CN2676058Y - Flame detection device - Google Patents

Abstract

A flame detecting device belongs to the field of electronic control and sensor technology. The flame detecting device mainly comprises a burner (21), an ignition detecting needle (22), conducting wires (23), an ignition detecting controller (24) and a pedestal (25). Since it just uses an ignition detecting needle which has two functions of the high voltage pulse ignition and the low voltage impulse flame detecting, the flame detecting device can be applied to the installation in the smaller space, and it has considerable effects such as simple structure, good sensibility, and low cost, etc. In addition, the flame detecting device also has good application future on the domestic gas apparatus.

Description

Flame detection device

                      

The utility model relates to a flame detection device, in particular to a flame detection device suitable for use on gas stoves, gas water heaters and other gas appliances, and belongs to the technical field of electronic control and sensors.

Background technique

There are several types of flame detection devices, such as optical sensors and mechanical sensors. These sensors are usually complex in structure and high in cost. There is also a temperature sensor, such as a thermocouple, although the cost is relatively low, but there is a certain lag time for the establishment and disappearance of the thermoelectric potential when igniting and extinguishing, which increases the complexity of the control circuit and leads to the overall cost of the device. Increased costs. In addition, the inventor Chen Yunfei disclosed a flame detector composed of two metal electrodes in the Chinese patent "Flame Detector" (Patent No.: ZL94239042.3). This flame detector places two electrodes in the flame of the burner. The flame ionizes the air between the two electrodes to generate a weak electromotive force. Once the flame is extinguished, the electromotive force disappears. If the weak electromotive force is amplified, the alarm or re-ignition can be performed according to different requirements when the flame is generated or extinguished. The device has the advantages of simple structure, high sensitivity, fast response, etc. Its shortcoming is that the flame detector uses two detection needles, usually one is a flame detection needle and the other is an ignition discharge needle, because the flame detection There must be a certain installation distance between the ignition needle and the ignition discharge needle detection needle, otherwise the ignition discharge needle will discharge the flame detection needle and affect the normal operation of the circuit, so the installation of these needles is cumbersome, and in some specific occasions, For example, in a vehicle-mounted water heater, in order to reduce the space, two needles are not allowed to be installed next to the burner. Secondly, the material of the flame needle is a refractory metal or alloy material.

Contents of utility model

The purpose of the utility model is to provide a single-needle, high-sensitivity, fast and low-cost flame detection device to simplify the flame detection device and solve the problem of installing the flame detection device in a small space.

The flame detection device of the present invention includes a burner 21, an ignition detection needle 22, a wire 23, an ignition detection controller 24 and a base 25, and is characterized in that there is only one ignition detection needle 22.

The ignition detection controller 24 described in the flame detection device of the present utility model includes a microcontroller 1, an ignition circuit 2, an isolation circuit 3, a solenoid valve control circuit 4, a flame detection circuit 5, and an ignition detection needle 22, and is characterized in that An isolation circuit (3) is included, and the isolation circuit (3) is composed of two diodes, the cathodes of the two diodes are relatively connected in series, and the anodes are respectively connected to two output terminals of the microcontroller.

The flame detection device of the present invention uses only one ignition detection needle, and this ignition detection needle is compatible with two functions of high-voltage pulse ignition and low-voltage pulse flame detection, and the ignition pulse oscillation is realized through a microcontroller and an isolation circuit The common use of the detector and the flame detection oscillator, so it can realize the functions of automatic ignition with a single needle, automatic closing of the gas valve and alarm after accidental flameout, compared with the previous double-needle or multi-pin flame detector, it is suitable for smaller The flame detection device is installed in space, and has remarkable effects such as simple structure, high sensitivity and low cost.

Description of drawings

Figure 1 is a structural diagram of the flame detection device

Figure 2 is a structural diagram of the ignition detection controller of the flame detection device

Fig. 3 is the microcontroller circuit diagram in the ignition detection controller of the flame detection device

Detailed ways

The specific embodiment of the utility model is described below in conjunction with accompanying drawing of description:

In the structure diagram of the flame detection device of the present utility model, the ignition detection controller 24 is fixed on the base 25, the ignition detection needle 22 is controlled by the ignition detection controller 24, the combustible gas is sent out by the burner 21, and the ignition detection needle 22 is connected with the ignition wire 23. The detection controller is connected by 24 wires.

The structure diagram of the fire detection controller of the flame detection device includes microcontroller 1, which is the control core of the system; ignition circuit 2, including oscillator, step-up transformer and high voltage package; isolation circuit 3; solenoid valve control circuit 4; flame detection circuit 5; the ignition detection needle 22, which is installed near the burner, has the functions of ignition and flame detection.

