Air-layer temperature-sensitive gas filter canister life failure indicator and its use method

Abstract

The present invention discloses an air-insulated temperature-sensitive gas filter canister life failure indicator and a method of use, comprising a main gas filter layer, one end of the main gas filter layer is an air inlet, and the other end is an air outlet; one end of the air outlet is connected to the opening of a hollow air blower; the opening of the other end of the air blower is connected to a rear gas filter layer; the rear gas filter layer is a hollow structure with openings on both sides, and one end is connected to the air blower. The device solves the problems of the existing gas filter canister (box) life failure indicator being high in price, small in scope of application, and only adaptable to a few special poisonous gases, and having large limitations, and has the characteristics of low price, easy promotion, and wide scope of application.

Description

Technical Field

[0001] The present invention relates to the technical field of filtering respiratory protection, and in particular to an air-insulated temperature-sensitive gas filter canister life failure indicator, which is mainly used for early warning indication before failure of a gas filter device in individual protective equipment and collective protective equipment. Background Art

[0002] At present, foreign canister (box) life failure indicators are divided into active and passive types. Active failure indicators are expensive, and an active failure indicator is only suitable for a limited number of toxic chemicals. Passive failure indicators are cheap, but have poor operability, the scene must be well lit and difficult to observe, requiring users to observe at all times, which interferes with the user's concentration and work efficiency. They also have the same limitations as active failure indicators - they are only suitable for indicating a limited number of toxic chemicals.

[0003] Domestic research on life failure indicators for gas canisters (boxes) is in its infancy, and no substantial technical breakthroughs have been made in the application research of sensors with broad spectrum, miniaturization and practicality. The domestic patent "Surface Acoustic Wave Gas Mask Failure Warning Device" with publication number CN205983768U discloses an active life failure indicator for gas canisters (boxes). The sensor probe of the failure warning device described in the patent can only detect specific toxic and harmful chemicals. In order to detect a variety of toxic and harmful chemicals, the sensing components must be made into multiple sensor probes in an array in theory, which has a complex structure and high technical requirements. In addition, in order to eliminate the influence of temperature and humidity, additional water vapor removal and temperature calibration devices need to be added; the domestic patent "A Hollow Layer Gas Filter Unit" with patent number 201720341451.0 and the domestic patent "Dual Gas Filter Body Structure for Installing Gas Canister Failure Alarm Sensor" with patent number 201720341931.7 propose the installation of a failure alarm sensor structure, but do not specify which sensor to install, and do not fundamentally solve the sensor problem. The industry urgently needs substantial technological breakthroughs in the sensor components of the gas filter canister (box) life failure indicator.

[0004] Whether at home or abroad, the existing or under-development life failure indicators of gas filter canisters (boxes) are not only limited by the types of toxic and harmful gases, but also affected by multiple factors such as gas concentration, multiple gas combined attacks, ambient temperature and humidity, user's breathing frequency, breathing volume, etc. It is an urgent task for the industry to develop a broad-spectrum, high-efficiency gas filter canister (box) life failure indicator that is not related to these complex factors. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an air-insulated temperature-sensitive gas filter canister life failure indicator and a method of use. The device solves the problems of the existing gas filter canister (box) life failure indicators being relatively high in price, having a relatively small scope of application, being only adaptable to a few specific types of toxic gases, and having relatively large limitations. The device has the characteristics of being low in price, easy to promote, and having a wide range of applications.

[0006] To realize the above design, the technical solution adopted by the present invention is: an air-insulating layer temperature-sensitive gas filter canister life failure indicator, including a main gas filter layer, one end of the main gas filter layer is an air inlet, and the other end is an air outlet; one end of the air outlet is connected to the opening of a hollow air supply unit; the opening at the other end of the air supply unit is connected to a rear gas filter layer; the rear gas filter layer is a hollow structure with openings on both sides, one end of which is connected to the air supply unit, and a failure indicator device is arranged in the rear gas filter layer.

[0007] The inner wall of the rear gas filtering layer is connected with an adsorption layer, and an air-insulating layer with a cavity structure is formed between the adsorption layer and the air supply device.

[0008] The failure indication device comprises an insulation layer temperature sensor, and the insulation layer temperature sensor is connected to the inner wall of the insulation layer.

