JPH0223976Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an incomplete combustion warning device for a combustor that issues an alarm when incomplete combustion occurs during use of the combustor.

If a combustor such as a gas water heater is used continuously for a long time in a closed room, it may become deficient in oxygen, making it impossible to secure the oxygen concentration necessary for the combustion reaction, or when the fins of the heat exchanger become clogged or the exhaust stack becomes clogged. Due to poor exhaust, the amount of air needed for the combustion reaction cannot be sent to the main burner, resulting in incomplete combustion. As a result, a large amount of carbon monoxide is generated, which has an adverse effect on the human body and is extremely dangerous. Therefore, various devices have been proposed that automatically stop the use of the combustor in dangerous conditions by stopping the supply of combustion gas when incomplete combustion occurs. It is inconvenient to stop combustion when there is no problem even if it continues, and it is also inconvenient that the user may not be able to understand the reason why combustion has stopped.

Furthermore, since it is dangerous to operate the ignition with the main burner open, it is necessary to issue an alarm to call attention to the situation if the operation is erroneous.

In view of the above points, the present invention provides a notification to the user that incomplete combustion has occurred before or at the same time as the incomplete combustion prevention device operates and stops the gas supply. alarm,
The purpose is also to issue an alarm in case of erroneous operation.

The gist is that it is equipped with a quick-start mechanism that opens and holds an electromagnetic safety valve using a pre-charged capacitor during ignition operation, and detects changes in the voltage of a pair of thermocouples connected with opposite polarity when incomplete combustion occurs. Then, an incomplete combustion prevention device is used that controls the opening and closing of the electromagnetic safety valve based on changes in voltage, and the voltage applied to the coil of the electromagnetic safety valve is input to an amplifier circuit, which amplifies it to a certain percentage. A comparator circuit compares the output voltage of the circuit with a reference voltage, and when the output voltage is low due to the reference voltage, an output signal is generated from the comparator circuit, and the output signal activates an alarm activation circuit to issue an alarm. Furthermore, the power supply circuit is equipped with a switch for opening and closing the power supply circuit, so that an alarm is issued even if the ignition operation is mistakenly performed while the main burner is open.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In Fig. 1, A connects the first thermocouple 1 and the second thermocouple 2 with opposite polarity and connects them to the coil 3 of the electromagnetic safety valve, so that when incomplete combustion occurs, the voltage applied to the coil 3 decreases. This is an incomplete combustion prevention circuit that closes the safety valve. In addition, 4 is a capacitor, and the capacitor 4 is connected to the DC power supply 5 before ignition, and when the ignition is operated, a discharge current is sent to the coil 3 by the changeover switch 16, and the electromagnetic safety valve is rapidly opened and held from the ignition operation. It constitutes a mechanism. B is an amplifier circuit that takes the voltage across the coil 3 of the electromagnetic safety valve as an input signal and amplifies it at a constant rate with an amplifier 17, and C is a comparison circuit that receives the output voltage of the power supply circuit E, which will be described later, from resistors 7 and 8. The voltage at the voltage dividing point a is used as a reference voltage, and this reference voltage and the output voltage of the amplifier circuit B are input to the comparator 6, and the output voltage of the amplifier circuit is lower than the reference voltage. It is designed to emit an output signal when the D is an alarm activation circuit, in which the output terminal of the comparator 6 is connected to the base of a transistor 10 via a base resistor 9, and the collector circuit of the transistor 10 is connected to an indicator lamp, an alarm buzzer, etc. Alarm 11
is connected to obtain a predetermined input and the transistor 10
When the switch operates to conduct, current flows to the alarm device 11 and an alarm is issued. E is a DC power supply 12, a resistor 13 and a Zener diode 1
This is a power supply circuit formed by connecting a constant voltage circuit using a DC power supply 12, and a switch 15 for opening and closing the power supply circuit, which is turned on when a passage to the main burner is opened, is interposed in series with the DC power supply 12. The DC power supply 12 is connected to the collector circuit of the transistor 10 via the switch 15, and the output end of the constant voltage circuit is connected to the resistor voltage divider circuit, the comparator 6, etc.

A specific example of the heat-sensitive element and the pilot burner constituting the incomplete combustion prevention circuit A will be explained with reference to FIG.
A first thermocouple 1 is inserted into the outer flame of the pilot burner 21, and a second thermocouple having a small diameter primary air hole 24 is inserted into the outer flame of the pilot burner 21.
The second thermocouple 2 is inserted into the inner flame of the pilot burner 22, and the first thermocouple 1 and the second thermocouple 2
The first pilot burner 2 is connected to the coil 3 of the electromagnetic safety valve with opposite polarity so as to mutually cancel out the thermal electromotive force generated by the burner.
1 sharply reduces the electromotive force generated by the first thermocouple 1 due to the elongation of the inner flame due to the reduction in the combustion speed and the cooling of the flame by the primary air. On the other hand, the temperature of the flame of the second pilot burner 22, which has a small amount of primary air, decreases slowly, and the thermoelectromotive force generated by the second thermocouple 2 located in the inner flame gradually decreases.
Therefore, the voltage applied to the coil 3 of the electromagnetic safety valve decreases as the oxygen concentration decreases, and when the voltage falls below the safety valve withdrawal voltage, the electromagnetic safety valve is closed and combustion is stopped.

