JP3881774B2 - Open gas combustion appliance - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an open-type gas combustion appliance such as a non-stop type water heater that takes combustion air from the room and discharges the combustion gas into the room as it is.
[0002]
[Prior art]
In the above open-type gas combustion appliance, for example, a water heater, the air for combustion is used when the indoor ventilation is insufficient or the gap between the fins of the heat exchanger is clogged due to adhesion of combustion products. Incomplete combustion prevention device (hereinafter abbreviated as “non-combustion prevention device”) that detects gas in advance and shuts off the gas supply is provided. The Specifically, the polarity of 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 are reversed. The combined electromotive force obtained in series is directly used for holding a magnet electromagnetic valve provided in the gas flow path, or is monitored by a controller that controls opening and closing of the magnet electromagnetic valve. Therefore, when the oxygen concentration in the room has decreased, the electromotive force of the primary thermocouple decreases due to the lift and extinguishment of the flame of the burner, and when the fin closure of the heat exchanger has progressed due to long-term use, Since the combined electromotive force is lowered by increasing the electromotive force of the secondary thermocouple in the combustion chamber window due to the combustion exhaust heat, the magnet solenoid valve is closed directly or via the controller to supply gas. Will be cut off.
[0003]
[Problems to be solved by the invention]
Among the causes of the above incomplete combustion, if the fin is blocked, if it continues to be used without maintenance, the blockage will proceed and damage the heat exchanger, etc., or the flame may overflow outside the combustion chamber. Therefore, once this is detected, it is desirable to prohibit the reuse of the appliance (so-called interlock).
On the other hand, in the case of lack of oxygen, the cause of the combustion abnormality can be easily solved by ventilating the room. If re-use is prohibited up to this point, the usability may be impaired. However, in the conventional non-combustion preventive 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 it is not possible to distinguish between them. The supply of gas is temporarily cut off, and when the instrument is reused, a decrease in the synthetic electromotive force is detected again to stop the combustion. However, during this reuse, the incombustibility prevention device does not work during the time until the electromotive force of the thermocouple rises and the combustion abnormality can be detected. If it has occurred, the blockage proceeds by repeated use of this time, and the heat exchanger is damaged. During this time, the indoor air is polluted by the generated CO every time it is used, so there is a risk of CO poisoning.
[0004]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an open-type gas combustion instrument that can reliably detect the cause of combustion abnormality and can take appropriate measures in accordance with the cause. .
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 individually monitors information obtained by the first detection means for detecting the flame of the burner and the second detection means for detecting the combustion exhaust heat of the burner. When each of the detection means detects a combustion abnormality of the burner, each of the operation prohibiting means stops the combustion of the burner and prohibits the use of the appliance. An abnormality detection determination means for determining whether the detection is due to the means, and a timer means for counting the use prohibition time of the appliance, and when it is determined that the detection of the combustion abnormality is due to the first detection means, The use prohibition is canceled when the use prohibition time reaches a predetermined time.
In addition to the object of claim 1, the invention described in claim 2 uses a thermoelectric element for each of the first and second detection means in order to improve detection accuracy by each detection means. The electromotive force is compared with an individual determination electromotive force set in advance at a predetermined determination time.
In addition to the object of claim 2, the invention described in claim 3 provides the determination time and / or the determination electromotive force as the capability of the instrument or the fuel in order to perform a comparison with the determination time and the determination electromotive force set appropriately. It can be changed according to the type of gas.
According to a fourth aspect of the present invention, in addition to the object of any one of the first to third aspects of the present invention, the burner is equipped with a forgetting timer for stopping the burner combustion when the burner continuous combustion time reaches a set time. In order to effectively prevent the risk of CO poisoning due to reuse, when the continuous combustion time of the burner reaches a set time, the operation prohibiting means stops the burning of the burner and prohibits the use of the instrument. When the use prohibition time of the appliance reaches a predetermined time by counting the means, the use prohibition is canceled.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described 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 combustion appliance, FIG. 2 is a schematic view thereof, and the water heater 1 is disposed in the combustion chamber 2. A heat exchanger 5 that heats the water from the water supply pipe 3 connected to the water supply with the combustion heat of the burner 4 and sends it out as hot water from the hot water discharge pipe 6 is provided upstream of the water supply pipe 3 by pressing the operation button 7. A faucet 9 that is controlled to open and close via a lever 8 and a primary pressure chamber 11 of the diaphragm 10 are arranged, and a venturi 13 formed downstream of the primary pressure chamber 11 is connected to the secondary pressure of the diaphragm 10 via a differential pressure pipe 14. It is connected to the chamber 12. Further, a projecting rod 15 is connected to the diaphragm 10, and when water is passed through the water supply pipe 3 by opening the faucet 9, the pressure in the secondary pressure chamber 12 is caused by water passing through the venturi 13. When the diaphragm 10 moves to the secondary pressure chamber 12 side after being lowered from the primary pressure chamber 11, the projecting rod 15 is interlocked with the operation and the magnet electromagnetic valve 16 disposed in the gas flow path to the burner 4 is opened. The valve mechanism 16a is operated to open it, and then the water pressure responsive valve 17 is opened. Reference numerals 19 and 20 are water pressure switches that are sequentially turned on in conjunction with the opening of the magnet solenoid valve 16 and the water pressure responsive valve 17 in conjunction with the operation of the projecting rod 15, and 21 is associated with the pressing operation of the operation button 7. Each ON signal is input to the controller 22 by a lever switch that is turned on via the lever 8. Further, an instrument plug 18 that opens when the operation button 7 is pushed is provided on the downstream side of the water pressure responsive valve 17 in the gas flow path.
