TWI796722B - Volatile organic substance canister burst detection and warning device - Google Patents

Abstract

A volatile organic substance canister breakout detection and warning device consists of a housing, a sensor, a microcontroller, a vibration motor and a main power supply. The device is installed between the face body of the respiratory protective equipment and the canister, and the air intake valve can effectively reduce the direct influence of carbon dioxide on the measured value; in addition, in the respiratory impedance experiment, it is found that the device has little effect on the overall impedance (the present invention The average impedance value increased by the detection and warning device is 2.6 mmH ₂ O, and the test flow rate is 85 L/min), so it will not increase the breathing burden on the user. According to the test results, the present invention defines two conditions for the exposure of volatile organic substances (taking toluene as an example) to the environment. One (taking toluene as an example, 10 ppm) is used as the breaking warning condition; the other breaking condition is to calculate the value difference ratio (rising slope) within 5 seconds. If the ratio is greater than 1.5, the canister is considered broken. However, this device uses a lithium battery with a capacity of 800 mAh as the main power supply. Under the test conditions, it can achieve 8 hours of continuous measurement and continuous alarm when the canister is broken.

Description

Volatile organic substance canister burst detection and warning device

The invention relates to a volatile organic substance canister burst detection and warning device device, especially refers to a device installed between the canister and the respirator, which not only does not damage the function of the respirator, but also achieves the breakthrough measurement of organic solvents, especially refers to the ability to absorb different amounts according to the canister (different time) and whether there are pollutants re-released in different temperature and humidity environments, put forward suggestions on the use and management of canisters, so as to break the myth that laborers have to wear protective respiratory protection, and give managers a reference to replace the canister The timing of the tank.

Business units often carry out complex and potentially hazardous respiratory exposure due to product manufacturing requirements. The process may produce a lot of dust, smoke, steam, acid-base mist/steam, organic gas, toxic gas, biogas, etc., as well as an oxygen-deficient environment. Through the concept of occupational hygiene, it can be improved and spread from the source However, there have been many actual cases in the past that were often emergencies or occurred without understanding of environmental issues, so it was not possible to effectively improve or reduce the exposure of personnel to harmful substances through process improvement and ventilation devices. Therefore, protective measures for workers must be considered, and the most important emergency respiratory protection measure is to wear appropriate canister gas masks (air-purifying respirators). However, to achieve the effect of protecting workers, respiratory protective equipment must be Choose appropriate and effective respiratory protective equipment, and then require workers to use it correctly.

Regarding the selection of respiratory protective equipment, the oxygen content of the working environment must first be considered. If you want to use the pipeline air supply type or the active air intake type breathing protective equipment with the back cylinder, if the oxygen content in the air is normal, you must consider whether the hazardous substance you are facing is granular or gaseous and its type and concentration, and then choose Respiratory protective equipment suitable for protection factor. Among them, the air-purified respiratory protection for gaseous substances mainly relies on the canister to absorb or absorb pollutants to reduce the hazards of inhalation exposure. The literature puts forward management suggestions, but there is a lack of test data for reference, and past research experience shows that when the canister is actually used, it is often used for a long time. Once the effective use time of the anti-virus filter material is exceeded, the protective equipment without the canister is still used , will inevitably cause health hazards.

Looking at the current literature and research, most of them can only show the durability of respiratory protective equipment or However, in actual application, the user still encounters the question of when to replace it. In the past, some scholars used miniature temperature and humidity detectors placed inside the respirator body to measure the temperature and humidity changes to evaluate the duration of wearable respirators. There are also studies using infrared thermal imaging cameras to analyze the wearing fit of N95. The results show that using thermal imaging cameras can detect the leakage of respiratory protective equipment, and it may be used as a tool to evaluate the wearing tightness. In addition, there have been studies using computational fluid dynamics simulation with infrared images to evaluate the face tightness and leakage of respirators. The computational fluid dynamics simulation method was verified by comparing the facial temperature and leakage location measured from infrared images of eight subjects. , where most leaks occur in the nose area. However, none of the above-mentioned tools can immediately inform the user whether they are exposed to hazards, and remind the user to replace the filter material of the protective equipment.

In view of the fact that respiratory protective equipment is the last line of defense before entering the human body, public institutions use In addition to choosing a suitable respirator for use, the user's wearing tightness and proper use time management are also very important. However, most respirators cannot warn users and managers that the filter material has reached saturation. Urge managers or users to replace new respirators or filter materials as soon as possible. Therefore, general users cannot meet the needs of users in actual use.

The main purpose of the present invention is to overcome the above-mentioned problems encountered in the prior art and Provide volatile organic substances (take toluene as an example) as the main research material, select a half-hedron respiratory protective device as the test item, and install this device between the canister and the respiratory protective device, through the integration of the control board, The sensor and other components are integrated, not only does not destroy the function of the respiratory protective equipment, but also can achieve the breakthrough measurement of organic solvents, which can be determined according to the different amount of canister adsorption (different time) and whether there is pollution under different temperature and humidity environments To solve the problem of re-release of canisters, put forward suggestions on the use and management of canisters, so as to break the myth that workers have to wear protective respiratory protection, and give managers a reference to the timing of replacing canisters to detect the release of volatile organic substances. Check the warning device.