With the above configuration, when starting combustion, the first and second pilot burners 21 and 22 are activated by the ignition operation.
A combined electromotive force of the electromotive forces in opposite directions of the first and second pilot burners 21 and 22 is applied to the coil 3 and the amplifier 17, and an electromagnetic safety valve for gas supply to the pilot burners is opened. Since the amplifier circuit output exceeds the reference voltage at the same time, the output signal from the comparator 6 is 0. After that, when the gas passage to the main burner is opened, the switch 15 for opening and closing the power circuit is activated in conjunction with the opening.
When turned on, amplifier circuit B, comparison circuit C, and alarm activation circuit D are energized. When incomplete combustion occurs, the combined thermoelectromotive force of the first thermocouple 1 and the second thermocouple 2 decreases, the voltage applied to the coil 3 of the electromagnetic safety valve decreases, and the input to the amplifier circuit B decreases, causing amplification. The output of the circuit also decreases. The voltage at the voltage division point a of the resistor voltage divider circuit of the comparator circuit C, that is, the reference voltage, is input to the comparator 6, and when the output of the amplifier circuit B becomes lower than the reference voltage, the output signal from the comparator 6 causes the alarm activation circuit. When the transistor 10 of D becomes conductive, a current flows to the alarm 11 connected to the collector circuit, and when the alarm 11 is an indicator lamp, it lights up, and when it is an alarm buzzer, it sounds. If the reference voltage is set so that an alarm is issued when the voltage across the coil 3 of the electromagnetic safety valve is slightly higher than the voltage that closes the electromagnetic safety valve (safety valve release voltage), the electromagnetic safety valve closes and combustion is stopped. If the reference voltage is set so that the alarm is issued before the combustion occurs, and the reference voltage is set so that the alarm is issued when the voltage is equal to the safety valve withdrawal voltage, the alarm can be issued when combustion stops due to the occurrence of incomplete combustion. In addition, in the power supply circuit E, a switch 15 for opening and closing the power supply circuit connected in series to the DC power supply 12 is
It is turned ON in conjunction with a valve that opens the gas passage that supplies gas to the main burner when the combustor is in use, and when the combustor is not in use, the incomplete combustion alarm system of this invention is activated and a malfunction occurs. It does not issue an alarm when necessary.

Therefore, if the gas passage of the main burner is opened prior to the ignition operation, the switch 15 for opening/closing the power supply circuit is ON, and the above-mentioned combined electromotive force is 0.
Therefore, the alarm 11 is actuated at the same time as the gas passage is opened to issue a warning so that an operational error can be detected, which also has the effect of eliminating the drawback that a large amount of raw gas leaks.

As described above, according to the present invention, incomplete combustion is detected as a voltage change, and in the incomplete combustion prevention circuit that opens and closes the electromagnetic safety valve based on this voltage change, the voltage across the coil of the electromagnetic safety valve is amplified and used as a reference. The system is configured to issue an alarm when the voltage drops below the reference voltage, so if incomplete combustion occurs, the electromagnetic safety valve closes and an alarm is issued before combustion is stopped, prompting the user to ventilate. You can remind them to do so. In addition, by changing the reference voltage, etc., the activation timing of the incomplete combustion warning device can be easily changed, so an alarm can be issued at the same time as the electromagnetic safety valve closes to notify that combustion has stopped due to incomplete combustion. . In addition, the voltage applied to the coil of the electromagnetic safety valve is amplified and compared with the reference voltage, so changes in voltage at both ends of the coil are accurately detected and activated, so even the slightest incomplete combustion can be detected. can issue an alarm. Furthermore, since the incomplete combustion warning device of the present invention can be installed on top of the conventional incomplete combustion prevention device, even if the incomplete combustion prevention device does not operate, accidents caused by incomplete combustion in the combustor can be prevented. can be prevented.

In addition, if you operate the ignition with the passage to the main burner open, the alarm will activate and issue a warning to prevent erroneous operation.Furthermore, even if the pilot burner goes out while the main burner is burning, this alarm circuit will activate. Since the system is activated, it can be used as an incomplete combustion alarm system for combustors and has the effect of further increasing safety.

[Brief explanation of the drawing]

FIG. 1 is an electrical circuit diagram of an incomplete combustion warning device for a combustor according to the present invention, and FIG. 2 is a schematic front view showing a pilot burner of the incomplete combustion prevention device. A...Incomplete combustion prevention circuit, B...Amplification circuit,
C... Comparison circuit, D... Alarm activation circuit, E...
Power supply circuit, 3... Coil of electromagnetic safety valve, 4... Capacitor, 15... Switch for opening and closing the power supply circuit.

Claims (1)

[Scope of utility model registration request] Equipped with a quick start mechanism that opens and holds the electromagnetic safety valve using a pre-charged capacitor 4 during ignition operation, it detects the change in voltage of a pair of thermocouples connected with opposite polarity when incomplete combustion occurs, and detects the change in voltage. an incomplete combustion prevention circuit A that controls the opening and closing of the electromagnetic safety valve, an amplifier circuit B that amplifies the voltage across the coil 3 of the electromagnetic safety valve in the incomplete combustion prevention circuit A, and an output voltage and a reference voltage of the amplifier circuit B. Comparator circuit C that compares and issues an output signal, alarm activation circuit D that activates an alarm upon receiving the output signal from comparison circuit C, and a power supply circuit that turns on in conjunction with opening of the gas passage to the main burner. 1. An incomplete combustion warning device for a combustor, characterized in that it comprises a power supply circuit E in which an opening/closing switch 15 is interposed.