JPH02187517A - Combustion controlling circuit for burner - Google Patents

Abstract

PURPOSE:To prevent the leakage of gas by providing a discharge subcircuit for a capacitor, which is formed through a switch that is closed cooperatively with an operation for opening a main gas passage communicating to a main burner. CONSTITUTION:When a faucet is opened simultaneously with, or in a little delay, the manipulation of igniting sub-burners 2 which are in the state of non- ignition, the normally closed switch of a change-over switch 22 is opened cooperatively with the opening of an automatic valve 7. On the other hand, since the normally open switch thereof is closed, the electric charge of a capacitor 17 is discharged through a discharge circuit 21 in which a resistor 23 is interposed and through a discharge sub-circuit 25 in which a resistor 26 is interposed, so that the discharge current value of the capacitor 17 drops sharply. Accordingly, the discharge current value rapidly reaches the value of a released current that closes a solenoid safety valve 4. Therefore, when the sub-burners 2 are not ignited, the solenoid safety valve 4 is closed rapidly, and the release of a raw gas can be controlled as promptly as possible.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a combustion control circuit for a combustor equipped with an electromagnetic safety valve.

(Prior Art) Conventionally, a combustion control circuit for this type of combustor includes a changeover switch that operates in conjunction with manual opening of an electromagnetic safety valve interposed in the gas passages of the main burner and the auxiliary burner. The solenoid is switched from intervening in the charging circuit of the capacitor to intervening in the discharging circuit of the capacitor, and the safety valve It is known that the valve is held in an open state.

In addition, a normally closed switch that opens in conjunction with the operation of opening the main gas passage connected to the main burner is interposed in the discharge circuit of the capacitor of the combustion control circuit, so that if the sub burner does not ignite due to a firing error, the main burner There are also known burners that prevent a large amount of raw gas from being released from the main burner for a relatively long time when the main gas passage connected to the main burner is opened (for example, the
7-105529).

(Problems to be Solved by the Invention) In the former prior art described above, if the extinguishing operation is performed after the ignition operation and before the end of the discharge of the capacitor, an electric charge remains in the capacitor. In addition, in the latter case of the conventional technology, when the normally closed switch is opened before the discharge of the capacitor is completed due to water flow operation relatively quickly following the ignition of the auxiliary burner by the ignition operation, an electric charge remains in the capacitor. . Therefore, during such a fire extinguishing operation or a fire extinguishing operation after a relatively quick water flow operation, the solenoid of the electromagnetic safety valve is inserted into the capacitor's charging circuit, and a charging current of opposite polarity is applied to the thermoelectromotive current due to the residual heat of the thermocouple of the solenoid. However, a sufficiently large charging current does 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, if the ignition push button is pressed shallowly to the extent that the ignition switch does not close during a short period of time after such a fire extinguishing operation or after a relatively quick water flow operation following the ignition operation, the shutoff valve will open. Since the valve is opened, gas leaks from the auxiliary burner, and furthermore, when the water faucet is opened, gas is also released from the main burner, causing an inconvenience.

An object of the present invention is to provide a combustion control circuit free from such disadvantages.

(Means for Solving the Problems) The present invention is provided with a changeover switch that operates in conjunction with manual opening of an electromagnetic safety valve interposed in the gas passages of the main burner and the sub-burner, and the changeover switch causes the solenoid of the safety valve to be connected to the capacitor. Switching from intervention in the charging circuit of the capacitor to intervention in the discharging circuit of the capacitor, the safety valve is opened by the discharge current of the capacitor and the electromotive current that reaches a predetermined value in the thermocouple facing the sub-burner. The device is characterized in that a sub-discharge circuit for the capacitor is formed via a switch that is opened in conjunction with the opening operation of the main gas passage connected to the main burner.

(Example) An embodiment of the present invention will be described with reference to a water heater shown in the drawings.

