above the burner. A fin-tube type heat exchanger for heating water flow, a first thermoelectric element provided near the burner and directly heated by the flame of the burner, and combustion between the burner and the heat exchanger It is provided facing the combustion chamber window opened on the side wall of the chamber, and is heated by the combustion gas overflowing from the combustion chamber window when the space between the fins of the heat exchanger is closed by adhesion of combustion products or the like. A second thermoelectric element, the first thermoelectric element and the second thermoelectric element are connected in series and in opposite polarities, and based on a combined electromotive force obtained from the two thermoelectric elements, Detect incomplete combustion In the discharge gas burning appliance, the single electromotive force of the first thermoelectric element or the single electromotive force of the second thermoelectric element or both of the single electromotive forces are detected together with the combined electromotive force, and based on the detected electromotive force, Whether incomplete combustion is due to lack of oxygen in the room due to poor ventilation, etc.
The gist of the present invention is to determine whether the heat exchanger is caused by a blockage between the fins of the heat exchanger.

According to a second aspect of the present invention, there is provided the open-type gas-burning apparatus according to the first aspect, wherein one of the first thermoelectric element and the second thermoelectric element is used alone. The gist of the present invention is to provide a calculating means for detecting the electromotive force and calculating the single electromotive force of the other thermoelectric element from the detected single electromotive force and the combined electromotive force.

[0008] The open-type gas-burning apparatus according to the first aspect of the present invention having the above-described structure, is a combined electromotive force obtained by connecting the first thermoelectric element and the second thermoelectric element in series and in opposite polarities. The incomplete combustion can be detected with high reliability on the basis of the single electromotive force of the first thermoelectric element or the single electromotive force of the second thermoelectric element, or based on the single electromotive force of both and the combined electromotive force. It is possible to quickly determine whether combustion is due to lack of oxygen or fin blockage of the heat exchanger.

In the open-type gas-burning appliance according to a second aspect of the present invention, the single electromotive force that is not detected by the first thermoelectric element or the second thermoelectric element is the one that the arithmetic circuit detects as the combined electromotive force. By obtaining the value by calculation using the single electromotive force, it is possible to more accurately determine the fin blockage and the oxygen deficiency.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In order to further clarify the configuration and operation of the present invention described above, a preferred embodiment of an open-type gas burning appliance of the present invention will be described below.

FIG. 1 is a structural view of a main water heater 1 (hereinafter simply referred to as a water heater 1) as an open-type gas burning appliance, and FIG. 2 is a system configuration diagram thereof. The water heater 1 includes a fin tube type heat exchanger 5 in the combustion chamber 2, which heats water from a water supply pipe 3 connected to a water supply system with combustion heat of a burner 4 and sends out the hot water from a tapping pipe 6. . A water faucet 9, which is controlled to open and close via a lever 8 by pressing an operation button 7, and a water pressure responsive device 14 are sequentially provided upstream of the water supply pipe 3. The hydraulic pressure responsive device 14 is provided with a diaphragm 10 that can move back and forth, and a primary pressure chamber 11 and a secondary pressure chamber 12 are formed by partitioning the diaphragm 10. A venturi 13 is provided in the middle of the water supply pipe 3. The venturi 13 narrows the flow path and has a horizontal hole perpendicular to the flow path, and communicates with the secondary pressure chamber 12 of the hydraulic pressure responsive device 14. Diaphragm 10 has protruding rod 1
When water is passed through the water supply pipe 3 by opening the faucet 9, the water in the venturi 13 causes the pressure in the secondary pressure chamber 12 to fall below the pressure in the primary pressure chamber 11 and the diaphragm 10 Moves to the secondary pressure chamber 12 side, the protruding rod 15 is linked to the operation, and the valve opening mechanism 16a of the magnet solenoid valve 16 arranged in the gas flow path to the burner 4 is operated to open it. Then, the hydraulic pressure responsive valve 17 is opened. On both sides of the protruding rod 15, a first hydraulic pressure switch 1 that is turned on / off in conjunction with the operation of the protruding rod 15 is provided.
9, a second hydraulic pressure switch 20 is provided, and on one side of the lever 8, a lever switch 21 that is turned on / off in conjunction with the operation of the lever 8 is provided. Then, an ON signal of each switch is input to the controller 22. Further, an instrument plug 18 that opens the gas flow path in response to the pressing operation of the operation button 7 is provided downstream of the water pressure responsive valve 17 in the gas flow path.
Is provided.

