JPH0251092B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a combustion control circuit for a combustor, and more particularly, the present invention relates to a combustion control circuit for a combustor, and more particularly, the present invention includes a manual operation member that can be freely switched between a closed position, an open position, and an ignition position, and a method for controlling the operation of the operation member to the ignition position. Press to open the electromagnetic safety valve interposed in the gas passage connected to the burner unit and ignite the burner unit, and release the pressure on the safety valve by operating the operating member to the open position. The present invention relates to a combustion control circuit that maintains a valve in an open state by the electromotive force of a thermocouple provided in a burner unit.

Conventionally, this type of device has a capacitor discharging circuit using a solenoid of an electromagnetic safety valve, and a power supply circuit charges the capacitor by operating the operating member from the closed position using a changeover switch linked to a manual operating member. Switching connection to the discharge circuit,
After ignition to the burner unit, until the thermocouple generates a predetermined electromotive force, the safety valve is forcibly held in the open state by energization of the solenoid due to the discharge from the capacitor, and the operating member is held open for the period of time. It is known that the safety valve does not close even if the pressure on the safety valve is released by switching it to the open position without waiting for the elapsed time, but in this case, the capacitor starts discharging at the ignition position of the operating member. Therefore, the discharge time, that is, the forced holding time of the safety valve is equal to the purge time required until the burner unit is ignited after the air in the gas passage is removed after the operation member is operated to the ignition position. Requires a relatively long setup time in addition to the time required to heat the pair. According to this, if the user operates the operating member to the ignition position and then immediately operates it to the open position without checking the ignition, even though the burner unit is not ignited,
The safety valve is forced to remain open for a relatively long period of time including the purge time, resulting in the inconvenience that raw gas is released.

In order to eliminate such inconvenience, for example,
A switch interposed in the discharge circuit disclosed in Japanese Patent No. 57-105529 may be opened in its open position in conjunction with the operating member.

However, in this case, the discharge circuit is always opened when the switch is opened, so even if the burner unit is ignited, the electromotive force of the thermocouple is not producing the specified electromotive force. However, if the operating member is operated to the open position, the electromagnetic safety valve closes and the burner unit is inconveniently extinguished.

In other words, in this type of control device, when the burner unit is ignited, it is necessary to use the electric charge of the capacitor to keep the electromagnetic safety valve open even if the electromotive force of the thermocouple is not sufficient. When the operating member is operated to the open position without igniting the unit, there is a demand for closing the electromagnetic safety valve as soon as possible.

The object of the first invention is to obtain a combustion control device that satisfies such requirements, and includes a manual operation member that can be switched between a closed position, an open position, and an ignition position, and the operation member is moved to the ignition position. This operation presses the electromagnetic safety valve interposed in the gas passage leading to the burner unit to open and ignites the burner unit, and the operation of the operating member to the open position releases the pressure on the safety valve. A combustion control circuit that maintains the safety valve in an open state by the electromotive force of a thermocouple provided in the burner unit is provided with a capacitor discharge circuit that intervenes with a solenoid of the safety valve, and a changeover switch that is linked to the operating member In a device in which the capacitor is switched from a power supply circuit that charges the capacitor to the discharging circuit by operating the operating member from the closed position, the capacitor is connected to the discharging circuit in conjunction with the operating member. It consists of a control switch which is opened in the open position and a resistor in parallel with the control switch.

The object of the second invention is to obtain a device that can cope with misfires after ignition that cannot be eliminated in the first invention, and is a device that can be manually operated to switch between a closed position, an open position, and an ignition position. An operating member is provided, and when the operating member is operated to the ignition position, the electromagnetic safety valve interposed in the gas passage leading to the burner unit is pressed open and the burner unit is ignited, and the operating member is moved to the open position. A capacitor discharging circuit in which a solenoid of the safety valve is interposed in a combustion control device that releases the pressure on the safety valve and holds the safety valve in an open state by an electromotive force of a thermocouple provided in the burner unit. is provided, and a changeover switch linked to the operating member switches the capacitor from the power supply circuit for charging the capacitor to the discharging circuit by operating the operating member from the open position, and the switch is linked to the operating member. and a control switch that is opened when the control switch is in the open position, and a resistor that is parallel to the control switch, and a sub-discharge circuit of the capacitor that is closed by the switching operation of the control switch when the control switch is in the open position. and a resistor is interposed in the sub-discharge circuit.