In Fig. 1, (1) is the main burner, (2) is the auxiliary burner, and (3) is the gas passage that supplies combustion gas to the main burner (1). 4) and
It consists of a shutoff valve (5) and an automatic valve (7) that responds to a hydraulic response member (6), and the shutoff valve (5) and electromagnetic safety valve (4) can be suppressed and opened by a manual operation member (8). be excused. To explain this in detail, the operation member (8) is an ignition push button (8a) that passes through the operation panel (9) on the front of the water heater.
and an operating rod OG inserted into the gas passageway (3) in front of this, and the above-mentioned shutoff valve (5) is attached to the operating rod GO.
is provided, and a return spring (
8b), the shutoff valve (5) is suppressed to open at the intermediate position of the pressing operation, and at the end position, the electromagnetic safety valve (4) is pressed to open via the lever (12). I made it so that it would be done. The auxiliary burner (2) is composed of a pilot burner (2b) and a constant flame burner (2a), and the constant gas is connected to the constant flame burner (2a) between the shutoff valve (5) and the automatic valve (7). Combustion gas is supplied through the passage I'l'D, and the pilot burner (2b) has a narrow diameter part (10a) provided on the side wall of the gas passage (3) and the operating rod GO.
The gas passage (
Combustion gas is supplied through the gas passage aΦ which is connected between the shutoff valve (5) of 3) and the automatic valve (D).The ignition valve 03 is connected to the end position of the ignition push button (8a) The valve is configured to open according to suppression. (+51 is a thermocouple facing the sub-burner (2), (IG is also a thermocouple facing the sub-burner (2)
), the igniter rAaO is actuated by an ignition switch (16a) which closes in the suppressed position past the intermediate position of the push button (8a).

The present invention relates to a circuit for controlling the safety valve (4) interposed in the gas supply path (3) of the combustor.

FIG. 2 shows a circuit of this embodiment.

In the same figure, the solenoid (4a) of the electromagnetic safety valve (4)
are the movable contact (18c) and fixed contact (18a) of the changeover switch ■, which is closed when the capacitor ■ is extinguished in the combustor.
and a changeover switch ■ which is connected to the charging circuit ■ of the capacitor (17) connected to the power source agl via the ignition switch (16a), and is closed when the push button (8a) is pressed. movable contact (18
c) and a discharge circuit (2) which is discharged via a fixed contact (18b), the automatic valve (7)
The fixed contact 22a) and the movable contact CI!, which constitute the normally closed switch of the changeover switch ■, which operates in conjunction with the valve opening operation of the switch !
2c) is inserted, and a resistor is connected in parallel with the normally closed switch, and a capacitor (+7) is connected in series with the fixed contact Eb) and movable contact 22c) that constitute the normally open switch of the changeover switch (2). A resistor (2) is connected to one end to form a capacitor (+71 sub-discharge circuit (2).

Next, its operation will be explained.

When the operating member (8) is pressed by the ignition push button (8a), the switch (■) is switched to the side that closes the discharge circuit (■), and then the shutoff valve (5) opens at the intermediate position and closes the electromagnetic valve (5) at the terminal position. Push open the safety valve (4) and close the ignition switch (16a) at the same time. For this reason, the capacitor (+
The charge stored in 71 starts discharging via the normally closed switch of the changeover switch (■) that intervenes in the discharge circuit (2), and the solenoid (4a) is excited by this discharged charge and holds the electromagnetic safety valve (4) open. .

Therefore, even if the push button (8a) is released, the electromagnetic safety valve (4) remains open. Incidentally, during this operation, the operating member (8) is locked by the locking device ω at an intermediate position to keep the shutoff valve (5) open when the suppressing operation is released.

The charge in the capacitor (17) decreases over time and reaches the release current value of the electromagnetic safety valve after a predetermined time has elapsed, but when combustion occurs normally in the auxiliary burner (2),
Since thermoelectromotive force is generated in the thermocouple (115), the electromagnetic safety valve (4) continues to be held open.

However, if the water faucet is opened at the same time as the ignition operation or a little later than the ignition operation when the sub burner (2) is not lit, the automatic valve 0
In conjunction with the opening of the valve in 7), the normally closed switch of changeover switch ■ is opened, and on the other hand, the normally open switch is closed.
Since the charge of the capacitor (17) is discharged through the discharge circuit (2) in which the resistor (2) is interposed and the sub-discharge circuit (2) in which the resistor (2) is interposed, the discharge current value of the capacitor (17) rapidly decreases.

