Portable dangerous gas concentration detection device

Abstract

The application provides a portable dangerous gas concentration detection device, and belongs to the technical field of electrochemical detection; the device comprises a detection module, a signal acquisition module, a control module, a display module and an audible and visual alarm module; the conductive gel in the detection module produces conductivity change under the action of dangerous gas; the signal acquisition module acquires the conductivity change signal; the control module carries out filtering, amplification and analog-digital conversion processing on the acquired signal; the control module converts the processed signal into the concentration value of the dangerous gas in real time and displays the concentration value through the display module; when the detected concentration exceeds the safety threshold, the control module synchronously triggers the audible and visual alarm module; the application has the advantages of mobile and portable power supply mode and fixed position power supply mode, and can realize the switching of high-energy detection mode and low-energy alarm mode through a hardware switch; the application has the advantages of high detection precision, good sensitivity, rapid response, portability and the like, and is suitable for the on-site monitoring of dangerous gas in multiple scenes.

Description

Technical Field

[0001] This invention relates to the field of electrochemical detection technology, and more specifically, to a portable hazardous gas concentration detection device. Background Technology

[0002] Real-time detection and accurate identification of hazardous gases are of great significance in industrial safety production, environmental quality monitoring, and public health protection. These gases mainly include flammable, explosive, and toxic gases. In recent years, with the continuous development of the chemical, energy, and fine manufacturing industries, various hazardous gases pose a potential risk of leakage during production processes, storage, and transportation. Once a leak occurs and spreads to the surrounding environment, it may cause serious fires or violent explosions, or lead to acute poisoning symptoms or chronic health damage.

[0003] Existing methods for detecting hazardous gases mainly include chromatography, mass spectrometry, electrochemical sensing, semiconductor gas sensing, optical sensing, and fluorescence colorimetric sensing. Among these, traditional chromatography and mass spectrometry have high detection accuracy and can achieve precise quantitative analysis of target gas components. However, chromatography and mass spectrometry instruments are usually large and sophisticated equipment, with relatively large size, complex operation procedures, and long detection cycles. They are difficult to meet the actual needs of real-time online monitoring in industrial sites and outdoor environments. At the same time, the purchase and maintenance costs of such instruments are high, and they require professional personnel to operate, making them unsuitable for widespread distribution as personal protective equipment.

[0004] In comparison, gas detection devices based on functional materials exhibit significant advantages in terms of portability, manufacturing cost, and real-time response. These devices utilize specific sensitive functional materials to interact with target gas molecules, converting chemical recognition events into measurable physical quantities such as electrical or optical signals, thereby achieving gas detection. Electrochemical sensors are one of the most widely used types, which achieve detection by measuring the current signal generated by the electrochemical reaction of the gas to be tested on the electrode surface.

[0005] Despite significant progress in functionalized material detection devices, several pressing challenges remain in practical applications. Specifically: First, the detection accuracy of some gas detection devices is insufficient. When measuring low concentrations of hazardous gases, the nonlinear distortion of the output signal is severe, making it difficult to meet the requirements for accurate measurement of trace gases. Second, the detection sensitivity of some devices needs improvement, especially for trace gases, where the response signal is weak, resulting in a low signal-to-noise ratio and susceptibility to environmental electromagnetic interference, leading to false alarms or missed detections. Third, the response time of some detection devices is relatively long, from the time gas molecules come into contact with the sensor to the time the sensing signal reaches a stable output. The time required for detection is often tens of seconds or even minutes, which is difficult to meet the actual needs for rapid early warning in the event of a sudden leak of hazardous gas; fourth, some existing detection devices use precious metals as electrode materials or require complex micro-machining processes, resulting in high device manufacturing costs and limiting their large-scale promotion and application; fifth, some existing detection equipment is usually designed for laboratory analysis or fixed monitoring station applications, and its overall size and weight are large and heavy, making it inconvenient for operators to carry it and move and deploy it flexibly between different scenarios. At the same time, the above-mentioned equipment has high power consumption and often needs to be continuously connected to an external power supply, making it impossible to work for a long time in the field or temporary work sites without power supply facilities.

