JPH06347037A - Ignition device for combustion device - Google Patents

Abstract

PURPOSE:To attain a silent ignition by a method wherein an ignition device for a combustion device is operated such that an external oscillation is controlled by an oscillation circuit for generating a frequency exceeding an audible frequency to a switching element connected to a primary coil of a voltage increasing transformer. CONSTITUTION:There are provided a voltage increasing transformer 1 having a primary coil 3 having a capacitor 2 connected in parallel with it, a switching element 10 connected to the primary coil 3, and a driving circuit having an oscillation circuit 12 for switching the switching element 10 at a frequency exceeding an audible frequency without having any relation with the primary coil 3. As a result, an adjustment of a switching timing can be freely obtained, a detection of current in the primary coil 3 is not necessary and the voltage increasing transformer 1 can be manufactured in less-expensive cost. In addition, an oscillation frequency can be set to a wide range and a silent spark electrical discharge ignition can be obtained without producing any noise even during a continuous electrical discharging from a starting of the electrical discharge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition device for a combustor used for an oil fan heater or the like.

[0002]

2. Description of the Related Art Conventionally, as an ignition device for a combustor of this type, Japanese Patent Application Laid-Open No. 4-3811 and Japanese Utility Model Laid-Open No. 4-82554 have been used.
Publications and the like are known. These are configured to have a step-up transformer having a primary coil to which a capacitor is connected, a drive circuit (igniter circuit) that is a combination of a switching element and a gate circuit.

[0003]

However, in each of the above-mentioned prior arts, a coil for synchronizing with the oscillation frequency for detecting the current flowing in the primary coil is provided in the step-up transformer, that is, in the synchronous transformer. A coil for self-excitation is included in order to take it, and it has to be driven by the coil for self-excitation, which is troublesome. Further, since the oscillation cycle is greatly affected by the characteristics of the coil and the element of the oscillating unit, it is impossible to oscillate in a wide range, and the switching element may generate heat due to the variation of the oscillating unit.

In view of the above situation, the present invention is to provide a combustor ignition device in which the switching element is provided with a frequency exceeding an audible frequency regardless of the state of the primary coil and silent ignition is performed. It is intended.

[0005]

According to the present invention, there is provided a step-up transformer having a primary coil in which a capacitor is connected in parallel, a switching element connected to the primary coil of the step-up transformer, and the switching regardless of the primary coil. It has a drive circuit equipped with an oscillation circuit that switches elements at frequencies exceeding the audible frequency.

[0006]

As described above, the rectified voltage is supplied to the step-up transformer having the primary coil in which the capacitor is connected in parallel, and the energy is stored in the capacitor and the primary coil when the switching element is turned on. . When the switching element is OFF, a voltage of more than ten KV is output to the secondary coil side of the step-up transformer and discharge is started.
In this case, the discharge cycle is determined by the frequency of the oscillator circuit connected to the switching element. The oscillation circuit starts oscillating at a frequency exceeding the audible frequency by a signal from the control unit, and the switching element switches in synchronization with this frequency. Therefore, a quiet spark discharge is ignited.

[0007]

The present invention will be described below with reference to the drawings of the embodiments.

FIG. 1 is a schematic view showing an ignition device of an oil combustor, and 1 is a primary coil 3 in which a capacitor 2 is connected in parallel.
In the step-up transformer having the step-up transformer 1, the secondary coil 4 of the step-up transformer 1 is provided with a discharge part 5 serving as an ignition plug, and a rectifying diode 7 for converting to a direct current is provided on the side of the AC power source 6 on the side of the primary coil 3.
And a rectifying capacitor 8 are connected to each other, a switching element 10 is connected to the other end of the primary coil 3 via a power limiting resistor 9, and the switching element 10 includes a control unit 1
The oscillator circuit 12 which operates by the signal from 1 is connected.

To explain this action, as ignition by spark discharge of the ignition device in the oil combustor, first, a rectifying diode 7 and a rectifying capacitor 8 which will be a rectifying circuit.
2 supplies the rectified voltage from the commercial power source, and the voltage V1 becomes as shown in FIG. 2. When the switching element 10 is turned on, the voltage V1 is accumulated in the capacitor 2 and the primary coil 3, and when the switching element 10 is turned off, the step-up transformer is turned on. Since a voltage of more than ten KV is output to the secondary coil 4 side of No. 1, a predetermined discharge is started in the discharge unit 5.

Here, the switching element 10 is determined by the frequency of the oscillation circuit 12, and this frequency is set to a frequency exceeding the audible frequency. Therefore, the frequency output to the secondary coil 4 is the frequency set by the oscillator circuit 12.

For this reason, the spark discharge sound that occurs synchronously in the discharge section 5 has a frequency exceeding the audible frequency, so that the discharge sound cannot be heard by the human ear.

[0012]

As described above, in the ignition device for the combustor of the present invention, the switching element connected to the primary coil of the step-up transformer uses the separately excited oscillation controlled by the oscillation circuit that emits a frequency exceeding the audible frequency. The switching timing can be adjusted freely, and there is no need to detect the current in the primary coil, so that the step-up transformer can be manufactured at low cost. In addition, the oscillation frequency can be set in a wide range, and silent operation that does not cause discomfort even after continuous discharge from the start of discharge can be performed.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an ignition device for an oil combustor showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between the rectified voltage and an oscillation signal.

[Explanation of symbols]

 1 Boost Transformer 2 Resonance Capacitor 3 Primary Coil 4 Secondary Coil 5 Discharge Unit 10 Switching Element 11 Control Unit 12 Oscillation Circuit

Claims (1)

[Claims] 1. A step-up transformer having a primary coil in which a capacitor is connected in parallel, a switching element connected to the primary coil of the step-up transformer, and the switching element having a frequency exceeding an audible frequency regardless of the primary coil. An ignition device for a combustor, comprising a drive circuit having an oscillating circuit for switching.