[0009] The failure indication device also includes a gas filtering layer temperature sensor, which is installed in the adsorption layer.

[0010] The inner wall of the air-insulating layer is provided with a through hole, and the wires of the air-insulating layer temperature sensor and the gas filtering layer temperature sensor pass through the through hole; the through hole is coated with sealant.

[0011] The outer surface of the air-insulating layer is connected with an alarm device; the gas filtering layer temperature sensor, the air-insulating layer temperature sensor and the alarm device are all connected with the control system.

[0012] The method for using the air-insulated temperature-sensitive gas canister life failure indicator comprises the following steps:

[0013] S1, connect the wires of the air-insulation layer temperature sensor and the gas-filtering layer temperature sensor to the control system, and set the temperature difference threshold for triggering the alarm device;

[0014] S2, the gas to be filtered enters the main filter layer from the air inlet and is discharged from the outlet of the rear gas filter layer; during this period, the air-insulating layer temperature sensor and the gas filter layer temperature sensor continuously monitor the temperature of the adsorption layer and the air-insulating layer of the rear gas filter layer; when the main gas filter layer is not invalid, the rear gas filter layer does not contact and adsorb the poison gas, there is no adsorption heat reaction, the temperature difference is less than the set temperature difference threshold, and the alarm is not triggered;

[0015] S3, when the main gas filter layer fails, the rear gas filter layer comes into contact with the poisonous gas, an adsorption heat reaction occurs, the temperature of the gas filter layer temperature sensor rises, and the temperature difference with the temperature sensor of the air isolation layer is greater than the set temperature difference threshold, the alarm is triggered, so as to judge in real time whether the main gas filter layer is penetrated by toxic and harmful gases, and effectively and reliably indicate the time node of the main gas filter layer failure.

[0016] A temperature-sensitive air filter canister life failure indicator includes a main filter layer, one end of the main filter layer is an air inlet, and the other end is an air outlet; one end of the air outlet is connected to the opening of a hollow air blower; the opening of the other end of the air blower is connected to a rear filter layer; the rear filter layer is a hollow structure with openings on both sides, one end is connected to the air blower, and a failure indicator device is arranged in the rear filter layer. The device solves the problems of the existing filter canister (box) life failure indicator being high in price, small in scope of application, and only adaptable to a few special poisonous gases and having large limitations, and has the characteristics of low price, easy promotion, and wide scope of application.

[0017] In the preferred solution, the inner wall of the rear gas filter layer is connected to an adsorption layer, and a cavity structured air barrier is formed between the adsorption layer and the air supply device. The structure is simple, and when in use, a rear gas filter layer is added to the rear end of the air duct of the main gas filter layer; the airflow to be filtered flows from the main gas filter layer to the rear gas filter layer for detection and adsorption, thereby determining whether the adsorption effect of the main gas filter layer is reduced.

[0018] In a preferred solution, the failure indicating device includes an insulation layer temperature sensor, and the insulation layer temperature sensor is connected to the inner wall of the insulation layer.

[0019] In a preferred solution, the failure indication device further includes a gas filter layer temperature sensor, which is installed in the adsorption layer. The structure is simple. When in use, the gas filter layer temperature sensor detects the temperature of the rear gas filter layer; the air barrier layer temperature sensor detects the air temperature in the air barrier layer, that is, the temperature of the air after filtering through the main gas filter layer. The temperature difference between the two sensors can be used to determine whether the air in the air supply device has been completely filtered by the main gas filter layer.

[0020] In a preferred solution, a through hole is provided on the inner wall of the air-insulating layer, and the wires of the air-insulating layer temperature sensor and the gas-filtering layer temperature sensor pass through the through hole; and the through hole is coated with sealant.