On the other hand, the controller 22 is connected to an ignition electrode 23 for igniting a burner, an igniter 24, and a flame rod 25 for detecting a flame, and is provided in the vicinity of a sensing burner 4a provided along with the burner 4. 4
And a primary thermocouple 26 as a first thermoelectric element directly heated by the flame of the sensing burner 4a, and a combustion chamber window 44 opened on a side wall of the combustion chamber 2 between the burner 4 and the heat exchanger 5. And a secondary thermocouple 27 as a second thermoelectric element that is heated by the combustion gas overflowing from the combustion chamber window 44 when the space between the fins of the heat exchanger 5 is closed due to adhesion of combustion products and the like. Are connected in series with the (+) and (-) polarities reversed, and primary and secondary thermocouples 26 and 27 are connected.
Are input to the controller 22. Further, the intermediate position between the primary thermocouple 26 and the secondary thermocouple 27 connected in series is also connected to the controller 22, so that the electromotive force of the secondary thermocouple 27 is input to the controller 22 independently. ing. The controller 22 includes a dry battery 28 for supplying power,
A battery lamp 29 for notifying that the remaining charge amount has decreased, and a non-combustion prevention lamp 43 for notifying whether the cause of incomplete combustion when the non-combustion prevention device is activated is due to lack of oxygen or fin blockage. .

As shown in FIG. 3, the controller 22 utilizes a microcomputer 30 (hereinafter, simply referred to as a microcomputer 30) to control ignition and incomplete combustion, which will be described later (hereinafter simply referred to as non-combustion prevention control). Each input port (indicated by PI) has a lever switch 21,
An ON signal of the first hydraulic pressure switch 19, the ON signal of the second hydraulic pressure switch 20, and a voltage detection signal from the voltage monitoring circuit 33 of the dry battery 28 are input, respectively, and a flame detection circuit 34 for detecting a current value of the frame rod 25; The burner 4 is connected via a combined electromotive force determination circuit 35 for detecting the combined electromotive force of the thermocouple 26 and the secondary thermocouple 27 and a secondary electromotive force determination circuit 36 for detecting the electromotive force of the secondary thermocouple 27. The detection and determination signals of the combustion state are input. Further, the input ports PI ₉ are provided with judgment times T ₁ , T ₂ and judgment electromotive forces Vr ₀ , Vr ₁ , V used in the non-combustion prevention control described later.
Gas type switching resistors 39 and 40 for changing various set values such as r ₂ according to the type of gas are connected, and the input port PI
₁₀ include determination times T ₁ , T ₂ and determination electromotive forces Vr ₀ , Vr
Capability switching interlocking resistors 41 and 42 for changing various set values such as r ₁ and Vr ₂ according to the capability adjustment (gas amount adjustment) of the appliance.
Is connected. On the other hand, an ignition circuit 37 for operating the igniter 24 and an electromagnetic valve driving circuit 38 for supplying the attraction and holding current to the magnet electromagnetic valve 16 are connected to each output port (indicated by PO). The operation is controlled in accordance with the output. The microcomputer 30 includes a reset circuit 31 for monitoring the battery voltage and resetting the microcomputer 30 when the battery voltage is equal to or lower than a set value, and a clock circuit 32.

The operation of the water heater configured as described above will be described with reference to the flowchart of FIG. First, when the operation button 7 is pressed, the lever switch 21 is turned on, and the instrument plug 18 and the water tap 9 are each opened, and the magnet 15 is operated by the operation of the projecting rod 15 accompanying the flow of water through the water supply pipe 3 as described above. The electromagnetic valve 16 is also opened, and the water flows into the instrument (S1). Next, when the first hydraulic pressure switch 19 is turned on with the operation of the protruding rod 15 (S2), it is determined whether the battery voltage input from the voltage monitoring circuit 33 is 2.1 V or more (S3). If the voltage is below 2.1 V, the battery lamp 29 is turned on to notify the user that the dry battery 28 is exhausted (S4). On the other hand, if the voltage is 2.1 V or more, the igniter 24 is operated to continuously spark the ignition electrode 23, and the attraction current is supplied to the magnet solenoid valve 16 (S5). Next, the ON signal of the second hydraulic switch 20 is confirmed (S6). If this ON signal is not obtained within 2 seconds from the ON of the first hydraulic switch 19 in step 2, the hydraulic pressure response by the protruding rod 15 is performed. It is determined that the valve 17 has not been opened (S6: NO), the igniter 24 is turned off, the magnet solenoid valve 16 is closed (S7), and the ignition control is terminated. Conversely, if the ON signal of the second hydraulic pressure switch 20 is properly obtained, the hydraulic pressure responsive valve 1
It is determined that the gas is supplied by opening the valve 7 and the igniter 24
Only OFF is performed (S8). When the burner 4 is ignited in this way and the combustion of the burner 4 is confirmed from the flame rod 25 via the flame detection circuit 34 (S9: YES), the adsorption current to the magnet solenoid valve 16 is reduced to the holding current 2 (S10). . If an ignition error or extinguishment occurs, a flame detection signal cannot be obtained (S9: NO).
Stops the supply of the attracting current to the magnet solenoid valve 16 by the output to the solenoid valve drive circuit 38, closes the magnet solenoid valve 16 to cut off the gas supply (S15), and ends the ignition control.