As a result, the withdrawal current value that closes the electromagnetic safety valve (4) is quickly reached. Therefore, when the auxiliary burner (2) is not ignited, the electromagnetic safety valve (4) closes quickly, and the release of raw gas can be suppressed as much as possible.

On the other hand, if the sub-burner (2) is ignited but the thermocouple a9 is not generating the specified electromotive force and the water faucet is opened and the gas passage (3) is opened, the resistor ■ Since the composite current of the discharge current through the thermocouple and the thermoelectromotive current of the thermocouple (151) can be kept above the withdrawal current value of the electromagnetic safety valve (4), the electromagnetic safety valve (4) is kept open and cannot be closed. There is no.

To extinguish the fire, press the fire extinguishing push button QΦ to unlock the locking device ω, the operating member (8) automatically returns to its original position due to the spring (8b), and this action closes the cutoff valve (5), shutting off both burners. The supply of fuel gas to (1) and (2) is cut off to extinguish the fire, and the return operation of the operating member (8) switches the selector switch (■) to the side that closes the charging circuit.

Next, for example, following the ignition of the auxiliary burner (2), the water is turned on relatively quickly, then the water is stopped after a predetermined period of time, and then the fire extinguishing operation is performed by pressing the extinguishing push button @, and then for a short time. The operation when the ignition push button (8) is pressed during this period and a suppression operation in which the amount of suppression is particularly small is performed will be described.

If water is supplied after the ignition operation and before the capacitor ■ has finished discharging, the residual charge in the capacitor (17) will continue to flow through the resistance ■
The fire extinguishing push button [phase]
When a sufficiently large charge 7a current flows from the power supply a9 and the residual heat cancels out the thermoelectromotive current of the thermocouple (15+) flowing to the solenoid (4a), the electromagnetic safety valve (4a)
) closes immediately.

In this way, even if the ignition push button (8a) is repeatedly pressed within a short period of time after pressing the fire extinguishing push button [phase] to an extent that does not close the ignition switch (IGa), the auxiliary burner (2) will not be activated. There is no gas leakage, and even if the faucet is opened in this state, gas will not be released from the main burner (1).

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

This characteristic applies to the capacitor C in the circuit shown in Figure 2.
″b is 8.3F, resistance ■ is 2.5Ω, resistance ■ is 0.3Ω
Although not shown, the capacitor (17
) when a 1.3Ω resistor is inserted in the charging/discharging circuit.

In Figure 3, A (-X-) is the solenoid (4a)
The charging/discharging current of capacitor 0, B(-0-), which flows to
(--) indicates the combined current of A and B flowing through the solenoid (4a), and the current value shown below the zero line indicates the polar current value flowing through the solenoid (4a) from the top to the bottom of the figure.

According to Fig. 3, if water is supplied after 2 seconds after ignition when the capacitor ■ has not discharged much, then the water is stopped after a predetermined period of time, say 7 seconds, and then the fire is extinguished after a short period of time, say 1 second. The voltage applied to the solenoid (4a) is 1
．． 158V, the charging current flowing is 445mA. On the other hand, since the thermal electromotive current of the thermal lightning pair QSI due to residual heat at the time of extinguishing is 400 mA, the combined current is 45 mA, and the withdrawal current value (100 mA) that closes the electromagnetic safety valve (4)
A) The following is true. Therefore, the electromagnetic safety valve (4) closes almost simultaneously with the extinguishing operation.

Figure 6 shows the circuit disclosed in the above-mentioned Japanese Utility Model Publication No. 57-105529, with the same conditions for the parts common to the circuit shown in Figure 2, and ignition, water flow, water shutoff, and extinguishing under the same conditions. The operating characteristic diagram at the time is shown.

In the figure, B' and C' correspond to A and B in FIG.

Each corresponds to C. As is clear from this figure, according to the circuit disclosed in the publication, the combined current flowing through the solenoid of the electromagnetic safety valve at the time of extinguishing the fire is 110 mA, which is greater than the withdrawal current. Therefore, the electromagnetic safety valve (4) does not close at the same time as the fire extinguishing operation, but remains open until the thermal lightning pair is naturally cooled.