[0021] In the preferred scheme, the outer surface of the air-insulating layer is connected with an alarm device; the gas filter layer temperature sensor, the air-insulating layer temperature sensor and the alarm device are all connected to the control system. The structure is simple. When in use, when the main gas filter layer works effectively, the poison gas is completely adsorbed and does not penetrate the main gas filter layer; the air-insulating layer is filled with non-toxic air sent from the main gas filter layer, and the rear gas filter layer does not contact or adsorb the poison gas, and there is no adsorption heat reaction. Therefore, the temperature of the gas filter layer temperature sensor and the air-insulating layer temperature sensor is small and not greater than the set temperature difference alarm threshold, and the alarm device does not alarm; when the main gas filter layer fails, the poison gas penetrates the main gas filter layer, enters the rear gas filter layer and reacts with the adsorption layer by adsorption heat; the temperature difference detected by the gas filter layer temperature sensor and the air-insulating layer temperature sensor is large and greater than the set temperature alarm threshold, and the alarm device alarms; the temperature difference detected by the two temperature sensors is used as the alarm input signal, which is independent of complex factors such as the performance of the gas filter, the storage conditions of the gas filter, the type and concentration of the poison gas, the composite attack of multiple poison gases, the ambient temperature and humidity, the user's breathing frequency, the breathing volume, etc., and is broad-spectrum, efficient, simple and reliable.

[0022] In a preferred embodiment, the method for using the above-mentioned air-insulated temperature-sensitive canister life failure indicator comprises the following steps:

[0023] S1, connect the wires of the air-insulation layer temperature sensor and the gas-filtering layer temperature sensor to the control system, and set the temperature difference threshold for triggering the alarm device;

[0024] S2, the gas to be filtered enters the main filter layer from the air inlet and is discharged from the outlet of the rear gas filter layer; during this period, the air-insulating layer temperature sensor and the gas filter layer temperature sensor continuously monitor the temperature of the adsorption layer and the air-insulating layer of the rear gas filter layer; when the main gas filter layer is not invalid, the rear gas filter layer does not contact and adsorb the poison gas, there is no adsorption heat reaction, the temperature difference is less than the set temperature difference threshold, and the alarm is not triggered;

[0025] S3, when the main gas filter layer fails, the rear gas filter layer comes into contact with the poisonous gas, an adsorption heat reaction occurs, the temperature of the gas filter layer temperature sensor rises, and the temperature difference with the temperature sensor of the air isolation layer is greater than the set temperature difference threshold, the alarm is triggered, so as to judge in real time whether the main gas filter layer is penetrated by toxic and harmful gases, and effectively and reliably indicate the time node of the main gas filter layer failure.

[0026] A space-layer temperature-sensitive gas filter canister life failure indicator and a method of use, comprising a main gas filter layer, one end of the main gas filter layer is an air inlet, and the other end is an air outlet; one end of the air outlet is connected to the opening of a hollow air blower; the opening at the other end of the air blower is connected to a rear gas filter layer; the rear gas filter layer is a hollow structure with openings on both sides, one end is connected to the air blower, and a failure indicator device is arranged in the rear gas filter layer. The device solves the problems of the existing gas filter canister (box) life failure indicator being high in price, small in scope of application, and only adaptable to a few special poisonous gases, and having large limitations, and has the characteristics of low price, easy promotion, and wide scope of application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present invention.

[0028] Figure 2 It is a structural schematic diagram of a specific embodiment of the present invention.

[0029] The reference numerals in the figure are: rear filter layer 1, adsorption layer 11, filter layer temperature sensor 2, insulation layer temperature sensor 3, wire 4, alarm device 5, insulation layer 6, air supply device 7, main filter layer 8, air inlet 81, and air outlet 82. DETAILED DESCRIPTION

[0030] Embodiment 1:

[0031] like Figure 1 In the invention, a life failure indicator of a gas filter canister with an air-insulated layer and a temperature-sensitive type is provided, which includes a main gas filter layer 8, one end of which is an air inlet 81 and the other end is an air outlet 82; one end of the air outlet 82 is connected to the opening of a hollow air blower 7; the opening of the other end of the air blower 7 is connected to a rear gas filter layer 1; the rear gas filter layer 1 is a hollow structure with openings on both sides, one end of which is connected to the air blower 7, and a failure indicator device is arranged in the rear gas filter layer 1. The device solves the problems of the existing life failure indicator of the gas filter canister (box) being high in price, small in scope of application, and only adaptable to a few special poisonous gases and having large limitations, and has the characteristics of low price, easy promotion and wide scope of application.