In order to achieve the above purpose, the present invention is a kind of volatile organic substance canister burst detection The detection and warning device is installed between the surface body of a protective device and the canister, which includes: a housing with an accommodating space and an air passage, which is connected to the air inlet of the protective device. There is a switch and an indicator light on the side of the casing, the switch provides power to the device on or off, and the indicator light reminds the user whether the device is powered on, whether the device is currently in the measurement state, and the currently used device. Whether the canister has been broken; a sensor, a part of which is set in the accommodating space of the casing, and another part is exposed through the air passage of the casing and faces the air inlet of the protective device, used To measure the concentration of carbon dioxide and total volatile organic substances (total volatile organic substance, TVOC) for real-time automatic detection of whether the canister currently in use is broken; a micro-controller is installed in the container of the housing The microcontroller includes a control board and a circuit board, the control board has an internal memory, the circuit board is connected to the control board to provide the relevant interface on the control board to be connected to the circuit board, the The circuit board can be used to electrically connect the switch, the indicator light and the sensor, and the control board controls the sensor through the communication interface to read the carbon dioxide and the TVOC value measured by the sensor, and Use the internal memory for data storage, the control board accesses the TVOC value through the internal memory, calculates whether the TVOC value exceeds the preset condition for breaking the canister, and according to the calculation result, makes the circuit board pass through The control board respectively controls the light to illuminate to inform the user of the current measurement status, and controls the switch to turn on or off the power supply; a vibration motor is arranged in the housing space of the casing and electrically The circuit board connected to the micro-controller is used to control the vibration of the vibration motor through the control board according to the judgment result, so as to inform the user of the current measurement status; and a main power supply is located on the The accommodating space of the casing is electrically connected to the sensor, the microcontroller, the indicator light and the vibration motor for the sensor, the microcontroller, the indicator light and the vibration The motor is powered.

In the above-mentioned embodiment of the present invention, the material of the housing is acrylonitrile-butadiene-styrene Acrylonitrile Butadiene Styrene (ABS) resin, or a material that is resistant to acid, alkali, salt corrosion and can tolerate organic solvent dissolution.

In the above embodiments of the present invention, the sensor is an air quality sensor equipped with an inter-integrated circuit (I ² C) communication interface.

In the above-mentioned embodiments of the present invention, the indicator light is an LED light, which reminds the user to Whether the device was in a normal state before, whether the device is in an abnormal state at present, or whether the canister currently in use is in the canister break warning state.

In the above-mentioned embodiment of the present invention, the indicator light flickers once a second to indicate that the device is currently Set it to the normal state; the indicator light is always on, which means that the device is currently in the abnormal state that needs to be dealt with status; the indicator flashes quickly and vibrates at the same time, indicating that the canister currently in use is in the broken canister warning state.

In the above-mentioned embodiment of the present invention, the microcontroller controls the indicator light and the vibration motor through the electrical signal processing of the General Purpose I/O Port (GPIO), and communicates with the vibration motor through the I ² C communication interface. The sensor communicates, reads back relevant information, and informs the user of the current reading status through a Universal Asynchronous Receiver/Transmitter (UART).

In the above-mentioned embodiments of the present invention, the main power supply is a lithium battery with a capacity of 700-900 mAh pool.

In the above-mentioned embodiments of the present invention, the switch and the indicator light are connected by a detachable electrical Connect the board.

In the above-mentioned embodiments of the present invention, the preset breaking condition of the canister is a threshold and The dynamic change value of the concentration difference in a unit time, the threshold value is one-tenth of 100 ppm of the permissible exposure limit-time weighted average (PEL-TWA) used in the workplace for eight hours; The dynamic change value calculates whether the TVOC value difference ratio within 5 seconds exceeds a preset value.

In the above-mentioned embodiment of the present invention, the default value is 1.5, and the dynamic change value is calculated When the concentration difference ratio of the continuously detected TVOC value within 5 seconds is greater than 1.5, it is considered that the canister currently in use has been broken.

； 於其中，該

為當下所偵測到的濃度；該

；及該

為該

與該

的差值除以5後所得到的上升斜率。 In the above-mentioned embodiments of the present invention, the formula for calculating the dynamic change value is as follows:

; in which the

is the concentration detected at the moment; the

and the

for the

with the

The rising slope obtained after dividing the difference by 5.

In the above-mentioned embodiment of the present invention, the vibration motor will generate a vibration when the device is just turned on. Vibration reminder.

In the above-mentioned embodiment of the present invention, the device further includes a buzzer, located in the housing The accommodating space is electrically connected to the circuit board, so that the circuit board can control the buzzer to sound through the control board according to the judgment result, so as to inform the user of the current measurement status.

Please refer to "Fig. 1 to Fig. 23", which are respectively the volatile oils of the present invention. Schematic diagram of the installation of the organic substance canister breaking detection warning device and respiratory protective equipment, a schematic diagram of the system architecture of the device proposed by the present invention, a schematic diagram of the operation flow of the device proposed by the present invention, a schematic diagram of the appearance of the housing of the device proposed by the present invention, Schematic diagram of each pin row and connecting seat of the circuit board of the present invention, a schematic diagram of the sensor exposed in the airway of the present invention, a schematic diagram of the experimental environment of the present invention, a schematic diagram of the five-point concentration measurement results of the FID of the present invention, and a canister of the present invention Breakout schematic diagram, schematic diagram of the power monitoring framework of the main power supply of the present invention, a schematic diagram of the measurement results of the sensor of the present invention at an ambient toluene concentration of 2.2 ppm, a schematic diagram of the measurement results of the sensor of the present invention at an ambient toluene concentration of 5.14 ppm, and the schematic diagram of the present invention Schematic diagram of the measurement results of the sensor at an ambient toluene concentration of 11.75 ppm, a schematic diagram of the measurement results of the sensor of the present invention at an ambient toluene concentration of 22.02 ppm, a schematic diagram of the measurement results of the sensor of the present invention at an ambient toluene concentration of 51.39 ppm, this Schematic diagram of the five-point concentration correlation measurement results of the inventive sensor, a schematic diagram of the long-term stability test results of the inventive sensor, a schematic diagram of the respiratory rhythm experiment results of the present invention, a relationship diagram of the bursting condition of the canister of the present invention, The schematic diagram of the system operation test (voltage value change) of the present invention with 800 mAh, the schematic diagram of the system operation test (current value change) of the present invention with 800 mAh, the present invention with the 800 mAh canister burst alarm test (voltage value change) ) schematic diagram, and a schematic diagram of the present invention using an 800 mAh canister to continuously break the alarm test (current value change). As shown in the figure: the present invention takes the painting field as the experimental situation (the main substance that may be used is toluene), selects the half-hedron respirator 1 as the test item, and designs a canister 2 and the respirator 1 The detection and warning device 3 for the burst of the canister of volatile organic substances is installed between the face body 10 of the respirator 1 and the canister 2. The device 3 includes a housing 30, a sensor Detector 31, a microcontroller 32, a vibration motor 33, and a main power supply 34 constitute.

