Flame detector based on ultraviolet cathode MCP-PMT and system thereof

Abstract

The invention discloses a flame detector based on an ultraviolet cathode MCP-PMT. The flame detector comprises a large-view-field ultraviolet lens, a high-voltage power supply, an amplifying circuit, the ultraviolet cathode MCP-PMT, a solar-blind ultraviolet light filter, a signal processing board, a DC 12V input connector, a DB9 serial port signal output head and a bottom board. The solar blind ultraviolet filter is installed inside or behind the large-view-field ultraviolet lens, the amplifying circuit is installed at a flange position of one side, facing the large-view-field ultraviolet lens, of the large-view-field ultraviolet lens, and the ultraviolet cathode MCP-PMT is installed at a flange position of one side, facing the large-view-field ultraviolet lens, of the large-view-field ultraviolet lens; the large-view-field ultraviolet lens, the high-voltage power supply, the signal processing board, the DC 12V input connector and the DB9 serial port signal output head are all installed on corresponding installation holes of the bottom board. According to the invention, the sensitivity is improved, the detection speed is improved, and the false alarm rate and energy consumption are greatly reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of photoelectric detection and imaging, and in particular relates to a flame detector based on an ultraviolet cathode MCP-PMT and a system thereof. Background Art

[0002] At present, flame detectors are mainly divided into three types: temperature-sensing type, smoke-sensing type and light-sensing type. Among them, temperature-sensing type and smoke-sensing type mainly detect the temperature rise and smoke generated by the fire. Due to their working principles, when the above two types of flame detectors are working, the fire has occurred for a long time, leaving less time for emergency treatment, and it is impossible to extinguish the fire in the early stage. The light-sensitive flame detector is mainly divided into infrared and ultraviolet flame detectors. Its working principle is that when the flame burns, it will generate infrared and ultraviolet band light. The corresponding band light can be detected to achieve flame detection and alarm. The light-sensitive detector is characterized by rapid response, but the infrared flame detector is easily affected by sunlight and artificial light, and the false alarm rate is low. The commonly used ultraviolet flame detectors generally use photoelectric tubes and semiconductor systems, with low detection sensitivity and low accuracy in detecting weak flames in the early stage of a fire. Summary of the invention

[0003] The present invention aims to provide a flame detector based on ultraviolet cathode MCP-PMT and a system thereof, which can improve sensitivity, increase detection speed, and greatly reduce false alarm rate and energy consumption.

[0004] In order to achieve the purpose of the present invention, on the one hand, the present invention provides a flame detector based on ultraviolet cathode MCP-PMT, including a wide-field ultraviolet lens, a high-voltage power supply, an amplifier circuit, an ultraviolet cathode MCP-PMT, a day-blind ultraviolet filter, a signal processing board, a DC 12V input connector, a DB9 serial port signal output head, and a bottom plate; the day-blind ultraviolet filter is installed inside or behind the wide-field ultraviolet lens, the amplifier circuit is installed at the flange position of the wide-field ultraviolet lens facing one side, and the ultraviolet cathode MCP-PMT is installed at the flange position of the wide-field ultraviolet lens detector facing one side; the wide-field ultraviolet lens, the high-voltage power supply, the signal processing board, the DC 12V input connector, and the DB9 serial port signal output head are all installed on the corresponding mounting holes of the bottom plate;

[0005] The signal processing board is used to process the output level signal of the amplifier circuit.

[0006] The ultraviolet cathode MCP-PMT includes a light window, a cathode surface, a cathode, a microchannel plate input, a microchannel plate output, a microchannel plate, and an anode; the light window is made of quartz material, and the cathode surface is made on its inner end surface; the cathode, the microchannel plate, and the anode are installed in sequence behind the cathode surface; a high voltage is applied between the microchannel plate input and the microchannel plate output for electron multiplication; the microchannel plate is used as an electron multiplier, and the output is received by the anode when it is close to the electric field.

[0007] On the other hand, the present invention also provides a flame detector system based on an ultraviolet cathode MCP-PMT, wherein the signal processing board pre-sets a signal acquisition cycle, an alarm threshold, and an alarm mode; the ultraviolet cathode MCP-PMT outputs an electrical signal to the amplifier circuit, the amplifier circuit amplifies the input electrical signal, the amplification is a 0-5V level signal, and then inputs the signal processing board for signal acquisition, the signal processing board analyzes and processes the input level signal, and counts the sum of time when the level value is higher than 3V within a set period; when the sum of time in two consecutive periods is greater than a preset threshold, the DB9 serial port signal output head reports an alarm signal, and when the sum of time is less than a preset threshold, it returns to the signal processing board for signal acquisition until the sum of time in two consecutive periods is greater than the preset threshold; the alarm emits an audible and visual alarm after receiving the alarm signal.

