JPS63207918A - Combustion controller of gas water heater - Google Patents

Abstract

PURPOSE:To prevent a controlling computer from running away due to spark noise or the like generated at the time of an igniting operation and to improve the safety of the gas water heater by interposing and connecting a safety switch in and to a circuit for operating a solenoid valve, said safety switch being turned on and off in linkage with ON and OFF of a water current switch. CONSTITUTION:In the case where a safety switch 30 is constituted of a contact 31a of a relay 31 connected in series to a water stream switch 18, a controlling computer 24 runs away due to a spark noise or the like from an ignition circuit 19, a burner 5 is not ignited, and a relay 28 is supplied with power and operated dispite a fact that a signal indicating no flame is emitted from a flame detection circuit 24 due to a comparator 32 and the contact 28a of the relay 28 has been closed, a hot water supply tap 9 is closed and the water stream switch 18 is turned off and a relay 31 is inactivated, whereby it is possible to open the contact 31a of the relay 31 to open a driving circuit 29, and to close a second solenoid valve 14. Even if the controlling computer 24 runs away, it is possible to immediately stop the discharge of a raw gas.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a combustion control device for a gas water heater using a computer.

(Prior Art) As shown in FIG. 3, a conventional device of this kind has a water flow detection circuit that detects whether the water flow switch a is on or off. A spark detection circuit e for detecting the presence or absence of a flame, a flame detection circuit Q for detecting the presence or absence of flame of the burner f, an output signal from the water flow detection circuit, an output signal from the spark detection circuit e, and an output signal from the flame detection circuit 0. It is equipped with a control computer j that inputs an output signal and controls the opening and closing of the solenoid valve 1 interposed in the gas supply path of the burner f, and after opening the hot water tap k and detecting the water flow, that is, the water flow detection circuit is connected to the water flow switch. After detecting that a is turned on, the control computer j causes a pre-purge to be performed, and then drives the ignition circuit C to generate a spark between its electrodes d and d, and opens the main valve l, which is activated by the spark detection circuit e. After the presence of a spark is detected, the burner f is ignited by opening the solenoid valve i, and after the presence of a flame in the burner f is detected by the flame detection circuit q, the combustion of the burner f is controlled by the temperature control circuit. It is known that proportional control is performed in response to a signal.

(Problems to be Solved by the Invention) However, according to the above conventional device, spark noise and radiation noise from the ignition circuit C enters the control computer j during the ignition operation of the barb f, and if the control computer Suppose that computer j goes out of control, burner f is not ignited, and even though the flame detection circuit Q is outputting a flame heat signal of burner f, the control computer j sends a message to the drive circuit m of solenoid valve i that It is possible that the open signal continues to be emitted, and in this case, raw gas continues to be released, which is dangerous.

(Means for Solving the Problems) The present invention aims to provide a device that eliminates the above-mentioned danger, and is provided between a water flow detection circuit that detects on/off of a water flow switch and an ignition electrode of an ignition circuit. A spark detection circuit that detects the presence or absence of a generated spark; a flame detection circuit that detects the presence or absence of a burner flame; and an output signal from the water flow detection circuit and an output signal from the spark detection circuit that drives the ignition circuit. A control computer that inputs the output signal of the flame detection circuit and controls the opening and closing of the solenoid valve interposed in the gas supply path of the burner, wherein the solenoid valve drive circuit controls the on/off of the water flow switch. It consists of interlocking safety switches that turn on and off in conjunction with each other.

(Function) The present invention has the above configuration, and according to this, the control computer goes out of control due to spark noise etc. generated during ignition operation, and even though the flame detection circuit is outputting a signal indicating the flame heat of the burner, If the control computer continues to issue a solenoid valve open signal to the solenoid valve drive circuit,
When the hot water tap is turned off and the water flow switch is turned off, the safety switch is also turned off and the drive circuit is opened, so the solenoid valve is closed and the continued release of raw gas is prevented, making it safe.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

In Figure 1, (1) has a ventilation hole (2) at the bottom,
A gas water heater main body including an exhaust pipe (3) at the top,
Inside the main body (1), a heat exchanger (4) and a burner (5) for heating the heat exchanger (4) are provided in the middle part, and the burner (5) is provided in the lower part.
The combustion chamber (8) is equipped with a direct current fan (6) that supplies combustion air to the exhaust pipe (3), and a combustion chamber (8) that connects to the exhaust port (D) connected to the exhaust pipe (3) is housed in the upper part. The water sent from the water supply pipe (10) on the upstream side of the heat exchanger (4) is heated in the heat exchanger (4), and the hot water is discharged from the hot water outlet pipe Crt+ on the downstream side of the heat exchanger (4). At the same time, the combustion exhaust gas is discharged to the outside through the exhaust stack (3).

In the figure, (IZ indicates a gas supply path connected to the burner (5) via the fan (6), and the gas supply path 03 includes a first solenoid on-off valve (13) which is the main valve and a second solenoid on-off valve (13) which is the solenoid valve. Valve (+
41 and an electromagnetic proportional valve (+51) were installed.