The housing 30 mentioned above has an accommodating space 301 and an air passage 302, the airway 302 is connected to the air inlet of the respirator 1. A switch 35 and an indicator light 36 are provided on the side of the casing 30. The switch 35 provides the power to turn on or off the device 3. The indicator light 36 is an LED light to remind the user of the current measurement status of the device 3. If Flashing once per second means that the device 3 is currently in a normal state; if it is always on, it means that the device 3 is in an abnormal state to be dealt with; In breakout, please replace the canister as soon as possible and leave the current field for safety.

A part of the sensor 31 is set in the accommodating space 301 of the casing 30, and the other A part is exposed through the air passage 302 of the casing 30 and faces the air inlet of the respiratory protective device 1, so that it can detect in time whether the used canister 2 breaks out. The sensor 31 is an air quality sensor equipped with an integrated circuit bus (inter-integrated circuit, I2C) communication interface, and is used for measuring the concentration of carbon dioxide and total volatile organic substances (total volatile organic substance, TVOC). It is used for real-time automatic detection of whether the canister 2 currently in use is broken.

The micro-controller 32 is located in the accommodation space 301 of the casing 30 . The micro The controller 32 includes a control board 321 and a circuit board 322. The control board 321 has an internal memory 3211. The circuit board 322 is connected to the control board 321 to provide the related interface on the control board 321 to be connected to the circuit. Board 322. The circuit board 322 can be electrically connected to the switch 35 , the indicator light 36 and the sensor 31 . The control board 321 controls the sensor 31 through the I2C communication interface to read the carbon dioxide and TVOC measured by the sensor 31 and store the data in the internal memory 3211. The control board 321 accesses the TVOC value through the internal memory 3211, calculates whether the TVOC value exceeds the preset canister breaking condition, and according to the calculation result, makes the circuit board 322 respectively control through the control board 321 The indicator light 36 is illuminated to inform the user of the current measurement status, and the switch 35 is controlled to turn on or off the power supply.

The vibration motor 33 is located in the accommodating space 301 of the housing 30, and electrically The circuit board 322 connected to the micro-controller 32 is used to control the vibration of the vibration motor 33 through the control board 321 according to the judgment result, so as to inform the user of the current measurement status.

The main power supply 34 is a lithium battery with a capacity of 700-900 mAh. In this embodiment, 800 mAh mAh is used as the battery life source of the device 3 . The main power supply 34 is set in the accommodation space 301 of the casing 30, and is electrically connected to the sensor 31, the microcontroller 32, the indicator light 36 and the vibration motor 33, for the sensor The detector 31, the microcontroller 32, the indicator light 36 and the vibrating motor 33 provide power. If so, a brand-new volatile organic substance canister burst detection and warning device 3 is formed by the structure disclosed above.

In one embodiment, the above-mentioned device 3 further includes a buzzer (not shown in the figure) shown), set in the accommodating space of the casing, and electrically connected to the circuit board, for making the circuit board control the buzzer to sound through the control board according to the judgment result, so as to inform the user that the current measurement status.

As shown in Figure 2, it is the system architecture diagram designed for this device 3, from the 800 on the right The mAh main power supply 34 supplies power to all components, and the middle block is the microcontroller 32 of the core processing unit of the present invention, which controls peripheral components such as indicator lights through the electrical signal processing of the General Purpose I/O Port (GPIO) 36 and the vibration motor 33, and communicate with the sensor 31 through the I2C communication interface, and then read back the relevant information and inform the user of the current reading value through a Universal Asynchronous Receiver/Transmitter (UART) situation.

As shown in Figure 3, it is the operation flow of this device 3, first step s11 is the system Initialization, including timing function, data display function, control interface and other function initialization from top to bottom, then enter step s12, sensor initialization, after initialization is completed, it will enter the boot process, and the vibration motor will generate a vibration prompt at this time, The vibration lasts for 1.5 seconds to indicate power-on, and then it will enter the measurement mode, as in step s13, to measure the TVOC value at a frequency of reading once per second, and to judge whether the current TVOC value is Exceeding the breaking condition of the canister obtained through the experiment of the present invention, as soon as the breaking condition is exceeded, as in step s15, the vibration and LED flashing quickly remind the use The victim should replace the canister as soon as possible and leave the current field immediately for safety.

The size of this device 3 is about 9 x 4.8 x 2.8 (unit: centimeter), and the figure 4 shows this Appearance of device 3, use 3D printing technology to create shell 30, made of acrylonitrile-butadiene-styrene (Acrylonitrile Butadiene Styrene, ABS) resin, or other corrosion-resistant acid, alkali, salt and can be in a certain Materials that tolerate organic solvent dissolution to a certain extent.

Based on the above, the device 3 is provided with the switch 35 and the indicator on the side of the housing 30. Light 36, when the switch 35 is pressed, the device will be started; otherwise, the device will be turned off. Whether the canister 2 has been broken.

This device 3 uses a small control board 321 for development, through the I2C interface and sensor The sensor 31 is controlled to obtain the measurement value of the sensor 31 (carbon dioxide and TVOC values). Open the upper cover 303 of the housing 30 of the device 3 to find a circuit board 322, the purpose is to transfer the relevant interface on the control board 321 to the circuit board 322 to facilitate testing and installation, as shown in Figure 5, the circuit board 322 is connected to the sensor 31 in the middle of the left side, and the sensor 31 will be exposed in the air channel 302 of the housing 30, as shown in Figure 6, compared with placing the sensor on the edge of the air channel, implementing this installation method When the poisonous gas passes through the airway 302, the sensor 31 exposed in the airway 302 can detect the toxic gas more effectively, which can avoid the defect that the sensor placed on the edge of the airway cannot detect whether there is toxic gas.