[0008] Compared with the prior art, the significant progress of the present invention is that: the present invention uses a large-field-of-view ultraviolet lens to perform wide-area flame target imaging, uses a day-blind ultraviolet filter to suppress out-of-band false alarm targets, uses a microchannel plate photomultiplier tube (MCP-PMT) to perform photoelectric conversion and amplification of weak light signals, uses an amplifier circuit to perform low-noise amplification of electrical signals, and uses a signal processing board to process electrical signals and give an alarm; based on the above functions, the present invention has a higher sensitivity for detecting small fire sources, a faster flame detection speed, an extremely low false alarm rate, and reduces power consumption.

[0009] In order to more clearly illustrate the functional characteristics and structural parameters of the present invention, further description is given below in conjunction with the accompanying drawings and specific implementation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0011] Figure 1 It is the overall appearance diagram of the present invention;

[0012] Figure 2 It is a schematic diagram of the overall assembly structure of the present invention;

[0013] Figure 3 It is a schematic structural diagram of MCP-PMT of the present invention;

[0014] Figure 4 It is a working principle diagram of the signal processing board of the present invention;

[0015] Figure 5 It is a trial operation diagram of the garage fire prevention monitoring system of the present invention. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0017] The flame detector based on ultraviolet cathode MCP-PMT of the present invention is combined with Figure 1-2 , including a large-field-of-view ultraviolet lens 1, a high-voltage power supply 2, an amplifier circuit 3, an ultraviolet cathode MCP-PMT4, a day-blind ultraviolet filter 5, a signal processing board 6, a DC 12V input connector 7, a DB9 serial port signal output head 8, and a bottom plate 9; the day-blind ultraviolet filter 5 is installed inside or behind the large-field-of-view ultraviolet lens 1, the amplifier circuit 3 is installed at the flange position of the large-field-of-view ultraviolet lens 1 on the side facing the lens, and the ultraviolet cathode MCP-PMT4 is installed at the flange position of the large-field-of-view ultraviolet lens 1 on the side facing the detector; the large-field-of-view ultraviolet lens 1, the high-voltage power supply 2, the signal processing board 6, the DC 12V input connector 7, and the DB9 serial port signal output head 8 are all installed on the corresponding mounting holes of the bottom plate 9;

[0018] The signal processing board 6 is used to process the output level signal of the amplifier circuit. It has the function of counting the time of the signal above the threshold voltage within a set period, and has the functions of signal acquisition period adjustment, time and threshold setting, reporting of time above the threshold, setting the number of continuous calculation cycles, and signal alarm.

[0019] Combination Figure 3The ultraviolet cathode MCP-PMT4 includes a light window 10, a cathode surface 11, a cathode 12, a microchannel plate input 13, a microchannel plate output 14, a microchannel plate 15, and an anode 16; the light window 10 is made of quartz material, and the cathode surface 11 is made on its inner end surface; the cathode 12, the microchannel plate 15, and the anode 16 are sequentially installed behind the cathode surface 11; a high voltage is applied between the microchannel plate input 13 and the microchannel plate output 14 for electron multiplication; the microchannel plate 15 is used as an electron multiplier, and is received and output by the anode 16 when it is close to the electric field.

[0020] The effective diameter of the cathode surface 11 is φ10 mm.

[0021] The anode 16 outputs a micro-current signal which is amplified by the amplifier circuit 3 to be a 0-5V level signal, and then input into the processing board 6 for signal processing.

[0022] The ultraviolet cathode MCP-PMT4 is used to detect ultraviolet band signals, and adopts an alkali metal cathode with an effective diameter of 10-25 mm. A double microchannel plate 15 is used as an electron multiplier, and a metal anode outputs a current signal.

[0023] The field of view of the large-field-of-view ultraviolet lens 1 is greater than or equal to 120°.

[0024] The solar-blind ultraviolet filter 5 is used to filter out background interference outside the ultraviolet signal band, and its passband is 250-280nm, and the peak transmittance is greater than or equal to 25%.

[0025] The present invention also includes a system of flame detectors based on ultraviolet cathode MCP-PMT, combined with Figure 4 , the signal processing board 6 pre-sets the signal acquisition cycle, alarm threshold, and alarm mode; the ultraviolet cathode MCP-PMT4 outputs an electrical signal to the amplifier circuit 3, the amplifier circuit 3 amplifies the input electrical signal, the amplification is a 0-5V level signal, and then inputs the signal processing board 6 for signal acquisition, the signal processing board 6 analyzes and processes the input level signal, and counts the sum of time when the level value is higher than 3V in the set cycle; when the sum of time in two consecutive cycles is greater than the preset threshold, the DB9 serial port signal output head 8 reports an alarm signal, in order to suppress the false alarm caused by the background dark emission noise of the ultraviolet cathode MCP-PMT4, when the sum of time is less than the preset threshold, it returns to the signal processing board 6 for signal acquisition until the sum of time in two consecutive cycles is greater than the preset threshold; the alarm emits an audible and visual alarm after receiving the alarm signal.

