CN115410334A - A flame detection device and method - Google Patents

Abstract

The application discloses a flame detection device and method, and relates to the technical field of fire alarm. The flame detection device comprises an ultraviolet detection module and a control module, wherein the ultraviolet detection module comprises an ultraviolet photoelectric tube, a detection unit and a signal generation unit; the detection unit and the signal generation unit are respectively connected with the ultraviolet phototube and the control module; the detection unit is used for generating a self-discharge signal corresponding to the ultraviolet phototube; the signal generating unit is used for generating a first electric signal from the ultraviolet radiation detected by the ultraviolet photoelectric tube; and the control module is used for judging the fire according to the first electric signal and the self-discharge signal. Based on above-mentioned device, detect through the self-discharge signal that corresponds to ultraviolet ray photoelectric tube, realize optimizing the signal of telecommunication that ultraviolet radiation corresponds, and then avoid ultraviolet ray electro-optic self-discharge phenomenon to cause the influence to the conflagration judgement result of detector, improve the accurate accuracy of conflagration judgement.

Description

A flame detection device and method

technical field

The present application relates to the field of fire alarm technology, in particular to a flame detection device and method.

Background technique

With the gradual improvement of people's awareness of fire prevention, the demand for fire alarm systems has increased dramatically. A fire detector is a device used in a fire alarm system to detect a scene and discover a fire. Its function is to monitor whether there is a fire in the environment. One of the commonly used fire detectors is a red-ultraviolet composite flame detector, including ultraviolet sensors and infrared sensors, which can detect hydrocarbon combustion flames, such as hydrogen, hydroxyl compounds, and metal and inorganic combustion flames.

In the process of using red-ultraviolet composite flame detectors for flame detection, it is usually necessary to sense the ultraviolet radiation of the flame at the ultraviolet photoelectric cell, generate electrical signals, and judge whether a fire has occurred based on the electrical signals. However, in the process of converting ultraviolet radiation into electrical signals, there will be interference signals, resulting in the generation of electrical signals that cannot truly reflect the intensity of ultraviolet radiation, thereby affecting the accuracy of fire discrimination.

Contents of the invention

The application discloses a flame detection device and method. When judging a fire, the self-discharge signal corresponding to the ultraviolet photoelectric tube is detected to optimize the electrical signal corresponding to the ultraviolet radiation, thereby avoiding the self-discharge of the ultraviolet photoelectric light. The phenomenon affects the fire judgment result of the detector and improves the accuracy of fire judgment.

In a first aspect, the present application provides a flame detection device, the device includes an ultraviolet detection module and a control module, the ultraviolet detection module includes an ultraviolet photocell, a detection unit, and a signal generation unit; the detection unit and the a signal generation unit connected to the ultraviolet photocell and the control module respectively;

The detection unit is used to generate a self-discharge signal corresponding to the ultraviolet photocell; the signal generation unit is used to generate a first electrical signal from the ultraviolet radiation detected by the ultraviolet photocell; the control module uses Fire judgment is performed according to the first electrical signal and the self-discharge signal.

Based on the above device, by detecting the self-discharge signal corresponding to the ultraviolet photocell, the electrical signal corresponding to the ultraviolet radiation is optimized, thereby avoiding the influence of the ultraviolet photoelectric self-discharge phenomenon on the fire judgment result of the detector, and improving the fire judgment standard accuracy.

In a possible design, the ultraviolet detection module further includes a drive unit, the drive unit includes a setting circuit, a transformer, and a switch circuit, the switch circuit is connected to the transformer, and the transformer is connected to the setting circuit , the setting circuit is connected to the ultraviolet photocell;

The switch circuit is used to access the first power supply through the pulse width modulation PWM signal; the transformer is used to transform the first power supply to obtain the second power supply; the setting circuit is used to control the The second power supply is adjusted to obtain a driving power supply, wherein the driving power supply is used to drive the ultraviolet photoelectric tube.

Based on the above device, the power supply of the ultraviolet detection module can be converted into a high-voltage pulse driving voltage, thereby avoiding continuous power supply to the ultraviolet detection module and prolonging the service life of the ultraviolet detection module without affecting the normal use of the ultraviolet detection module.