As shown in Figure 5 above, two sets of pin headers are reserved on the circuit board 322, the upper left corner The functions of the pin row area A from left to right are: positive charge, programming pin SWCLK, programming pin SWDIO and ground wire. Generally, red is used as positive power, black is used as ground wire, and the two programming pins are not specified. Cable color; the pin row area B in the lower left corner is to display the value currently read by the sensor. The hardware interface on the control board 321 is UART, and the pin row from left to right is the transmission, reception and ground wires, usually There is no specified cable color for the transmission and ground wires, as long as it is easy for users to identify.

There are two sets of connection points C and D on the circuit board 322, and the connection points C and D are The indicator light is controlled by the control board to inform the user of the current measurement status; the connection D is connected to a switch to turn on or off the main power supply. These two sets of connections C and D are detachable, because if the circuit When the board 322 or the control board fails, it is easy to disassemble to reduce maintenance time.

The following examples are only examples for understanding the details and connotation of the present invention, but are not intended to limit Make the scope of the patent application for the present invention.

Fig. 7 is the experimental environment of the present invention for the sensor 31 using SGP30, Fig. The flow direction of the air flow is from right to left, and the toluene aeration bottle 41 on the far right will pass through a flow valve 4a and mix with high-pressure air 42 to reduce the concentration of toluene. The high-pressure air has been deodorized and dehydrated by activated carbon. Degreasing, the relative humidity is close to 15% and the temperature is about 20°C. The flow rate of each flow valve 4a, 4b, 4c is 2.5 liters of air flow per minute. The air auxiliary 43 drives the airflow so that the toluene gas will flow through the sensor 31. At this time, the toluene concentration of the current sensor 31 in this experimental environment can be measured; the other branch is connected to the flame ion detector (flame ion detector) ionization detector, FID) 44, the purpose is to maintain and monitor the toluene concentration in the current experimental environment, and the excess gas is discharged from this environment, and it is also filtered before the exhaust gas is discharged.

After the experimental environment is set up, the sensor is first set up with a relative humidity of 15% and a temperature of The high-pressure air with a temperature of 20°C performs a 0-point calibration for about 45 minutes. The purpose is to remove the existing pollutants on the sensor first. After the 0-point calibration, use the flame ion detector to configure the specified toluene to measure the concentration ,point They are 2.2 ppm, 5.14 ppm, 11.75 ppm, 22.02 ppm and 51.39 ppm. Experimental data measurement of the line sensor.

[Example 1] In the sensor experiment, in addition to testing the upper limit of the sensor, the concentration of five drugs to be tested is configured, and the flame ion detector is used to determine whether the tested substance is close to the target concentration, as shown in Figure 8. The concentration setting of the five-point calibration is shown in Table 1. Table I Gas bag capacity Reagent Grade Toluene Toluene concentration Analyze readings with FID L 99.99%, ml ppm ppm 100 0.3 2.20 3.2 100 0.7 5.14 6.1 25 0.4 11.75 12.8 10 0.3 22.02 25.2 10 0.7 51.39 59.8

[Embodiment 2] Long-term stability test The long-term stability test of the sensor is carried out to test the measurement stability of the sensor in the presence of pollutants, that is, whether there will be any drift in the reading value. The experiment time is about 17 hours and a fixed concentration of toluene (20-45 ppm) is passed through. In addition, a flame ion detector is used as the benchmark instrument for this experiment and as the source of data for this experiment.

[Embodiment 3] Sensor respiratory rhythm experiment This experiment simulates the breathing rate of the human body to test the sensor. The purpose of the experiment is to simulate the situation of a real person wearing a respiratory protective device and installing a canister and the detection and warning device of the present invention. The external environment of the experiment is set to 1000 ppm , while the diameter of the piston tube of the breathing simulator is 10 cm, the stroke of the piston is 20.5 cm, the breathing rate is set at 14 breaths per minute, the single breathing volume is about 1.6 L, and the breathing volume per minute is about 22.5 L. The volume is about 11.3 L/min.

[Example 4] Respiratory Impedance Experiment In order to explore whether the additional installation of the detection and warning device of the present invention will cause additional breathing burden to the user, this experiment measures the pressure difference between the external environment and the breathing channel of the detection and warning device of the present invention, and measures The high-pressure air flow rate is 85 liters per minute (Liter Per Minute, LPM), and the measuring instrument is TSI 8130A (filter material efficiency test system).

[Example 5] Influence of Humidity on Sensor Measurement Some chemical substances have good water solubility, so the external environment will absorb the substances and reduce the gaseous measurement objects, resulting in a decrease in the ambient gas concentration. This experiment evaluates the impact of different relative humidity on the measurement of the sensor, using The breathing simulator is used for measurement, the rated breathing volume is 13.5 L, and the breathing rate is 14.6 breaths per minute.

(式1) 其中，

為當下所偵測到的濃度（ppm），

（ppm），

為時間（s），

為該

與該

的差值除以5後所得到的上升斜率（ppm/s），若

超過預設值則視為濾毒罐已破出。表二及第９圖圓圈處說明濾毒罐破出條件。 表二 濾毒罐破出條件 訂立依據 實際應用 閥值 在工作場所中八小時日時量平均容許濃度(PEL-TWA) 100 ppm之十分之一。 濃度變化不大時，經長時間量測若超過10 ppm則發出告警。 動態變化 單位時間內濃度變化比值超過一預設值。 預防環境突來高濃度而濾毒罐無法即時吸附。 [Example 6] The canister breakout test is to establish the breakout condition of the canister (taking toluene as an example), including a threshold value and a dynamic change value of the concentration difference per unit time. The threshold value is expected to be used In the workplace, the eight-hour daily average allowable concentration (permissible exposure limit-time weighted average, PEL-TWA) is one-tenth of 100 ppm, and 10 ppm is used as the threshold for breaking one of the warning conditions. The concentration difference per unit time is used as the evaluation standard. The breakout condition defined in the present invention is whether the concentration difference ratio of the continuously detected TVOC value within 5 seconds exceeds a preset value. The calculation formula is expressed in formula 1.