On the other hand, an ignition electrode 23 for igniting the burner 4, an igniter 24, and a flame detection frame rod 25 are connected to the controller 22, and first detection means provided in the vicinity of the sensing burner 4 a provided to the burner 4. And a secondary thermocouple 27 as second detecting means provided above the burner 4 so as to face the inner shell window below the heat exchanger 5 in the combustion chamber 2. 22, and each electromotive force is input to the controller 22. In addition, 28 is a dry cell and 29 is an LED lamp.
[0007]
FIG. 3 is a block diagram of a control circuit in the controller 22. Here, a microcomputer (hereinafter abbreviated 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. 30) is used to perform ignition control and incomplete combustion prevention control, which will be described later. In each input port (indicated by PI), the ON signal of the lever switch 21, the water pressure switches 19, 20 and the dry battery 28 A voltage detection signal from the voltage monitoring circuit 33 is input, a flame detection circuit 34 that detects the current value of the frame rod 25, a primary electromotive force determination circuit 35 that detects the electromotive force of the primary thermocouple 26, and two The combustion state detection and determination signals of the burner 4 are input via the secondary electromotive force determination circuit 36 that detects the electromotive force of the secondary thermocouple 27. On the other hand, each output port (indicated by PO) is connected to an ignition circuit 37 for operating the igniter 24 and an electromagnetic valve drive circuit 38 for supplying adsorption and holding current to the magnet electromagnetic valve 16. The operation is controlled according to the output.
[0008]
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 pushed, the lever switch 21 is turned ON in S1, and the appliance plug 18 and the water tap 9 are opened, and the operation of the projecting rod 15 accompanying the water flow through the water supply pipe 3 as described above. As a result, the magnet solenoid valve 16 is also opened, and water is passed into the instrument. Next, when the water pressure switch 19 is turned on with the operation of the projecting rod 15 in S2, it is determined whether or not there is an interlock request 1 in S3. That is, whether or not the operation is prohibited is confirmed. Request 1 is due to an interlock for oxygen deficiency detection described later. If interlock claim 1 wherein the determination, in S4, it is determined whether or not the interlock from the time T ₃ has elapsed. When not reached the T ₃ where time, subsequent control is not performed, the magnet solenoid valve 16 in step S5 is turned OFF, the interlock is continued. On the other hand, if the elapsed time T _3, at S6, it is determined whether there is an interlock request 2. This request 2 is due to the interlock of fin blockage detection described later. If there is an interlock request 2 in this determination, the interlock is continued as it is in S5.
[0009]
On the other hand, if there is no interlock request 2 in the determination in S6, it is determined in next S7 whether or not the battery voltage input from the voltage monitoring circuit 33 is 2.1 V or higher. If the voltage is below 2.1 V, the LED lamp 29 is turned on in S8. On the other hand, if it is 2.1 V or more, the igniter 24 is operated in S9 to cause the ignition electrode 23 to continuously spark, and the magnet electromagnetic valve 16 is energized with the adsorption current 1. Next, in S10, the ON signal of the water pressure switch 20 at the same time as the opening of the water pressure responsive valve 17 by the projecting rod 15 is confirmed. This ON signal is obtained within 2 seconds from the ON of the water pressure switch 19 in S2. If not, the igniter 24 is turned off in S5, the magnet electromagnetic valve 16 is closed, and the ignition control is terminated. On the other hand, if the ON signal of the water pressure switch 20 is properly obtained, only the igniter 24 is turned off in S11 because the gas is supplied by opening the water pressure responsive valve 17. When the burner 4 is ignited in this way and combustion of the burner 4 is confirmed from the frame rod 25 via the flame detection circuit 34 in S12, the adsorption current to the magnet electromagnetic valve 16 is lowered to the holding current 2 in S13. Note that if an ignition error or extinction occurs, a flame detection signal cannot be obtained in S12, so the microcomputer 30 stops supplying the adsorption current to the magnet solenoid valve 16 by the output to the solenoid valve drive circuit 38, and the magnet solenoid valve. 16 is closed to shut off the gas supply (S5).