In a possible design, the switch circuit includes a first resistor, a triode, and a first diode; the first end of the first diode is connected to the first power supply; the first diode The second end of the tube is connected to the first end of the triode; the second end of the triode is grounded; the third end of the triode is connected to the first resistor, wherein the first resistor is used to receive the the PWM signal described above.

Based on the above device, the PWM signal is used to drive the switching circuit, thereby converting the power supply of the fire detection module into a pulse power supply, thereby helping to prolong the service life of the ultraviolet detection module.

In a possible design, the tuning circuit includes a second diode, a first capacitor, a second resistor, a second capacitor, and a third resistor; the first end of the second diode and the transformer connected, and the second end of the second diode is connected to the second resistor; a first preset point between the second resistor and the first end of the second diode, and A first capacitor is set between the ground points; the second resistor is connected to the third resistor, and is located at a second preset point between the second resistor and the third resistor, and between the ground point A second capacitor is arranged between them; the second resistor is connected to the ultraviolet photoelectric cell.

Based on the above device, the voltage output by the transformer can be adjusted, and the transformed AC pulse voltage can be adjusted to a DC pulse voltage, so that the power supply quality is more stable.

In a possible design, the detection unit includes a fourth resistor, a fifth resistor, and a sixth resistor; the first end of the fourth resistor is connected to the ultraviolet photocell, and the first end of the fourth resistor The two ends are connected to the ground point through the fifth resistor; the fourth resistor is connected in parallel with the sixth resistor after being connected in series with the fifth resistor; the non-ground terminal of the sixth resistor is connected to the signal generating unit connect.

Based on the above device, it is possible to detect the self-discharge signal of the ultraviolet photoelectric cell, thereby helping to prevent the self-discharge signal from affecting the electrical signal corresponding to the ultraviolet radiation, and improving the accuracy of the flame detector in judging fire.

In a possible design, the signal generation unit includes a seventh resistor, a third capacitor, a third triode, and a comparator; the first end of the seventh resistor is connected to the detection unit; the first The second end of the seven resistors is connected to the first end of the third capacitor, and the second end of the third capacitor is grounded; the second capacitor is connected in parallel with the third triode, and the second The parallel connection point corresponding to the first end of the capacitor is connected to the comparator; the comparator is connected to the control module.

Based on the above device, the ultraviolet radiation sensed by the ultraviolet photocell can be converted into an electrical signal for the controller to judge whether a fire has occurred.

In a possible design, the device further includes an infrared detection module, and the infrared detection module includes an infrared sensor, a signal filter amplifier, and an amplification factor regulator; the infrared sensor is connected to the signal filter amplifier; the signal The filter amplifier is connected to the control module; the amplification factor regulator is connected to the control module and the signal filter amplifier;

The infrared sensor is used to sense infrared radiation and convert the infrared radiation into a second electrical signal, wherein the second electrical signal includes time domain information and frequency domain information; the signal filter amplifier is used to The second electrical signal is filtered and amplified to generate a third electrical signal; the amplification factor regulator is used to adjust parameters of the signal filter amplifier.

Based on the above device, the electrical signal corresponding to the infrared radiation is generated, so that when the control module judges whether a fire has occurred according to the electrical signal, the frequency domain information and the time domain information of the electrical signal corresponding to the infrared radiation are considered at the same time, so as to enhance the accuracy of fire judgment.

In a second aspect, the present application provides a flame detection method based on any of the above flame detection devices, the method comprising:

Obtain the self-discharge signal of the ultraviolet photocell;

Calculate the anti-false alarm signal corresponding to the ultraviolet photoelectric cell according to each pulse interval corresponding to the self-discharge signal;

calculating a first effective electrical signal corresponding to the ultraviolet photoelectric cell according to the anti-false alarm signal and the first electrical signal corresponding to the ultraviolet photoelectric cell;

According to the first effective electrical signal, it is judged whether the currently detected flame data causes a fire.

Through the above method, when calculating the effective electrical signal corresponding to the ultraviolet radiation, the influence brought by the self-discharge phenomenon of the ultraviolet photoelectric tube is fully considered, thereby improving the accuracy of fire judgment.