(Formula 1) where,

is the detected concentration (ppm) at the moment,

(ppm),

is time(s),

for the

with the

The rising slope (ppm/s) obtained after dividing the difference by 5, if

If it exceeds the preset value, it is considered that the canister has been broken. Table 2 and the circle in Figure 9 illustrate the conditions for the canister to break out. Table II Canister burst condition Basis for conclusion practical application Threshold One-tenth of 100 ppm in the eight-hour daily time average allowable concentration (PEL-TWA) in the workplace. When the concentration does not change much, an alarm will be issued if it exceeds 10 ppm after long-term measurement. Dynamic changes The concentration change ratio per unit time exceeds a preset value. Prevent the environment from sudden high concentration and the canister cannot absorb immediately.

[Example 7] The battery (main power supply) endurance test is to test the battery endurance. In this experiment, the SEN0291 power measurement module 51 is used to detect the main power supply 34 ( 800mAh lithium battery) for voltage and current monitoring. The communication interface of the power measurement module 51 is I ² C. It is controlled through the control board 52 and then the voltage value and the attached current value of the main power supply 34 are obtained through the UART. The overall measurement architecture is shown in Figure 10. In the experiment, the 800mAh lithium battery was measured once per second as a benchmark for the TVOC value and recorded the power change degree of the main power supply 34 to evaluate the feasibility of achieving the 8-hour continuous measurement target; in addition, the canister burst alarm test was carried out , the experiment is conducted on an 800 mAh lithium battery, with the vibrating motor vibrating once every two seconds as the benchmark, and recording the degree of change in the power of the main power supply 34, and evaluating and simulating how long it will last under different power levels when the canister is broken. The 34 battery life of the main power supply can warn the user that the canister has been broken.

[Implementation Result 1] Sensor Experiment Results The experiment conducted a five-point concentration test experiment on the sensor to check the linearity of the sensor for the measurement of the specified drug. The concentrations of toluene configured in the experiment were 2.2 ppm, 5.14 ppm, and 11.75. ppm, 22.02 ppm, and 51.39 ppm were measured using sensors, and the five-point concentrations obtained are shown in Table 3, and the toluene concentrations at each point (that is, the toluene concentration of the sensor in the environment were 2.2 ppm, 5.14 ppm, 11.75 ppm, and 22.02 ppm and 51.39 ppm) measurement results curves are shown in Figure 11 to Figure 15. At the same time, the correlation analysis between the sensor data and the ambient concentration of toluene is carried out, and the results are shown in Figure 16. The analysis results show that the two The R ² correlation reaches 0.9868, showing that the sensor (SGP30) used in the present invention has a good linear relationship with the concentrations of these five points. Table three Toluene concentration Sensor (SGP30) measurement results mean ± standard deviation 2.20 0.556 ± 0.005 5.14 0.793±0.01 11.75 1.081±0.048 22.02 1.759±0.022 51.39 2.886±0.035 The reading value of the sensor (SGP30) is then back-returned by the flame ion detector through the regression equation. The back-push values are shown in Table 4. Although the values are slightly different, the main goal is to protect workers while using respiratory protective equipment. It can remind you of the usage situation, and the most important purpose is to detect the broken canister. The reading value of the sensor using SGP30 relative to the flame ion detector can be converted to a value, as long as the measurement linearity of the sensor is in good condition , which can be used as a canister burst sensing element. Table four Environmental toluene concentration ppm SGP30 measurement results mean ± standard deviation ppm SGP30 reading value ppm by regression formula Difference (environmental toluene concentration - SGP30 reading value by regression formula, ppm) 2.2 0.556 ± 0.005 0.396 1.804 5.14 0.793±0.01 5.391 -0.251 11.75 1.081±0.048 11.461 0.289 22.02 1.759±0.022 25.751 -3.701 51.39 2.886±0.035 49.505 1.885

[Implementation result 2] Long-term stable test results The purpose of this experiment is to monitor whether the sensing value of the sensor (SGP30) changes significantly through a fixed toluene concentration. The experiment time is 17 hours and 20-45 ppm toluene is continuously passed through. Figure 17 shows the results of the long-term stability test of the sensor (SGP30). The X-axis is the measurement time point, and the value is measured once per second; the Y-axis is the toluene concentration value measured by the sensor (SGP30), in units In ppb, the measurement curve shows a slow rise, and the measured value of the flame ion detector also rises slowly. The reason for the slow rise of the measurement curve is that the daily high and low temperature difference will make the compression ratio of the high pressure air different. , At the same time, the difference in air flow rate also affects the measured concentration of the sensor.

[Implementation Result 3] Experimental results of sensor breathing rhythm The present invention conducts a respiratory rhythm experiment on the detection and warning device, and conducts the experiment with a 3M6001 canister. The purpose is to simulate the condition of the human body when breathing to design the conditions for the canister to break out. The respiratory protective mask used in the experiment is a half-face mask of the 3M 7500 series Body protective mask, the device on one side is in contact with ambient air; the device on the other side is put into a gas chamber, and 1000 ppm toluene is passed into the gas chamber at the same time, and then the experiment is carried out with a breathing simulator, and the experimental results are as follows Figure 18 shows.

