Gas alarm Baidu Encyclopedia knowledge introduction two gas alarm Baidu Encyclopedia knowledge introduction two
Gas alarm installation and use
The gas alarm is composed of a detector and an alarm control host. It is widely used in the petrochemical industry where there are toxic gases such as petroleum, gas, chemical, oil depots, etc. It is used to detect the leakage of dangerous places indoors and outdoors, which is important for ensuring production and personal safety. instrument. When there is a toxic gas in the tested place, the detector converts the gas signal into a voltage signal or a current signal and transmits it to the alarm meter. The instrument displays the percentage concentration value of the lower limit of the toxic gas explosion. When the concentration of toxic gas exceeds the alarm set value, an audible and visual alarm signal will be generated, and the on-duty personnel will take safety measures in time to avoid the occurrence of a blasting accident.
1. Precautions during application, once the gas alarm is installed in place, its position is not easy to change. The following points should be considered for specific applications.
(1) Find out the possible leak points of the devices to be monitored, analyze their leakage pressure, direction and other factors, and draw the probe position distribution map, according to the severity of the leakage into three levels I, II, III.
(2) According to the specific factors such as airflow direction and wind direction of the site, determine the leakage direction of toxic gas when a large amount of leakage occurs.
(3) According to the density of the leaking gas (greater or smaller than the air), combined with the trend of air flow, integrated into a three-dimensional flow trend diagram of the leak, and an initial set point scheme is made at the downstream position of the flow.
(4) Study whether the leakage state of the leak point is a micro leak or a spray. If it is a micro leak, set the position of the point close to the leak point. If it is a jet leak, it should be slightly away from the leak. Based on these conditions, a final set-up plan is drawn up. In this way, the quantity and variety that need to be purchased can be estimated.
(5) For places where there is a large toxic gas leak, according to the relevant regulations, a detection point should be set for each distance of 10-20m. For small, non-continuously operating pump rooms that are unattended, attention should be paid to the possibility of toxic gas leakage. Generally, a detector should be installed at the downwind.
(6) For places with hydrogen leaks, the detector should be installed on the plane above the leak point.
(7) For media with a gas density greater than air, the detector should be mounted on a lower surface below the leak point, and pay attention to the surrounding environment. Special attention should be paid to the setting of safety monitoring points for places where toxic gases are easily accumulated.
(8) For open toxic gas diffusion and escape environment, if there is no good ventilation condition, it is easy to make the toxic gas content in a certain part of the air close to or reach the lower explosion limit concentration. These are safety monitoring points that cannot be ignored. . According to the analysis of on-site accidents, more than half of them were caused by incorrect installation and calibration. Therefore, it is necessary to introduce the correct precautions for installation and calibration to reduce malfunctions.
2. Gas alarm installation precautions
(1) The alarm probe is mainly a detecting element that contacts the combustion gas sensor. The platinum wire coil is coated with alumina and a binder to form a spherical shape, and the outer surface thereof is provided with a rare metal such as platinum or palladium. Therefore, be careful when installing to avoid breaking the probe.
(2) The installation height of the alarm should generally be 160-170cm, so that maintenance personnel can carry out routine maintenance.
(3) The alarm device is a safety instrument with sound and light display function. It should be installed in a place that is easy for the staff to see and hear, so as to eliminate hidden dangers in time. (4) There must be no strong electromagnetic fields (such as high-power motors and transformers) that affect the operation of the instrument.
(5) The density of the gas to be measured is different, and the installation position of the indoor probe should also be different. When the measured gas density is less than the air density, the probe should be installed 30cm away from the roof, and the direction is downward; otherwise, the probe should be installed 30cm away from the ground, and the direction is upward. The controller uses a three-core shielded wire to connect with the detector (Note: the single-core wire diameter is not less than 0.75mm national standard wire, depending on the actual distance), and the shielding layer is connected to the controller casing and reliably grounded. When using RVV cables, metal pipes should be worn and the metal pipes should be reliably grounded.