In a possible design, the calculation of the anti-false alarm signal corresponding to the ultraviolet photocell according to each pulse interval corresponding to the self-discharge signal includes:

Calculating the time length corresponding to the pulse interval between any two adjacent pulses in the self-discharge signal;

determining a difference between a maximum time length and a minimum time length of the respective time lengths;

The anti-false alarm signal is calculated according to the difference, the maximum pulse amplitude of the self-discharge signal, and the discharge time length of the self-discharge signal.

Through the above method, the false alarm prevention information is calculated, thereby improving the accuracy of fire judgment.

In a possible design, the calculation of the first effective electrical signal corresponding to the ultraviolet photoelectric cell according to the anti-false alarm signal and the first electrical signal corresponding to the ultraviolet photoelectric cell includes:

calculating a discrete integral corresponding to each pulse signal in the first electrical signal;

finding a first difference between the discrete integral and the anti-false alarm signal;

The first difference is determined as the first effective electrical signal corresponding to the ultraviolet photocell.

Through the above method, the effective electrical signal corresponding to the ultraviolet photoelectric cell is calculated, and then the interference of the self-discharge signal of the ultraviolet photoelectric cell is eliminated, and the accuracy of fire judgment is improved.

In a possible design, the judging whether the currently detected flame data causes a fire according to the first effective electrical signal includes:

judging whether the first effective electrical signal is greater than a first preset threshold;

If so, then determine that the currently detected flame data causes a fire;

If not, it is determined that the currently detected flame data does not cause a fire.

Through the above method, judging whether a fire has occurred based on the first electrical signal can effectively eliminate the interference of the self-discharge signal corresponding to the ultraviolet photocell, and improve the accuracy of fire judgment.

In a possible design, the judging whether the currently detected flame data causes a fire according to the first effective electrical signal includes:

acquiring a second electrical signal corresponding to the infrared radiation;

calculating the frequency domain characteristics corresponding to the infrared radiation according to the signal strength and average power corresponding to the second electrical signal;

calculating a second effective signal corresponding to the infrared radiation according to the frequency domain feature and the time domain feature corresponding to the infrared radiation;

According to the first valid signal and the second valid signal, it is judged whether the currently detected flame data causes a fire.

Through the above method, the fire judgment is carried out by considering the time-domain characteristics and frequency-domain characteristics of infrared radiation at the same time. Compared with only considering the time-domain characteristics, the accuracy of fire judgment can be improved and false alarms can be prevented.

Description of drawings

Fig. 1 is one of structural schematic diagrams of a kind of flame detection device provided by the present application;

Fig. 2 is the second structural schematic diagram of a flame detection device provided by the present application;

Fig. 3 is the third structural schematic diagram of a flame detection device provided by the present application;

Fig. 4 is the fourth structural schematic diagram of a flame detection device provided by the present application;

Fig. 5 is the fifth structural diagram of a flame detection device provided by the present application;

Fig. 6 is the sixth structural schematic diagram of a flame detection device provided by the present application;

Fig. 7 is the seventh structural diagram of a flame detection device provided by the present application;

Fig. 8 is the eighth structural schematic diagram of a flame detection device provided by the present application;

FIG. 9 is a schematic flowchart of a flame detection method provided by the present application.

Detailed ways

In order to make the purpose, technical solution and advantages of the application clearer, the application will be further described in detail below in conjunction with the accompanying drawings. The specific operation methods in the method embodiments can also be applied to the device embodiments or system embodiments. It should be noted that in the description of the present application, "plurality" is understood as "at least two". "And/or" describes the association relationship of associated objects, indicating that there may be three types of relationships, for example, A and/or B may indicate: A exists alone, A and B exist simultaneously, and B exists independently. The connection between A and B can mean: A and B are directly connected and A and B are connected through C. In addition, in the description of the present application, words such as "first" and "second" are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order.

The embodiments of the present application will be described in detail below in conjunction with the accompanying drawings.

The red-ultraviolet composite flame detector is a commonly used flame detector. In the process of using the red-ultraviolet composite flame detector for flame detection, it is usually necessary to sense the ultraviolet radiation of the flame at the ultraviolet photocell, generate an electrical signal, and send The pulse density characteristics of electrical signals are used as one of the criteria for judging whether a fire occurs. However, due to the existence of the self-discharge phenomenon of the ultraviolet photocell, it will affect the pulse density characteristics of the electrical signal, and then affect the accuracy of fire discrimination.

