JPH11304144A - Open type gas combustor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To discriminate the cause of abnormal combustion by comparing a synthesized electromotive force with a preset decision level during a predetermined decision time immediately after ignition of a burner and then controlling the operating state of an apparatus based on the comparison results. SOLUTION: When a first decision time T1 elapsed after a flame is detected immediately after ignition of a burner (S11), a decision is made whether a synthesized electromotive force V exceeds a decision level V0 or not. If V is lower than V0 (S12), a decision is made that a flame has lifted or went out due to deficiency of oxygen and holding current supply to a magnet solenoid valve is stopped to close the valve thus interrupting gas supply (S7). It V exceeds V0 , a decision is made whether V is lower than V0 when a second decision time T2 is reached after flame detection (S13, S14). If V is lower than V0 , the time t when V is lower than V0 is determined and interlock request is delivered (S15, S16) before the solenoid valve is closed (S7).

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 the above-mentioned open-type gas-burning apparatus, for example, a main-stop type water heater, when the indoor ventilation is insufficient, or when the gap between the fins of the heat exchanger becomes blocked due to the adhesion of combustion products, the air-burning apparatus is closed. Is an incomplete combustion prevention device (hereinafter abbreviated as "non-combustion prevention device") which detects these in advance and shuts off the gas supply, because it is difficult to take in combustion air and may lead to incomplete combustion. Is provided. Specifically, the primary thermocouple installed near the burner of the water heater and the secondary thermocouple facing the combustion chamber window of the heat exchanger above the burner, so that the polarities are opposite. They are connected in series, and the combined electromotive force obtained here is directly used for holding a magnet solenoid valve provided in a gas flow path, or is monitored by a controller that controls opening and closing of the magnet solenoid valve.
Therefore, when the oxygen concentration in the room is decreasing, the electromotive force of the primary thermocouple is reduced due to the lift or extinguishing of the burner flame, and if the fin blockage of the heat exchanger progresses due to long-term use, As the electromotive force of the secondary thermocouple in the combustion chamber window increases due to the combustion exhaust heat, the combined electromotive force decreases in each case. Therefore, the magnet solenoid valve is closed directly or via a controller to supply gas. Will be shut off.

[0003]

Among the causes of the above incomplete combustion, in the case of clogging of the fin, if the fin is continuously used without performing maintenance, the clogging progresses and damages a heat exchanger or the like. Since there is a possibility that the flame may overflow into the outside of the combustion chamber, it is desirable to prohibit the reuse of the device (so-called interlock) after detecting this once.
However, in the above-described conventional non-combustible device, both the lack of oxygen in the room and the blockage of the fins are detected by the same decrease in the combined electromotive force, so that the two cannot be distinguished. However, if the interlock is applied regardless of the cause, if the oxygen is insufficient, ventilation can easily eliminate the cause of the combustion abnormality, and if reuse is prohibited until this case, the usability will be impaired Will be. Therefore, as in the case of the above-described non-combustible device, the supply of gas is temporarily interrupted, and the combustion must be stopped again by detecting a decrease in the combined electromotive force when the appliance is reused. However, at the time of this re-use, the non-combustible protection device does not operate until the electromotive force of the thermocouple rises and the combustion abnormality can be detected, so the equipment can be used during that time, and the fins may be blocked. In this case, the room air is generated by repeated use of this time.
More and more, and at the risk of CO poisoning. Further, the fins are blocked, which causes damage to the heat exchanger.

[0004] Therefore, the first aspect of the present invention provides an open-type gas burning appliance which distinguishes and detects the cause of a combustion abnormality such as oxygen deficiency or fin clogging, and can take appropriate measures according to the cause. It is intended for.

[0005]

