JPS60122823A - Method for detecting flame on burner and device thereof - Google Patents

Abstract

PURPOSE:To increase the accuracy and the reliability in detecting of flame, by respectively taking out an element of direct current of which voltage is changed by presence and absence of flame and an element of alternating current which is produced by the change in flame, from flame burning on a burner. CONSTITUTION:The voltage (e) between both terminals of a flame eye 1 is amplified by an amplifying circuit 6 and is input in an element of direct current detecting circuit 4 to detect an element of direct current eDC. The element of alternating current produced between the terminals of a flame eye 1 is converted into direct current by a diode 10 to detect waves and a smoothing capacitor 11, and the voltage eAC is detected in an element of alternating current detecting circuit 5. The element of alternating current produced between the terminals of a flame eye 1 shows the fluctuation in voltage caused by the change in flames that is the flickering of flames during combustion. In regard to the element of direct current, high and constant value can be obtained when flames are absent, while flat, low and roughly constant value can be obtained when flames are present.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flame detection method and apparatus for a burner, which reliably detects the presence or absence of a flame at the time of start-up and ignition of the burner.

Conventionally, various types of burners have been equipped with flame eyes, flame rods, etc. that detect the presence or absence of flame in order to confirm whether combustion has started reliably at the time of ignition and to initiate operation to continue combustion. There is.

By the way, the flame eye described above has an electrical resistance that decreases when it receives light emitted from a flame, and detects the presence or absence of a flame by converting this change in electrical resistance into an electrical signal. When illuminated, etc., this light acts on the 7-ray eye, and it is determined that there is a flame even though there is no flame, which may cause a malfunction in control such as when starting and igniting the burner. If a malfunction occurs in the control such as when starting and igniting the burner, fuel leakage may occur, which is dangerous.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional situation, it is an object of the present invention to provide a method and apparatus for carrying out the method that can reliably detect the presence or absence of a flame in a burner without error.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method and apparatus according to the present invention shown in the drawings will be described below.

In Fig. 1, 1 is a flame eye, and this flame eye 1 detects the presence or absence of light emitted by the flame in the burner.When it receives light, its electrical resistance increases in proportion to the intensity of the light. It has the characteristic of becoming smaller. 2 is a DC power supply that maintains a constant voltage, and the frame eye 1 is connected to the DC power supply 2 with a fixed resistor 3 in series. 4
5 is a detection circuit for a DC component, and 5 is a detection circuit for an AC component. This is a detection circuit. T is a smoothing capacitor for obtaining a stable DC component ena. On the other hand, the AC component detection circuit 5 is connected between the terminals of the frame eye 1 via a coupling capacitor 8 for cutting the DC component and an F wave generator 9, 10 is a detection diode, and 11 is a smoothing capacitor. It is. The AC component generated between the terminals of the frame eye 1 is converted into DC by a detection diode 10 and a smoothing capacitor 1.
The AC component detection circuit 5 detects the magnitude eAa. The alternating current component that occurs between the terminals of the flame eye 1 is a voltage fluctuation due to changes in the flame (fluctuations during combustion), and the z4 wave generator 9 cuts unnecessary alternating current components outside the frequency band that occur due to flame fluctuations. It is for the purpose of

FIG. 2 shows the operation of the apparatus constructed as described above, which will now be explained.

In the above device, if the voltage of the DC power supply 2 is E, the resistance of the fixed resistor 3 is Z1, and the resistance of the frame eye 1 is R, then the voltage e between the terminals of the frame eye 1 is e=E−transfer]−. be.

By the way, when there is no flame in the burner, the resistance R of the flame eye 1 is high, so the voltage e between its terminals exhibits a high constant value. However, when a flame is generated by starting ignition, the flame eye 1 receives the light. Since the resistance R becomes smaller, the voltage e between its terminals drops. However, since the flame in this state has not yet transitioned to complete combustion and has large fluctuations, the voltage e between the terminals of the 7 lame eye 1 fluctuates and becomes a stable low constant value when the complete combustion state is reached. In the DC component detection circuit 4, the DC component eo is detected.

