Limited space hydrogen sulfide gas detection device, circuit and method

Abstract

The invention discloses a device, a circuit and a method for detecting hydrogen sulfide gas in a limited space, which are characterized in that after a gas detection chip is subjected to chemical reaction with hydrogen sulfide in the limited space under the condition that the surface is wet, two ionized negatively charged sulfate ions generate charged charges in a drifting or moving process; the electric charges move under the action of an electrode micro electric field to generate weak current, and the weak current is absorbed by a conductive electrode fixed on a substrate, is input into an operational amplifier in a detection circuit, is converted into weak voltage at the primary stage of the operational amplifier, and then is amplified by the operational amplifier to be converted into measurable high voltage to be output. And the signal is transmitted to the sound-light alarm device through the driving circuit for sound and light alarm reminding. The method is easy to operate and low in manufacturing cost.

Description

Technical Field

[0001] The present invention relates to the technical field of gas detection, and in particular to a device, circuit and method for detecting hydrogen sulfide gas in a confined space. Background Art

[0002] Hydrogen sulfide is a toxic and harmful gas that poses a serious threat to human health. It is especially important to detect hydrogen sulfide in confined spaces. Confined space hydrogen sulfide gas working environment, such as: closed equipment: such as storage tanks, vehicle-mounted tanks, reaction towers (kettles), pressure vessels, pipelines, flues, boilers, etc.; underground confined spaces: such as underground pipelines, underground projects, culverts, tunnels, culverts, pits, abandoned wells, cellars, sewage pools (wells), biogas tanks, septic tanks, sewers, etc.; above-ground confined spaces: such as garbage stations and other confined space workplaces. There are many existing methods for hydrogen sulfide gas detection, but they are generally inconvenient to operate, the detection principle is complicated, and the cost is relatively high. Summary of the invention

[0003] The purpose of the present invention is to provide a hydrogen sulfide gas detection device which is simple to operate and low in cost, and to provide a detection circuit and a detection method with a simple detection principle.

[0004] To achieve the above-mentioned purpose, the present invention provides a confined space hydrogen sulfide gas detection device, including a hand-held part and a detection part. The hand-held part is electrically connected to the detection part. The hand-held part is a rectangular structure, with a power supply inside and a buzzer speaker and an indicator light opening outside; the detection part is a cylindrical structure, with a hydrogen sulfide gas pickup chip and a detection circuit inside the detection part, wherein the hydrogen sulfide gas pickup chip is inserted between the bent spring sheets and is electrically connected to the detection circuit.

[0005] As a further solution of the invention: the hydrogen sulfide gas pickup chip includes a substrate, on the front and back sides of the substrate are symmetrically laid out a circuit board and a gas detection chip, the gas detection chip is coated with a coating of copper sulfate powder; a conductive electrode is provided at one end of the substrate.

[0006] A detection circuit in a limited space hydrogen sulfide gas detection device comprises an integrated circuit IC1 and a drive circuit IC2. The integrated circuit IC1 comprises an operational amplifier OPA. Pins 3 and 4 of the integrated circuit IC1 are respectively connected to two positive and negative electrodes of an external gas pickup chip. Pin 3 of the integrated circuit IC1 is connected to the positive electrode of the operational amplifier OPA and one end of a resistor R3 after being connected in series with an internal resistor R1. The other end of the resistor R3 is connected to the output end of the operational amplifier OPA. Pin 4 of the integrated circuit IC1 is internally connected to the negative electrode of the operational amplifier OPA and one end of a resistor R2. The other end of the resistor R2 is connected to pin 2 of the integrated circuit IC1 and is grounded. Pin 1 of the output port of the integrated circuit IC1 is connected to the base of a transistor Q1. The emitter of the transistor Q1 is connected in series with a resistor R5 and is then grounded. The collector of the transistor Q1 is divided into two paths, one of which is connected to pin 5 of the drive circuit IC2 and the other is connected to one end of a resistor R4. The other end of the resistor R4 is respectively connected to pin 5 of the integrated circuit IC1 and pin 6 of the drive circuit IC2. The drive circuit IC2 Pin 6 of the driving circuit is also connected to the +3V power supply. Pin 1 of the driving circuit IC2 is divided into two paths. One path is connected in series with LED1 and resistor R5 and then connected to the +3V power supply and one end of the resistor R13. The other path is connected in series with resistor R12 and then connected to the base of the transistor Q2. Pin 2 of the driving circuit IC2 is divided into two paths. One path is connected in series with LED2 and resistor R6 and then connected to the +3V power supply and one end of the resistor R13. The other path is connected in series with resistor R11 and then connected to the base of the transistor Q2. Pin 3 of the driving circuit IC2 is divided into two paths. One path is connected in series with LED2 and resistor R6 and then connected to the +3V power supply and one end of the resistor R13. The other path is connected in series with resistor R11 and then connected to the base of the transistor Q2. LED3 and resistor R7 are connected to the +3V power supply and one end of the resistor R13, and the other is connected to the base of the transistor Q2 after being connected in series with resistor R10; pin 4 of the driving circuit IC2 is divided into two paths, one is connected in series with LED4 and resistor R8, then connected to the +3V power supply and one end of the resistor R13, and the other is connected in series with resistor R9, then connected to the base of the transistor Q2; pin 7 of the driving circuit IC2 is grounded; the collector of the transistor Q2 is connected in series with the buzzer FM and the other end of the resistor R13, and the emitter of the transistor Q2 is grounded.