FIG. 4 shows a circuit diagram of another embodiment of the invention.

This circuit is a modification of the circuit shown in the second diagram, in which the resistor (■) of the circuit shown in the second diagram is connected in series with the normally closed contact of the changeover switch (■) and in parallel with the resistor (■) via the normally closed contact. It is. Since the resistor (2) suppresses the value of the discharge current flowing to the discharge circuit (2) through the normally closed contact of the changeover switch (2), there is an advantage that wear and tear associated with opening and closing of the contact can be reduced.

Other operations are similar to those shown in the second figure.

FIG. 5 shows yet another embodiment of the invention. This embodiment circuit does not require a normally closed switch that operates in conjunction with the opening operation of an automatic valve (n) in the discharge circuit ■, as in the circuits shown in FIGS. 2 and 4, and only the auxiliary discharge circuit ■ A normally open switch Q^) that opens in conjunction with the opening operation of the automatic valve (7) is inserted.

According to this circuit, unlike the circuits shown in Figures 2 and 4, the resistor ■ is not inserted in the discharge circuit ■, so the charge on the capacitor a7) is more quickly charged than in the circuits shown in Figures 2 and 4. Therefore, the object of the present invention can be achieved more reliably than in the embodiments described above.

Incidentally, since the above embodiment is applied to a water heater,
Although the opening operation of the gas passage is performed by an automatic valve (1) that responds to water pressure, the circuit of the present invention can also be applied to a bath control circuit, etc. In this case, a manual valve that is opened and closed manually is used to open the gas passage. Open and close passages.

In this way, according to the present invention, a changeover switch is provided that is linked to manual opening of the electromagnetic safety valve, and the changeover switch switches the solenoid of the safety valve from intervention in the capacitor charging circuit to intervention in the capacitor discharge circuit. The safety valve is maintained in an open state by the discharge current of the capacitor and the thermoelectromotive current of the thermocouple facing the sub-burner which has reached a predetermined value. Since we have provided a sub-discharge circuit for the capacitor that is formed via a switch that is closed in conjunction with the circuit operation, the extinguishing operation is performed after the ignition operation and before the end of the discharge of the capacitor, and then the electromotive force due to the residual heat of the thermocouple is Gas will not leak from the secondary burner even if the ignition push button is pressed lightly to the extent that the ignition switch does not close during a short period of time before the ignition switch falls to a predetermined value. This has the effect of preventing gas from being released from the burner.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a water heater to which the present invention is applied, Fig. 2 is a circuit diagram of an embodiment of the present invention, Fig. 3 is a diagram of the operating characteristics of the specific circuit, and Fig. 4 is a sectional view of a water heater to which the present invention is applied. FIG. 5 shows a circuit diagram of still another embodiment of the present invention, and FIG. 6 shows an operating characteristic diagram of a conventional circuit. (1)...Main burner (h...Sub-burner (
3)... Gas passage (4)... Solenoid safety valve (4a)... Solenoid a9 of the electromagnetic safety valve... Thermocouple OO... Igniter (17)... Capacitor aO... Changeover switch Os...Power supply...Charging circuit■...Discharging circuit
■...Choice switch CI'2A)...Normally open switch [Phase]...Push button for extinguishing ■...Resistance
■...At the time of sub-discharge circuit Applicant: Rinnai Co., Ltd. Representative: Kingai Kitamura 3 people 1 Figure 3 Figure 6

Claims (1)

[Claims] A changeover switch is provided that is linked to manual opening of an electromagnetic safety valve interposed in the gas passages of the main burner and the sub-burner, and the changeover switch switches the solenoid of the safety valve from intervention in the capacitor charging circuit to intervention in the capacitor discharge circuit. In the device in which the safety valve is maintained in an open state by the discharge current of the capacitor and the electromotive current reaching a predetermined value of the thermocouple facing the sub-burner, the main gas connected to the main burner A combustion control circuit for a combustor, characterized in that a sub-discharge circuit for the capacitor is formed via a switch that is closed in conjunction with the opening operation of the passage.