[0006] In summary, there is an urgent need in this field to provide a portable hazardous gas detection device that can simultaneously achieve high detection accuracy and sensitivity, has rapid response characteristics, low manufacturing cost, is easy for operators to carry, and can flexibly switch between multiple working modes to adapt to different application scenarios. Summary of the Invention

[0007] The present invention aims to provide a portable hazardous gas concentration detection device to solve the problems of low detection accuracy, insufficient detection sensitivity, long response time, high manufacturing cost, and inconvenience of carrying in the prior art.

[0008] To achieve the above objectives, the present invention provides a portable hazardous gas concentration detection device, comprising a detection module, a signal acquisition module, a control module, a display module, an audible and visual alarm module, a power supply module, and a mode switching module; wherein:

[0009] The detection module is used to generate a change in electrical conductivity under the action of hazardous gases. It includes a first mounting base, a second mounting base, a copper electrode, a platinum microelectrode, and a reaction tank.

[0010] The first mounting base has a first slot, and the edge of the first slot has a plurality of copper electrodes arranged symmetrically; the second mounting base is located on the side of the first mounting base, and the second mounting base has a second slot; the platinum microelectrode is inserted into the second slot, and the reaction tank is located between adjacent platinum microelectrodes, and the inner wall of the reaction tank is coated with conductive gel.

[0011] When hazardous gas molecules from the environment under test diffuse into the reaction tank, the conductivity of the conductive gel changes due to the action of the gas molecules; the platinum microelectrode and the copper electrode together form a detection electrode pair, which is used to measure the change in conductivity of the conductive gel in real time.

[0012] The signal acquisition module is connected to the detection module and is used to acquire the conductivity signal generated by the detection module. The above signal is an analog electrical signal, and its amplitude change reflects the change in conductivity of the conductive gel.

[0013] The control module is connected to the signal acquisition module. The control module first preprocesses the received conductivity signal, which includes filtering, amplification, and analog-to-digital conversion. Among these processes, filtering is used to eliminate environmental noise and circuit background noise; amplification is used to boost the weak electrical signal to a voltage range suitable for analog-to-digital conversion; and analog-to-digital conversion is used to convert the continuous analog signal into a discrete digital signal.

[0014] Subsequently, the control module converts the pre-processed digitized conductivity signal into the concentration value of hazardous gas in real time according to the internal preset mapping model; the preset mapping model is a mathematical model established by conducting systematic calibration experiments on conductive gel materials.

[0015] The display module is connected to the control module and is used to receive and display the hazardous gas concentration values ​​calculated by the control module. The display module can intuitively present the currently detected gas concentration information to the user in the form of numbers or charts.

[0016] The audible and visual alarm module is connected to the control module. The control module has a preset safety threshold. When the calculated concentration of hazardous gas exceeds the preset safety threshold, the control module immediately triggers the audible and visual alarm module, which then emits a strong audible and visual alarm signal to alert on-site personnel to take emergency measures.

[0017] The power supply module provides power to the entire device; it is configured to provide two different power supply modes: a portable detection mode for mobile scenarios and a long-term detection mode for fixed locations; wherein:

[0018] The portable detection mode for mobile scenarios relies on a built-in rechargeable battery, allowing the device to work independently without connecting to an external power source, meeting the needs of mobile scenarios such as inspections and field operations; the long-term detection mode for fixed locations connects directly to mains power or industrial power through an external power interface, enabling the device to operate continuously and uninterruptedly at a fixed monitoring point.

[0019] The mode switching module is connected to both the power supply module and the control module. The mode switching module controls the control module to switch between high-energy detection mode and low-energy alarm mode; where:

[0020] The high-energy detection mode is a full-function working mode. At this time, the main functional units such as the control module and display module are all powered on and working, which can realize quantitative detection, real-time display and historical data recording of gas concentration.

[0021] The low-power alarm mode is a low-power monitoring mode. In this mode, only the control module and the audible and visual alarm module are powered on, while high-power units such as the display module are powered off. In this mode, the device does not display specific concentration values, but continuously monitors the gas concentration in the environment. Once the threshold is exceeded, an alarm is triggered immediately.

[0022] The beneficial effects of this invention are as follows:

[0023] 1. This invention utilizes conductive gel as a gas-sensitive functional material, taking advantage of the repeatable and significant change in conductivity of the conductive gel after contact with the target hazardous gas, to achieve highly sensitive detection of hazardous gases; experimental data shows that the detection device has a strong response signal and a high signal-to-noise ratio for trace hazardous gases.