After such ignition control, the microcomputer 30
The combined electromotive force of the primary thermocouple 26 and the secondary thermocouple 27 and the electromotive force of the secondary thermocouple 27 are each used to determine a combined electromotive force determination circuit 3
5 and the secondary electromotive force determination circuit 36 to prevent the occurrence of incomplete combustion due to lack of oxygen in the room, clogging of the fins of the heat exchanger 5 or a combination thereof, and the incomplete combustion is prevented. In order to determine whether the problem is due to oxygen shortage or fin blockage, the non-combustion prevention control in step 11 and subsequent steps is executed.

In this non-combustion prevention control, first, the flame in step 9
First judgment time T from detection₁Waits until (S1)
1), first determination time T₁After the elapse, the second judgment time T₂Is
Until that time, the following independent electromotive force determination processing is performed.
First, the secondary electromotive force V obtained from the secondary thermocouple 27₂But,
Determination electromotive force Vr₂The following (| V₂| ≧ | Vr₂|) Or not
Is determined (S13). This is shown in FIG.
In the case of starting use in the closed state of the₂But
Rise larger than the secondary electromotive force V (2) during normal operation shown in FIG.
Therefore, the first determination time T₁Is the judgment electromotive force Vr₂Reached
Fin blockage can be detected by checking whether
It is what it was. Therefore, here, YES,
Power V₂Is the determination electromotive force Vr₂The following (| V₂| ≧ | Vr₂
If |), it is determined that fins are blocked and
The lamp 43 is turned on and off (S14), and fin blockage occurs.
To the user. And the magnet
The supply of the holding current to the magnetic valve 16 is stopped and the valve is closed.
(S15) The supply of gas is shut off, and the control is terminated. This
, The secondary electromotive force V₂Is the judgment electromotive force Vr₂Compare with
The conventional combined electromotive force V₀Has a peak value
Wait for the peak value to pass and determine fin blockage
Can be determined more quickly than when
The combustion time in the combustion state can be shortened. For this reason, the user
To re-use equipment many times after fire-prevention device is activated
Danger of carbon monoxide poisoning
Can be suppressed. On the other hand, the secondary electromotive force V₂Is determined
Force Vr₂If it is larger (| V₂| <| Vr ₂|), Two
Next electromotive force V₂And the combined electromotive force V₀From the primary thermocouple 26
Primary electromotive force V₁Is calculated using the following equation
(S16). Primary electromotive force V₁= Synthetic electromotive force V₀-Secondary electromotive force V₂ And the primary electromotive force V₁Is the determination electromotive force Vr₁Or not
Is determined (S17). This is shown in FIG.
In the case of starting use in a room with insufficient oxygen, primary electromotive force
V₁Is the primary electromotive force V (1) at the time of normal rise shown in FIG.
Rises slowly and slower than the rise of
Fixed time T₁Is the judgment electromotive force Vr₁Check if you have reached
This makes it possible to detect oxygen deficiency. Yo
Therefore, here, NO, that is, the primary electromotive force V₁Is the determination electromotive force V
r₁Lift or extinguish flames due to lack of oxygen if:
The non-combustible lamp 43 is turned on.
(S18) Inform the user that oxygen deficiency has occurred.
Let The supply of the holding current to the magnet solenoid valve 16 is performed.
The supply is stopped, the valve is closed (S15), and the supply of gas is stopped.
Shut off and end control.

In the state where the processing for determining whether the fin is blocked or the oxygen is insufficient is repeated, the second determination time T ₂
After elapse, control for preventing incomplete combustion by monitoring the combined electromotive force is further performed. That is, when the second determination time T ₂ in step 12 it is determined that it has passed, the resultant electromotive force V _0, it is determined whether the determination electromotive force Vr ₀ or more (S20). If the resultant electromotive force V ₀ if lower than the determination electromotive force Vr ₀ (S20: NO), then closes the magnet electromagnetic valve 16 as an incomplete combustion by oxygen deficiency or fins closed or multiple factors thereof has occurred (S15 ), Shut off the gas supply and end the control. If the combined electromotive force V ₀ is equal to or larger than the determination electromotive force Vr ₀ , the above-described processing of determining the fin occlusion and oxygen deficiency in step 13 and thereafter is performed. In this way, the non-combustion prevention control process is repeated until it is determined that 20 minutes have passed after the detection of the ON of the first hydraulic pressure switch 19 in step 2 (S19: YES), and the timer for closing the magnet solenoid valve 16 is turned off. .