[0007] As a further solution of the invention: the internal circuit of the driving circuit IC2 includes a resistor R01, one end of the resistor R01 is connected to the 5th pin of the driving circuit, and the other end is divided into two paths, one is connected to the base of the transistor Q01, and the other is connected in series with resistors R02, R03, and R04 in sequence, the resistors R02 and R03 are connected to the base of the transistor Q02, the resistors R03 and R04 are connected to the base of the transistor Q03, and the other end of the resistor R04 is connected to the base of the transistor Q04; the emitter of the transistor Q01 is divided into two paths, one is connected in series with the resistor R05 and connected to the 5th pin of the driving circuit IC2, and the other is connected to the driving circuit The emitter of transistor Q02 is divided into two paths, one of which is connected in series with resistor R06 and connected to pin 5 of driving circuit IC2, and the other is connected to pin 2 of driving circuit IC2; the emitter of transistor Q03 is divided into two paths, one of which is connected in series with resistor R07 and connected to pin 5 of driving circuit IC2, and the other is connected to pin 3 of driving circuit IC2; the emitter of transistor Q04 is divided into two paths, one of which is connected in series with resistor R08 and connected to pin 5 of driving circuit IC2, and the other is connected to pin 4 of driving circuit IC2; the collectors of transistors Q01, Q02, Q03, and Q04 are all connected to pin 7 of driving circuit IC2.

[0008] A detection method for a hydrogen sulfide gas detection device in a limited space comprises the following steps: a gas detection chip is wetted, a detection part is placed in the limited space to be detected, and after the gas detection chip reacts chemically with the hydrogen sulfide in the limited space when the surface is wetted, two negatively charged sulfate ions are ionized and generate charged charges during the drift or movement process; the charges move under the action of the electrode micro-electric field to generate a weak current, the weak current is absorbed by the conductive electrode fixed on the substrate, is input into an operational amplifier in the detection circuit, is converted into a weak voltage at the primary of the operational amplifier, and then is amplified and converted into a measurable high voltage output by the operational amplifier, and is transmitted to an audible and visual alarm device through a driving circuit to give an audible and visual alarm reminder.

[0009] As a further solution of the invention: the chemical equation of the chemical reaction is:

[0010] H2S+CuSO4=CuS↓+H2SO4

[0011] During this reaction, copper sulfate ionizes into copper ions (Cu 2+ ) and sulfate ions The ionic formula is:

[0012] H2S+Cu 2+ =CuS↓+2H + .

[0013] As a further solution of the invention: the detection device includes a hand-held part and a detection part, the detection part is a cylindrical structure, the hydrogen sulfide gas pickup chip and the detection circuit are arranged inside the detection part, wherein the hydrogen sulfide gas pickup chip is inserted between the bent spring sheets and electrically connected to the detection circuit; the hand-held part is a rectangular structure, with a power supply inside and a buzzer speaker and an indicator light opening outside; the hand-held part amplifies and drives the electrical signal transmitted from the detection part to realize LED graded display and buzzer sounding.

[0014] Compared with the prior art, the detection device of the present invention utilizes the detection part to perform other detections of hydrogen sulfide in a limited space, is simple to operate, has low cost, and has a simple detection circuit structure that is easy to implement. Hydrogen sulfide gas is chemically reacted with copper sulfate, and two ionized negatively charged sulfate ions generate charged charges during the drift or movement process; the amplifier is then used for amplification, so that hydrogen sulfide gas in a limited space can be effectively detected, and the detection method is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of a confined space hydrogen sulfide gas detection device of the present invention.