[0024] 2. This invention combines a conductive gel gas-sensitive probe with a recyclable platinum microelectrode. The conductive gel is applied to the reaction tank using a micro-coating method, requiring only a very small amount per use. The platinum microelectrode is detachably connected to the electrode mold via a limiting buckle and slot structure, allowing for easy removal, cleaning, and reuse after use. This structural design significantly reduces the long-term operating cost of the detection device, overcoming the high cost of consumables in traditional disposable sensors.

[0025] 3. This invention adopts a handheld shell design and highly integrates all functional modules inside the shell, which significantly improves the portability and field applicability of the detection device. Operators can hold the device with one hand and carry it with them to any place that needs to be tested, realizing mobile inspection.

[0026] 4. By setting up dual power supply modes and dual working modes, the present invention enables the device to flexibly adapt to different application scenarios. In mobile scenarios, it relies on battery power and operates in high-energy detection mode to achieve quantitative detection and on-site reading. At fixed monitoring points, it can be connected to an external power source for long-term operation. During standby or nighttime periods when real-time reading is not required, it can switch to low-energy alarm mode, which can significantly extend battery life or reduce energy consumption for fixed monitoring.

[0027] 5. The present invention has the advantage of rapid response. Based on the rapid dynamic characteristics of the interaction between conductive gel and hazardous gas molecules, combined with efficient peripheral signal processing circuitry, the total response time of the device from gas contact to stable output of concentration value is significantly shorter than that of existing similar products. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the device structure according to an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram of module connections according to an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the circuit principle of an embodiment of the present invention;

[0031] Figure 4 This is a three-dimensional structural diagram of the detection module in an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the electrical hardware wiring according to an embodiment of the present invention;

[0033] Figure 6 This is a binomial fitting curve between the relative change in conductivity and the commonly used logarithm of steam concentration in an embodiment of the present invention.

[0034] In the figure, 1-first mounting base, 2-first slot, 3-copper electrode, 4-second mounting base, 5-second slot, 6-platinum microelectrode, 7-reaction tank, 8-limiting buckle. Detailed Implementation

[0035] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings. The described embodiments are for explaining the present invention and are not intended to limit the scope of protection of the present invention.

[0036] Please see Figures 1-3 This embodiment provides a portable hazardous gas concentration detection device for rapid on-site detection of the concentration of hazardous gases such as flammable gases and toxic gases in the environment. It includes a detection module, a signal acquisition module, a control module, a display module, an audible and visual alarm module, a power supply module, and a mode switching module.

[0037] The following section will describe in detail the specific structure and connection relationships of each module.

[0038] The detection module is used to generate a measurable change in conductivity under the influence of hazardous gases. Please refer to [link / reference]. Figure 4 The detection module includes a first mounting base 1, a second mounting base 4, a copper electrode 3, a platinum microelectrode 6, and a reaction tank 7. Specifically, the first mounting base 1 and the second mounting base 4 are both made of insulating material and are integrally formed by three-dimensional printing technology, and both are in the shape of a block.

[0039] The first mounting base 1 is recessed inward to form a U-shaped first slot 2 with its opening facing downward. Two copper electrodes 3 are respectively embedded on the inner sidewall edge opposite to the first slot 2, and the two are arranged symmetrically. The length direction of the copper electrode 3 is consistent with the length direction of the first slot 2. One end of the copper electrode 3 is located inside the first slot 2, and the other end extends to the outside of the sidewall of the first mounting base 1, serving as a terminal for connection with external circuit.

[0040] The second mounting base 4 is located on the side of the first mounting base 1, and the first mounting base 1 and the second mounting base 4 are aligned along the same axis. The overall size of the second mounting base 4 is smaller than that of the first mounting base 1. A second slot 5 is provided at the center of the upper surface of the second mounting base 4. The second slot 5 extends through the entire length of the second mounting base 4, and two platinum microelectrodes 6 are inserted into the second slot 5.