Embodiments of the present invention will be described with reference to the drawings.

In the drawings, 1 indicates a burner unit, which includes a main burner 1a and a pilot burner 1b.
It consists of.

Reference numeral 2 indicates a gas supply path for supplying fuel gas to the burner unit 1, and the gas supply path 2 includes an electromagnetic safety valve 3 and a cutoff valve 4, both of which are in the closed position. The valve is opened by pressing a manual operating member 5 which can be switched between an open position and an ignition position.To explain this in detail, the operating member 5 is a push button 5a provided on an operating panel 6 on the front side of the combustor. It is composed of an operating rod 5b with an attached valve, a valve rod 5c extending rearward on the same axis and inserted into the gas passage 2, and a lever 5d at the rear end, and the valve rod 5c
supports the shutoff valve 4 and the valve rod 5.
an ignition valve 7 consisting of a small diameter portion formed at c;
Return spring 8 of the operating rod 5b from the illustrated closed position
According to the push operation against the pressure, the shutoff valve 4 goes through an intermediate open position where it is opened, and then the shutoff valve 4 and the ignition valve 7 are opened and the safety valve 3 is opened via the lever 5d.
When the push operation is switched to the final ignition position where the valve is opened and the push operation is released at the ignition position, the return operation by the return spring 8 of the operating rod 5b causes the projection on the outer periphery of the operating rod 5b to It is stopped in the open position by a stopper 10 that engages with the projection 9, and is restored to the closed position when the stopper 10 is released from the projection 9 by pushing a fire extinguishing button 11 arranged side by side with the push button 5a. It consists of

The present invention relates to a control circuit for the safety valve 3 interposed in the gas supply path 2 of the combustor. Solenoid 3 of safety valve 3
The circuit shown in FIG. A charging circuit 16 for a capacitor 13 is connected to a power source 15 through one contact 14a of a changeover switch 14 when the operating member 5 is pressed.
and a discharge circuit 17 connected to the capacitor 13 via the other contact 14b of the changeover switch 14. A switch 18 that opens upon return and a resistor 19 in parallel with the switch 18
It is formed by intervening.

The aforementioned changeover switch 14 is switched to a state in which the contact 14a connecting the capacitor 13 to the charging circuit 16 side is selected when the manual operation member 5 is in the closed position, and when the switch is pressed from the closed position, the discharging circuit 17 and the capacitor 13 are connected. The state changes to a state in which the contact 14b to be connected is selected. In the figure, reference numeral 20 indicates an igniter facing the pilot burner 1b, and 21 indicates an ignition switch intervening therein. The ignition switch 21 is closed by pressing the manual operation member 5 to the ignition position.

When the manual operating member 5 is pushed from the starting end closed position to the ending ignition position, the selector switch 14 is first switched to the side that selects the discharge circuit 17, and then the shutoff valve 4 is opened at the intermediate open position. At the ignition position, the switch 21 is closed to operate the igniter 20, and at the same time as the electromagnetic safety valve 3 is pushed open, the switch 18 intervening in the discharge circuit 17 is closed. Therefore, the charge stored in the capacitor 13 is discharged relatively quickly through the switch 18 of the discharge circuit 17 as shown by A in FIG.
is excited by this discharge charge and the electromagnetic safety valve 3
Keep the valve open. Therefore, fuel gas is supplied to the burner unit 1, and is ignited by a spark from the igniter 20.