As described above, according to the water heater 1 of this embodiment, the primary thermocouple 26 and the secondary thermocouple 27 are provided.
By directly measuring and monitoring the combined electromotive force, incomplete combustion due to oxygen deficiency, fin clogging, or a combination thereof can be reliably prevented. Further, due to the secondary electromotive force of the secondary thermocouple 27 measured simultaneously at this time and the primary electromotive force of the primary thermocouple 26 calculated from the secondary electromotive force and the combined electromotive force, incomplete combustion is caused by oxygen deficiency. It is possible to quickly determine whether the object is due to fin blockage. Further, the user is notified of the cause of the incomplete combustion by turning on the non-combustion prevention lamp 43 in the case of insufficient oxygen and blinking the non-combustion prevention lamp 43 in the case of fin occlusion to notify the user. It is possible to perform optimal treatment according to the cause. Moreover, at this time, since one non-combustible lamp 43 informs whether the cause is the lack of oxygen or the fin is blocked, it is possible to suppress an increase in the cost of manufacturing the appliance.

In the above embodiment, as shown in FIG. 3, the input port PI ₉ (A / D conversion port) of the microcomputer 30 is provided with two divided resistors 3 as gas type switching resistors.
The partial pressure values of 9, 40 can be input. This is because a plurality of determination times T ₁ , T ₂ and determination electromotive forces Vr ₀ , Vr ₁ , Vr ₂ used in the above-described non-combustion prevention control are prepared in advance in accordance with the type of gas, and divided in accordance with the type of gas. Resistance 3
By replacing 9, 40, these determination times T ₁ , T ₂ and determination electromotive force Vr ₀ ,
By changing Vr ₁ and Vr ₂ , it is possible to determine an appropriate electromotive force according to the type of gas. Similarly, the input port PI ₁₀ (A / D conversion port) has a divided resistor 4 as a capacity switching interlocking resistor, one of which is a variable resistor 42.
It is possible to input the partial pressure values by the reference numerals 1 and 42. This also uses the above variable resistor to adjust the capability of the equipment (gas amount adjustment)
, The determination times T ₁ , T ₂ and the determination electromotive forces Vr ₀ , Vr ₁ ,
Vr ₂ is changed (for example, if the ability is small, the determination time is delayed and the determination electromotive force is reduced), so that an appropriate electromotive force can be determined according to the capability of the appliance.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments at all, and it goes without saying that the present invention can be carried out in various modes without departing from the gist of the present invention. is there. For example, in the present embodiment, the electromotive force of the secondary thermocouple 27 and the combined electromotive force are directly measured, and the electromotive force of the primary thermocouple 26 is calculated from the measured values. Although it is determined whether it is due to fin blockage, the electromotive force of the primary thermocouple 26 and the combined electromotive force are directly measured, and the electromotive force of the secondary thermocouple 27 is calculated from the value. It doesn't matter. Further, the primary electromotive force, the secondary electromotive force, and the combined electromotive force may be directly measured.
In addition, when it is determined that incomplete combustion is due to fin blockage, it is difficult for a general user to take the necessary measures, so that reuse of the appliance is prohibited (so-called interlock is applied. ). Further, the time begins to compare T ₁ and determining the electromotive force Vr ₂ secondary electromotive force V _2, but the time T ₂ to start comparing the resultant electromotive force V ₀ and the determination electromotive force Vr ₀ are then at different times However, the comparison may be started at the same time T.

Although the primary electromotive force is calculated from the directly measured secondary electromotive force and the combined electromotive force, the primary electromotive force need not be calculated. In this case, it is determined from the value of the combined electromotive force whether or not the combustion is incomplete, and from the value of the secondary electromotive force, it is determined whether or not the cause of the incomplete combustion is fin blockage. Nevertheless, when it is determined that the combustion is incomplete, it is determined that the incomplete combustion is due to lack of oxygen.