[0041] The platinum microelectrode 6 is sheet-shaped and its length is greater than that of the second mounting base 4. Therefore, when the platinum microelectrode 6 is fully inserted into the second slot 5, both ends of it extend beyond the second mounting base 4. One end of the platinum microelectrode 6 extends toward the first mounting base 1 to form an electrical contact with the copper electrode 3 on the first mounting base 1, while the other end extends outward away from the first mounting base 1 to extend into the reaction tank 7.

[0042] In this embodiment, the center distance between two adjacent platinum microelectrodes 6 is smaller than the center distance between two adjacent copper electrodes 3; when the first mounting base 1 and the second mounting base 4 are in the assembled state, the end of the platinum microelectrode 6 facing the first mounting base 1 is tightly fitted with the end of the copper electrode 3 facing the second mounting base 4, and the fitting is achieved by the limiting buckle 8.

[0043] The limiting buckle 8 is located on the inner wall of the first mounting base 1, and the copper electrode 3 is connected to the first mounting base 1 through the limiting buckle 8. Specifically, the limiting buckle 8 adopts the existing elastic barb structure. When the electrode is inserted into the position, the barb automatically engages with the positioning groove on the electrode to achieve reliable fixation and positioning.

[0044] The reaction tank 7 is located between two adjacent platinum microelectrodes 6. Specifically, the reaction tank 7 is located on the second mounting base 4 at one end away from the first mounting base 1. The reaction tank 7 is a micro-groove with an upward opening, and its bottom is connected to the ends of the two platinum microelectrodes 6. The end portions of the platinum microelectrodes 6 are exposed inside the reaction tank 7, serving as the working electrode and the counter electrode.

[0045] The inner wall of the reaction tank 7 is coated with conductive gel. The conductive gel is a sensitive material designed for specific target hazardous gases, and silver-π-conductive polymer gel can be used. When the gas molecules to be tested diffuse into the reaction tank 7 and come into contact with the conductive gel, the conductivity of the conductive gel changes accordingly. The platinum microelectrode 6 and the copper electrode 3 together form the detection path. The platinum microelectrode 6 extracts the conductivity signal in the reaction tank 7, while the copper electrode 3 serves as the interface for connecting to the subsequent signal acquisition module.

[0046] Please see Figure 5 The signal acquisition module is electrically connected to the detection module. In this embodiment, the signal acquisition module uses a TDS sensor chip and its peripheral circuit. The TDS sensor can measure the conductivity of the solution or gel material and convert it into a corresponding voltage or frequency signal. The input terminal of the signal acquisition module is connected to the copper electrode 3 terminal on the first mounting base 1 through a wire. The output terminal of the signal acquisition module is connected to the input terminal of the control module. The signal acquisition module is responsible for acquiring the original conductivity analog signal of the conductive gel in the reaction tank 7 in real time and transmitting the above signal to the control module.

[0047] The control module uses an ESP8266 microcontroller core development board, which integrates a central processing unit, memory, and multiple input / output interfaces. The control module is connected to the signal acquisition module via an external signal processing circuit, which includes an RC low-pass filter circuit, a high-precision operational amplifier circuit, and a 24-bit analog-to-digital converter chip connected in series.

[0048] RC low-pass filter circuits are used to filter out high-frequency noise and power supply ripple in signals;

[0049] High-precision operational amplifier circuits are used to amplify the weak electrical signals output by the signal acquisition module to a standard voltage range of 0 to 5 volts;

[0050] A 24-bit analog-to-digital converter chip is used to convert amplified analog voltage signals into high-resolution digital signals;

[0051] The control module reads the digital signal and runs a data processing algorithm inside it to process and convert the conductivity signal.

[0052] The display module is connected to the output of the control module. It uses a resistive touch screen, which is not only used to display information, but also integrates human-machine interaction functions. The display module is used to receive the dangerous gas concentration values ​​sent by the control module and display them to the user in a clear digital or graphical manner. At the same time, the touch screen has an embedded human-machine interface, on which the user can manually set safety thresholds, manually switch the working mode of the device, and view the historical concentration data and alarm records stored in the device through touch operation.

[0053] The audible and visual alarm module is also connected to a general-purpose input / output pin of the control module, which includes an LED strobe indicator and a high-decibel buzzer; wherein: the LED strobe indicator can emit a bright red light and flash; the high-decibel buzzer can emit an alarm sound greater than 85 decibels.