[Implementation Result 4] Respiratory Impedance Experimental Results This experiment aimed at the change of respiratory impedance after wearing the detection and warning device of the present invention, using TSI 8130A to measure, first use an empty board to measure as the reference point of respiratory impedance, and then Use the detection and warning device of the present invention to measure, then measure the impedance of the 3M6001 canister, and finally measure the respiratory impedance after adding the two, and the measured flow rate is 85 LPM. The actual respiratory impedance data are shown in Table 5 and Table 6: in the base point experiment of the empty board, the average impedance value is 4.3 mmH ₂ O; after the empty board is put on the measurement module, the one that affects the impedance is installed in the airway The average impedance value of the empty board and the sensor is 6.9 mmH ₂ O; the actual increase of the average impedance value of the detection and warning device of the present invention is 2.6 mmH ₂ O; when the 3M6001 canister is replaced, the overall impedance can be found to increase Quite a few, far from the detection and warning device of the present invention, the average impedance value is 33.4 mmH ₂ O; the last experiment is to put on the detection and warning device of the present invention and 3M6001 canister, the average impedance value is 35.9 mmH ₂ O, it can be found that most of the impedance is concentrated on the canister, and this device only increases the overall impedance by 2.5 mmH ₂ O on average, which has little effect, so it will not increase the breathing burden for the user. Table five empty board This device + empty board 1 2 3 average 1 2 3 average 4.4 4.2 4.3 4.3 7.1 6.7 6.9 6.9 Table six 3M6001 canister + empty board This device + 3M6001 canister + empty board 1 2 3 average 1 2 3 average 33.3 33.5 33.5 33.4 36.2 35.6 35.9 35.9

[Implementation Result 5] Effect of Humidity on Sensor Measurement Results were measured using a breathing simulator with a rated breathing capacity of 13.5 L and a breathing rate of 14.6 breaths per minute. The impact of different relative humidity on sensor measurement , the test results are shown in Table 7. Regardless of the concentration of the gas, when the relative humidity exceeds 90%, the flame ionization detector or the SGP30 sensor will have a numerical underestimate. There are many water molecules, and the combination of gas and water molecules in the air makes the flame ion detector unable to fully burn and underestimate. The same situation occurs with the SGP30 sensor. Table Seven Relative humidity(%) FID (ppm) SGP30 (ppm) High concentration 54% 54 45.6 75% 55 49.3 92% 32 35.6 Low concentration 55% 5 2.1 93% 4 1.1

[Implementation Result 6] Canister Breakout Test Toluene is the main substance in the painting situation, so two types of canister breakout are defined, one is the average allowable concentration of 1/100 ppm in the eight-hour day in the workplace, and 10 ppm is used as one of the warning conditions for breakout; Another breaking condition is to calculate the ratio of the value difference within 5 seconds. If the ratio is greater than 1.5, it is considered that the canister has broken, and the user needs to be informed of the current situation for contingency disposal. The present invention has passed three break-out tests. When the environmental background toluene concentration is about 1000 ppm, when the canister break-out concentration reaches 10 ppm (1/10 toluene TWA value), the concentration value of five seconds before and after breaking out of the detection and warning device is tested. , and the calculated average slope is about 1.5, which is set as the slope of the warning standard. The meaning of the curve in Figure 19, the sensor (SGP30) measurement curve (blue solid line) represents the data curve of the original measurement value of SGP30 converted by the regression formula, and the value is compared with the Y axis on the left side of the chart; the concentration change ratio within 5 seconds Curve (orange solid line), the calculation of the curve is shown in the above formula 1; the value is compared with the Y axis on the right side of the chart; the concentration change of the canister breaks out the condition (red dotted line), with 10 ppm as the threshold value, and the value is compared with the Y axis on the left side of the chart Axis; canister measurement breakout condition (green dotted line), calculated according to formula 1, and the value is compared with the Y axis on the right side of the chart. According to the definition of breaking conditions, when "the blue curve is higher than the red dotted line" or "the orange curve is higher than the green dotted line", it will inform the user that the current canister has been broken. Therefore, in Figure 19, first, No. 1 black To the left of the dotted line, although the slope has not yet exceeded 1.5, the SGP30 measurement curve has gradually risen above the red dotted line, which means that the current canister has been broken. Secondly, between the No. 1 black dotted line and No. 2 black dotted line, it means that the current concentration change curve within 5 seconds and the SGP30 measurement curve are in a oscillating state, and the SGP30 measurement curve also maintains an upward state. If the concentration rise slope (a) reaches 1.5 The above means that the canister is broken. And, when the SGP30 measurement curve and the concentration change curve within 5 seconds are lower than the red and green dotted lines at the same time, the alarm is released.

[Implementation Result 7] Battery life test results System Operation Test The purpose of the system operation test is to measure the endurance of the main power supply (800 mAh lithium battery) under the normal measurement of the sensor. Figure 20 shows the voltage change of the measured battery, and the initial state of the main power supply (800 mAh lithium battery) can be observed. The voltage value is about 4.1 V, which means that the current main power supply (800 mAh lithium battery) is fully charged. After a period of measurement, it is found that the battery life of the main power supply (800 mAh lithium battery) drops rapidly when the voltage is about 3.1 V. Finally, the main power supply (800 mAh lithium battery) drops rapidly. When the voltage of the power supply (800 mAh lithium battery) drops to 2.4 V, it can no longer continue to supply power to the load, which means that the current power of the main power supply (800 mAh lithium battery) has been completely consumed, and the battery needs to be charged or replaced. Another discussion is the current change of the load. When the device is just turned on, there will be a vibration prompt, so the current will rise to 125 mA, and the vibration will last for about 1 second and end. In Figure 21, it can be found that the curve is at Steady state, that is to say, the load is in the TVOC measurement state at this time, the LED indicator flashes once per second, and the average current consumption is about 49.6 mA. From the above experiments, it can be found that a total of 42,631 data points have been measured, and one data point is recorded per second. Therefore, it can be estimated that the endurance time of the main power supply (800 mAh lithium battery) is about 11.8 hours. Canister continuously broken alarm test The canister continuously broke alarm test. The purpose of this experiment is that after a period of TVOC measurement, if the external environment changes drastically, the device will send out an alarm to inform the user that the canister is currently broken. Let's discuss how long this warning mechanism can last. Figure 22 is a simulation of the voltage change of the alarm test when the canister is broken. The vibration motor rotates at a speed of 100 revolutions per second, vibrates for one second, and stops for two seconds for actual measurement. After the actual measurement, when the motor vibrates, there is obvious The sense of vibration informs the user that the voltage value will drop when the vibration motor is started from Figure 22; otherwise, the change is not obvious, and the voltage difference between the two is between 0.05 and 0.08 V. When the main power supply (800 mAh lithium battery) the lower the voltage, the closer the voltage difference between starting and non-starting. Another thing that needs to be discussed is the current consumption of the vibration motor. The measured results are shown in Figure 23. The current monitoring is to record one data per second. When the vibration motor starts, the instantaneous current will break through to 140 mA About two seconds after the vibration ends, it will return to the normal current value (about 49mA). Therefore, it can be estimated from the figure 23 that the 800 mAh lithium battery can continue to alarm for about 9 hours. If there is a sudden alarm after a certain period of time, you can compare Figure 22 and Figure 23 to find out how long the alarm can last.