[0010]
Subsequently, after the ignition control, the microcomputer 30 is input via the primary electromotive force determination circuit 35 and the secondary electromotive force determination circuit 36 by the rising of the electromotive force of the primary thermocouple 26 and the secondary thermocouple 27, respectively. In order to prevent the occurrence of incomplete combustion due to insufficient oxygen in the room or the fin blockage of the heat exchanger 5 by individually monitoring the determination signal, the incomplete combustion prevention control (hereinafter referred to as “non-combustion prevention control”) of S14 and below. ) Is running.
First, in S14, it is determined whether the flame detection in S12 or has passed the T ₁ first determination time. Once you reach the first determination time T _1, in the next S15, the primary electromotive force v ₁ obtained from the primary thermocouple 26, to determine whether the determination electromotive force V ₁ or more. As shown in FIG. 5 (A), the rise of the primary electromotive force v ₁ of the primary thermocouple 26 is normal when the use is started in an oxygen-deficient state in the room (heating from water, so-called cold start). Since it gradually rises later than the rising edge v _o , it is possible to detect oxygen shortage by confirming whether or not the judgment electromotive force V ₁ has been reached at the first judgment time T ₁ . Therefore, if NO, that is, if the primary electromotive force v ₁ is lower than the determination electromotive force V ₁ , it is assumed that a flame lift or extinguishment due to lack of oxygen has occurred, and an interlock request 1 is output in S16, and in S5 The supply of the adsorption current to the magnet electromagnetic valve 16 is stopped and the valve is closed to prevent the instrument from being reused (interlock). On the other hand, if the primary electromotive force v ₁ is equal to or greater than the determination electromotive force V _1, it is determined in the next S17 whether or not the second determination time T ₂ has elapsed since the flame detection. Once you reach the second determination time T _2, at S18, in turn secondary electromotive force v ₂ obtained from the secondary thermocouple 27, to determine whether the determination electromotive force V ₂ or more. As shown in FIG. 5B, in the case of the start of use in the closed state of the fin (cold start), the rise of the secondary electromotive force v ₂ of the secondary thermocouple 27 is earlier than the normal rise v _o , Since it rapidly rises, it is possible to detect the fin blockage by confirming whether or not the determination electromotive force V ₂ has been reached at the second determination time T ₂ . Thus, where YES, that is if the secondary electromotive force v ₂ is determined electromotive force V ₂ or more, as by clogging of the fin closing magnet solenoid valve 16 in S5 and outputs an interlock request 2 in S19 And prohibit the reuse of equipment. Note that if fin blockage is not detected in S18, combustion continues, but if 20 minutes elapse after S2 detection of the water pressure switch 19 is detected in S20, the magnet solenoid valve 16 is closed. The forgetting-off timer that automatically extinguishes the burner 4 is activated. At this time, the interlock request 1 is issued in S16 and the burner 4 is extinguished. and, only available when confirming the passage of time T ₃ in the determination of S4. Therefore, it is not immediately reused after the operation of the forgetting-off timer, and a CO poisoning accident due to continuous reuse can be effectively prevented.
[0011]
As described above, in the above embodiment, the electromotive force of the primary thermocouple 26 and the secondary thermocouple 27 is individually monitored, so that oxygen deficiency and fin clogging are reliably detected and interlock is applied. Countermeasures are possible. However, in the case of oxygen deficiency, considering that the cause of prohibition of reuse by indoor ventilation is eliminated, it is determined here whether the interlock is due to oxygen deficiency or fin blockage. In the case of an interlock due to a shortage, as long as the time T _{3 has} passed as in S3 to S6 above, usability is ensured as a time-limited interlock that allows the instrument to be reused. Therefore, it is possible to take appropriate measures according to the cause of the combustion abnormality.
Further, here, the determination electromotive force of the primary thermocouple 26 primary electromotive force v ₁ and the secondary thermocouple 27 of the secondary electromotive force v _2, V _1, V ₂ and since the set individually In addition, it is possible to set an appropriate determination level according to oxygen deficiency and fin blockage, and to improve detection accuracy.
[0012]
In the above embodiment, as shown in FIG. 3, the divided voltage values by the two divided resistors 39 and 40 can be input to the input port PI ₉ (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 determination electromotive forces V ₁ and V ₂ used for the incombustible prevention control are prepared in advance according to the type of gas, and according to the type of gas. By changing the dividing resistor 40, the judgment times T ₁ and T ₂ and the judgment electromotive forces V ₁ and V ₂ are changed according to the difference in the input partial pressure value, so This makes it possible to determine the electromotive force.