[0016] Figure 2 It is a schematic diagram of the internal structure of the detection unit of the present invention.

[0017] Figure 3 It is a physical schematic diagram of the hydrogen sulfide gas pickup chip of the present invention.

[0018] Figure 4 It is the detection circuit diagram of the present invention.

[0019] Figure 5 It is a driving circuit diagram of the present invention.

[0020] In the figure: 11, hand-held part, 12, detection part, 13, buzzer speaker, 14, indicator light opening, 15, power supply, 16, hydrogen sulfide gas pickup chip, 17, spring sheet, 18, detection circuit. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings.

[0022] like Figures 1 to 3As shown, a hydrogen sulfide gas detection device for a limited space includes a handheld part 11 and a detection part 12. The handheld part 11 is electrically connected to the detection part 12. The handheld part is a rectangular parallelepiped structure, with a power supply 15 inside, a buzzer speaker 13 and an indicator light opening 14 outside; the detection part 12 is a cylindrical structure, with a hydrogen sulfide gas pickup chip 16 and a detection circuit 18 inside the detection part 12, wherein the hydrogen sulfide gas pickup chip 16 is inserted between the bent spring sheets 17 and electrically connected to the detection circuit 18. The hydrogen sulfide gas pickup chip 16 includes a substrate, and a circuit board and a gas detection chip are symmetrically laid on the front and back surfaces of the substrate in sequence, and the gas detection chip is a coating coated with copper sulfate powder; a conductive electrode is provided on one end of the substrate. The detection part 12 is used to penetrate into a limited working space. In order to facilitate the adsorption of more ions and improve the sensitivity of the detection, the gas detection chip detects the hydrogen sulfide gas in the limited space operation when the surface is wet, and a slight change of ions is generated through chemical reaction, which is absorbed by the conductive electrode of the gas pickup chip. The handheld part 11 amplifies and drives the electrical signal transmitted from the detection part 12 to realize LED graded display and buzzer sounding.

[0023] Detection principle: When copper sulfate comes into contact with hydrogen sulfide gas at the test point on the surface, a chemical reaction will occur, and the chemical equation is:

[0024] H2S+CuSO4=CuS↓+H2SO4

[0025] During this reaction, copper sulfate ionizes into copper ions (Cu 2+ ) and sulfate ions The ionic formula is:

[0026] H2S+Cu 2+ =CuS↓+2H +

[0027] During this reaction, the two negatively charged sulfate ions that are ionized generate charged charges during the drift or movement. These charges are distributed on the coating. The charges move under the action of the electrode micro-electric field and generate weak currents. These weak currents are absorbed by the conductive electrodes fixed on the substrate.

[0028] As the concentration of hydrogen sulfide varies, the extent of this chemical reaction varies, the amount of electric charge varies, the size of the weak current generated varies, and the weak current generated on the substrate electrode varies.

[0029] like Figure 4As shown, the detection circuit 18 includes an integrated circuit IC1 and a drive circuit IC2. The integrated circuit IC1 includes an operational amplifier OPA. Pins 3 and 4 of the integrated circuit IC1 are respectively connected to the two positive and negative electrodes of the external gas pickup chip. Pin 3 of the integrated circuit IC1 is connected to the positive electrode of the operational amplifier OPA and one end of the resistor R3 after being connected in series with an internal resistor R1. The other end of the resistor R3 is connected to the output end of the operational amplifier OPA; Pin 4 of the integrated circuit IC1 is internally connected to the negative electrode of the operational amplifier OPA and one end of the resistor R2, respectively. The other end of the resistor R2 is connected to pin 2 of the integrated circuit IC1 and grounded; Pin 1 of the output port of the integrated circuit IC1 is connected to the base of the transistor Q1, and the emitter of the transistor Q1 is connected in series with a resistor R5 and then grounded. The collector of the transistor Q1 is divided into two paths, one of which is connected to pin 5 of the drive circuit IC2, and the other is connected to one end of the resistor R4. The other end of the resistor R4 is respectively connected to pin 5 of the integrated circuit IC1 and pin 6 of the drive circuit IC2; the pin 6 of the drive circuit IC2 is also connected to +3 V power supply, the 1st pin of the driving circuit IC2 is divided into two paths, one of which is connected in series with LED1 and resistor R5 and then connected to the +3V power supply and one end of the resistor R13, and the other is connected in series with resistor R12 and then connected to the base of the transistor Q2; the 2nd pin of the driving circuit IC2 is divided into two paths, one of which is connected in series with LED2 and resistor R6 and then connected to the +3V power supply and one end of the resistor R13, and the other is connected in series with resistor R11 and then connected to the base of the transistor Q2; the 3rd pin of the driving circuit IC2 is divided into two paths, one of which is connected in series with LED 3. Resistor R7 is connected to the +3V power supply and one end of the resistor R13, and the other is connected to the base of the transistor Q2 after being connected in series with resistor R10; Pin 4 of the driving circuit IC2 is divided into two paths, one is connected in series with LED4 and resistor R8, then connected to the +3V power supply and one end of the resistor R13, and the other is connected in series with resistor R9, then connected to the base of the transistor Q2; Pin 7 of the driving circuit IC2 is grounded; the collector of the transistor Q2 is connected in series with the buzzer FM and the other end of the resistor R13, and the emitter of the transistor Q2 is grounded.

