JPH0141010Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an ignition safety device for gas water heaters, and consists of a thermocouple that generates thermoelectromotive force when heated by the pilot burner flame, and an electromagnetic coil of the ignition valve that opens and closes the gas passage. The thermocouple safety circuit becomes
Connect the capacitor to a DC power source before ignition operation,
The charged capacitor is kept in a charged state, and when the ignition is operated, the charged capacitor is connected to the thermocouple safety circuit so that it is discharged, and the electric charge stored in the capacitor is discharged to the electromagnetic coil of the safety valve, and the safety valve is opened when the ignition is operated. This is a gas water heater equipped with a so-called quick-start ignition safety device that shortens the time it takes to press the ignition knob. In gas water heaters that allow ignition and extinguishing operations, if the ignition operation fails while water is flowing, the gas valve is opened by a hydraulic response device or the like while water is flowing.
In addition, the electromagnetic coil of the safety valve is energized and the safety valve is attracted and held open for a period of time until the discharge current of the capacitor decreases to a value below the release level of the safety valve. This is extremely dangerous as raw gas is blown out. Further, even if the ignition operation is performed when the water is stopped, if the hot water tap is opened to start hot water supply immediately after the pilot burner is ignited, the safety valve closes, closing the gas passage and stopping combustion.

This idea was made in view of the above-mentioned drawbacks, and its gist is that in a quick-start type ignition safety device, a switch for water flow detection is connected in parallel to the thermocouple safety circuit including the electromagnetic coil of the safety valve. A series circuit is connected between the switch and the switch that operates only when the ignition button is pressed, and when the ignition operation is performed while water is flowing, the discharge current of the capacitor will not flow to the electromagnetic coil, and the safety valve will be activated as soon as the ignition button is released. Returns to its original position and closes it, and also prevents the capacitor discharge circuit from being short-circuited, closing the gas passage and stopping combustion when the hot water tap is opened immediately after the ignition operation. It is.

Examples of this invention will be described below based on the drawings.

Figures 1 and 2 show an example of an ignition safety device in which this invention is applied to a gas water heater that can be turned on and off with a single touch using an ignition button and an extinguishing button. Thermocouple 1 that is heated by the burner flame and generates thermoelectromotive force
and a thermocouple safety circuit consisting of an electromagnetic coil 2 of a safety valve that opens and closes the gas passage, 3 supplies direct current 4 to an igniter 5 only when an ignition button (not shown) is pressed.
10 is a short-circuit switch that operates in conjunction with igniter switch 3 and turns on only when the ignition button is pressed; 8 is a short-circuit switch that is connected to It is a changeover switch. B connects the DC power source 4 to the igniter 5 using the igniter switch 3, and connects the spark plug 6 to the igniter 5.
The ignition circuit 7 is a capacitor that is connected to the DC power source 4 via the changeover switch 8 and the igniter switch 3 before the ignition operation, and is connected to the DC power supply 4 through the changeover switch 8 and the resistor 9 during the ignition operation. It is designed to discharge to the electromagnetic coil of thermocouple safety circuit A. Reference numeral 11 denotes a water pressure switch for water flow detection that is turned on by water pressure when water is flowing.The water pressure switch 11 is connected in series with the short circuit switch 10, and this series circuit is a thermocouple safety circuit made up of the electromagnetic coil 2. A is connected in parallel with the water pressure switch 11 and the short circuit switch 10.
The configuration is such that when turned on, the discharge current of the capacitor 7 is short-circuited.