[0054] The LED strobe indicator and the high-decibel buzzer are designed to work in tandem, meaning they are triggered by the same control signal. When the concentration of hazardous gas calculated by the control module exceeds the user-preset safety threshold, the control module will pull the potential of the general-purpose input / output pin from low to high. This high-level signal drives the LED strobe indicator to start flashing rapidly, while simultaneously driving the high-decibel buzzer to emit a rapid alarm sound.

[0055] The power supply module provides operating power to the entire portable hazardous gas concentration detection device. It features two power supply modes: a rechargeable battery pack and an external power interface.

[0056] The rechargeable battery pack is used to provide a portable detection mode for mobile scenarios. The battery pack consists of two high-capacity lithium-ion rechargeable batteries. One battery is dedicated to powering the core circuits such as the control module and signal acquisition module, while the other battery is dedicated to powering the display module to meet the high power consumption requirements of the touch screen. An external power interface is used to provide a long-term detection mode in a fixed position.

[0057] The external power interface uses a universal Type-C charging port. When the device works at a fixed monitoring point for a long time, it can be connected to an AC power adapter or a USB power interface via a Type-C data cable to directly power the entire device and charge the internal rechargeable battery.

[0058] The mode switching module is connected to the power supply module and the control module. The mode switching module controls the entire device to switch between high-energy detection mode and low-energy alarm mode. The mode switching module includes a first switch and a second switch, wherein:

[0059] The first switch is a metal light switch with a metal casing and a built-in indicator light. It is connected in series in the main circuit of the power supply module to supply power to the control module and is used to control whether the control module is powered on.

[0060] The second switch is a toggle switch, which is connected in series in the circuit branch of the power supply module that supplies power to the display module, and is used to control whether the display module is powered on.

[0061] When only the first switch is turned on, the power supply module only supplies power to the control module, signal acquisition module, and audible and visual alarm module, while the display module is powered off. At this time, the control module enters the low-energy alarm mode. In the low-energy alarm mode, the device does not display real-time concentration values, but the control module continues to acquire and analyze conductivity signals. Once the concentration exceeds the safety threshold, the audible and visual alarm module is immediately triggered. The device consumes very little power in the above mode, making it very suitable for long-term standby monitoring.

[0062] When the first and second switches are turned on simultaneously, both the control module and the display module receive power. At this time, the control module enters the high-energy detection mode. In the high-energy detection mode, all functional modules of the device are activated. The device can not only perform threshold alarms, but also read the concentration value of hazardous gases in real time and quantitatively through the display module. Users can perform precise measurements and data recording in this mode.

[0063] In addition, this embodiment also includes a handheld housing, which is injection molded from lightweight, high-strength engineering plastic. Its overall size is designed for easy one-handed gripping. A flexible wire is provided on the top to communicate with the external environment. The detection module is connected to the end of the flexible wire via a plug-in connection. The above design allows the platinum microelectrode 6 to be flexibly bent, making it easy to insert into narrow or irregularly shaped detection areas. At the same time, the main circuit boards of the signal acquisition module, control module, and power supply module are all firmly housed in the internal cavity of the handheld housing. The display module is embedded in the front of the housing, with its screen surface flush with the housing surface, making it convenient for users to observe and operate.

[0064] The working principle of this device will be described in detail below, using silver-π-conductive polymer gel as the sensing material and hydrazine vapor as the hazardous gas to be detected.

[0065] First, the operator needs to prepare for the test, namely, to prepare the conductive gel gas-sensitive probe. The installation steps are as follows: Take out the second mounting base 4, use a micropipette to draw a preset volume of liquid silver-π-conductive polymeric gel precursor, carefully drop it onto and coat it on the inner wall of the reaction tank 7. The coating amount needs to be precisely controlled so that the conductive gel just completely covers the end surface of the platinum microelectrode 6 exposed in the reaction tank 7, but does not overflow the reaction tank 7. After the conductive gel solidifies at room temperature or by auxiliary heating, the gas-sensitive probe is prepared. After use, the platinum microelectrode 6 can be removed from the second mounting base 4, cleaned with a special cleaning agent and dried for reuse. The second mounting base 4 can be directly discarded or recycled.