In order to solve the above problems, the present application provides a flame detection device and method, by detecting the self-discharge signal corresponding to the ultraviolet photocell, to realize the optimization of the electrical signal corresponding to the ultraviolet radiation, and then avoid the self-discharge phenomenon of ultraviolet photoelectricity It will affect the fire judgment result of the detector and improve the accuracy of fire judgment.

As shown in Figure 1, it is a schematic structural diagram of a flame detection device provided by the present application, including an ultraviolet detection module 11 and a control module 12, and the ultraviolet detection module 11 includes an ultraviolet photocell 11a, a detection unit 11b, and a signal generation unit 11c; The detection unit 11b and the signal generation unit 11c are respectively connected to the ultraviolet photoelectric cell 11a and the control module 12 .

The detection unit 11b is configured to generate a self-discharge signal corresponding to the ultraviolet photoelectric cell 11a; the signal generating unit 11c is configured to generate a first electrical signal from the ultraviolet radiation detected by the ultraviolet photoelectric cell 11a; the control module 12 is configured to generate a first electrical signal according to the first electrical signal Signal, self-discharge signal to judge fire.

Based on the above device, the first discharge information corresponding to the ultraviolet radiation and the self-discharge signal corresponding to the ultraviolet photoelectric cell can be acquired simultaneously. Therefore, when the control module 12 makes a fire judgment, it can eliminate the interference of the self-discharge information of the ultraviolet photoelectric cell, and improve the accuracy of the fire judgment.

In a possible application scenario, as shown in FIG. 2, the ultraviolet detection module 11 also includes a drive unit 21, the drive unit 21 includes a setting circuit 21a, a transformer 21b, and a switch circuit 21c, the switch circuit 21c is connected to the transformer 21b, and the transformer 21b It is connected with the setting circuit 21a, and the setting circuit 21a is connected with the ultraviolet photoelectric tube 11a.

The switch circuit 21c is used to access the first power supply through the pulse width modulation PWM signal. Specifically, when the PWM signal is at a high level, the first power supply is turned on, and when the PWM signal is at a low level, the first power supply is turned off. Controlling the duty cycle of PWM can control the time of connecting and disconnecting the first power supply. At the same time, by controlling the high-level time and low-level time of the PWM signal, the frequency of connecting and disconnecting the first power supply can be controlled. , so as to realize the control of the effective value of the voltage of the first power supply, so as not to affect the normal operation of the ultraviolet detection module.

The transformer 21b is used to transform the first power supply to obtain the second power supply, wherein the voltage amplitude of the second power supply can be adjusted by adjusting the parameters of the transformer; the setting circuit 21a is used to set the second power supply, and then The AC voltage corresponding to the second power supply is set to a DC voltage to obtain a driving power supply, and the UV photoelectric tube 11a is driven by the DC driving power supply, which can improve power supply stability and prolong the service life of the UV photoelectric tube.

In a possible application scenario, as shown in FIG. 3, the switch circuit 21c includes a first resistor 31, a transistor 32, and a first diode 33; the first end of the first diode 33 is connected to the first power supply; The second end of the first diode 33 is connected with the first end 32a of the triode 32; the second end 32b of the triode 32 is grounded; the third end 32c of the triode 32 is connected with the first resistor 31, wherein the first resistor 31 is used for receiving PWM signals.

Based on the above device, when the PWM signal is at a high level, the first terminal 32a and the second terminal 32b of the triode 32 are conducted, at this time, through the action of the first diode 33, the voltage value at both ends of the first power supply, That is, the input voltage of the transformer 21b. When PWM is a low-level signal, the first terminal 32a and the second terminal 32b of the transistor 32 are disconnected, and at this time, the transformer 21b has no voltage input.

In a possible application scenario, as shown in FIG. 4, the transformer 21b includes a primary side 41 and a secondary side 42, the primary side 41 is connected in parallel with the first diode 33, and both ends of the secondary side 42 are connected to a tuning circuit, wherein, The primary side 41 and the primary side 41 and the secondary side 42 have different coil compositions respectively. By adjusting the coil turns ratio of the primary side 41 and the secondary side 42, the voltage of the secondary side 42 can be adjusted to realize the voltage transformation of the first power supply. Get a second power supply.