With the above configuration, before the ignition operation, a charging circuit is formed by the capacitor 7, the changeover switch 8, the igniter switch 3, the DC power source 4, the resistor 9, and the electromagnetic coil 2, and the capacitor 7 is kept in a charged state, and when the ignition operation is performed, the ignition button is pressed. When is pressed, the safety valve is opened, and the gas passage to the main burner is closed by an on-off valve (not shown) that works in conjunction with the ignition button, and in conjunction with this, the changeover switch 8 is switched and the capacitor 7, resistor 9, and A discharge circuit is constituted by an electromagnetic coil 2, and the electric charge stored in the capacitor 7 flows to the electromagnetic coil 2 and excites it, and even if the ignition button is subsequently released, the safety valve is held open by attraction, and The on-off valve is opened, and gas is supplied to the pilot burner and also to the position of the gas valve provided in front of the main burner. Then, as the ignition button is pressed, the igniter switch 3 is also switched to the igniter 5 side, the DC power source 4 is connected to the igniter 5, the spark plug 6 continuously emits sparks, the pilot burner is ignited, and the pilot burner flame generates thermoelectric power. The pair 1 is heated and generates a thermoelectromotive current. The thermoelectromotive current flows to the electromagnetic coil 2, and the electromagnetic coil 2
A composite current of the discharge current of the capacitor 7 and the thermoelectromotive current flows through the capacitor 7, and the discharge current of the capacitor 7 eventually decreases, but the thermocouple 1 is sufficiently heated and the generated thermoelectromotive current increases, so the safety valve remains open. connected to. Then, when the hot water tap is opened as necessary, a gas valve provided in front of the main burner is opened by the action of the hydraulic response device, gas is supplied to the main burner, and the pilot burner flame ignites the hot water to start hot water supply.

Furthermore, when the hot water tap is opened immediately after the ignition operation and hot water supply starts, the water pressure switch 11 is turned on as water flows, but the short-circuit switch 10 is turned off at the same time as the ignition button is released, so the capacitor discharge circuit is short-circuited. The discharge current continues to flow through the electromagnetic coil 2 without any interruption. Therefore, even if the hot water tap is opened immediately after the pilot burner is ignited and before the thermoelectromotive force generated by the thermocouple 1 reaches a value sufficient to attract and hold the safety valve open, the safety valve will not open and combustion will continue. do. When you finish using the gas water heater, press the extinguish button to return the ignition button to its original position, and in conjunction with this, the changeover switch 8 is changed over, and the igniter switch 3 is changed at the same time as the ignition button is released. Since the switch is switched to the switch 8 side, the capacitor 7 is connected to the DC power supply 4, and the short circuit switch 10 is also linked to the changeover switch 8, and turns off when the ignition button is released.
Therefore, the state returns to the state before the ignition operation, and the capacitor 7 starts charging via the resistor 9 and the electromagnetic coil 2 in preparation for the next ignition operation.

The electromagnetic coil 2 is excited due to the thermal conductivity of the thermocouple 1, where a thermoelectromotive current flows for a while after the extinguishment, but the charging current of the capacitor 7 flows in the opposite direction to the thermoelectromotive current caused by the thermocouple 1, so the electromagnetic coil The excitation of No. 2 is released at the same time as the extinguishing button is pressed, and the safety valve is immediately closed.

