JPS60105826A - Burning control circuit for burner - Google Patents

Abstract

PURPOSE:To prevent the release of raw gas from a burner unit by providing an auxiliary discharge circuit for condenser that is formed via a switch which is closed as a manual actuator is brought to its open position. CONSTITUTION:Although a manual actuator 5 is returned to its open position and a normally-opened switch of a selector switch 18 is opened, the residual electrical load in a condenser 13 continues to be discharged via a resistor 19. A normally-closed switch of the selector switch 18 is then closed to allow the discharge by an auxiliary discharge circuit 22, and so, as no electrical load is left in the condenser 13 at the time of extinguishing, a charging electric current which is great enough flowed from a power source 15 to a solenoid 4a. Therefore, such charging electric current cancels the thermoelectromotive current of a thermocouple 12 flowing to an electromagnetic safety valve 3 dur to the residual heat. In this manner, the release of gas from a burner unit can be prevented.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a combustion control circuit for a combustor.

(Prior Art) Conventionally, this type of combustion control circuit includes a changeover switch that is linked to a manually operated member that can be switched between a closed position, an open position, and an ignition position, and the changeover switch is operated from the closed position of the member to switch the burner on and off. The solenoid of the electromagnetic safety valve interposed in the gas passage connected to the unit is switched from intervening in the capacitor charging circuit to intervening in the capacitor discharging circuit, and by operating the member to the ignition position, the safety valve is pressed open and the burner is activated. Activate the igniter of the unit, release the pressure opening of the safety valve by operating the member to the open position, and release the discharge current of the capacitor and the thermoelectromotive current of the thermocouple provided in the burner unit that has reached a predetermined value. It is known that the safety valve is held open in the open state, but the forced holding time of the safety valve due to the discharge of the capacitor is limited to the time when the air in the gas passage is removed after the member is operated to the ignition position. .

Tehana unit ignites n/! Since it requires a relatively long setting time including the time required for 1 and the time required for heating the thermocouple described above, the user operates the member to the ignition position and then immediately returns it to the open position without confirming ignition. When operated, the safety valve is forced to remain open for a long time even though the burner unit is not ignited, resulting in the inconvenience that raw gas is released. To solve this problem, for example, as shown in Japanese Utility Model Application Publication No. 57-105529, a switch is inserted into the discharge circuit of the capacitor, and the switch is opened when the member is in the open position to cut off the discharge current and close the safety valve. I hope to speak to you.

(Problem to be Solved by the Invention) However, with the above method, the manual operation member is pressed to the ignition position to ignite the Pana unit, and then the member is opened at a relatively early point before the end of the discharge of the capacitor. When the capacitor is operated to the position, a charge remains in the capacitor.

Therefore, even if the solenoid of the electromagnetic safety valve is inserted into the charging circuit of the capacitor during such a fire extinguishing operation and a charging current of opposite polarity to the thermoelectromotive current due to residual heat of the thermocouple is passed through the solenoid, a sufficiently large charging current will not flow. Thus, the safety valve does not close immediately, but closes when the thermoelectromotive current of the thermocouple drops to a predetermined value due to natural cooling.

Therefore, when the ignition push button is pressed lightly to the extent that the ignition switch does not close within a short period of time after such extinguishing operation,
Since the shutoff valve is opened, raw gas is released from the burner unit, causing an inconvenience.

An object of the present invention is to provide a combustion control circuit for a combustor that does not have such disadvantages.

(Means for Solving the Problems) The present invention includes a changeover switch linked to a manually operated member that can be freely switched between a closed position, an open position, and an ignition position, and the changeover switch is operable from the closed position of the member. The solenoid of the electromagnetic safety valve interposed in the gas passage connected to the burner unit is switched from intervening in the capacitor charging circuit to intervening in the capacitor discharging circuit, and when the member is operated to the ignition position, the safety valve is pressed open. The valve and the igniter of the burner unit are activated, and the safety valve is maintained in an open state by the discharge current of the capacitor and the thermoelectromotive current of the thermocouple provided in the burner unit that has reached a predetermined value. A sub-discharge circuit for the capacitor is provided, which is formed via a switch that is connected to the member and is closed in the open position.

