JPH10311534A - Controller for gas instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of explosion sound upon re-starting after mistaken stopping by a method wherein the stopping of operation of a gas instrument can be released only when the supply of an electric power to a controller is stopped once. SOLUTION: When the operation of a gas instrument is stopped once by error, a controller 1 will not release the stopping condition by error even when a starting switch 11 is operated. In order to release the error stopping condition by the controller 1, a power supply chord 12 should be pulled from a socket off to intercept the supply of power. In order to restart a gas warm-air heater, the power supply chord 12 is to be inserted into the socket and, thereafter, a starting switch is to be operated. The power supply chord 12 is required to be pulled off from the socket once to re-start the operation of the gas warm- air heater and the re-starting can not be effected immediately after stopping by error in such a manner whereby unburned gas, remaining around a gas burner B during a period of time until the instrument is re-started, is diffused and explosion sound will not be generated upon re-igniting the gas warm-air heater.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control apparatus for a gas appliance which supplies gas to a burner by operating an ignition device and opening an electromagnetic gas valve by turning on a start switch.

[0002]

2. Description of the Related Art As a gas appliance, for example, a gas hot air heater includes a gas burner inside and a convection fan for mixing combustion gas generated by the gas burner with air to supply hot air of an appropriate temperature and blow it into a room. When the start switch of the gas hot air heater is turned on, first, the convection fan starts in advance and scavenges air around the gas burner. After a lapse of a predetermined time (pre-purge time) from the start of the convection fan, the ignition device is activated, and the electromagnetic gas valve attached to the gas supply pipe to the gas burner is opened to start supplying gas to the gas burner.

[0003] A control device for performing these controls forcibly stops the operation of the gas appliance when detecting an abnormality of the gas valve (a state in which the control device cannot control the opening and closing of the gas valve) during the operation of the gas appliance ( Error stop). As described above, when the gas appliance stops with an error, conventionally, when the start switch is pressed, the error stop in the sequence is released, and when the start switch is pressed again, the gas appliance is operated according to the above-described procedure.

On the other hand, when the start switch is turned on, the control device checks the operation of the gas valve and other devices to be controlled, and when an abnormality is detected for a predetermined time (determination time for abnormality detection), the abnormality of the device is detected. And the operation of the gas appliance is forcibly stopped.

[0005] The abnormality detection decision time is set shorter than the pre-barge time. Therefore, when the gas appliance is restarted by pressing the start switch twice after an error stop, if the gas valve remains in an abnormal state, the operation of the gas appliance is forcibly stopped before the pre-purge time elapses, and the gas appliance is stopped. The ignition device will not operate with the valve in an abnormal state.

[0006]

When a pre-purge time is provided as in the above-described conventional apparatus, if gas (hydrocarbon) remains around the burner at the time of startup, it is discharged into the room by a convection fan without burning. Failure occurs. Therefore, in recent years, there is a tendency that the sequence is programmed such that when the start switch is turned on, the ignition device is immediately activated without providing a pre-purge time. However, if the engine is restarted immediately after the error stop, the ignition device may be started without the gas valve being once closed, which may cause an explosion sound at the time of ignition.

[0007] In view of the above problems, an object of the present invention is to provide a control apparatus for a gas appliance which prevents explosion sound from being generated at the time of restart after an error stop.

[0008]

According to the present invention, there is provided a gas supply system for supplying gas to a burner by operating an ignition device and opening an electromagnetic gas valve by turning on a start switch. A control device for the appliance,
The operation of the gas appliance is stopped when the abnormality of the gas valve is detected, wherein the suspension of the operation of the gas appliance can be released only when the power supply to the control device is once interrupted.