[0032] In the preferred solution, the inner wall of the rear filter layer 1 is connected to an adsorption layer 11, and a cavity-structured air barrier layer 6 is formed between the adsorption layer 11 and the air supply device 7. The structure is simple, and when in use, the rear filter layer 1 is added to the rear end of the air duct of the main filter layer 8; the airflow to be filtered flows from the main filter layer 8 to the rear filter layer 1 after being filtered, and is detected and adsorbed, so as to determine whether the adsorption effect of the main filter layer 8 is reduced.

[0033] In a preferred solution, the failure indication device includes an insulation layer temperature sensor 3 , and the insulation layer temperature sensor 3 is connected to the inner wall of the insulation layer 6 .

[0034] In the preferred solution, the failure indication device further includes a gas filter layer temperature sensor 2, which is installed in the adsorption layer 11. The structure is simple, and when in use, the gas filter layer temperature sensor 2 detects the temperature of the rear gas filter layer 1; the air insulation layer temperature sensor 3 detects the air temperature in the air insulation layer 6, that is, the temperature of the air after being filtered through the main gas filter layer 8. The temperature difference between the two sensors can be used to determine whether the air in the air supply device 7 has been completely filtered by the main gas filter layer 8.

[0035] In a preferred solution, a through hole is opened on the inner wall of the air-insulating layer 6, and the wires 4 of the air-insulating layer temperature sensor 3 and the gas-filtering layer temperature sensor 2 pass through the through hole; the through hole is coated with sealant.

[0036] In the preferred solution, the outer surface of the air-insulating layer 6 is connected with an alarm device 5; the gas filtering layer temperature sensor 2, the air-insulating layer temperature sensor 3 and the alarm device 5 are all connected to the control system. The structure is simple. When in use, when the main filter layer 8 works effectively, the poison gas is completely adsorbed and does not penetrate the main filter layer 8; the interior of the air barrier layer 6 is non-toxic air sent from the main filter layer 8, and the rear filter layer 1 does not contact or adsorb the poison gas, and there is no adsorption heat reaction. Therefore, the temperature of the filter layer temperature sensor 2 and the air barrier layer temperature sensor 3 is relatively small, not greater than the set temperature difference alarm threshold, and the alarm device 5 does not alarm; when the main filter layer 8 fails, the poison gas penetrates the main filter layer 8, enters the rear filter layer 1 and the adsorption layer 11, and an adsorption heat reaction occurs; the temperature difference detected by the filter layer temperature sensor 2 and the air barrier layer temperature sensor 3 is relatively large, greater than the set temperature alarm threshold, and the alarm device 5 alarms; the temperature difference detected by the two temperature sensors is used as the alarm input signal, which is independent of complex factors such as the performance of the filter, the storage conditions of the filter, the type and concentration of the poison gas, the combined attack of multiple poison gases, the ambient temperature and humidity, the user's breathing frequency, the breathing volume, etc., and is broad-spectrum, efficient, simple and reliable.

[0037] In a preferred embodiment, the method of using the above-mentioned air-insulating layer 6 temperature-sensitive gas canister life failure indicator is as follows:

[0038] S1, connect the wires 4 of the air-insulating layer temperature sensor 3 and the gas-filtering layer temperature sensor 2 to the control system, and set the temperature difference threshold triggered by the alarm device 5;

[0039] S2, the gas to be filtered enters the main filter layer from the air inlet 81 and is discharged from the outlet of the rear gas filter layer 1; during this period, the air-insulating layer temperature sensor 3 and the gas filter layer temperature sensor 2 continuously monitor the temperatures of the adsorption layer 11 and the air-insulating layer 6 of the rear gas filter layer 1; when the main gas filter layer 8 is not invalid, the rear gas filter layer 1 does not contact and adsorb the poison gas, there is no adsorption heat reaction, the temperature difference is less than the set temperature difference threshold, and the alarm is not triggered;

[0040] S3, when the main gas filter layer 8 fails, the rear gas filter layer 1 comes into contact with the poisonous gas, an adsorption heat reaction occurs, the temperature of the gas filter layer temperature sensor 2 rises, and the temperature difference with the air isolation layer temperature sensor 3 is greater than the set temperature difference threshold, the alarm is triggered, so as to judge in real time whether the main gas filter layer 8 is penetrated by toxic and harmful gases, and effectively and reliably indicate the time node of the failure of the main gas filter layer 8.