In a possible application scenario, as shown in FIG. 5, the tuning circuit 21a includes a second diode 51, a first capacitor 52, a second resistor 53, a second capacitor 54, and a third resistor 55; The first end of the tube 51 is connected to the transformer 21b, and the second end of the second diode 51 is connected to the second resistor 53; the first end between the second resistor 53 and the first end of the second diode 51 The preset point, the first capacitor 52 is set between the ground point; the second resistor 53 is connected to the third resistor 55, and is located at the second preset point between the second resistor 53 and the third resistor 55, and between the ground point A second capacitor 54 is arranged between them; the second resistor 53 is connected to the ultraviolet photoelectric cell 11a.

Based on the above-mentioned device, when the voltage across the second diode 51 is a forward voltage, the voltage across the first capacitor 52 is the output voltage of the transformer 21b, and the output voltage is divided by the second resistor 53 to obtain the voltage is the voltage across the second capacitor 54, the voltage is divided by the third resistor 55, and the obtained voltage is the input voltage of the ultraviolet photoelectric cell 11a. By adjusting the component parameters of the second capacitor 54 and the third resistor 55, the discharge time and recovery time of the ultraviolet photoelectric tube 11a can be controlled.

In a possible application scenario, as shown in FIG. 6, the detection unit 11b includes a fourth resistor 61, a fifth resistor 62, and a sixth resistor 63; the first end of the fourth resistor 61 is connected to the ultraviolet photocell 11a, and The second end of the fourth resistor 61 is connected to the ground point through the fifth resistor 62; after the fourth resistor 61 is connected in series with the fifth resistor 62, it is connected in parallel with the sixth resistor 63; the non-ground end of the sixth resistor 63 is connected to the signal generating unit 11c connect.

Based on the above-mentioned device, when carrying out the self-discharge experiment of the ultraviolet photoelectric tube, after the voltage is divided by the fourth resistor 61, the voltage obtained at both ends of the fifth resistor 62 is the self-discharge signal. After the self-discharge signal is input into the control module 12, it can avoid Effect of self-discharge signal on fire judgment.

In a possible application scenario, as shown in FIG. 7 , the signal generating unit 11c includes a seventh resistor 71, a third capacitor 72, a third transistor 73, and a comparator 74; the first terminal of the seventh resistor 71 is connected to The detection unit 11b is connected; the second end of the seventh resistor 71 is connected to the first end of the third capacitor 72, and the second end of the third capacitor 72 is grounded; the third capacitor 72 is connected in parallel with the third transistor 73, and the The non-ground terminals of the three capacitors 72 and the third triode 73 are connected to the comparator 74 ; the comparator 74 is connected to the control module 12 .

Through the above-mentioned device, after the ultraviolet photodiode 11a converts the ultraviolet radiation into an electrical signal, after the seventh resistor 71 divides the voltage, the voltage at both ends of the third capacitor 72 is obtained, and the voltage at the two ends of the third capacitor 72 is greater than the corresponding preset value of the comparator 74. When the voltage is set, a high-level signal is generated, and when the voltage across the third capacitor is less than the preset voltage, a low-level signal is generated. The high-level signal and the low-level signal generated by the comparator 74 together form the corresponding the first electrical signal.

In a possible application scenario, as shown in FIG. 8, the flame detection device also includes an infrared detection module 81, and the infrared detection module 81 includes an infrared sensor 81a, a signal filter amplifier 81b, and an amplification factor regulator 81c; the infrared sensor 81a and the signal The filter amplifier 81b is connected; the signal filter amplifier 81b is connected with the control module 12; the amplification factor regulator 81c is connected with the control module 12 and the signal filter amplifier 81b;

The infrared sensor 81a is used to sense infrared radiation and convert the infrared radiation into a second electrical signal, wherein the second electrical signal includes time domain information and frequency domain information; a signal filter amplifier 81b is used to process the second electrical signal Perform filtering and amplification processing to generate a third electrical signal; after sending the third electrical signal to the control module 12 , the amplification factor adjuster 81c adjusts the parameters of the signal filter amplifier 81b through the feedback result of the control module 12 .