[0030] like Figure 5As shown, the internal circuit of the driving circuit IC2 includes a resistor R01, one end of the resistor R01 is connected to the 5th pin of the driving circuit, and the other end is divided into two paths, one is connected to the base of the transistor Q01, and the other is connected in series with resistors R02, R03, and R04 in sequence, the resistors R02 and R03 are connected to the base of the transistor Q02, the resistors R03 and R04 are connected to the base of the transistor Q03, and the other end of the resistor R04 is connected to the base of the transistor Q04; the emitter of the transistor Q01 is divided into two paths, one is connected in series with the resistor R05 and connected to the 5th pin of the driving circuit IC2, and the other is connected to the 1st pin of the driving circuit IC2 pin; the emitter of transistor Q02 is divided into two paths, one of which is connected in series with resistor R06 and connected to pin 5 of drive circuit IC2, and the other is connected to pin 2 of drive circuit IC2; the emitter of transistor Q03 is divided into two paths, one of which is connected in series with resistor R07 and connected to pin 5 of drive circuit IC2, and the other is connected to pin 3 of drive circuit IC2; the emitter of transistor Q04 is divided into two paths, one of which is connected in series with resistor R08 and connected to pin 5 of drive circuit IC2, and the other is connected to pin 4 of drive circuit IC2; the collectors of transistors Q01, Q02, Q03, and Q04 are all connected to pin 7 of drive circuit IC2.

[0031] The working principle of the detection circuit is as follows: the weak electrical signal output by the gas pickup chip is input to the operational amplifier OPA, which converts and amplifies the weak electrical signal to form a voltage value of about 55 to 200 mV between the base and emitter of the transistor Q1. After further conversion and amplification by Q1, a voltage value of about V CC -V R4 =V C +V R5 The voltage is output to the driving circuit IC2.

[0032] The input current of the integrated circuit IC1 is 0.15nA~1μA, and the input voltage is -0.2~+0.2V. When it is detected that the coating on the gas detection chip can produce a chemical reaction and generate a weak current greater than 0.15nA, the integrated circuit IC1 has an input.

[0033] When the weak current generated on the gas detection chip changes, the input current changes. Through the conversion of the operational amplifier OPA, the input weak current is converted into a voltage change with a larger amplitude and then output.

[0034] When the changing +55~200mV low voltage output by the integrated circuit IC1 passes through the base of the transistor Q1, the transistor Q1 is in the working area, and its output terminal voltage changes with the change of the input voltage.

[0035] Since the weak input current of the integrated circuit IC1 is caused by the weak current formed by the movement of ions due to the chemical reaction on the gas detection chip, the intensity of the chemical reaction directly affects the input current of the integrated circuit IC1, and also affects the output voltage of the integrated circuit IC1, and affects the input and output voltages of the transistor Q1. Therefore, the gas concentration encountered by the gas detection chip in a limited space directly affects the intensity of the chip's chemical reaction. It is the difference in the intensity of the chemical reaction that causes the input current of the integrated circuit IC1 to change, and the output of the transistor Q1 to change, thereby realizing the gas detection function of the present invention.

[0036] Sound and light alarm principle: The +55~200mV voltage output from the integrated circuit IC1 passes through the transistor Q1 and the drive circuit IC2 to obtain V C +V R5 The voltage output changes the size of resistors R4 and R5, and controls the transistor Q1 within the working area and amplification area of ​​the transistor.