[0041] In the preferred embodiment, the thickness of the rear gas filtering layer 1 is the minimum effective thickness of the carbon adsorption layer 11 for filtering toxic and harmful gases, and the maximum value of the minimum effective thicknesses of several classic toxic and harmful gases is taken.

[0042] In the preferred solution, the temperature of the air entering the air-insulating layer 6 from the main air-filtering layer 8 changes to a certain extent due to the adsorption heat reaction generated when the main air-filtering layer 8 effectively filters the gas. This solution uses two temperature sensors, and the difference in the temperature values ​​detected by the two temperature sensors eliminates the influence of the air temperature change of the air-insulating layer 6, accurately measures the temperature change of the carbon layer of the rear air-filtering layer 1, determines whether the carbon layer of the rear air-filtering layer 1 has an adsorption reaction, and judges whether the main air-filtering layer 8 is penetrated by toxic and harmful gases, effectively and reliably indicating the time point when the main air-filtering layer 8 fails.

[0043] Embodiment 2:

[0044] like Figure 2 In the invention, a life failure indicator of a gas filter canister with an air-insulated layer and a temperature-sensitive type is provided, which includes a main gas filter layer 8, one end of which is an air inlet 81 and the other end is an air outlet 82; one end of the air outlet 82 is connected to the opening of a hollow air blower 7; the opening of the other end of the air blower 7 is connected to a rear gas filter layer 1; the rear gas filter layer 1 is a hollow structure with openings on both sides, one end of which is connected to the air blower 7, and a failure indicator device is arranged in the rear gas filter layer 1. The device solves the problems of the existing life failure indicator of the gas filter canister (box) being high in price, small in scope of application, and only adaptable to a few special poisonous gases and having large limitations, and has the characteristics of low price, easy promotion and wide scope of application.

[0045] In the preferred solution, the inner wall of the rear filter layer 1 is connected to an adsorption layer 11, and a cavity-structured air barrier layer 6 is formed between the adsorption layer 11 and the air supply device 7. The structure is simple, and when in use, the rear filter layer 1 is added to the rear end of the air duct of the main filter layer 8; the airflow to be filtered flows from the main filter layer 8 to the rear filter layer 1 after being filtered, and is detected and adsorbed, so as to determine whether the adsorption effect of the main filter layer 8 is reduced.

[0046] In a preferred embodiment, the failure indication device includes a gas filter layer temperature sensor 2 installed in the adsorption layer 11. The structure is simple, and when in use, the gas filter layer temperature sensor 2 detects the temperature of the rear gas filter layer 1.

[0047] In a preferred solution, a through hole is provided on the inner wall of the air-insulating layer 6, and the wire 4 of the gas filtering layer temperature sensor 2 passes through the through hole; and a sealant is coated on the through hole.

[0048] In the preferred solution, the outer surface of the air-insulating layer 6 is connected with an alarm device 5; the gas filter layer temperature sensor 2 and the alarm device 5 are both connected to the control system. The structure is simple, and when in use, when the main gas filter layer 8 works effectively, the poison gas is completely adsorbed and does not penetrate the main gas filter layer 8; the air-insulating layer 6 contains non-toxic air sent from the main gas filter layer 8, and the rear gas filter layer 1 does not contact or adsorb the poison gas, and there is no adsorption heat reaction, so the temperature of the gas filter layer temperature sensor 2 will not change dramatically, and will not be greater than the set temperature change alarm threshold, and the alarm device 5 will not alarm; when the main gas filter layer 8 fails, the poison gas penetrates the main gas filter layer 8, enters the rear gas filter layer 1, and reacts with the adsorption layer 11 by adsorption heat; the temperature of the gas filter layer temperature sensor 2 changes dramatically, and is greater than the set temperature change alarm threshold, and the alarm device 5 alarms; the temperature change value detected by the gas filter layer temperature sensor 2 is used as the alarm input signal, which is independent of complex factors such as the performance of the gas filter, the storage conditions of the gas filter, the type and concentration of the poison gas, the composite attack of multiple poison gases, the ambient temperature and humidity, the user's breathing frequency, the breathing volume, etc., and is broad-spectrum, efficient, simple and reliable.