In order to achieve the above object, the present invention is characterized in that the combined electromotive force is compared with a predetermined determination electromotive force at a predetermined determination time immediately after the burner ignition. And operation control means for controlling the operation state of the appliance based on the comparison result by the comparison means. In addition to the object of claim 1, the invention according to claim 2 performs the comparison by the comparison means in order to ensure the distinction between the oxygen deficiency and the fin occlusion and to take appropriate measures according to each. Performed during the first determination time before the rise of the combined electromotive force and the second determination time thereafter, and when the combined electromotive force is smaller than the determination electromotive force in the first determination time, the operation control unit stops burning the burner. And if the combined electromotive force is smaller than the determined electromotive force during the second determination time, the operation control means may control the burner. To stop the burning of the equipment and to prohibit reuse of the equipment. According to the third aspect of the present invention, in addition to the object of the second aspect, in order to eliminate erroneous detection due to an accidental decrease in the combined electromotive force and enhance the reliability of the fin blockage detection, the comparison in the second determination time is performed. In this case, the reuse of the appliance is prohibited only when the time during which the combined electromotive force is lower than the determination electromotive force is equal to or longer than a predetermined time. According to the invention described in claim 4, in addition to the object of claim 2 or 3, even if the reuse of the device is prohibited, the device may be usable depending on the capability of the device. for,
An appliance capability storage unit that stores the capability of the appliance when the reuse of the appliance is prohibited, and an appliance capability detection unit that can detect the capability of the appliance that can be arbitrarily switched, wherein the reuse of the appliance is prohibited. In this state, when the appliance capability detecting unit detects a capability smaller than the capability stored by the appliance capability storage unit, the prohibition of reuse of the appliance is released.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a structural diagram of a main stop type water heater (hereinafter, referred to as “water heater”) as an open-type gas burning appliance. FIG. 2 is a schematic diagram thereof.
A heat exchanger 5 that heats water from a water supply pipe 3 connected to a water supply system with the combustion heat of a burner 4 and sends out the hot water from a tapping pipe 6.
A water faucet 9 whose opening and closing is controlled via a lever 8 by pressing an operation button 7 and a primary pressure chamber 11 of a diaphragm 10 are arranged upstream of the water supply pipe 3.
A venturi 13 formed downstream of 1 is connected to a secondary pressure chamber 12 of the diaphragm 10 via a differential pressure tube 14. A protruding rod 15 is connected to the diaphragm 10. When water is passed through the water supply pipe 3 by opening the faucet 9, the pressure in the secondary pressure chamber 12 is reduced by the water flowing through the venturi 13. When the diaphragm 10 moves down to the secondary pressure chamber 12 side below the primary pressure chamber 11, the protruding rod 15 is interlocked with the operation, and the magnet solenoid valve 16 arranged in the gas flow path to the burner 4 opens. The valve mechanism 16a is operated to open it, and then the hydraulic pressure responsive valve 17 is opened. In addition, 19 and 20 are interlocked with the operation of the protruding rod 15, respectively,
A water pressure switch 21 that is sequentially turned on in accordance with the opening of the magnet solenoid valve 16 and the water pressure responsive valve 17,
Each of the ON signals is input to the controller 22 by a lever switch which is turned ON via the lever 8 in accordance with the pressing operation of the button. Further, an instrument plug 1 that opens when the operation button 7 is pressed is located downstream of the water pressure responsive valve 17 in the gas flow path.
8 are provided. On the other hand, the controller 22 is connected to an ignition electrode 23 for igniting the burner 4, an igniter 24, and a flame rod 25 for detecting a flame.
A primary thermocouple 26 as a first thermoelectric element provided in the vicinity of a sensing burner 4a provided in parallel with the second thermocouple provided above the burner 4 and facing an inner trunk window below the heat exchanger 5 in the combustion chamber 2 above the burner 4. The secondary thermocouple 27 as an element
The (+) and (-) polarities are connected in series with the polarities reversed, and the combined electromotive force of the primary and secondary thermocouples 26 and 27 is input to the controller 22. In addition, 28 is a dry battery and 29 is an LED lamp.

FIG. 3 is a block diagram of a control circuit in the controller 22. Here, a microcomputer (hereinafter referred to as "microcomputer") having a reset circuit 31 for monitoring the minimum compensation voltage of the battery voltage and a clock circuit 32 for original oscillation. ) Is used to perform ignition control and incomplete combustion prevention control, which will be described later.
I), a lever switch 21, a water pressure switch 1
9 and 20 ON signal and dry cell 28 voltage monitoring circuit 33
And a flame detection circuit 34 for detecting a current value of the frame rod 25, and an electromotive force determination circuit 35 for detecting a combined electromotive force of the primary thermocouple 26 and the secondary thermocouple 27. , A detection and determination signal of the combustion state of the burner 4 is input. On the other hand, an ignition circuit 36 for operating the igniter 24 and an electromagnetic valve driving circuit 37 for supplying an attraction and holding current to the magnet electromagnetic valve 16 are connected to each output port (indicated by PO). The operation is controlled according to the output.