Obtain the following conclusions by the above-mentioned various experiments: 1. The data of the selected metal oxide semiconductor sensor of the present invention and the ambient concentration of toluene, the ^R2 correlation of the two reaches 0.9868, showing that the sensor has a certain effect on the concentration of these five points. Good linear relationship, can be used as canister burst detection. 2. In the respiratory impedance experiment, it is found that most of the impedance is concentrated on the canister, and the detection and warning device of the present invention has little effect on the overall impedance, so it will not increase the burden of breathing on the user. 3. The present invention takes toluene as the main exposure substance, and defines two kinds of canister breaking conditions, one is one-tenth of the average allowable concentration (PEL-TWA) of eight-hour daily volume in the workplace; the other breaking condition is Calculates the ratio of numerical differences over 5 seconds. 4. This device uses a lithium battery with a capacity of 800 mAh as the main power supply. Under the test conditions, it can achieve 8 hours of continuous measurement and continuous alarm when the canister is broken. 5. This device is designed to be installed between the canister and the surface body, and the influence of carbon dioxide on the measured value can be effectively reduced by the intake valve. 6. In order to implement the management of the replacement of respiratory protective equipment and provide a beneficial real-time management tool for business units to provide more complete protection for workers, this invention uses toluene as the main evaluation substance (painting operation situation) to make and apply an integrated miniaturized gas sensor Detection components and warning components, constructing a volatile organic substance canister burst detection warning device, including a sensor that can detect TVOC and an alarm device that can issue an alarm effect, and automatically detect the gas in the respiratory protective equipment at the user's end Leakage concentration, alarm function of vibration, warning flash or warning sound, and real-time management device that can reach more than 8 hours, so it can be used as an important tool for managing filter replacement, and can be used as a reference for business unit management.

In summary, the present invention is a kind of volatile organic substance canister burst detection warning The device can effectively improve the various shortcomings of conventional use. The main research material is toluene, a volatile organic substance, and a half-hedron respiratory protective device is selected as the test item, and the device is installed between the canister and the respiratory protective device. By integrating control boards, sensors and other components, not only does not destroy the function of the respiratory protective equipment, but also can achieve the breakthrough measurement of organic solvents. Whether there is a problem of re-release of pollutants in a humid environment, put forward suggestions on the use and management of canisters, so as to break the myth that laborers have to wear protective respiratory protection, and give managers a reference to the timing of replacing canisters, and then make the present invention The production can be more advanced, more practical, and more in line with the needs of users, and it has indeed met the requirements for patent applications for inventions, and patent applications should be filed in accordance with the law.

But what is described above is only a preferred embodiment of the present invention, and should not be limited to this Therefore, all simple equivalent changes and modifications made according to the scope of the patent application for the present invention and the contents of the description of the invention shall still fall within the scope covered by the patent of the present invention.

Respiratory Protective Equipment 1 Facet 10 Canister 2 Volatile organic substance canister burst detection and warning device 3 Shell 30 Storage space 301 Airway 302 Upper cover 303 Sensor 31 Microcontroller 32 control panel 321 Internal Memory 3211 circuit board 322 vibration motor 33 main power supply 34 switch 35 indicator light 36 Flow valves 4a, 4b, 4c Toluene aeration bottle 41 High pressure air 42 Air help 43 Flame ion detector 44 Power measurement module 51 control panel 52 Needle area A, B Connections C and D Steps s11 to s15

Figure 1 is the combination of the volatile organic substance canister burst detection and warning device and respiratory protective equipment of the present invention. Installation diagram. Figure 2 is a schematic diagram of the system architecture of the device proposed by the present invention. Figure 3 is a schematic diagram of the operation flow of the device proposed by the present invention. Figure 4 is a schematic diagram of the appearance of the housing of the device proposed by the present invention. Fig. 5 is a schematic diagram of each pin row and connecting seat of the circuit board of the present invention. Figure 6 is a schematic diagram of the sensor exposed in the airway of the present invention. Fig. 7 is a schematic diagram of the experimental environment of the present invention. Figure 8 is a schematic diagram of the five-point concentration measurement results of the FID of the present invention. Fig. 9 is a schematic diagram of breaking out of the canister of the present invention. Figure 10 is a schematic diagram of the power monitoring architecture of the main power supply of the present invention. Figure 11 is a schematic diagram of the measurement results of the sensor of the present invention at an ambient toluene concentration of 2.2 ppm. Figure 12 is a schematic diagram of the measurement results of the sensor of the present invention at an ambient toluene concentration of 5.14 ppm. Figure 13 is a schematic diagram of the measurement results of the sensor of the present invention at an ambient toluene concentration of 11.75 ppm. Figure 14 is a schematic diagram of the measurement results of the sensor of the present invention at an ambient toluene concentration of 22.02 ppm. Figure 15 is a schematic diagram of the measurement results of the sensor of the present invention at an ambient toluene concentration of 51.39 ppm. Figure 16 is a schematic diagram of the measurement results of the five-point concentration correlation of the sensor of the present invention. Figure 17 is a schematic diagram of the long-term stability test results of the sensor of the present invention. Fig. 18 is a schematic diagram of the experimental results of breathing rhythm of the present invention. Fig. 19 is a relational diagram of the breaking conditions of the canister of the present invention. Figure 20 is a schematic diagram of the present invention's system operation test (voltage value change) with 800 mAh. Fig. 21 is a schematic diagram of the present invention with 800 mAh system operation test (current value change). Fig. 22 is a schematic diagram of the present invention using an 800 mAh canister to continuously burst an alarm test (change in voltage value). Figure 23 is a schematic diagram of the present invention using an 800 mAh canister to continuously burst an alarm test (change in current value).