[0049] In a preferred embodiment, the method of using the above-mentioned air-insulating layer 6 temperature-sensitive gas canister life failure indicator is as follows:

[0050] S1, connect the wires 4 of the air-insulating layer temperature sensor 3 and the gas-filtering layer temperature sensor 2 to the control system, and set the temperature difference threshold triggered by the alarm device 5;

[0051] S2, the gas to be filtered enters the main filter layer from the air inlet 81 and is discharged from the outlet of the rear gas filter layer 1; during this period, the air-insulating layer temperature sensor 3 and the gas filter layer temperature sensor 2 continuously monitor the temperatures of the adsorption layer 11 and the air-insulating layer 6 of the rear gas filter layer 1; when the main gas filter layer 8 is not invalid, the rear gas filter layer 1 does not contact and adsorb the poison gas, there is no adsorption heat reaction, the temperature difference is less than the set temperature difference threshold, and the alarm is not triggered;

[0052] S3, when the main gas filter layer 8 fails, the rear gas filter layer 1 comes into contact with the poisonous gas, an adsorption heat reaction occurs, the temperature of the gas filter layer temperature sensor 2 rises, and the temperature difference with the air isolation layer temperature sensor 3 is greater than the set temperature difference threshold, the alarm is triggered, so as to judge in real time whether the main gas filter layer 8 is penetrated by toxic and harmful gases, and effectively and reliably indicate the time node of the failure of the main gas filter layer 8.

[0053] The above-mentioned embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. An air-insulated temperature-sensitive gas filter canister life failure indicator, comprising a main gas filter layer (8), one end of the main gas filter layer (8) being an air inlet (81) and the other end being an air outlet (82); characterized in that: One end of the air outlet (82) is connected to the opening of a hollow air blower (7); the opening of the other end of the air blower (7) is connected to the rear gas filter layer (1); the rear gas filter layer (1) is a hollow structure with openings on both sides, and one end is connected to the air blower (7); the inner wall of the rear gas filter layer (1) is connected to an adsorption layer (11), and an air barrier layer (6) with a cavity structure is formed between the adsorption layer (11) and the air blower (7); a through hole is opened on the inner wall of the air barrier layer (6), and the wires (4) of the air barrier layer temperature sensor (3) and the gas filter layer temperature sensor (2) pass through the through hole; the through hole is coated with sealant; the outer surface of the air barrier layer (6) is connected to an alarm device (5); the gas filter layer temperature sensor (2), the air barrier layer temperature sensor (3) and the alarm device (5) are all connected to a control system.

2. The air-insulated temperature-sensitive canister life failure indicator according to claim 1 is characterized in that: An insulation layer temperature sensor (3) is connected to the inner wall of the insulation layer (6).

3. The air-insulated temperature-sensitive canister life failure indicator according to claim 2 is characterized in that: A gas filter layer temperature sensor (2) is installed in the adsorption layer (11).

4. The method for using the air-insulated temperature-sensitive canister life failure indicator according to claim 3 is characterized in that: It includes the following steps: S1, connecting the wires (4) of the air-insulating layer temperature sensor (3) and the gas-filtering layer temperature sensor (2) to the control system, and setting the temperature difference threshold for triggering the alarm device (5); S2, the gas to be filtered enters the main gas filter layer (8) from the air inlet (81) and is discharged from the outlet of the rear gas filter layer (1); during this period, the air barrier layer temperature sensor (3) and the gas filter layer temperature sensor (2) continuously monitor the temperatures of the adsorption layer (11) and the air barrier layer (6) of the rear gas filter layer (1); when the main gas filter layer (8) is not invalid, the rear gas filter layer (1) does not contact or adsorb the poison gas, there is no adsorption heat reaction, the temperature difference is less than the set temperature difference threshold, and the alarm device (5) is not triggered; S3, when the main gas filter layer (8) fails, the rear gas filter layer (1) comes into contact with the poisonous gas, an adsorption heat reaction occurs, the temperature of the gas filter layer temperature sensor (2) rises, and the temperature difference with the air-insulating layer temperature sensor (3) is greater than the set temperature difference threshold, the alarm device (5) is triggered, thereby determining in real time whether the main gas filter layer (8) is penetrated by the poisonous and harmful gas, and effectively and reliably indicating the time point when the main gas filter layer (8) fails.

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