The operation of the water heater 1 configured as described above will be described with reference to the flowchart of FIG. First, when the operation button 7 is pressed, in S1, the lever switch 21 is turned ON, and the instrument tap 18 and the faucet 9 open respectively.
As described above, the magnet solenoid valve 16 is also opened by the operation of the protruding rod 15 accompanying the flow of water through the water supply pipe 3, and water is flowed into the device. Next, in S2, the water pressure switch 1
When 9 is turned on, in S3, it is determined whether or not the battery voltage input from the voltage monitoring circuit 33 is 2.1 V or more. If the voltage is lower than 2.1 V, the LED lamp 29 is turned on at S4.
Lights up. On the other hand, if the voltage is 2.1 V or more, the igniter 24 is operated in S5 to continuously spark the ignition electrode 23, and the attraction current 1 is supplied to the magnet solenoid valve 16. Next, in the determination of S6, the ON signal of the hydraulic pressure switch 20 at the same time as the opening of the hydraulic pressure response valve 17 by the protruding rod 15 is confirmed. This ON signal is obtained within 2 seconds from the ON of the hydraulic pressure switch 19 in S2. If not, the igniter 24 is turned off in S7 to close the magnet solenoid valve 16,
The ignition control is terminated. On the contrary, the water pressure switch 20 is turned on.
If a signal is properly obtained, it is determined that gas is supplied by opening the hydraulic pressure responsive valve 17 and only the igniter 24 is turned off in S8.
FF. In this way, the burner 4 is ignited, and when the combustion of the burner 4 is confirmed from the flame rod 25 via the flame detection circuit 34 in S9, the adsorption current to the magnet solenoid valve 16 is reduced to the holding current 2 in S10. If an ignition error or extinguishment occurs, a flame detection signal cannot be obtained in S9.
The microcomputer 30 stops the supply of the attracting current to the magnet solenoid valve 16 by the output to the solenoid valve drive circuit 37, closes the magnet solenoid valve 16, and shuts off the gas supply (S7).

Subsequently, after the above-described ignition control, the microcomputer 30 determines whether the primary thermocouple 26 and the secondary thermocouple 2 are input at the rising edge.
7 is monitored via an electromotive force determination circuit 35, and in order to prevent incomplete combustion due to lack of oxygen in the room or clogging of the fins of the heat exchanger 5, incomplete combustion prevention control of S11 and below. (Hereinafter, abbreviated as “non-combustion prevention control”). First, in S11, it is determined whether the flame detection of S9 or has passed the T ₁ first determination time. When the first determination time T ₁ has been reached, in the next S12, the combined electromotive force V obtained here
Is greater than or equal to the determination electromotive force V _O. Synthetic electromotive force V
Is lower than the determination electromotive force V _O , it is determined that the lift or extinguishment of the flame due to lack of oxygen has occurred, and the supply of the holding current to the magnet solenoid valve 16 is stopped in S7 to close the valve. Shut off supply. On the other hand, synthetic electromotive force V is equal to or determined electromotive force V _O or, in the next S13, it is determined whether the flame detection of S9 or have passed the second determination time T _2.
Once you reach the second determination time T _2, at S14, again resultant electromotive force V is determined whether or not the determined electromotive force V _O is less than. If the combined electromotive force V is lower than the determination electromotive force V _O , the process proceeds to S15
It is checked whether or not the time t below this is equal to or longer than the predetermined time Δt. If the time t is equal to or longer than Δt, an interlock request is output in S16 assuming that the fin is blocked, and the magnet solenoid valve in S7 is output. The valve of No. 16 is closed to prohibit the subsequent use of the device (interlock). If this oxygen deficiency or fin blockage does not occur, combustion is continued. However, in S17, the hydraulic pressure switch 19 in S2 is used.
When it is confirmed that 20 minutes have passed after the detection of ON, at S7, the magnet electromagnetic valve 16 is closed, and a fire extinguishing timer for automatically extinguishing the burner 4 is activated.

The reason why the determination of the combined electromotive force V is made twice in the first determination time T ₁ and the second determination time T ₂ is as follows. Figure 5 (heating from the water, the so-called cold start) used at the start of the instrument electromotive force V ₁ of the primary thermocouple 26 in electromotive force V ₂ and the secondary thermocouple 27, a change in the resultant electromotive force V, The cases of oxygen shortage (A) and the case of fin blockage of the heat exchanger 5 (B) are shown separately. As is clear here, in the case of oxygen shortage, the electromotive force V of the primary thermocouple is shown. for ₁ rising slow, resultant electromotive force V is gradually increased, never reaching the first determination time T ₁ in determining the electromotive force V _O. On the other hand, in the case of the fins closed, slow rise of the electromotive force V ₂ also secondary thermocouple 27 from the electromotive force V ₁ of the primary thermocouple 26, resultant electromotive force V
Shows a rapid rise to reach the determination electromotive force V _O within the first determination time T ₁ , but tends to fall toward a peak on the way with the rise of the electromotive force V ₂ . Therefore, by detecting that the combined electromotive force V falls below the determination electromotive force V _O at the second determination time T ₂ from the difference in the change of the combined electromotive force V, it is possible to distinguish the case from the case of oxygen shortage. It was done. In the above S15, the condition that the time t lower than the determination electromotive force V _O in the second determination time T ₂ is equal to or longer than the predetermined time Δt is that accidental combined electromotive force V such as fluctuation of flame due to wind.
This is to eliminate erroneous detection due to a decrease in the number.

