JPS605251Y2 - Combustion safety device display device - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The invention is equipped with a combustion detection circuit that detects the combustion state of the burner, and closes an electromagnetic safety valve installed in the burner fuel passage in the event of poor combustion or misfire of the burner. In addition, the electromagnetic safety valve can be forcibly held in the open state by a timer circuit until the post-ignition combustion detection circuit operates normally and output is generated. Related to display devices.

(Prior art) As a conventional device of this type, according to Utility Model Application Publication No. 52-16913, an alarm made of a light emitting diode is incorporated into a timer circuit, and the alarm is activated to indicate that the timer circuit is on forced hold. Those who make themselves known will be known.

(Problem to be solved by the invention) Considering safety, it is desirable to be able to display this even when the electromagnetic safety valve is closed due to poor combustion in the burner, etc. However, the above-mentioned conventional technology However, since the alarm is only activated during forced hold, such a display cannot be made.

In this case, the operation of the alarm is controlled in conjunction with the combustion detection circuit, and the alarm is activated after ignition until output is generated from the combustion detection circuit or when the output of the combustion detection circuit decreases due to poor combustion, etc. By doing so, it is possible to substantially display both electromagnetic safety forced hold and valve closing.

However, if the combustion detection element in the combustion detection circuit is sensitive to changes in the burner flame, the output of the combustion detection circuit will decrease due to fluctuations in the flame due to wind, etc., and the electromagnetic safety valve will close at this time. If the valve is closed, it becomes inconvenient to use, so it is desirable to use a forced hold timer circuit to prevent the electromagnetic safety valve from closing even if the output of the combustion detection circuit temporarily decreases. If the operation of the alarm is controlled solely by the output of the combustion detection circuit, the alarm may be activated unnecessarily due to a temporary decrease in the output of the combustion detection circuit due to fluctuations in the flame, causing unnecessary anxiety to the user. I'll put it in.

The purpose of the present invention is to solve this problem and provide a device that can activate the alarm only when the electromagnetic safety valve is forcibly held and when the valve is closed due to an abnormality such as poor combustion or misfire. do.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a combustion detection circuit that generates an output when the burner burns normally, and a capacitor that is charged via a power switch. A timer circuit that generates an output until the capacitor is charged to a predetermined potential is provided, and a switching element that is turned on by the output of the combustion detection circuit is intervened in the discharge circuit of the capacitor, and the fuel of the burner is controlled by the output of the timer circuit. An electromagnetic safety valve interposed in the passage is held open, and a determination circuit for determining the presence or absence of output from the combustion detection circuit and the timer circuit, and an alarm whose operation is controlled by the determination circuit are provided. The present invention is characterized in that the alarm is activated before the combustion detection circuit generates an output for the first time and thereafter when the output of the timer circuit disappears.

(Example) The present invention will be explained with reference to the illustrated embodiments.

In the figure, 1 is a combustion detection element made of an oxygen concentration battery element such as zirconia, which generates an electromotive force according to the oxygen concentration difference between the front and back electrodes 1a and 1b when heated to an operating temperature of about 800°C. As shown in FIG. 2, one electrode 1a is arranged so as to face the main burner A, and the other electrode 1b is always heated by the constant-fire burner B in an oxygen-deficient state.

According to this, during normal combustion in the main burner A, the flame F1 does not come into contact with one of the electrodes 1a, so an electromotive force is generated from the element 1 depending on the oxygen concentration, and during poor combustion, the flame extends like F2 and When it comes into contact with the electrode 1a, the oxygen concentration disappears and the electromotive force decreases.

The element 1 and a comparator 2 inputting its output constitute a combustion detection circuit, and the comparator 2 generates a high-level signal during normal combustion.

TM indicates a timer circuit, and the timer circuit TM includes a time constant circuit consisting of a resistor 4 and a capacitor 5 connected to a power supply 17 via a power switch 16, and a (-) terminal with a constant bias applied thereto. The comparator 6 has a terminal connected to the connection midpoint of the time constant circuit, and a high level signal is generated from the comparator 6 until the capacitor 5 is charged to a predetermined potential, and the burner A transistor 7 intervening in the operating circuit of an electromagnetic safety valve 8 interposed in the fuel passages A and B is turned on by a high level signal from the comparator 6 to keep the safety valve 8 open, and further the capacitor is A transistor 3, which is a switching element that is turned on by the output of the combustion detection circuit, that is, a high-level signal from the comparator 2, was inserted into the discharge circuit No. 5.

After turning on the power switch 16 and before the capacitor 5 is charged to a predetermined potential, the combustion detection element 1 is heated to a predetermined operating temperature and a high level signal is generated from the comparator 2. When the transistor 3 is turned on and the capacitor 5 is discharged, and the ignition occurs normally, a high level signal is continuously generated from the comparator 6 of the timer circuit TM, and the safety valve is activated at the initial stage of ignition. 8, the valve is held open, that is, forcedly held, and then the valve is held open during normal combustion.