[0066] Then, the prepared gas-sensitive probe is connected to the handheld housing via a flexible wire. The first switch is turned on to power on the control module. After the device starts up, the control module will first execute a self-test program and read an initial conductivity value. This value represents the baseline conductivity of the conductive gel in clean air; then, the control module enters the main loop program and begins to read the current conductivity value transmitted from the signal acquisition module in real time and continuously. .

[0067] The data processing program running inside the control module first calculates the relative rate of change of conductivity according to the following formula. :

[0068]

[0069] Next, the control module calls the preset mapping model stored internally. This model is pre-built through calibration experiments and written into the read-only memory of the control module. The specific steps for building this model are as follows:

[0070] The first step involves exposing multiple detection modules with the same formulation and preparation process to a series of standard hydrazine hydrate vapor environments with known concentrations C (in ppb);

[0071] The second step is to record the initial conductivity of each detection module when it is not exposed. and post-exposure response conductivity ;

[0072] The third step is to calculate the relative rate of change of conductivity at each concentration point using the formula described above. ;

[0073] The fourth step is to Using the common logarithm of concentration C as the ordinate, Use the x-axis to plot a scatter plot;

[0074] Fifth, use the binomial fitting algorithm to perform curve fitting on the above scattered points to obtain the fitting equation of the following form:

[0075]

[0076] In the formula, , , The constants obtained by the fitting algorithm, such as Figure 6 As shown, for the specific combination of silver-π-conductive polymer gel sensing hydrazine vapor, the fitted correlation coefficient R² is as high as 0.9957, indicating that the binomial model has extremely high linearity and prediction accuracy.

[0077] The sixth step is to determine the relative rate of change of conductivity from the measured value in actual measurements. Deducing the concentration of hydrazine hydrate vapor The control module will solve the equation to obtain its inverse function:

[0078]

[0079] In the formula, The solution to the above quadratic equation, the specific mathematical expression of the inverse function, is given by the constant. , , It is uniquely identified and written as program code, which is then embedded in the control module.

[0080] Therefore, in the actual testing process, the control module will calculate... Substituting into the inverse function above, the current concentration of hydrazine hydrate vapor can be quickly obtained. .

[0081] The example code provided in this embodiment is as follows:

[0082] #include<math.h>

[0083] float ecValue = 0;

[0084] float ecValue1 = 0;

[0085] float rate = 0;

[0086] float ppb = 0;

[0087] ecValue1 = readEC();

[0088] void loop() {

[0089] ecValue = readEC();

[0090] if (ecValue1 == 0) ecValue1 = ecValue;

[0091] rate = (ecValue1 - ecValue)*100 / ecValue1;

[0092] ppb = pow(10,((42.87-(sqrt(1838.64-18.64*(rate + 5.06)))) / 9.32));

[0093] if (ecValue > ecValue1) ppb = 0;

[0094] void sendPPBToScreen(float ppb) {

[0095] char cmd

[32] ;

[0096] sprintf(cmd, "n0.val=%.0f", ppb);

[0097] sendCommand(cmd);

[0098] }

[0099] void sendCommand(String cmd) {

[0100] tjcSerial.print(cmd);

[0101] tjcSerial.write(0xFF);

[0102] tjcSerial.write(0xFF);

[0103] tjcSerial.write(0xFF);

[0104] }

[0105] Finally, the control module sends the calculated concentration value (ppb) to the resistive touch screen via a serial communication interface. After receiving the data, the screen immediately updates and displays the current real-time concentration. At the same time, the judgment logic in the control module compares the ppb value with a preset safety threshold. If the ppb value is greater than the threshold, the control module changes the pin potential connected to the audible and visual alarm module, lights up the LED strobe indicator, and drives the buzzer to sound, thus completing the alarm.

[0106] Those skilled in the art will understand that the specific circuit parameters, material specifications, and algorithm constants in the above embodiments are examples given for specific applications. In practical applications, the housing, electrode mold size, platinum microelectrode specifications, conductive gel material composition, filter circuit resistance and capacitance values, and fitting algorithm constants can be adaptively adjusted according to different hazardous gas detection needs, environmental conditions, and cost control factors. For example, the mode switching module is not limited to a combination of a metal light switch and a toggle switch; other electronic or mechanical switch structures capable of independent or linked control, such as push-button switches or touch-sensitive switches, can also be used. Furthermore, the preset mapping model is not limited to binomial fitting; for other combinations of hazardous gases and conductive gels, linear fitting, exponential fitting, and other mathematical models can also be used. All of the above adjustments do not depart from the technical concept of this invention and remain within the scope of protection of this invention.