As described above, in the above-described embodiment, attention is paid to the fact that a difference in the rise of the combined electromotive force V due to lack of oxygen and fin clogging with time is observed, and this difference is detected by the determination time. By doing so, the cause of the combustion abnormality can be distinguished. Therefore, in the case of fin obstruction, interlock is applied to prohibit reuse of equipment and safety is ensured.On the other hand, in the case of oxygen shortage, combustion is stopped temporarily without interlock, and the equipment is ventilated. It is possible to take appropriate measures according to the cause of the abnormal combustion, such as reusability of the fuel cell and ensuring of usability. In particular, in the detection of fin blockage, the condition that the combined electromotive force V is lower than the determination electromotive force V _O by a predetermined time ΔT or more is conditioned, so that erroneous detection due to an accidental decrease in the combined electromotive force V is eliminated. The fin blockage can be detected, and the reliability of the non-combustion prevention control increases.

On the other hand, in the above-described embodiment, as shown in FIG. 3, the divided voltage by the two divided resistors 38 and 39 can be input to the input port PI ₈ (A / D conversion port) of the microcomputer 30. . This is because a plurality of first and second determination times T ₁ and T ₂ and a determination electromotive force V _O used for the above-described non-combustion prevention control are prepared in advance in accordance with the type of gas, and the dividing resistor 39 is set according to the type of gas. By changing, the judgment times T ₁ , T ₂ and the judgment electromotive force V _O are changed in accordance with the difference of the input partial pressure value, and it is possible to judge an appropriate combined electromotive force according to the type of gas. It is what it was. Similarly, to the input port PI ₉ (A / D conversion port), it is possible to input a divided voltage value by divided resistors 40 and 41 each having a variable resistor 41. This is for changing the variable resistor 41 in conjunction with the adjustment of the capacity of the equipment (adjustment of the gas amount) to detect the performance of the equipment, and to store the performance when the interlock is applied in the non-combustible control. Specifically, as shown in FIG. 6, in the non-combustion prevention control (S1) from S9 to S16 in FIG. 4, when the interlock is applied in S2, the capability at the time of stop is stored. afterwards,
When the capability switching operation of the appliance is confirmed in S3, the subsequent S4
Then, it is determined whether or not the switching value of the switched ability is smaller than the storage value of the ability stored in S2. If the switching value is equal to or greater than the storage value, the interlock of S2 is continued. In step S5, control is performed to release the interlock and enable use of the device. The reason for releasing the interlock by ability in this way is that
Even if it is necessary to prohibit the use of equipment at or above the capacity at the time of the interlock, it is safe to use the equipment at a lower capacity. This is to improve usability as much as possible. Of course, even in the case of this reuse, since the ignition control and the non-combustion prevention control of FIG. 4 are executed, the second determination time T
_{When the} combined electromotive force V falls below the determination electromotive force V _O by a predetermined time Δt or more in 2, the interlock is applied. Therefore, the reusable ability gradually decreases with each interlock, and can always be used in the safety zone.

As a specific structure of the device capability detecting means, as shown in FIG. 7, a capability switching shaft 42 arranged in a gas flow path to the burner 4 is rotated via a capability switching lever (not shown). Thus, in the case of adjusting the gas amount by adjusting the opening degree of the hole diameter formed in the capacity switching shaft 42,
A semi-fixed volume 45 is coaxially connected by a mounting plate 44 to a dial gauge 43 coaxially fixed to the capacity switching shaft 42 and connected to the controller 22 as a variable resistor. 4
A structure for rotating 5 is conceivable. According to this, since the resistance value continuously changes integrally with the rotation of the performance switching shaft 42, the tool performance can be accurately detected. In place of the semi-fixed volume 45, as shown in FIG. 8, a micro switch 48 is disposed above a cam-shaped dial gauge 46 via a mounting plate 47, and a switch plate 49 of the micro switch 48 is dialed. By contacting the cam 46a at a predetermined rotational position of the gauge 46, the micro switch 48 is turned on.
A configuration is also conceivable in which N is input to the microcomputer 30.
In this case, the instrument capability is detected by the ON signal of the micro switch 48, and this time is set as a threshold value at which the interlock is released and the apparatus can be used. It should be noted that a plurality of the microswitches 48 may be provided to set a plurality of rotation positions of the dial gauge 46 which is turned on by coming into contact with the cam 46a to detect the capability of the device stepwise.