Point A to point B in Figure 3 is the isolation circuit 3, which is composed of Z1 and Z2. The flame detection channels are C1, C2, D1, D2, and R1, as well as the software in the MCU. P1 is the ignition detection pin 22; B1 is a high-voltage package, B2, Q1, R5, and R6 form an inductive three-point oscillator to maintain part of the oscillation. The MCU turns on or off part of the oscillation through Q2, R8, and D4 to achieve a common detection pin. The other parts are basically conventional standards. The circuit will not be described in detail in this paper.

When the tap of the water heater is turned on or the burner switch is turned on, the controller is powered on, and the ignition detection pin 22 cannot detect the flame because there is no gas burning, and the flame detection circuit 5 outputs a voltage of about 200 millivolts to the microcontroller 1, After calculation and comparison, the microcontroller 1 issues an instruction to turn on the ignition circuit 2, and then after the oscillation transformer is inverted and boosted, an ignition pulse is generated, which is boosted again by the ignition high-voltage package, and the output high-voltage pulse of about 15 kV is sent to the ignition detection Pin 22, the ignition detection pin 22 outputs a high-voltage arc to discharge the burner. After 1 second, the microcontroller opens the solenoid valve control circuit 5, and the combustible gas burns when it meets the high-voltage arc on the burner. After burning, the ignition detection pin 22 immediately Detecting the weak flame ion conduction, the flame detection circuit 5 outputs a negative 200 mV signal to the microcontroller 1, after the microcontroller 1 detects this signal, it knows that the flame is burning, wait for 500 milliseconds, and wait for the flame to stabilize , the microcontroller 1 partially turns off the oscillator, thereby the step-up transformer and the high-voltage package stop working, the ignition detection pin 22 stops arc discharge, and the burner enters a normal operating state.

The aforementioned partial shutdown of the oscillator means that under the coordinated control of the microcontroller 1 , the detection of the high-voltage and high-power discharge pulse and the low-voltage micro-current can be completed on the same ignition detection needle. When the power is turned on, there is a weak oscillation on the oscillator 2, which is transmitted to the ignition detection pin 22 through the Zener tube isolation circuit 3, and has been detecting the flame. When the microcontroller 1 sends an ignition command, the oscillation starts to work, after Boost the secondary inverter, and the ignition arc occurs on the ignition detection pin 22. At this time, there are two signals on the ignition detection pin 22 at the same time, a high-voltage pulse of tens of thousands of volts and a low-voltage signal of several millivolts for flame detection. The microcontroller 1 When the ignition arc occurs, the flame is not detected, and no other processing is performed, and it is in a dormant state, so as not to interfere with the flame detection by a strong electromagnetic pulse; after the arc ends, the microcontroller 1 starts quickly, partially turns off the oscillator, and detects the flame through the flame detection channel and perform other work, which is typically completed in less than 1 millisecond, after which the microcontroller 1 immediately turns on the oscillator and waits for the next arc. Therefore, the two signals with greatly different amplitudes are perfectly concentrated on the same steel needle through the time-sharing processing of the Zener tube isolation circuit 3 and the microcontroller 1 .

If the flame is suddenly turned off during normal combustion, it will cause dangers such as gas leakage. The utility model adopts a time-limited ignition method, that is, the MCU can not detect the flame and immediately re-ignites. If it cannot be ignited within the set time, the gas solenoid valve will be closed. A display device such as a diode notifies the user.

If the water temperature is too high or the power supply voltage is not in the normal range during normal combustion, the microcontroller can take measures to close the solenoid valve to ensure safety.

The flame detection device described in the utility model is not only suitable for installation and use in small spaces such as vehicle-mounted water heaters, but also has broad application prospects in other gas appliances such as household gas cookers and gas water heaters.

Claims (2)

1, a kind of flame detecting device comprises that burner (21), igniting detect pin (22), lead (23), igniting detection controller (24) and base (25), it is characterized in that described igniting detects pin (22) and has only one.

2, flame detecting device as claimed in claim 1, wherein igniting detection controller (24) comprises that microcontroller (1), firing circuit (2), solenoid valve control circuit (4), flame detection circuit (5), igniting detect pin (22), it is characterized in that also comprising buffer circuit (3), this buffer circuit (3) is made up of two diodes, two diode cathodes are cascaded relatively, and anode is connected to two outputs of microcontroller.

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