Similarly, the input port PI ₁₀ (A / D conversion port) can be input with a divided voltage value obtained by the divided resistors 41 and 42, one of which is a variable resistor 42. In this case, the variable resistor 42 is changed in conjunction with the instrument capacity adjustment (gas amount adjustment), so that the determination times T ₁ and T ₂ and the determination electromotive force V ₁ , V ₂ is changed (for example, if the capacity is small, the determination time is delayed and the determination electromotive force is reduced), and the appropriate electromotive force can be determined according to the ability of the appliance.
Further, in the non-combustible explosion control shown in the above embodiment, although the respective separate time to be compared with the primary electromotive force v ₁ and the secondary electromotive force v ₂ and the determination electromotive force (S14,17), a comparison at the same time You can go. Furthermore, the interlock timer time T ₃ due to the lack of oxygen can be changed in accordance with the instrument capacity, the combustion time, and the like.
[0013]
【The invention's effect】
According to the first aspect of the present invention, the information from the first detection means and the second detection means is individually monitored, and when the combustion abnormality of the burner is detected, the combustion of the burner is stopped. In the case where the detection of combustion abnormality is detected by the first detecting means, the use of the fin is preferably closed by releasing the use prohibition when the use prohibition time of the tool reaches a predetermined time. If there is a combustion abnormality due to a non-existing cause, the use of the equipment can be definitely prohibited and safety will be improved, while if a combustion abnormality such as lack of oxygen occurs, the use of a time limit will be prohibited. When the cause is resolved by ventilation, it can be reused, ensuring usability. Therefore, it is possible to take appropriate measures according to the cause of the combustion abnormality.
According to the second aspect of the present invention, in addition to the effect of the first aspect, the first and second detection means each use a thermoelectric element, and the electromotive force is set in advance at a predetermined determination time after burner ignition. By adopting a configuration for comparing with each of the determined individual electromotive forces, an appropriate determination electromotive force can be set according to the cause of the combustion abnormality to be detected, and highly accurate combustion abnormality detection can be performed.
According to the third aspect of the present invention, in addition to the effect of the second aspect, the determination time and / or the determination electromotive force can be changed according to the capability of the instrument or the type of fuel gas. Or a comparison in which the judgment electromotive force is set appropriately.
According to the invention described in claim 4, in addition to the effect of any one of claims 1 to 3, when the burner continuous combustion time reaches the set time, the operation prohibiting means stops the burner combustion. While prohibiting the use of appliances, if the use prohibition time of the appliance reaches a predetermined time due to the counting of the timer means, the use prohibition is canceled to prevent continuous reuse even after the forgetting-off timer has worked. Can be secured.
[Brief description of the drawings]
FIG. 1 is a structural diagram of a water heater.
FIG. 2 is a schematic view 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 changes in rising of primary electromotive force when oxygen is insufficient.
(B) It is a graph which shows the change of the rise of secondary electromotive force in the case of fin obstruction | occlusion.
[Explanation of symbols]
1 .. Water heater, 2 .... Combustion chamber, 4 .... Burner, 5 .... Heat exchanger, 7 .... Controller, 16 .... Magnet solenoid valve, 26 .... Primary thermocouple, 27 ... Secondary thermoelectric Pair of 30 ... microcomputer, 35 ... primary electromotive force judgment circuit, 36 ... secondary electromotive force judgment circuit, 38 ... solenoid valve drive circuit.

Claims (4)

Open type equipped with first detection means for detecting flame of the burner, second detection means for detecting combustion exhaust heat by the burner, and operation prohibiting means for stopping the burner and prohibiting subsequent use A gas burning appliance,
The information obtained by the first detection means and the second detection means is individually monitored, and when the combustion abnormality of the burner is detected by the detection means, the operation prohibiting means respectively performs combustion of the burner. And prohibiting the use of the appliance, while providing an abnormality detection discriminating means for discriminating which detection means the combustion abnormality is detected, and a timer means for counting the usage prohibition time of the appliance, An open-type gas combustion appliance, wherein when it is determined that detection of combustion abnormality is caused by the first detection means, the prohibition of use is canceled when the use prohibition time of the appliance reaches a predetermined time. 2. The open circuit according to claim 1, wherein the first and second detection means each use a thermoelectric element and compare the electromotive force with an individual determination electromotive force set in advance at a predetermined determination time after burner ignition. Mold gas burning appliance. The open type gas combustion appliance according to claim 2, wherein the determination time and / or the determination electromotive force can be changed according to the capability of the appliance or the type of fuel gas. When the burner's continuous combustion time reaches the set time, the operation prohibiting means stops the burner's combustion and prohibits the use of the instrument, while the timer means counts when the instrument's use prohibition time reaches a predetermined time. The open-type gas combustion appliance according to any one of claims 1 to 3, wherein the use prohibition is canceled.

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