(Example) Embodiments of the invention will be described with reference to the drawings.

In FIG. 1, (1) indicates a burner unit, and the burner unit (1) consists of a silkworm burner (la) and a pilot burner (1b).

(2) indicates a gas passage that supplies fuel gas to the burner unit (1), and the gas passage (2) is equipped with an electromagnetic safety valve (
3) and a shutoff valve (4), both valves (
3) In (4), the valve is opened by pressing a manual operating member (5) that can be switched between a closed position, an open position, and an ignition position. ) is a push button (5a) provided on the operation panel (6) on the front side of the combustor, and a valve lever (5c) extending rearward on the same axis and inserted into the gas passage (2); and a lever (5b) at the rear end, and the valve rod (5c) is connected to the shutoff valve (4).
) and an ignition valve (7) consisting of a small diameter portion formed in the valve rod (5c), so that the operating rod (5b) is pushed against the return spring (8) from the illustrated closed position. According to the operation, the shutoff valve (4) passes through an intermediate open position in which it is opened, and then the shutoff valve (4) and the ignition valve (7) are opened and the lever (5d)' When the safety valve (3) is pressed open via the switch to the final ignition position, when the igniter 1 is released from the push operation, the operating rod (5b) The return operation by the return spring (8) is stopped at the open position by the stopper aO that engages with the protrusion (9) on the outer periphery of the operating rod (5b). When the stop horns 00 are removed from the protrusion (9) by pressing the button 0υ, they return to the closed position.

The present invention relates to a control circuit for the safety valve (3) interposed in the gas passage (2) of the combustor.

FIG. 2 shows a circuit of one embodiment.

In Figure 2, the solenoid (3a) of the electromagnetic safety valve (3)
) is the movable contact (14c) of the changeover switch α4) when the capacitor α East is closed when the manual operation member (5) is in the closed position.
The capacitors (13) connected to the power supplies Q and QK through the fixed contacts (14a) intervene in the charging circuit 01G, and the charge in the capacitor α is transferred to the manual operation member (5).
), the movable contact (14c) and fixed contact (i4.b
), the discharge circuit (17) is interlocked with the suppression operation of the manual operation member (5), and is moved to the ignition position of the manual operation member (5). A fixed contact (18a) and a movable contact (18
c) intervenes and the normally open switch and the parallel button resistance Q
1 is connected, and a capacitor is connected in series with the fixed contact (18b) and the movable contact (18C) constituting the normally closed switch of the changeover switch α8) that closes when the manual operation member (5) returns to the open position. A resistor is connected to one end of the east end of the capacitor a3 to form a sub-discharge circuit (2) of the capacitor a3.

In the 1st section and Figure 2, the sub is the burner unit (1
), (a) is the pilot burner (1b).
) is an ignition switch that is closed by pressing the igniter (Q]) Fi manual operation member (5) to the ignition position.

Next, its operation will be explained.

When the manual operation member (5) f is pressed from the starting end position, which is the closed position, to the ending position, which is the ignition position, the selector switch 0 is first switched from the charging circuit (turn) side to the discharging circuit a1) side, and then it is switched to the open position. At the ignition position, the shutoff valve (4) opens, and at the ignition position, the ignition switch (2)'fc closes to activate the igniter (a), and simultaneously pushes open the electromagnetic safety valve (3) and intervenes in the discharge circuit αη. Changeover switch (to) (
D Close the normal H switch. Therefore, the capacitor θ
The electric charge stored in a is discharged through the normally open switch of the discharge circuit aη, and the solenoid (3a) is excited by this discharged electric charge and keeps the safety valve (3) open. Therefore, fuel gas is supplied to the burner unit (1), which is ignited by a spark generated by the igniter (e). Thereafter, when the manual operation member (5) is released from the pressing operation to return to the open position, the normally closed switch located next to the changeover switch a is closed.

Therefore, the electric charge in capacitor a is discharged in the discharge circuit 0η via the resistor θgJ and also in the sub-discharge circuit (a), so the current value decreases rapidly and the electromagnetic safety valve (3) closes in a short time. The withdrawal current value is reached.

Therefore, when the burner unit (1) is switched to the open position with no ignition, the electromagnetic safety valve (3) closes relatively quickly.