[0037] The driving circuit IC2 is an analog integrated circuit used to drive the LED and the buzzer FM. When the transistor Q1 has an output, the output voltage is respectively output to the driving transistors Q01 to Q04 through R01 to R04 according to the output voltage.

[0038] When the output voltage of the driving circuit IC2 is between 0.3V and 0.4V, the transistor Q01 is turned on; when the output voltage of the driving circuit IC2 is between 0.6V and 0.8V, the transistor Q02 is turned on; when the output voltage of the driving circuit IC2 is between 0.9V and 1.0V, the transistor Q03 is turned on; when the output voltage of the driving circuit IC2 is between 1.2V and 1.3V, the transistor Q04 is turned on.

[0039] After transistors Q01~Q04 are turned on, +3V passes through resistors R5~R8 to turn on LED1~LED4 to emit light. The number of LEDs that emit light is controlled by the output voltage of the drive circuit IC2 and the number of transistors Q01~Q04 that are turned on. When all transistors Q01~Q04 are turned on, all LEDs are lit, and the order of LED display is controlled by the input and output of the drive circuit IC2. The number of LEDs that emit light gradually increases with the increase of hydrogen sulfide concentration, and at most four indicator lights are lit.

[0040] At the same time, when the driving circuit IC2 has a signal output, one path directly drives the light-emitting diodes LED1~LED4, and the other path passes through resistors R9~R12 to the base of the transistor Q2, so that the transistor Q2 is turned on, and +3V passes through resistor R13 to power the buzzer FM and make a sound, thereby realizing the sound and light alarm function of the present invention.

[0041] A method for detecting hydrogen sulfide gas in a limited space includes the following steps: a gas detection chip is wetted, and a detection unit 12 is placed in the limited space to be detected. After the gas detection chip reacts chemically with the hydrogen sulfide in the limited space when the surface is wetted, two negatively charged sulfate ions are ionized and generate charged charges during the drift or movement process; the charges move under the action of the electrode micro-electric field and generate a weak current, which is absorbed by the conductive electrode fixed on the substrate and input into the operational amplifier in the detection circuit, converted into a weak voltage at the primary of the operational amplifier, and then amplified and converted into a measurable high voltage output by the operational amplifier, and transmitted to the sound and light alarm device through the driving circuit to give sound and light alarm reminders. The hydrogen sulfide gas pickup chip of the present invention is a disposable product, and the hydrogen sulfide gas pickup chip needs to be replaced before the next detection.

Claims

1. A confined space hydrogen sulfide gas detection device, comprising a handheld part (11) and a detection part (12), characterized in that: The handheld part (11) is electrically connected to the detection part (12); the handheld part (11) is a rectangular parallelepiped structure, a power supply (15) is provided inside, and a buzzer speaker (13) and an indicator light opening (14) are provided outside; the detection part (12) is a cylindrical structure, a hydrogen sulfide gas pickup chip (16) and a detection circuit (18) are provided inside the detection part (12), wherein the hydrogen sulfide gas pickup chip (16) is inserted between the bent spring sheets (17) and is electrically connected to the detection circuit (18).

2. A confined space hydrogen sulfide gas detection device according to claim 1, characterized in that: The hydrogen sulfide gas pickup chip (16) comprises a substrate, on the front and back of which a circuit board and a gas detection chip are symmetrically laid in sequence, wherein the gas detection chip is coated with a coating of copper sulfate powder; and a conductive electrode is provided at one end of the substrate.