In this case, even if a low-level signal is temporarily generated from the comparator 2 due to flame fluctuations and the transistor 3 is turned off, the transistor 3 is turned on again before the capacitor 5 is charged to a predetermined potential. , eventually due to poor combustion etc., the comparator 2
The electromagnetic safety valve 8 will not be closed unless a low level signal is continuously generated, and the safety valve 8 will not be closed unnecessarily due to flame fluctuations or the like.

Reference numeral 11 indicates a buzzer serving as an alarm, and the buzzer 11 is activated by a discrimination circuit that discriminates the presence or absence of high-level signals from the outputs of the combustion detection circuit and the timer circuit TM, that is, from each of the comparators 2 and 6. The discrimination circuit is configured to operate the buzzer 11 before a high level signal is first generated from the comparator 2 and when a low level signal is generated from the comparator 6 thereafter. It was assumed that

To explain this in detail with reference to the diagram, the discrimination circuit controls the operation of the buzzer 11 by turning on and off a pair of transistors 10.15 which are inserted in parallel with each other in the operation circuit of the buzzer 11. It has a thyristor 12 that controls on/off the transistor 10, and a transistor 14 that controls the on/off of the transistor 15.When the thyristor 12 is off, the transistor 10 is turned off, and when the transistor 14 is off, the transistor 15 is turned on. The output terminal of the comparator 2 was connected to the gate terminal of the thyristor 12, and the output terminal of the comparator 6 was connected to the base terminal of the transistor 14.

According to this, the transistor 10 is turned on until a high level signal is first generated from the comparator 2, and thereafter the thyristor 12 remains turned on even when a low level signal is generated from the comparator 2. Therefore, the thyristor 12
functions as a kind of memory element, the transistor 10 is kept in the off state, and the buzzer 11 is activated until the first high level signal is generated from the comparator 2, that is, during the above-mentioned forced hold time, and then Even if a low-level signal is temporarily generated from the comparator 2 due to flame fluctuations or the like, the buzzer 11 does not operate.

However, if a low level signal is continuously generated from the comparator 2 due to poor combustion or the like and a low level signal is generated from the comparator 6, the transistor 14 is turned off, the transistor 15 is turned on, and the buzzer 11 is turned on. Operate.

7 In the illustrated example, a light emitting diode 13, a transistor 9 that is turned on when the transistor 7 is turned on, and a thyristor 12 are connected in series, and the midpoint of the connection between the transistor 9 and the thyristor 12 is connected to the base of the transistor 10. connected to the terminal.

According to this, the transistor 9 is turned on during forced hold, but the thyristor 12 is turned off, so the diode 13 does not light up, and when the thyristor 12 is turned on afterwards, the diode 13 lights up, and then the comparison When a low level signal is generated from the device 6 and the electromagnetic safety valve 8 is closed, the transistor 9 is turned off and the diode 13 is turned off, and the lighting of the diode 13 indicates that normal combustion is occurring. I made it so that it would be done.

The table below shows changes in the output of the combustion detection circuit and timer circuit TM with respect to changes in the combustion state, and the operating states of the electromagnetic safety valve 8, buzzer 11, and light emitting diode 13.

In the table below, 0 indicates that each circuit has an output, that the electromagnetic safety valve 8 is open, that the buzzer 11 is sounding, and that the light emitting diode 13 is lit.

In the above embodiment, an oxygen concentration battery element such as zirconia was used as the combustion detection element 1, but a thermocouple or the like may also be used, and it is also possible to use something other than the buzzer 11 as the alarm.

In addition, a light emitting diode 13 is provided to indicate when the combustion is normal.
It's fine without it.

(Effect of the invention) As described above, according to the invention, even if the output of the combustion detection circuit is temporarily lost due to flame fluctuations, the timer circuit for forced hold functions as a delay element and the electromagnetic safety valve is not used. The valve will not close, the alarm will not be activated unnecessarily due to flame fluctuations, and will only be activated during forced hold or in abnormal situations such as poor combustion or misfire, making the user unnecessarily anxious. This has the effect of making it possible to perform accurate display without having to enter the screen, thereby increasing the reliability of the display.

[Brief explanation of drawings]

FIG. 1 is an electrical circuit diagram of an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the arrangement of combustion detection elements. 1... Combustion detection element, 2... Comparator of combustion detection circuit, 3... Switching element, TM
......Timer circuit, 5...Capacitor,
8... Solenoid safety valve 11... Alarm device,
16...Power switch.

Claims (1)

[Scope of utility model registration request] A combustion detection circuit that generates an output when the burner burns normally, and a timer circuit that includes a capacitor that is charged via a power switch and generates an output until the capacitor is charged to a predetermined potential, and a discharge circuit for the capacitor. A switching element that is turned on by the output of the combustion detection circuit is intervened in, and the output of the timer circuit causes an electromagnetic safety valve interposed in the fuel passage of the burner to be held open;
A discrimination circuit for discriminating the presence or absence of output from the combustion detection circuit and the timer circuit, and an alarm whose operation is controlled by the discrimination circuit are provided, and the detection circuit is provided with A display device for a combustion safety device, characterized in that the alarm is activated when the output of the timer circuit disappears.