The control of the gas water heater during ignition operation is carried out by a control circuit ae shown in detail in FIG. +!!l is equipped with an ignition electrode @■ and is a burner (
5) The ignition circuit that ignites the ignition electrode, ■ is the spark detection circuit that detects the spark that occurs between the ignition electrodes, ■ is the flame detection circuit for the flame rod type 0 circuit, [phase] is the ignition circuit (which drives I9 and The output signal from the water flow detection circuit■ and the output signal from the spark detection circuit■ and the flame detection circuit■
A control computer inputs the output signals from the controller and controls the opening and closing of the first and second electromagnetic valves (13), the opening of the electromagnetic proportional valve a9, and the rotation speed of the fan (6). When the hot water tap (9) is opened and the water flow switch (to) is turned on, and the water flow detection circuit (171) generates a water flow switch ON signal of 0 seconds by the photocoupler (■), the control computer @ The fan (6) is rotated to the minimum speed to perform a blip-purge, and after the blip-purge is completed, the ignition circuit (191) is driven and the first electromagnetic on-off valve a3 is opened, and a spark signal is generated from the spark detection circuit 0 by the comparator ■. When this happens, the control computer @ turns on the transistor ■, energizes the relay ■ connected to it, and closes its contact □□□a).

The contact (28a) is connected to the drive circuit of the second electromagnetic on-off valve a@, that is, the coil of the second electromagnetic on-off valve (I@), to the DC power source ω.
14a), and according to the conventional method in which only this contact (28a) is interveningly connected to the drive circuit (2), when the contact (28a) is closed, the coil (14a) is energized, the second electromagnetic on-off valve (+41) is opened, the minimum flow of gas is supplied to the burner (5), and the burner (5) is slowly ignited. However, during the above-mentioned ignition operation, In the unlikely event that the control computer ■ goes out of control due to spark noise or radiation noise from the ignition circuit a!Il, the burner (5) will not be ignited in the conventional drive circuit ■ described above, and the burner (5) will not be ignited from the flame detection circuit ■. 5) Despite the flame signal being output, the transistor is turned on by the control computer [phase], relay ■ is energized, its contact (ma) is energized, and its contact (28
There is a possibility that a) is closed, and in this case, the second electromagnetic on-off valve aΦ continues to be opened, and raw gas continues to be released, which is dangerous.

Therefore, in the present invention, the drive circuit (2) includes the water flow switch 0.
3 for e on/off! ! This is an intervention connection to a safety switch ω that turns on and off depending on the movement.To explain this in detail, the safety switch ω is composed of a contact point (31a) of a relay (3) connected in series to a water flow switch [phase], and the ignition circuit (The control computer QΦ goes out of control due to spark noise etc. from I9, and the burner (5) is not ignited, and even though the flame detection circuit ■ is generating a flame heat signal from the comparator ■, the control computer [phase] When the relay ■ is energized and its contact ■a) is closed, the hot water tap (9) is closed, the water flow switch ■ is turned off, and the relay ■ is activated.
By deactivating the contact (31a), the drive circuit ■ can be opened and the second electromagnetic on-off valve aΦ can be closed, so even if the control computer [phase] goes out of control, no damage will occur. Gas release can be stopped immediately.

In addition, when the hot water tap (9) is closed, the water flow switch (to)
is turned off and the control computer [phase] is reset and ready for restart.

In the case of normal operation where the control computer @ does not go out of control during ignition operation, a flame presence signal is generated from the flame detection circuit, and then the control computer [phase] The opening degree of the electromagnetic proportional valve (+! The burner (5
) is used to proportionally control the combustion amount of the water supply pipe (IG).
The water sent from the outlet was heated in a heat exchanger (4) so that hot water at a predetermined temperature could be obtained from the outlet pipe at+.

In Fig. 2, ■ indicates a diode for preventing backflow, ■ indicates a capacitor for noise absorption, and ■ and ■ indicate diodes for input/output protection of the comparator ■.

(Effects of the Invention) According to the present invention, the control computer can be prevented from running out of control during ignition operation by simply intervening a safety switch that turns on and off in conjunction with the on and off of the water flow switch in the drive circuit of the solenoid valve. However, if the solenoid valve opens and raw gas is released even though the burner is not ignited, the hot water can be immediately stopped, the water flow switch can be turned off, and the solenoid valve can be closed. This has the effect of improving safety compared to the conventional method.

[Brief explanation of the drawing]

FIG. 1 is a cutaway side view showing an example of the implementation of the present invention, FIG. 2 is a circuit diagram showing the main parts thereof, and FIG. 3 is a circuit diagram of a conventional example. (5)...Burner, 021...Gas supply path, 0Φ・
...Second electromagnetic on-off valve (electromagnetic valve), ■...Water flow detection circuit, (18...Water flow switch, a9...Ignition circuit, ■
...Ignition electrode, ■...Spark detection circuit, ■...
Flame detection circuit, ■... Control computer, (31a
)...Contact (safety switch). go outside

Claims (1)

[Claims] A water flow detection circuit that detects whether the water flow switch is on or off;
A spark detection circuit that detects the presence or absence of a spark generated between the ignition electrodes of an ignition circuit, a flame detection circuit that detects the presence or absence of a burner flame, and an output signal from the water flow detection circuit and the spark that drives the ignition circuit. A control computer that inputs the output signal from the detection circuit and the output signal of the flame detection circuit to control the opening and closing of the solenoid valve interposed in the gas supply path of the burner, wherein A combustion control device for a gas water heater that is constructed by intervening and connecting a safety switch that turns on and off in conjunction with the on and off of a water flow switch.