Claims

1. A portable hazardous gas concentration detection device, characterized in that, include: The detection module, used to generate a change in conductivity under the influence of hazardous gases, includes: First mounting base (1), the first mounting base (1) is provided with a first slot (2), and the edge of the first slot (2) is provided with a plurality of copper electrodes (3) arranged symmetrically; The second mounting base (4) is located on the side of the first mounting base (1), and the second mounting base (4) is provided with a second slot (5). A platinum microelectrode (6) is inserted into the second slot (5); A reaction tank (7) is located between adjacent platinum microelectrodes (6), and the inner wall of the reaction tank (7) is coated with conductive gel. A signal acquisition module, connected to the detection module, is used to acquire the conductivity signal; The control module is connected to the signal acquisition module. The control module filters, amplifies, and performs analog-to-digital conversion on the conductivity signal, and converts the processed conductivity signal into the concentration value of hazardous gas according to a preset mapping model. The display module, connected to the control module, is used to display the concentration value; An audible and visual alarm module is connected to the control module. When the concentration value exceeds a preset safety threshold, the control module triggers the audible and visual alarm module. The power supply module is used to provide power for both mobile detection mode and fixed-location long-term detection mode. The mode switching module, connected to the power supply module and the control module, is used to control the control module to switch between high-energy detection mode and low-energy alarm mode.

2. The portable hazardous gas concentration detection device according to claim 1, characterized in that, The copper electrode (3) is connected to the first mounting base (1), and the platinum microelectrode (6) is connected to the second mounting base (4) by a limiting buckle (8).

3. The portable hazardous gas concentration detection device according to claim 1, characterized in that, The control module is connected to the signal acquisition module via an external signal processing circuit. The peripheral signal processing circuit includes an RC low-pass filter circuit, a high-precision operational amplifier circuit, and a 24-bit analog-to-digital converter chip connected in sequence.

4. The portable hazardous gas concentration detection device according to claim 1, characterized in that, The audible and visual alarm module includes an LED strobe indicator and a high-decibel buzzer, which work in conjunction with each other.

5. The portable hazardous gas concentration detection device according to claim 1, characterized in that, The display module is a touch screen with an embedded human-machine interface. The human-machine interface is used for users to manually set the safety threshold, switch working modes, and view historical concentration data and alarm records.

6. The portable hazardous gas concentration detection device according to claim 1, characterized in that, The power supply module includes a rechargeable battery and an external power interface, wherein: The rechargeable battery is used to provide power for portable detection modes in mobile scenarios; The external power interface is used to provide power for the long-term detection mode at a fixed location.

7. The portable hazardous gas concentration detection device according to claim 1, characterized in that, The mode switching module includes a first switch and a second switch; When only the first switch is turned on, the control module enters a low-energy alarm mode; When the first switch and the second switch are turned on simultaneously, the control module enters the high-energy detection mode.

8. The portable hazardous gas concentration detection device according to claim 7, characterized in that, The first switch is a metal light switch that controls the power supply to the control module; The second switch is a toggle switch that controls the power supply to the display module.

9. The portable hazardous gas concentration detection device according to claim 1, characterized in that, Also includes a handheld casing; The outer casing is equipped with a flexible conduit that communicates with the external environment, and the detection module is plugged into the flexible conduit. The signal acquisition module, control module, and power supply module are housed inside the casing.

10. The portable hazardous gas concentration detection device according to claim 1, characterized in that, The preset mapping model is established in the following way: Obtain the initial conductivity of the detection module when it is not exposed to hazardous gases; Obtain the response conductivity of the detection module after exposure to a known concentration of hazardous gas; Calculate the relative rate of change of conductivity; A binomial fitting algorithm was used to establish the relationship between the relative rate of change of conductivity and the commonly used logarithm of hazardous gas concentration. The inverse function of the relationship is obtained and used as the preset mapping model.

Images