Based on the above-mentioned device, when considering infrared radiation for fire judgment, the time domain information and frequency domain information of the electrical signal corresponding to infrared radiation are considered at the same time, which is helpful to improve the accuracy of fire judgment compared with only considering time domain information.

Based on any of the above-mentioned flame detection devices, the embodiment of the present application also provides a flame detection method, as shown in Figure 9, which is a schematic flow chart of a flame detection method in the present application, including the following steps:

S91, acquiring the self-discharge signal of the ultraviolet photoelectric cell;

S92, according to each pulse interval corresponding to the self-discharge signal, calculate the anti-false alarm signal corresponding to the ultraviolet photoelectric cell;

S93, according to the anti-false alarm signal and the first electrical signal corresponding to the ultraviolet photoelectric cell, calculate the first effective electrical signal corresponding to the ultraviolet photoelectric cell;

S94. According to the first effective electrical signal, it is judged whether the currently detected flame data causes a fire.

In the embodiment of the present application, the self-discharge signal corresponding to the ultraviolet photoelectric cell is first detected by the detection module in the above-mentioned fire detection device, and then each pulse interval corresponding to the self-discharge signal is determined, and according to each pulse interval corresponding to the self-discharge signal, An anti-false alarm signal corresponding to the ultraviolet photoelectric cell is calculated, wherein the anti-false alarm signal represents an adjustment signal corresponding to the first electrical signal corresponding to the ultraviolet radiation. Specifically:

First, calculate the time length corresponding to the pulse interval between any two adjacent pulses in the self-discharge signal, for example, there are currently four pulses a, b, c, and d, the time corresponding to pulse a is t ₁ , and the time corresponding to pulse b is t ₂ , the time corresponding to pulse c is t ₃ , and the time corresponding to pulse d is t ₄ , then the time length corresponding to the three pulse intervals can be calculated. Wherein, the time length corresponding to the pulse interval between a and b pulses is T ₁ =t ₂ -t ₁ , the time length corresponding to the pulse interval between b and c pulses is T ₂ =t ₃ -t ₂ , and c The time length corresponding to the pulse interval between the , d pulses is T ₁ =t ₄ -t ₃ .

Further, the difference between the maximum time length and the minimum time length among the various time lengths is determined. For example, if the order of the above-mentioned time lengths is calculated as T ₁ >T ₂ >T ₃ , then the maximum time length T _max =T ₁ and the minimum time length T _min =T ₃ can be determined. At this time, the difference T _max -T _min =T ₁ -T ₃ between them is calculated.

Finally, the anti-false alarm signal is calculated according to the difference, the maximum pulse amplitude of the self-discharge signal, and the discharge time length of the self-discharge signal. The specific calculation formula is:

F＝β(T _max -T _min )+γT _1max +ρU _max (1)

In formula (1), β is the self-discharge time interval coefficient, γ is the time width coefficient, ρ is the pulse amplitude coefficient, T _1max is the maximum time width of the self-discharge signal pulse, U _max is the maximum amplitude of the self-discharge signal pulse value.

After the anti-false alarm signal corresponding to the ultraviolet photoelectric cell is calculated, the first effective electrical signal corresponding to the ultraviolet photoelectric cell is further calculated according to the anti-false alarm signal and the first electrical signal corresponding to the ultraviolet photoelectric cell. In the embodiment of the present application, the first electrical signal is obtained by a signal generating unit. The specific method for calculating the first effective signal includes: first, calculating the discrete integral corresponding to each pulse signal in the first electrical signal; then, calculating the first difference between the discrete integral and the anti-false alarm signal; calculating the first difference , determined as the first effective electrical signal corresponding to the ultraviolet photocell.

The calculation formula corresponding to the above-mentioned first effective electrical signal is:

In formula (2), K represents the first effective electrical signal, a(τ) represents the pulse in the first electrical signal, and F represents the anti-false alarm signal.