Sensor 31 Microcontroller 32 control panel 321 Internal Memory 3211 circuit board 322 vibration motor 33 main power supply 34 indicator light 36

Claims (13)

A volatile organic substance canister burst detection and warning device is installed between the surface of a protective gear and the canister, which includes: A casing has an accommodating space and an air passage, the air passage is connected to the air inlet of the protective device, a switch and an indicator light are provided on the side of the casing, the switch provides the power to turn on or off the device, the The indicator light reminds the user whether the device is powered on, whether the device is currently in the measurement state, and whether the canister currently in use has been broken; A sensor, a part of which is set in the accommodating space of the housing, and the other part is exposed through the air passage of the housing and faces the air inlet of the protective device, for measuring carbon dioxide and total volatility The concentration of total volatile organic substance (TVOC) is used for real-time automatic detection of whether the canister currently in use is broken; A micro-controller, located in the accommodation space of the casing, the micro-controller includes a control board and a circuit board, the control board has an internal memory, the circuit board is connected to the control board to provide the control board The relevant interface on the above is transferred to the circuit board, and the circuit board can be used for the electrical connection of the switch, the indicator light and the sensor, and the control board controls the sensor through the communication interface to read the sensor. The carbon dioxide and the TVOC value measured by the detector are stored in the internal memory, and the control panel accesses the TVOC value through the internal memory to calculate whether the TVOC value exceeds the preset canister break According to the calculation results, the circuit board controls the indicator light to emit light through the control board to inform the user of the current measurement status, and controls the switch to turn on or off the power supply; A vibrating motor is arranged in the accommodating space of the casing, and is electrically connected to the circuit board of the microcontroller, and is used to control the vibration of the vibrating motor by the circuit board through the control board according to the judgment result, to inform the user of the current measurement status; and A main power supply is arranged in the accommodating space of the housing and is electrically connected to the sensor, the micro-controller The controller, the indicator light and the vibration motor are used to supply power to the sensor, the microcontroller, the indicator light and the vibration motor. According to the volatile organic substance canister burst detection and warning device described in item 1 of the scope of the patent application, the housing is made of acrylonitrile butadiene styrene (Acrylonitrile Butadiene Styrene, ABS) resin, Or those with materials that are resistant to acid, alkali and salt corrosion and can tolerate the dissolution of organic solvents. According to the volatile organic substance canister burst detection and warning device described in item 1 of the scope of the patent application, the sensor is an air quality sensor equipped with an inter-integrated circuit (I2C) communication interface sensor. According to the volatile organic substance canister burst detection and warning device described in item 1 of the scope of the patent application, the indicator light is an LED light, which reminds the user whether the device is in a normal state and whether the device is currently in the normal state. Abnormal state, or whether the canister currently in use is in the warning state of broken canister. According to the volatile organic substance canister burst detection and warning device described in item 4 of the scope of patent application, the indicator light flashes once every second to indicate that the device is currently in the normal state; the indicator light is always on to indicate that the current The device is in an abnormal state that is waiting to be dealt with; the indicator light flashes rapidly and there is vibration at the same time, indicating that the canister currently in use has been broken, and the canister is in a broken warning state. According to the volatile organic substance canister burst detection and warning device described in item 1 of the scope of the patent application, the microcontroller is an electrical signal through a general purpose I/O port (GPIO) Process and control the indicator light and the vibration motor, and communicate with the sensor through the I2C communication interface, and then read back the relevant information and inform the user through a Universal Asynchronous Receiver/Transmitter (UART) Current reading status. According to the volatile organic substance canister burst detection and warning device described in item 1 of the scope of the patent application, the main power supply is a lithium battery with a capacity of 700-900 mAh. According to the volatile organic substance canister breach detection and warning device described in item 1 of the scope of the patent application, the switch and the indicator light are electrically connected to the circuit board in a detachable manner. According to the volatile organic substance canister burst detection and warning device described in item 1 of the scope of the patent application, the preset canister burst condition is a dynamic change of a threshold value and a concentration difference within a unit time Value, the threshold value is one-tenth of 100 ppm of the permissible exposure limit-time weighted average (PEL-TWA) used in the workplace for eight hours; and the dynamic change value is calculated within 5 seconds Whether the TVOC value difference ratio exceeds a preset value. According to the volatile organic substance canister burst detection and warning device described in item 9 of the scope of the patent application, the default value is 1.5, and the dynamic change value is calculated within 5 seconds of the TVOC value for continuous detection When the concentration difference ratio is greater than 1.5, it is considered that the canister currently in use has broken. According to the volatile organic substance canister burst detection and warning device described in item 10 of the scope of patent application, the calculation formula of the dynamic change value is as follows:

; in which the

is the concentration detected at the moment; the

and the

for the

with the

The rising slope dd obtained after dividing the difference by 5. According to the volatile organic substance canister burst detection and warning device described in item 1 of the scope of the patent application, the vibration motor will generate a vibration prompt when the device is just turned on. The volatile organic substance canister breach detection and warning device described in item 1 of the scope of the patent application further includes a buzzer, which is set in the accommodating space of the housing and is electrically connected to the circuit board is used to make the circuit board control the buzzer to sound through the control board according to the judgment result, so as to inform the user of the current measurement status.

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