If the manual operation member (5) is returned to the open position when the burner unit (1) is ignited or the thermoelectromotive current of the thermocouple (2) has not reached the predetermined value, the capacitor (13) The discharge current value of the electromagnetic safety valve (3) drops rapidly, but the thermoelectromotive current of the thermocouple (2) is added to the discharge current. 3) continues to be held open.

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Since the engagement with the protrusion (9) of the pa 00 is broken, the manual operation member (5) is closed by the spring (8).
It returns automatically, and during this operation, the shutoff valve (4) closes to cut off the supply of fuel gas to the burner unit (1). The selector switch (14) is activated when the manual operation member (5) returns to the closed position.
is switched to the side that closes the charging circuit (A), a charging current flows through the solenoid (3a) to cancel out the thermal electromotive current of opposite polarity due to the residual heat of the thermocouple (2), and the electromagnetic safety valve (3) is closed. Close the valve immediately.

Next, the manual operation member (5) is suppressed to the ignition position to open the gas passage (2), and then the suppression operation is released relatively early before the discharge of the capacitor α field ends to return to the open position. Then, after a predetermined period of time has elapsed after turning the switch to the open position, press the fire extinguishing push button (ill e), and then press the ignition push button (5a) in a short period of time to reduce the amount of pressure to the extent that it does not activate the igniter. The case where a suppression operation is performed will be explained.

Even if the manual operation member (5) is returned to the open position and the normally open switch of the selector switch (G) is opened, the fC charge remaining in the capacitor α continues to be discharged through the resistor Q'l and is then closed. It is discharged in the auxiliary discharge circuit (a) through the normally closed switch of the changeover switch (to), and no charge remains in the capacitor θ■ during extinguishing operation, so the power supply (10
Therefore, a sufficiently large charging current flows through the solenoid (4a) K.

Thus, this charging current cancels the thermal electromotive current of the thermocouple (b) flowing to the electromagnetic safety valve (3) due to residual heat, and the solenoid (
As a result of reducing the current flowing through 3a) below the withdrawal current, the electromagnetic safety valve (3) closes immediately. Therefore, during the difficult time after the fire extinguishing operation, the ignition push button (5a) is suppressed to the extent that all ignition switches 0υ are not closed, and the manual operation member (5) is rotated h.
Even if the burner unit (1) is kept at 1, no dregs will be released from the burner unit (1).

FIG. 3 shows an operational characteristic diagram of a specific circuit in such a case.

This characteristic is expressed by the capacitor Q in the circuit shown in Figure 2.
3 is 3.3F, resistance 09 is 2. ! M), a resistor (having a value of 24 Ω, an, and a resistor of 1.30 Ω, not shown) inserted in the charging/discharging circuit of the capacitor 03.

In Fig. 3, A (- (
-) indicates the sweet-acid current of A and B flowing through the solenoid (3a), and the current value shown below the zero line is the solenoid (3a).
) shows the polarity current values flowing from the top to the bottom of the figure.

According to FIG. 3, the manual operation member (5) is pressed to the ignition position, and after ignition the capacitor is 0; after 2 seconds have elapsed when the friction has not discharged much, the manual operating member (5) is pressed down, and after a predetermined period of time, e.g. 5 seconds, the capacitor is turned off. Press the fire extinguishing push button 0υ to release the member (5) C with total closure.
c If it is restored, the solenoid (3a)
The voltage applied to is 0.98V.

The charging current that flows is 377 mA. On the other hand, since the thermoelectromotive current of the thermocouple @ due to residual heat at the time of extinguishing the fire is 345 mA, the sweet acid current is -32 mA, and the electromagnetic safety valve (3) is closed l:;l# De-energizing current value I U Om
It will be below A+. Therefore, the electromagnetic safety valve (3) closes almost simultaneously with the extinguishing operation.

FIG. 5 shows a conventional circuit in which a switch that is opened when the manual operating member is in the open position intervenes in the discharge circuit, with the parts common to the circuit shown in FIG. The operating characteristic diagram when the is operated to the open position and the closed position is shown.

In the same figure, A', B', 0' are M3 (Figure 17) A, B
, respectively correspond to 0.

