JPH0217321A - Ignition device - Google Patents

Abstract

PURPOSE:To enable the most appropriate ignition to be carried out in a combustion equipment for gas using an ignition heater slow in temperature increase by a method wherein a combustion valve is opened after a temperature of an ignition heater is increased up to such a temperature as one required for performing ignition. CONSTITUTION:A high level signal applied to a point C in response to an igniting operation, a transistor 6 is turned ON and then a photo-triac 5 is closed. With this arrangement, an ignition heater 1 is energized and heated. An electrical resistance of the ignition heater 1 is set to a positive temperature characteristic, potentials VA and VB at the points A and B are applied to satisfy a relation of VB>VA, an output of a comparator 31 of a temperature sensing means 3 is set to a high level and then a fuel valve 44 is closed. Then, as a temperature of the ignition heater 1 is increased to satisfy a relation of VA>VB, an output from a computer 31 is reversed to have a low level, a photo-coupler 32 is turned OFF and the fuel valve 44 is opened. With this arrangement, it is possible to perform the most appropriate ignition under all conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an ignition device used in a combustion appliance that uses gas, oil, etc. as fuel and uses an ignition heater with a slow temperature rise.

2. Description of the Related Art In the past, spark ignition using high-voltage discharge was commonly used as an ignition device for combustion appliances that use gas, oil, etc. as fuel because of its durability and ease of maintenance.

However, in recent years, combustion appliances controlled by electronic circuits have become commonplace, and electrical noise caused by sparks can sometimes cause the electronic circuits to malfunction.As a result, ignition using ignition heaters, which generate less electrical noise, has been reconsidered. It's coming. In particular, recently, a highly durable and reliable ignition heater called a ceramic heater, in which a heater material is provided inside a porcelain material and sintered, has been developed and is being applied to ignition devices for combustion appliances.

Problems to be Solved by the Invention However, because ceramic heaters have a structure in which the heater material is protected by a ceramic layer, there are problems in that the load heat capacity is large and the temperature rise time is long. If the ignition device is energized and the fuel valve is opened at the same time, fuel will be supplied before the ignition temperature is reached, resulting in the spouting of unburned gas and unburned petroleum vapor, resulting in the risk of poisoning and odor. There was a problem in that when fuel leakage occurred and ignition occurred, the excess fuel that spouted out was combusted all at once, resulting in explosive ignition. In order to prevent this, it is possible to use a timer to delay the opening time of the fuel valve from the energization of the ignition device, but the temperature rise time may vary due to differences in conditions such as the ambient temperature and the residual heat of the ignition heater during re-ignition operation. There is a problem in that it is difficult to optimally ignite under all circumstances under a fixed timer time that is not constant and is set under certain conditions.

In order to solve the above problems, the present invention detects the temperature of the ignition heater and automatically opens the fuel valve when the temperature necessary for ignition is reached, thereby achieving optimal ignition under all circumstances. The purpose is to provide an ignition device that can.

Means for Solving the Problems In order to achieve the above object, the ignition device of the present invention uses gas,
an ignition heater for igniting a combustion appliance that uses petroleum or the like as fuel; a resistance bridge that includes the ignition heater as a component and detects the electrical resistance of the ignition heater; and a resistance bridge that detects the potential equilibrium point of the resistance bridge. A temperature detecting means for detecting the temperature of the ignition heater; and a fuel valve opening/closing means for opening and closing a fuel valve according to an output signal of the temperature detecting means; It is configured with a function to open the valve.

According to the above-described configuration, the resistance bridge, which is unbalanced before the ignition operation, becomes balanced when the ignition heater heats up due to the ignition operation, changes the electrical resistance value, and reaches the ignition temperature.
At this time, the temperature detection means operates and controls the fuel valve opening/closing means to open the fuel valve, so that fuel is supplied after the temperature of the ignition heater has risen reliably, regardless of the ambient temperature or the initial temperature of the ignition heater. This makes it possible to ignite the fire optimally under the circumstances.

The embodiment diagram is a configuration diagram showing an embodiment of the present invention. 1 is an ignition heater, 2 is a resistance bridge including the ignition heater 1 as one of its components, 3 is a temperature detection means, and 4 is a fuel valve opening/closing means. When the ignition operation is performed, a high signal appears at point C in the diagram.
A level signal is applied, turning on transistor 6 and closing phototriac 5, which is the power switch for ignition heater 1. When the phototriac 5 is closed, the ignition heater 1 is energized and heated, but the electrical resistance of the ignition heater 1 has a positive temperature characteristic, and the resistance value is low at the beginning of energization, and the resistance bridge 2 is unbalanced. The potentials VA and VB at points A and B in the diagram with respect to COM (red mark in the diagram) have a relationship of VB>VA. VA and VB are converted into direct current inside the temperature detection means 3 and compared by a comparator 31, but when VB>VA, the output of the comparator 31 is at a high level, so the photocoupler 32 is turned on.
The output signal of the temperature sensing means 3 is at a low level. Since the fuel valve opening/closing means 4 calculates the logical product of the ignition signal and the output signal of the temperature detecting means 3 in an internally provided logical product circuit 41, the output of the logical product circuit 41 is low when VB>VA.・
level, so the transistor 42 is off and the electromagnetic coil 43' of the fuel valve 44 driven thereby is not energized and the fuel valve 44 remains closed.

As the ignition heater 1 heats up further, the resistance value increases, the resistance bridge 2 passes through an equilibrium point, and the magnitudes of VA and VB are reversed and VA>VB. If the constants of the resistance bridge are set so that VA = V days at the ignition temperature, VA > VB at or above the ignition temperature, the output of the comparator 31 is inverted and becomes a low level, and the photocoupler 32 is turned off. The output signal of the temperature detection means 3 is high.
become the level. At this time, the two inputs of the AND circuit 41 (the ignition signal and the output of the temperature detection means 3) are both at a high level, and the output of the AND circuit 41 is at a high level, so the transistor 42 is turned on and is thereby driven. The electromagnetic coil 43 is energized, the fuel valve 44 is opened, and fuel is supplied. If the ignition occurs during the ignition time T, the flame detection means (
A flame detection signal from (not shown) is applied at the dot in the figure to keep transistor 42 on and combustion to continue.

Effects of the Invention As is clear from the above embodiments, the present invention detects the temperature of the ignition heater and opens the fuel valve after confirming that the temperature required for ignition has been reached. It has the excellent effect of minimizing the spout of gas and unburned petroleum vapor, reducing the risk of poisoning and odor, and preventing explosive ignition. Also, the ambient temperature,
Regardless of the initial temperature of the ignition heater, the ignition temperature is the same under all circumstances, and has the excellent effect that ignition can always be optimally ignited.

[Brief explanation of the drawing]

The figure is a configuration diagram showing an embodiment of the present invention. 1... Ignition heater, 2... Resistance bridge, 3... Temperature detection means, 4... Fuel valve opening/closing means.

Claims (1)

[Claims] An ignition heater for igniting a combustion appliance using gas, oil, etc. as fuel; a resistance bridge that includes the ignition heater as a component and detects the electrical resistance of the ignition heater; and a potential equilibrium point of the resistance bridge. temperature detection means for detecting the temperature of the ignition heater; and a fuel valve opening/closing means for opening/closing a fuel valve based on an output signal of the temperature detection means; ignition device that opens the fuel valve after a certain temperature has been reached.