After the first effective electrical signal corresponding to the ultraviolet photocell is calculated, further according to the first effective electrical signal, it is judged whether the currently detected flame data causes a fire, specifically including:

Judging whether the first effective electrical signal is greater than the first preset threshold, wherein the first preset threshold can be set to 0, and of course it can be adjusted according to specific conditions. Different first preset thresholds affect the flame detector’s response to fire Sensitivity of detection; if the first effective electrical signal is greater than the first preset threshold, it is determined that the currently detected flame data causes a fire, and an alarm operation is performed; otherwise, it is determined that the currently detected flame data does not cause a fire, and no alarm is issued .

In a possible application scenario, in order to further improve the accuracy of fire judgment, after calculating the first effective electrical signal corresponding to the ultraviolet photocell, it is necessary to obtain the second electrical signal corresponding to the infrared radiation. In the embodiment of this application Among them, the second electrical signal is detected by the infrared detection module; then, according to the signal strength and average power corresponding to the second electrical signal, the frequency domain characteristics corresponding to the infrared radiation are calculated, and the specific calculation method can be obtained by fast Fourier transform (fastFourier transform, FFT) to achieve.

Further, according to the frequency domain feature and the time domain feature corresponding to the infrared radiation, calculate the second effective signal corresponding to the infrared radiation, and judge whether the currently detected flame data causes a fire according to the first effective signal and the second effective signal.

Specifically, if the first effective signal is greater than the first preset threshold, or the second effective signal is greater than the second preset threshold, it is determined that the currently detected flame data causes a fire, and an alarm operation is performed; if the first effective signal is less than or equal to The first preset threshold, and the second effective signal is less than or equal to the second preset threshold, it is determined that the currently detected flame data does not cause a fire, and no alarm operation is performed.

Through the above method, the second electrical signal corresponding to the infrared radiation is judged whether a fire has occurred through the double-layer data of the time domain and the frequency domain, which can improve the accuracy of fire judgment. At the same time, by detecting the self-discharge signal corresponding to the ultraviolet photocell, the first electrical signal corresponding to the ultraviolet radiation is further processed to obtain the first effective electrical signal that can better reflect the intensity of the ultraviolet radiation, and judge based on the first effective electrical signal Whether a fire occurs, the influence of the self-discharge phenomenon of the ultraviolet photoelectric cell can be eliminated, and the accuracy of fire judgment can be improved.

While preferred embodiments of the invention have been described, additional changes and modifications to these embodiments can be made by those skilled in the art once the basic inventive concept is appreciated. Therefore, it is intended that the appended claims be construed to cover the preferred embodiment as well as all changes and modifications which fall within the scope of the invention.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (12)

1. A flame detection device is characterized by comprising an ultraviolet detection module and a control module, wherein the ultraviolet detection module comprises an ultraviolet photoelectric tube, a detection unit and a signal generation unit; the detection unit and the signal generation unit are respectively connected with the ultraviolet photoelectric tube and the control module;

the detection unit is used for generating a self-discharge signal corresponding to the ultraviolet phototube; the signal generating unit is used for generating a first electric signal from the ultraviolet radiation detected by the ultraviolet photoelectric tube; and the control module is used for judging fire according to the first electric signal and the self-discharge signal.

2. The apparatus of claim 1, wherein the ultraviolet detection module further comprises a drive unit, the drive unit comprising a tuning circuit, a transformer, and a switching circuit, the switching circuit connected to the transformer, the transformer connected to the tuning circuit, the tuning circuit connected to the ultraviolet phototube;

the switching circuit is used for being connected to a first power supply through a Pulse Width Modulation (PWM) signal; the transformer is used for transforming the first power supply to obtain a second power supply; the setting circuit is used for setting the second power supply to obtain a driving power supply, wherein the driving power supply is used for driving the ultraviolet phototube.

3. The apparatus of claim 2, wherein the switching circuit comprises a first resistor, a transistor, and a first diode; a first end of the first diode is connected with the first power supply; the second end of the first diode is connected with the first end of the triode; the second end of the triode is grounded; and the third end of the triode is connected with the first resistor, wherein the first resistor is used for receiving the PWM signal.