The explosion sound is generated at the time of restart after an error stop because the entire control device is not reset after the error stop but only the error stop state is reset. In the conventional control device, the error stop is reset and restarted only by pressing the start switch. In the present invention, even if the start switch is pressed, the control is not reset, and the reset is performed only by temporarily stopping the power supply to the control device. As described above, when the reset is performed by temporarily stopping the power supply, the entire control device is reset. For example, in a gas appliance operated by a commercial power supply, the control device cannot be reset unless the plug is once removed from the outlet. Therefore, in the case of an error stop, the entire control device is reset, and the gas valve is not restarted unless the gas valve is returned to a normal state.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, FH is a gas hot air heater, and a gas burner B disposed in a combustion case FB.
Is mixed with the air sucked from the air inlet I by the convection fan F and blown into the room from the air outlet E as an appropriate temperature hot air. In addition, P is an ignition plug (ignition device) for generating spark discharge between the gas burner B and performing ignition.

Referring to FIG. 2, gas ejected from nozzle N attached to the tip of gas supply pipe 2 and air entrained by the ejector effect are supplied into the mixing pipe of gas burner B. A first gas valve 21, a second gas valve 22, and a thermal power control valve 23 are sequentially attached to the gas supply pipe 2 in series from the upstream side. First gas valve 21 and second gas valve 2
Numeral 2 denotes an electromagnetic on-off valve, and the thermal power control valve 23 is a proportional control valve. Then, the first gas valve 21 and the second gas valve 2
2. Both the thermal power control valves 23 are connected to the control device 1, and the control device 1 controls opening / closing and opening. In addition, a start switch 11 is connected to the control device 1, and a power cord 12 for receiving power supply from a commercial power supply is attached. Further, a thermocouple TC for confirming that the gas burner B is ignited and a drive motor M for the convection fan F are connected to the control device 1.

When the start switch 11 is turned on by pressing the start switch 11, the control device 1 immediately activates the ignition plug P to generate a spark discharge between the control device 1 and the gas burner B, and also causes the first gas valve 21 and the second gas valve 22 to operate. , A relatively large current is caused to flow, and the thermal power control valve 23 is fully opened.
Then, a large amount of gas is supplied to the gas burner B, and ignition is reliably performed. When the control device 1 detects that the gas burner B is ignited via the thermocouple TC, the operation of the ignition plug P is stopped, and the first gas valve 21 and the second gas valve 2 are stopped.
The value of the current flowing through 2 is reduced in a range sufficient to maintain the valve open state. Further, the opening of the thermal power control valve 23 is changed to an opening corresponding to the temperature set by a temperature setting unit (not shown).

When the start switch 11 is pressed, the controller 1
Always checks the operation of the first gas valve 21 and the second gas valve 22. Then, the first gas valve 21 and the second gas valve 22
When the control content of the control valve 1 does not match the actual valve opening state, the control device 1 determines that an error has occurred and forcibly stops the operation of the gas warm air heater FH (error stop). The control device 1 according to the present invention does not release the error stop state even if the start switch 11 is operated once the error stops, and no other release switch or the like is provided. In order to release the error stop state by the control device 1, the power cord 12 must be disconnected from an outlet (not shown) to cut off the power supply. To restart the gas hot air heater FH, the power cord 12 is plugged into an outlet, and then the start switch 11 is pressed and operated. As described above, in order to restart the gas hot air heater FH, it is necessary to disconnect the power cord 12 from the outlet once. Unburned gas remaining around B diffuses, and no explosion sound is generated at the time of re-ignition.

[0014]

As is clear from the above description, according to the present invention, even if a gas appliance which is programmed so that gas (hydrocarbon) is not discharged outside the machine at the time of normal startup stops even if an error stops, The explosion sound can be prevented from being generated at the time of restart.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating the structure of a gas hot air heater.

FIG. 2 is a mechanism diagram illustrating a gas supply system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control device 2 Gas supply pipe 11 Start switch B Gas burner FH Gas hot air heater

Claims (1)

[Claims] 1. A control device for a gas appliance for supplying gas to a burner by operating an ignition device and opening an electromagnetic gas valve by turning on a start switch, wherein an abnormality of the gas valve is detected. Then, in the apparatus for stopping the operation of the gas appliance, the stop of the operation of the gas appliance can be released only when the power supply to the control device is once interrupted.