[0014]

According to the first aspect of the present invention, a comparison means for comparing the combined electromotive force with a predetermined judgment electromotive force at a predetermined judgment time immediately after the burner ignition, and a comparison result by the comparison means And the operation control means for controlling the operation state of the appliance based on the above, it is possible to detect the difference in the change of the combined electromotive force for each cause of the combustion abnormality in the determination time, so that the cause of the combustion abnormality Accordingly, appropriate measures can be taken in consideration of safety and usability. According to the second aspect of the present invention, in addition to the effect of the first aspect, the combustion of the burner is stopped when the combined electromotive force is smaller than the determined electromotive force in the first determination time by the comparison of the comparing means, And, when the combined electromotive force is larger than the determination electromotive force, and when the combined electromotive force falls below the determination electromotive force in the second determination time, the burner is stopped and the appliance is prohibited from being reused. In addition, the lack of oxygen in the room and the blockage of the fins can be reliably distinguished and detected, and appropriate measures can be taken in consideration of usability in the case of lack of oxygen and safety in the case of blockage of the fins. According to the third aspect of the present invention, in addition to the effect of the second aspect, during the comparison in the second determination time, the appliance is reused only when the time during which the combined electromotive force is lower than the determination electromotive force is equal to or longer than a predetermined time. Is prohibited, erroneous detection due to an accidental decrease in the combined electromotive force can be eliminated, and the reliability of fin blockage detection can be improved. According to a fourth aspect of the present invention, in addition to the object of the second or third aspect, the apparatus further comprises the appliance capability storage unit and the appliance capability detection unit. When a small ability is detected, the prohibition of reuse of the device is released, so that the device can be used in the safety zone and the usability can be improved.

[Brief description of the drawings]

FIG. 1 is a structural view 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. 5A is a graph showing a change in rising of a combined electromotive force when oxygen is insufficient. (B) A graph showing a change in rising of a combined electromotive force in the case of fin blockage.

FIG. 6 is a flowchart of the interlock release control based on the instrument ability.

FIG. 7 is an explanatory diagram showing a structure for detecting instrument performance using a semi-fixed volume.

FIG. 8 is an explanatory diagram showing a structure for detecting instrument performance using a microswitch.

[Explanation of symbols]

1. hot water heater, 2. combustion chamber, 4. burner, 5. heat exchanger, 7. operation button, 16. magnet solenoid valve, 22. controller, 26. primary thermocouple, 27
..Secondary thermocouple, 30..microcomputer, 35..electromotive force determination circuit, 37 .. solenoid valve drive circuit.

Claims (4)

[Claims] 1. A first thermoelectric element arranged near a burner and detecting a flame of the burner, and a second thermoelectric element arranged above the burner and detecting combustion exhaust heat by the burner in series. And an open-type gas burning appliance in which the polarity is connected in the opposite direction and the burning state of the burner can be detected by a combined electromotive force obtained from the two thermoelectric elements, wherein the burning condition is determined at a predetermined determination time immediately after the burner ignition. An open-type gas comprising: comparison means for comparing the combined electromotive force with a predetermined determination electromotive force; and operation control means for controlling an operation state of the appliance based on a comparison result by the comparison means. Burning appliances. 2. The method according to claim 1, wherein the comparison is performed by a first determination time before the rise of the combined electromotive force and a second determination time after the rise, and the combined electromotive force is smaller than the determined electromotive force in the first determination time. The operation control means stops the combustion of the burner and makes it reusable.If the combined electromotive force is larger than the determination electromotive force, the combined electromotive force further reduces the determination electromotive force in the second determination time. The open gas combustion appliance according to claim 1, wherein the operation control means stops combustion of the burner and prohibits reuse of the appliance when the temperature falls below the predetermined value. 3. The open-type gas-burning appliance according to claim 2, wherein during the comparison in the second determination time, the reuse of the appliance is prohibited only when the time during which the combined electromotive force is lower than the determination electromotive force is a predetermined time or more. 4. An appliance capability storage unit for storing the capability of the appliance when the reuse of the appliance is prohibited, and an appliance capability detection unit capable of detecting the capability of the appliance that can be switched arbitrarily, and 4. The apparatus according to claim 2, wherein in a state in which reuse is prohibited, when the appliance capability detection unit detects a capability smaller than the capability stored by the appliance capability storage unit, the prohibition of reuse of the appliance is released. 5. Open-type gas burning appliances.