4. The apparatus of claim 3, wherein the tuning circuit comprises a second diode, a first capacitor, a second resistor, a second capacitor, and a third resistor; a first end of the second diode is connected with the transformer, and a second end of the second diode is connected with the second resistor; a first preset point is arranged between the second resistor and the first end of the second diode, and a first capacitor is arranged between the first preset point and a grounding point; the second resistor is connected with the third resistor, a second preset point is arranged between the second resistor and the third resistor, and a second capacitor is arranged between the second preset point and the grounding point; the second resistor is connected with the ultraviolet phototube.

5. The apparatus of claim 1, wherein the detection unit comprises a fourth resistor, a fifth resistor, and a sixth resistor; the first end of the fourth resistor is connected with the ultraviolet phototube, and the second end of the fourth resistor is connected with the grounding point through the fifth resistor; the fourth resistor is connected with the fifth resistor in series and then connected with the sixth resistor in parallel; and the non-grounding end of the sixth resistor is connected with the signal generating unit.

6. The apparatus of claim 1, wherein the signal generation unit comprises a seventh resistor, a third capacitor, a third transistor, and a comparator; a first end of the seventh resistor is connected with the detection unit; the second end of the seventh resistor is connected with the first end of the third capacitor, and the second end of the third capacitor is grounded; the third capacitor is connected with the third triode in parallel, and the non-grounding ends of the third capacitor and the third triode are connected with the comparator; the comparator is connected with the control module.

7. The apparatus of claim 1, further comprising an infrared detection module comprising an infrared sensor, a signal filter amplifier, and an amplification factor adjuster; the infrared sensor is connected with the signal filtering amplifier; the signal filtering amplifier is connected with the control module; the amplification factor regulator is connected with the control module and the signal filtering amplifier;

the infrared sensor is used for sensing infrared radiation and converting the infrared radiation into a second electric signal, wherein the second electric signal comprises time domain information and frequency domain information; the signal filter amplifier is used for filtering and amplifying the second electric signal to generate a third electric signal; and the amplification factor adjuster is used for adjusting parameters of the signal filtering amplifier.

8. A method of flame detection according to any of the preceding claims 1 to 7, wherein the method comprises:

acquiring a self-discharge signal of the ultraviolet phototube;

calculating an error-report-preventing signal corresponding to the ultraviolet photoelectric tube according to each pulse interval corresponding to the self-discharge signal;

calculating a first effective electric signal corresponding to the ultraviolet photoelectric tube according to the false alarm prevention signal and the first electric signal corresponding to the ultraviolet photoelectric tube;

and judging whether the currently detected flame data causes a fire or not according to the first effective electric signal.

9. The method of claim 8, wherein calculating the false alarm prevention signal corresponding to the ultraviolet photocell according to each pulse interval corresponding to the self-discharge signal comprises:

calculating the time length corresponding to the pulse interval of any two adjacent pulses in the self-discharge signal;

determining a difference between a maximum time length and a minimum time length of the respective time lengths;

and calculating the false alarm prevention signal according to the difference, the maximum pulse amplitude of the self-discharge signal and the discharge time length of the self-discharge signal.

10. The method of claim 8, wherein said calculating a first valid electrical signal corresponding to said uv cell based on said false alarm prevention signal and a first electrical signal corresponding to said uv cell comprises:

calculating discrete integrals corresponding to all pulse signals in the first electric signal;

finding a first difference between the discrete integral and the false alarm prevention signal;

and determining the first difference value as a first effective electric signal corresponding to the ultraviolet photoelectric tube.

11. The method of claim 8, wherein determining whether the currently detected flame data is causing a fire based on the first valid electrical signal comprises:

judging whether the first effective electric signal is larger than a first preset threshold value or not;

if yes, determining that the fire disaster is caused by the currently detected flame data;

if not, it is determined that the currently detected flame data does not cause a fire.

12. The method of claim 8, wherein determining whether the currently detected flame data is causing a fire based on the first active electrical signal comprises:

acquiring a second electric signal corresponding to the infrared radiation;

calculating the frequency domain characteristics corresponding to the infrared radiation according to the signal intensity and the average power corresponding to the second electric signal;

calculating a second effective signal corresponding to the infrared radiation according to the frequency domain characteristic and the time domain characteristic corresponding to the infrared radiation;

and judging whether the currently detected flame data causes a fire or not according to the first effective signal and the second effective signal.

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