Thereafter, when the thermoelectromotive current of the thermocouple 12 heated by the combustion heat of the burner unit 1 (B in Fig. 7) does not reach the withdrawal current value a of the electromagnetic safety valve 3, the push operation is released and the manual operation member 5 is opened. When returned to the position, the switch 18 opens and the capacitor 13
Since the discharge current (C in Figure 7) flows through the resistor 19, it rapidly decreases, but since the thermoelectromotive current of the thermocouple 12 is added to this, this combined current (D in Figure 7) is Since the withdrawal current value of the electromagnetic safety valve 3 can be kept at or above the withdrawal current value, and thereafter the valve can be kept open only by the thermoelectromotive current of the thermocouple 12, the inconvenience of the electromagnetic safety valve 3 closing and extinguishing the fire does not occur.

In addition, if the manual operation member 5 is switched to the open position while the burner unit 1 is not ignited, the valve closes relatively quickly as shown by C in FIG. The inconvenience of release does not occur.

To extinguish the fire, press the fire extinguishing button 11, the stopper 10 is disengaged from the protrusion 9, the operating member 5 is automatically returned by the spring 8, and during this operation the shutoff valve 4 is closed and the burner unit 1 is closed. At the same time, the return operation of the operating member 5 switches the changeover switch 14 to the side that closes the charging circuit 16.

When the solenoid 3a is inserted into the charging circuit 16 of the capacitor 13 as shown in FIG. 2, the current from the power source 15 acts as a back electromotive force on the solenoid 3a due to the switching operation of the changeover switch 14 at the time of extinguishing the fire. This has the advantage that the electromagnetic safety valve 3 can be closed quickly, and the cutoff valve 4 can be omitted in some cases.

The circuit shown in FIG. 3 uses the switch 18 as a changeover switch in the circuit shown in FIG.
When one contact 18a is selected, the discharge circuit 17 is closed, and the capacitor 1 is connected via the other contact 18b.
A sub-discharge circuit 22 is provided to connect to 2.
Reference numeral 3 indicates a resistor interposed therein, and in the open position, the changeover switch 18 is caused to discharge through both the discharge circuits 17 and 22, ie, the auxiliary discharge circuit 22 and the discharge circuit 17. This prevents the discharge time from prolonging.

That is, in the case shown in FIG. 2, if the burner unit 1 is ignited by pushing the manual operation member 5 to the final position and then misfires for some reason, the thermoelectromotive current of the thermocouple 12 (as shown in FIG. B) rises to a certain extent and then begins to decrease at the same time as the misfire, and this thermal electromotive current is added to the discharge current of the capacitor 13, so this combined current (D in Figure 8) keeps the electromagnetic safety valve 3 open for a relatively long time. There is a risk that a relatively large amount of raw gas will be released.

However, as described above, by discharging also from the sub-discharge circuit 22, the discharge current value can be rapidly reduced as shown by E in FIG. 8, and this problem can be eliminated.

7 and 8 show the circuits shown in FIGS. 2 and 3 using a capacitor 13 of 3.3F, a resistor 19 of 2.5Ω, and a resistor 23 shown in FIG. 3 of 2.6Ω. , which is not shown, is the characteristic when a 1.3Ω resistor is inserted in the discharge circuit, and A in FIG. 8 is the same as A in FIG. 7 when the capacitor 13 is not inserted in the discharge circuit.
discharge characteristics.

The circuits shown in FIGS. 2 and 3 have the disadvantage that the solenoid 3a intervenes in the charging circuit 16 of the capacitor 13, which shortens the life of the battery 15 as a power source. By configuring the circuit as shown in FIGS. 5 and 6, this problem can be solved.
There is an advantage that the resistor 23 intervening in the discharge circuit 17 can be used as a resistor intervening in the discharge circuit 17.

In the above embodiment, the burner unit 1 is configured to include a main burner 1a and a pilot burner 1b, but in addition to these burners, it may also be configured to include a pilot burner for regular fire. In the embodiment, ignition is performed using an ignition circuit as the igniter, but it is of course possible to ignite using a piezoelectric igniter.