As is clear from the figure, according to the conventional circuit, the sweet acid current C' flows through the solenoid of the electromagnetic safety valve at the time of extinguishing the fire.
is 130 mA, which is greater than the withdrawal current. Therefore, the electromagnetic safety valve does not close at the same time as the fire extinguishing operation, but remains open until the thermocouple cools down naturally.

Figure M4 shows a circuit diagram of another embodiment of the invention.

This circuit is a modification of the circuit shown in the second diagram, and the resistance (c) of the circuit shown in the second diagram is changed by the switch o barrel. It is connected in series with one switch and in parallel with a resistor α via the normally open switch. for the resistor) is a selector switch (
Since the discharge current value flowing into the discharge circuit (17) via the normally open switch 18) is suppressed, there is an advantage that wear and tear associated with opening and closing of the normally open switch can be reduced.

Other operations are the same as those shown in the second figure.

In the above embodiment, the burner unit (1) is of a type equipped with a main burner (1a) and a pilot burner (1b). In the above embodiments, all ignition is performed using an ignition circuit, but a piezoelectric igniter may also be used for ignition.

′! ! In addition, although the above embodiment is applied to a 7L system having a shutoff valve (4) shown in the first diagram, since the electromagnetic safety valve (3) closes quickly when extinguishing a fire, the shutoff valve may (4) There is an advantage that it can be completely omitted.

(Effects of the Invention) As described above, the present invention includes a changeover switch linked to a manually operated member that can be freely switched between a closed position, an open position, and an ignition position, and the changeover switch is operable from the closed position of the member. The solenoid F:' of the electromagnetic safety valve interposed in the gas passage connected to the burner unit is switched from intervening in the capacitor charging circuit to intervening in the capacitor discharging circuit, and the safety valve is pressed by operating the member to the ignition position. The valve is opened and the igniter of the burner unit is activated, and the safety valve is maintained in the open state by the discharge current of the capacitor and the thermoelectromotive current of the thermocouple provided in the burner unit that reaches a predetermined value. 1. interlocking with the member and closing with the rotational opening; A sub-discharge circuit for the capacitor is provided, which is formed via a switch, so that following the operation of the manual operating member to the ignition position, the member is placed in the fully open position at a relatively early point before the capacitor has finished discharging. Then, after a predetermined period of time has elapsed, the extinguishing push button is suppressed, and the ignition push button is suppressed before the thermoelectromotive current due to the residual heat of the thermocouple drops to a predetermined value, so that the gas burner unit can be suppressed even when the amount of pressure is small. The raw gas released from n2 has a unique effect.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an IL combustor applied to the implementation of the present invention;
Fig. 2 is a circuit diagram of one embodiment of the present invention, Fig. 3 is an operational characteristic diagram of the specific circuit, Fig. 4 is a circuit diagram of another embodiment of the invention, and Fig. 5 is a diagram of a conventional circuit. An operating characteristic diagram is shown. (1)... Burner unit (2)... Gas passage (3
)...Solenoid safety valve (5)...Manual operation member αυ・
・・Push button for fire extinguishing (2)・・Thermocouple θ■・・Capacitor α4)・・Choice switch 0 phrase・・1E source H・
...Charging circuit (17)...Discharge circuit (]8)...Selector switch (a)...Sub-discharge circuit Patent applicant: 2 people other than Rinnai Corporation

Claims (1)

[Claims] A changeover switch is provided that is linked to a manually operated member that can be freely switched between a closed position, an open position, and an ignition position, and when the changeover switch is operated from the closed position of the member, an electromagnetic safety valve interposed in a gas passage connected to the burner unit is activated. switching the solenoid from intervening in the capacitor charging circuit to intervening in the capacitor discharging circuit, and operating the member to the ignition position to press open the safety valve and operate the igniter of the burner unit;
The safety valve is maintained in an open state by a discharge current of the capacitor and a thermoelectromotive current of a thermocouple provided in the burner unit that reaches a predetermined value, and the safety valve is linked to the member and closed in the open position. A combustion control circuit for a combustor, characterized in that a sub-discharge circuit for the capacitor is formed via a switch that is connected to the capacitor.