As the voltage, a high constant value is obtained when there is no flame, a smoothed low approximately constant value is obtained when a flame is generated, and a low constant value is obtained when the combustion is complete. On the other hand, before a flame is generated in the burner and the state of complete combustion is reached, the resistance R of the flame eye 1 changes due to the fluctuation of the flame. It is taken out through an r wave generator 9. However, the alternating current component eA is not detected when there is no flame or in a complete combustion state where the flame does not fluctuate. Therefore, in the alternating current component detection circuit 5, a substantially constant voltage eAo is obtained which is detected only during the period from when a flame is generated in the burner until the burner enters a complete combustion state.

Therefore, from the above action, if there is no flame, the DC component e
Although Do is a high constant value, the AC component eAo is zero,
In a complete combustion state, the DC component eDo is a low constant value, but the AC component e^0 is zero (or approximately zero). but,
Before the flame is generated and the state of complete combustion is reached, the direct current component e
no is low and the AC component eAa is high. Therefore, the fact that a flame was generated when the burner was started and ignited means that the direct current
Ingredient e. This can be determined from the fact that 0 is low and the AC component eAo is high.

When sunlight, illumination light, etc. hits the flame eye 1, the DC component eDo becomes low, but the AC component eAo is not detected. If the presence or absence of a flame is determined based on the relationship between the DC component eDo and the AC component eAo, it can be detected reliably and without error.

Although the flame eye 1 is used as the flame detector in the embodiment described above, the present invention can be applied to flame eyes that detect heat from flames or other detectors. It is possible to improve the accuracy and reliability of flame detection.

As is clear from the description of the above embodiment, the method and device according to the present invention is a method for detecting the presence or absence of a flame from light or heat emitted by the flame in a burner, and detects the presence or absence of a flame using a detector. This is a method of detecting the flame as a signal, extracting from this electric signal a DC component whose voltage changes depending on the presence or absence of a flame, and an AC component that occurs due to changes in the flame, and determining the presence or absence of a flame based on both these DC and AC components. , a sensor that receives light or heat emitted by the flame in the burner and converts it into an electrical signal K, a DC component detection circuit that generates a voltage difference when the sensor detects the presence or absence of a flame, and a DC component detection circuit that detects changes in the flame. The device is equipped with a detection circuit for the alternating current component that occurs as a result, and a circuit for determining the presence or absence of a flame from the direct current and alternating current components detected by these rain detection circuits. Flame detection can be reliably detected without being affected by heat, etc., and flame detection accuracy and reliability can be improved.

[Brief explanation of the drawing]

The drawings show an embodiment of the device according to the present invention, and FIG. 1 is a circuit diagram of the main part thereof, and FIG. 2 is an explanatory diagram of the same operation. DESCRIPTION OF SYMBOLS 1... Flame eye, 2... DC power supply, 3... Fixed resistor, 4... DC component detection circuit, 5... AC component detection circuit, 6... Amplification circuit, 7 ... Smoothing capacitor, 9... Sawa wave device, 10... Diode for detection, 11... Smoothing capacitor, eoa... DC component, eho... AC component Patent applicant Figure 1 2 figure time

Claims (1)

[Claims] (1) A method for detecting the presence or absence of a flame from the light or heat emitted by the flame in a burner, in which the presence or absence of the flame is detected as an electrical signal by a sensor, and from this electrical signal, the presence or absence of the flame is detected. A method for detecting flame in a burner, characterized in that the presence or absence of a flame is determined based on both the direct current component and the alternating current component, by extracting a direct current component whose voltage changes depending on the presence or absence of the flame, and an alternating current component caused by changes in the flame. (2. In the method described in claim 1, a flame eye whose electrical resistance decreases when it receives light is used as a sensor, and the voltage of the DC component detected from the circuit of the seven flame eyes decreases, and A flame detection method in a burner that determines the presence of a flame on the condition that an alternating current component from the circuit is detected. (3) A sensor that receives light or heat emitted by the flame in the burner and converts it into an electrical signal. , a detection circuit for a DC component that generates a voltage difference when the presence or absence of a flame is detected by this sensor, and a detection circuit for an AC component that occurs due to changes in the flame, and a detection circuit for a DC component and an AC component detected by these rain detection circuits. A flame detection device for a burner, characterized in that it is equipped with a circuit that determines the presence or absence of a flame from an alternating current component. (4) The sensor that detects the presence or absence of a flame is a flame eye whose electrical resistance decreases when it receives light. , the DC component detection circuit is configured to maintain a constant voltage and cause a voltage drop when flame is detected, and the AC component detection circuit is configured to detect the fluctuating component of the voltage drop. A flame detection device for a burner according to claim 3.