As described above, according to the first invention, a control switch that is opened in the open position in conjunction with the operating member and a resistor in parallel with the control switch are inserted into the capacitor discharge circuit, so that the capacitor is not discharged in the open position. The discharge is in a state where it is discharged through a resistor inserted in the discharge circuit, thereby rapidly reducing the discharge current value of the capacitor and quickly reaching the withdrawal current value at which the electromagnetic safety valve closes. In addition to preventing the inconvenience of continuous release of raw gas,
When the burner unit is ignited, even if the specified electromotive force is not generated in the thermocouple, the capacitor is gradually discharged due to the intervention of the resistor. The withdrawal current can be maintained at or above the withdrawal current value in a state where electric power is added.In other words, the withdrawal current is calculated by adding the electromotive force of the thermocouple, which gradually increases, and the discharge current of the capacitor, which gradually decreases from a certain value. Since it is designed to hold a current higher than the value, even if the ignition operation is released immediately after ignition, the electromagnetic safety valve can be kept open, making it inconvenient to extinguish the ignition even though it is ignited. It is effective in eliminating the problem.

Further, according to the second invention, since a sub-discharge circuit is provided in which a resistor is interposed and is closed by a control switch that is opened in the open position in conjunction with the operating member, the discharge circuit and the sub-discharge circuit are By appropriately setting the values of the two resistors interposed in the auxiliary discharge circuit, it is possible to discharge from the sub-discharge circuit without impairing the effect of the first invention, and the discharge of the capacitor is extremely extended and the current value is increased. This has the effect of eliminating the inconvenience of a delay in closing the electromagnetic safety valve due to the electromotive force of the thermocouple being added in the event of a misfire after ignition.

[Brief explanation of the drawing]

In the drawings, FIG. 1 is a side view of an apparatus according to one embodiment of the present invention, FIG. 2 is a control circuit diagram thereof, FIG. 3 is a circuit diagram of another embodiment, and FIGS. 4 to 6 are further diagrams of other embodiments. The circuit diagram of the example, FIG. 7 is a discharge characteristic curve of the capacitor in the case of the control circuit shown in FIG. 2, and FIG. It is a discharge characteristic curve diagram. 1...Burner unit, 2...Gas supply path, 3
... Solenoid safety valve, 12 ... Thermocouple, 13 ... Capacitor, 14 ... Selector switch, 17 ... Discharge circuit, 18 ... Control switch, 19 ... Resistor.

Claims (1)

[Scope of Claims] 1. An electromagnetic safety valve that is provided with a manual operating member that can be switched between a closed position, an open position, and an ignition position, and that is interposed in a gas passage leading to a burner unit when the operating member is operated to the ignition position. The pressure to open the valve and ignite the burner unit is applied, and the pressure on the safety valve is released by operating the operating member to the open position, and the safety valve is opened by the electromotive force of the thermocouple provided in the burner unit. A discharge circuit for a capacitor is provided in which a solenoid of the safety valve intervenes in the combustion control circuit, and the capacitor is connected to the combustion control circuit by operating the operating member from the closed position using a changeover switch linked to the operating member. In a device in which a charging power supply circuit is switched and connected to the discharging circuit, the discharging circuit includes a control switch that is opened in the open position in conjunction with the operating member, and a resistor in parallel with the control switch. Combustion control circuit consisting of intervening. 2. Equipped with a manual operating member that can be freely switched between a closed circuit, an open position, and an ignition position, and when the operating member is operated to the ignition position, an electromagnetic safety valve interposed in a gas passage leading to a burner unit is pressed open and opened. In addition to igniting the burner unit, the pressure on the safety valve is released by operating the operating member to the open position, and the safety valve is held in the open state by an electromotive force of a thermocouple provided in the burner unit. The combustion control device is provided with a capacitor discharge circuit that intervenes with the solenoid of the safety valve, and the capacitor is charged from a power supply circuit that charges the capacitor by operating the operating member from the closed position using a changeover switch that is linked to the operating member. A control switch which is selectively connected to the discharge circuit and which is opened in its open position in conjunction with the operating member, and a resistor in parallel with the control switch are interposed; A combustion control circuit comprising: a sub-discharge circuit for the capacitor which is closed by a switching operation to the sub-discharge circuit; and a resistor is interposed in the sub-discharge circuit.