[0026] The test combination of the present invention Figure 5The detector of the present invention is installed on the column at the entrance of the basement through the bracket, and external power is supplied through the DC 12V input connector 7. The DB9 serial port signal output connector 8 is connected to the alarm to detect the fire source in the garage. A lighter flame detection test is carried out in each corner of the basement. The test shows that the device can monitor the basement with a depth of 40 meters without blind spots. The test number is greater than 100 times, and the number of alarm missed reports is 0 times. After that, a continuous working test was carried out for 2 months, and the false alarm rate of the running device was 0, and the missed alarm rate was 0. The flame detection sensitivity and false alarm rate are significantly better than those of conventional flame detectors.

[0027] Compared with the prior art, the present invention has higher detection sensitivity for tiny fire sources, and the detection distance for a 2cm flame is better than 80 meters; the flame detection speed is fast, and the average response time for a 2cm flame at 30 meters is 0.13 seconds; the false alarm rate is extremely low, and 0 false alarms can be achieved after working continuously for 2 months; the power consumption is low, and the overall power consumption is less than 1W.

[0028] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0029] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A flame detector based on ultraviolet cathode MCP-PMT, characterized in that: It comprises a wide-field ultraviolet lens (1), a high-voltage power supply (2), an amplifier circuit (3), an ultraviolet cathode MCP-PMT (4), a day-blind ultraviolet filter (5), a signal processing board (6), a DC12V input connector (7), a DB9 serial port signal output head (8), and a base plate (9); the day-blind ultraviolet filter (5) is installed inside or behind the wide-field ultraviolet lens (1), the amplifier circuit (3) is installed at a flange position on the side of the wide-field ultraviolet lens (1) facing the lens, and the ultraviolet cathode MCP-PMT (4) is installed at a flange position on the side of the detector of the wide-field ultraviolet lens (1); the wide-field ultraviolet lens (1), the high-voltage power supply (2), the signal processing board (6), the DC12V input connector (7), and the DB9 serial port signal output head (8) are all installed on the corresponding mounting holes of the base plate (9); The signal processing board (6) is used to process the output level signal of the amplifier circuit.

2. A flame detector based on ultraviolet cathode MCP-PMT according to claim 1, characterized in that: The ultraviolet cathode MCP-PMT (4) comprises a light window (10), a cathode surface (11), a cathode (12), a microchannel plate input (13), a microchannel plate output (14), a microchannel plate (15), and an anode (16); the light window (10) is made of quartz material, and the cathode surface (11) is made on the inner end surface of the light window (10); the cathode (12), the microchannel plate (15), and the anode (16) are sequentially installed behind the cathode surface (11); a high voltage is applied between the microchannel plate input (13) and the microchannel plate output (14) for electron multiplication; the microchannel plate (15) is used as an electron multiplier, and the output is received by the anode (16) when it is close to the electric field.

3. A flame detector based on ultraviolet cathode MCP-PMT according to claim 2, characterized in that: The effective diameter of the cathode surface (11) is φ(10) mm.

4. A flame detector based on ultraviolet cathode MCP-PMT according to claim 2, characterized in that: The anode (16) outputs a micro-current signal which is amplified by the amplifier circuit (3) to obtain a 0-5V level signal, which is then input into the processing board (6) for signal processing.

5. A flame detector based on ultraviolet cathode MCP-PMT according to claim 2, characterized in that: The ultraviolet cathode MCP-PMT (4) is used to detect ultraviolet band signals, adopts an alkali metal cathode, the effective diameter of the alkali metal cathode is 10-25 mm, adopts two microchannel plates (15) as electron multipliers, and the metal anode outputs current signals.

6. A flame detector based on ultraviolet cathode MCP-PMT according to claim 1, characterized in that: The large-viewing-field ultraviolet lens (1) has a viewing field greater than or equal to 120°.

7. The flame detector based on ultraviolet cathode MCP-PMT according to claim 1, characterized in that: The solar-blind ultraviolet filter (5) is used to filter out background interference outside the ultraviolet signal band, and its passband is 250-280nm, and the peak transmittance is greater than or equal to 25%.

8. A flame detector system based on a UV cathode MCP-PMT according to any one of claims 1 to 7, characterized in that: The signal processing board (6) presets a signal collection cycle, an alarm threshold, and an alarm mode; the ultraviolet cathode MCP-PMT (4) outputs an electrical signal to the amplifier circuit (3); the amplifier circuit (3) amplifies the input electrical signal to obtain a 0-5V level signal, which is then input into the signal processing board (6) for signal collection; the signal processing board (6) analyzes and processes the input level signal, and calculates the total time when the level value is higher than 3V within a set cycle; when the total time within two consecutive cycles is greater than a preset threshold, the DB9 serial port signal output head (8) reports an alarm signal; when the total time is less than a preset threshold, the signal processing board (6) is returned to perform signal collection until the total time within two consecutive cycles is greater than the preset threshold; and the alarm emits an audible and visual alarm after receiving the alarm signal.

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