FIG. 8 shows a flowchart of the non-combustion prevention control in this case. Note that only different points from the above control will be described. In this control, without performing calculation for calculating the primary electromotive force V ₁ performed in S16 in the above-mentioned control, the primary electromotive force V
_The determination of oxygen deficiency by comparing ₁ with the determination electromotive force Vr ₁ is not performed. Instead, when it is determined in step 21 that the incomplete combustion is caused by comparing the combined electromotive force V ₀ with the determination electromotive force Vr ₀ , it is determined that incomplete combustion has occurred due to lack of oxygen, and in step S22, the incombustible lamp is controlled. 43 is turned on. Then, in S15, the supply of the holding current to the magnet solenoid valve 16 is stopped, the valve is closed, the supply of gas is cut off, and the control is terminated. In this case, incomplete combustion due to a combined factor of oxygen deficiency and fin blockage may be determined to be due to oxygen deficiency. In contrast, as the above-mentioned control, the cause of incomplete combustion when obtained by calculating the primary electromotive force V ₁ is be more accurately determinable whether closed or oxygen deficiency fins, reliability is increased. Conversely, based on only the primary electromotive force and the combined electromotive force, incomplete combustion and oxygen deficiency are determined, and when it is determined that there is no oxygen deficiency despite incomplete combustion, it is determined that the fin is clogged. It doesn't matter.

[0023]

As described in detail above, claim 1 of the present invention
According to the open-type gas burning appliance described, incomplete combustion can be detected with high reliability by the combined electromotive force of the first thermoelectric device and the second thermoelectric device, so that it can be used safely.
In addition, the incomplete combustion is caused by the lack of oxygen or the fin clogging of the heat exchanger due to the single electromotive force of the first thermoelectric element or the single electromotive force of the second thermoelectric element, or both of the single electromotive force and the combined electromotive force. Can be determined more quickly than a conventional appliance that determines from the difference in the rising characteristics of the combined electromotive force, and the combustion time in the incomplete combustion state can be shortened. For this reason, the risk of carbon monoxide poisoning can be suppressed even if the user performs an unreasonable use such as reusing the appliance many times even after the non-combustion prevention device operates.

Further, according to the open-type gas-burning apparatus according to the second aspect of the present invention, the single electromotive force that is not detected by the first thermoelectric element or the second thermoelectric element is obtained by calculation, so that the fin is closed. And oxygen deficiency can be more accurately determined, and the reliability increases.

[Brief description of the drawings]

FIG. 1 is a structural diagram of a water heater.

FIG. 2 is a schematic diagram of a water heater.

FIG. 3 is a block diagram of a control circuit in the controller.

FIG. 4 is a flowchart of ignition control and non-combustion prevention control.

FIG. 5 is a graph showing a change in rising of a combined electromotive force in a normal state.

FIG. 6 is a graph showing a change in rising of a combined electromotive force when oxygen is insufficient.

FIG. 7 is a graph showing a change in rising of a combined electromotive force when a fin is closed.

FIG. 8 is a flowchart of nonflammability prevention control.

FIG. 9 is a graph showing a change in rising of a combined electromotive force in a normal state.

FIG. 10 is a graph showing a change in rising of a combined electromotive force when oxygen is insufficient.

FIG. 11 is a graph showing a change in rising of a combined electromotive force when a fin is closed.

[Explanation of symbols]

1 ... water heater, 2 ... combustion chamber, 4 ... burner, 5 ... heat exchanger,
22: controller, 26: primary thermocouple, 27: secondary thermocouple, 30: microcomputer, 44: combustion chamber window.

Claims (2)

[Claims] A burner that burns fuel gas; a fin-tube heat exchanger that is provided above the burner and heats water flow with the combustion gas of the burner; A first thermoelectric element directly heated by the flame of the burner, and provided facing a combustion chamber window opened on a side wall of the combustion chamber between the burner and the heat exchanger, between the fins of the heat exchanger. Comprises a second thermoelectric element that is heated by the combustion gas overflowing from the combustion chamber window when closed due to adhesion of combustion products and the like, and the first thermoelectric element and the second thermoelectric element are connected in series and In an open-type gas-burning appliance for detecting the incomplete combustion of the burner based on the combined electromotive force obtained from the two thermoelectric elements by connecting the polarities in opposite directions, the single electromotive force of the first thermoelectric element or Second heat A single electromotive force of the element or both of them are detected together with the combined electromotive force. Based on the detected electromotive force, whether the incomplete combustion is due to lack of oxygen in the room due to poor ventilation or the like, the heat exchanger An open-type gas burning appliance characterized in that it is determined whether the fin is caused by a blockage between the fins. 2. A single electromotive force of one of the first thermoelectric element and the second thermoelectric element is detected, and a single electromotive force of the other thermoelectric element is calculated from the detected single electromotive force and a combined electromotive force. 2. The open-type gas burning appliance according to claim 1, further comprising a calculating means.