Next, when the hot water tap is opened and water is flowing, and the ignition operation is performed, the water pressure switch 11 for water flow detection is turned on, so when the ignition button is pressed, it is linked to this, and when the ignition button is pressed, Only the short-circuit switch 10 is turned on, the discharge circuit of the capacitor 7 to the electromagnetic coil 2 is short-circuited, and the discharge current of the capacitor 7 is switched on by the changeover switch 8 and the short-circuit switch 10.
Since the discharge current does not flow through the electromagnetic coil 2 through a closed circuit consisting of the water pressure switch 11 for water flow detection, when the ignition button is released, the safety valve is also closed and the gas passage is closed, so that water cannot flow. Even if the ignition operation is performed when the main burner is closed, the raw gas will not leak from the main burner and it is safe. Even when the on-off valve is not used, raw gas leaks only when the ignition button is pressed (spark discharge), and the amount of leakage is extremely small and safe. Figure 2 shows the operation of switching the short circuit switch 10 in the above embodiment. The series circuit of the transistor 10' and the water pressure switch 11 for water flow detection is connected in parallel to the thermocouple safety circuit A, and The capacitor 7 is connected to the DC power supply 4 via the changeover switch 8 and the igniter switch 3 before the ignition operation, and is connected to the thermocouple safety circuit A through the changeover switch 8 during the ignition operation. To explain the operation of the second embodiment described above, before the ignition operation, a charging circuit consisting of the capacitor 7, the changeover switch 8, the igniter switch 3, and the DC power supply 4 is configured, and the capacitor 7 is It is maintained in a charged state, and when the ignition button is pressed, the safety valve is opened, and the changeover switch 8 and igniter switch 3, which are linked to the ignition button, are both switched, and the electric charge stored in the capacitor 7 is discharged. A discharge circuit consisting of a resistor 9, an electromagnetic coil 2, and a changeover switch 8 discharges electricity to the electromagnetic coil 2, energizes it, and attracts and holds the safety valve open. On the other hand, the igniter switch 3 is also switched in conjunction with the ignition button, the DC power source 4 is connected to the igniter 5 and the base of the transistor 10', the igniter 5 is activated, and the spark plug 6 is turned on. Ignite the pilot burner with more spark.Transistor 1
Even if the input current flows into the base of 0', the water pressure switch 11 connected to the emitter for water flow detection is open in the water stop state, so the transistor 10' is
In the OFF state, the series circuit between the transistor 10' and the water pressure switch 11 for detecting water flow is opened, and the discharge current of the capacitor 7 flows to the electromagnetic coil 2 to keep the safety valve open. When the ignition operation is performed while water is flowing, the water pressure switch 11 for water flow detection is closed by the action of the water pressure response device.
The transistor 10' receives an input current from the DC power supply 4 and turns on, and the series circuit between the transistor 10' and the pressure switch 11 for water flow detection is closed.
The discharge current of the capacitor 7 is short-circuited and does not flow to the electromagnetic coil 2, and the safety valve is not held by suction, so when the ignition button is released, the safety valve is also closed and the gas passage is closed.

As mentioned above, according to this invention, even if the ignition operation is performed while water is flowing, the discharge current of the capacitor is short-circuited only during the period when the ignition button is pressed (spark discharge), and does not flow to the electromagnetic coil. Therefore, the safety valve closes as soon as the ignition button is released, minimizing invalid discharge and saving energy. Therefore, if the ignition operation is performed while water is flowing, the safety valve will not be energized, so a large amount of raw gas will not be released from the main burner and pilot burner. In addition, even if the ignition operation is normal and the hot water tap is opened immediately after the pilot burner is ignited (immediately after the ignition operation), the safety valve closes and the gas passage is closed and combustion starts. There is no inconvenience of having it stop. Therefore, all dangers during ignition operation can be prevented by the electric circuit at a low cost, improving safety and improving ease of use.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the ignition safety device for a gas water heater according to this invention, and FIG. 2 is a circuit diagram showing a different embodiment. 1... Thermocouple, 2... Electromagnetic coil, 4... DC power supply, 7... Capacitor, 10... Short circuit switch, 11... Water pressure switch, A... Thermocouple safety circuit.

Claims (1)

[Scope of utility model registration request] Before the ignition operation, a capacitor 7 connected to the DC power supply 4 is connected to the thermocouple safety circuit A consisting of the thermocouple 1 and the electromagnetic coil 2 of the safety valve so that it discharges to the electromagnetic coil 2 during the ignition operation, and from the ignition operation. In a quick start type ignition safety device in which a safety valve is held open by suction, a switch 11 that is turned on when water is flowing and a switch 10 that is activated only when the ignition button is pressed are connected in series, and The capacitor 7 is connected in parallel to the thermocouple safety circuit A, and when the ignition operation is performed when water is flowing, the discharge current of the capacitor 7 is short-circuited by the switch 11 and the switch 10, so that it does not flow to the electromagnetic coil 2. Ignition safety device for gas water heaters.