3. The detection circuit in a confined space hydrogen sulfide detection device according to claim 1, characterized in that: The detection circuit (18) comprises an integrated circuit IC1 and a drive circuit IC2. The integrated circuit IC1 comprises an operational amplifier OPA. Pins 3 and 4 of the integrated circuit IC1 are respectively connected to two positive and negative electrodes of an external gas pickup chip. Pin 3 of the integrated circuit IC1 is connected in series with an internal resistor R1 and is respectively connected to the positive electrode of the operational amplifier OPA and one end of a resistor R3. The other end of the resistor R3 is connected to the output end of the operational amplifier OPA. Pin 4 of the integrated circuit IC1 is respectively connected in series with the negative electrode of the operational amplifier OPA and one end of a resistor R2. The other end of the resistor R2 is connected to pin 2 of the integrated circuit IC1 and is grounded. Pin 1 of the output port of the integrated circuit IC1 is connected to the base of a transistor Q1. The emitter of the transistor Q1 is connected in series with a resistor R5 and is then grounded. The collector of the transistor Q1 is divided into two paths, one of which is connected to pin 5 of the drive circuit IC2 and the other is connected to one end of a resistor R4. The other end of the resistor R4 is respectively connected to pin 5 of the integrated circuit IC1 and pin 6 of the drive circuit IC2. Pin 6 of the drive circuit IC2 is also connected to + 3V power supply, the 1st pin of the driving circuit IC2 is divided into two paths, one of which is connected in series with LED1 and resistor R5 and then connected to the +3V power supply and one end of the resistor R13, and the other is connected in series with resistor R12 and then connected to the base of the transistor Q2; the 2nd pin of the driving circuit IC2 is divided into two paths, one of which is connected in series with LED2 and resistor R6 and then connected to the +3V power supply and one end of the resistor R13, and the other is connected in series with resistor R11 and then connected to the base of the transistor Q2; the 3rd pin of the driving circuit IC2 is divided into two paths, one of which is connected in series with LED 3. Resistor R7 is connected to the +3V power supply and one end of the resistor R13, and the other is connected to the base of the transistor Q2 after being connected in series with resistor R10; Pin 4 of the driving circuit IC2 is divided into two paths, one is connected in series with LED4 and resistor R8, then connected to the +3V power supply and one end of the resistor R13, and the other is connected in series with resistor R9, then connected to the base of the transistor Q2; Pin 7 of the driving circuit IC2 is grounded; the collector of the transistor Q2 is connected in series with the buzzer FM and the other end of the resistor R13, and the emitter of the transistor Q2 is grounded.

4. A confined space hydrogen sulfide gas detection circuit according to claim 3, characterized in that: The internal circuit of the driving circuit IC2 includes a resistor R01, one end of which is connected to the 5th pin of the driving circuit, and the other end is divided into two paths, one of which is connected to the base of the transistor Q01, and the other is connected in series with resistors R02, R03, and R04 in sequence, the resistors R02 and R03 are connected to the base of the transistor Q02, the resistors R03 and R04 are connected to the base of the transistor Q03, and the other end of the resistor R04 is connected to the base of the transistor Q04; the emitter of the transistor Q01 is divided into two paths, one of which is connected in series with a resistor R05 and connected to the 5th pin of the driving circuit IC2, and the other is connected to the 1st pin of the driving circuit IC2. The emitter of transistor Q02 is divided into two paths, one of which is connected in series with resistor R06 and connected to pin 5 of drive circuit IC2, and the other is connected to pin 2 of drive circuit IC2; the emitter of transistor Q03 is divided into two paths, one of which is connected in series with resistor R07 and connected to pin 5 of drive circuit IC2, and the other is connected to pin 3 of drive circuit IC2; the emitter of transistor Q04 is divided into two paths, one of which is connected in series with resistor R08 and connected to pin 5 of drive circuit IC2, and the other is connected to pin 4 of drive circuit IC2; the collectors of transistors Q01, Q02, Q03, and Q04 are all connected to pin 7 of drive circuit IC2.

5. The detection method of a confined space hydrogen sulfide gas detection device according to claim 1, characterized in that: The method comprises the following steps: wetting the gas detection chip, placing the detection part in the confined space to be detected, and after the gas detection chip chemically reacts with the hydrogen sulfide in the confined space when the surface is wet, the two negatively charged sulfate ions ionized generate charged charges during the process of drifting or moving; Charges will move under the action of the electrode micro-electric field and generate weak current. The weak current is absorbed by the conductive electrode fixed on the substrate and input into the operational amplifier in the detection circuit. It is converted into a weak voltage at the primary of the operational amplifier and then amplified by the operational amplifier to a measurable high voltage output. It is transmitted to the sound and light alarm device through the drive circuit to give sound and light alarm reminders.

6. A method for detecting hydrogen sulfide gas in a confined space according to claim 5, characterized in that: The chemical equation of the chemical reaction is: H2S+CuSO4=CuS↓+H2SO4 During this reaction, copper sulfate ionizes into copper ions (Cu 2+ ) and sulfate ions The ionic formula is: <h2 style=";text-align:left;direction:ltr">H2S+Cu<h2 style=";text-align:left;direction:ltr"> 2+ <h2 style=";text-align:left;direction:ltr"> =CuS↓+2H<h2 style=";text-align:left;direction:ltr"> + <h2 style=";text-align:left;direction:ltr"> 。

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