Construction wiring diagram of gas alarm
Refer to the controller and detector wiring diagram, connect the controller to the corresponding terminal of the detector. Connect the input controller terminal to the detector terminal. ◆ Connect the output terminal to the linkage device. ▲. When the inductive device such as the exhaust fan meets When the condition is less than or equal to 5A/220VAV, it can be directly connected to the output terminal, but the load device should be directly connected to the output terminal as much as possible. When the load device is larger than 5A/220VAV, the external transfer device must be connected; ▲. Controller, detector To ensure reliable grounding; ▲. When performing various installation operations, you need to power off first, otherwise the host may be burned out. The detectors used with the controller and the detectors used in conjunction with the controller are: point type gas detectors. Technical parameters: ◆ Detection principle: catalytic combustion, electrochemical ◆ Detection gas: combustible gas, toxic gas ◆ Sampling method: natural diffusion ◆ Indication error: ± 5% F · S / ± 10% / ± 5 × 10mol / mol ◆ Response time: ≤30s ◆ Working voltage: DC12V～30V ◆ Rated power: ≤3W ◆ Temperature: -40°C～60°C ◆ Humidity: ≤95%RH ◆ Connection cable: ≥RVV3×0.75mm (national standard line) ◆ Transmission Distance: ≤1200m ◆ Explosion-proof grade: ExdIICT6 ◆ Installation method: fixed bracket, tube installation, wall installation ◆ Installation screw: G1/2〃 Installation position: The detector should be installed in a gas leaking place, the specific position should be relative to the gas to be tested The proportion of air is determined. When the specific gravity of the detected gas is greater than the specific gravity of the air, the detector should be installed at a distance of 30 to 60 cm from the ground and the sensor portion is downward. When the specific gravity of the detected gas is less than the specific gravity of the air, the detector should be installed at a distance of 30 to 60 cm from the ceiling and the sensor portion is downward. In order to use the detector correctly and prevent the detector from malfunctioning, please do not install it in the following locations: ◆ Where it is directly affected by steam or oil smoke; ◆ Where the air flow, ventilation fan, door, etc. flow is large; ◆ Water vapor and water droplets Place (relative humidity: ≥90%RH); ◆ Temperature below -40 °C or above 55 °C; ◆ Where there is a strong electromagnetic field.
5 treatment methods
edit
1. Please open the door and window immediately, turn off the hazardous gas source, and do not turn on or off any electrical switch.
2. Report to the gas management department immediately and have it checked and handled by professionals.
3. After being handled by professionals, the alarm should be ventilated.
6 emergency treatment
When the detector leaks due to gas leakage and uses the automatic cut-off device, do not turn on the light or turn on any electrical switch; immediately open the window for ventilation, and wait for the red alarm indicator of the detector to go out, find the cause of the gas leak (cannot When confirming the cause, you should contact the relevant gas company for processing) and eliminate it. Confirm that the detector does not continue to alarm (the gas does not continue to leak), press the manual switch to turn on the automatic cut-off device to recover the gas. Do not touch the power of the household gas alarm at will to prevent the detector from working properly.
7 technical parameters
Voltage selection: AC 220V/AC110; DC9V-16V
Low power alarm static power consumption:
High power alarm static power consumption: <3.3W (calculated by 220VAC)
Alarm concentration: combustible gas: liquefied gas 0.1% to 0.5%; natural gas 0.1% to 1%; city gas (H2) 0.1% to 0.5%; carbon monoxide: 1‰ to 0.4‰
Adopting the US imported PIC 16F676 is one of the best ICs in the world.
Gas response, recovery time: ≤30S Carbon monoxide response, recovery time: ≤200S Alarm volume: ≥70dB
Working environment: Humidity ≤97%RH Temperature: -15°C-+50°C
8 unique features
The automatic shut-off manipulator automatically closes the main ball valve when the gas alarm occurs. This makes it possible to fully realize the 24-hour alarm alarm function.
(1) Added sensor drift automatic compensation function, which can prevent false alarms and false negatives according to the drift of the sensor. At present, this technology is the first in China.
(2) The alarm fault prompt function, the sensor damage is automatically prompted for the user to replace and repair, preventing the report from being reported.
(3) MCU full control, working temperature is -40 degrees to 80 degrees. The robot can be automatically reset, no need to manually reset, to ensure timely management in the first time
Combustible gas and carbon monoxide harm to human body
1. When the concentration of flammable gas exceeds the lower limit of explosion, explosion occurs in case of fire (lighter, electrical switch, static electricity, etc.), causing injury.
2, carbon monoxide is a colorless and odorless highly toxic gas, inhaled through the respiratory tract and human hemoglobin, causing the body to be hypoxic and poisoned.
3. The city gas itself contains a large amount of carbon monoxide. Therefore, when the gas leaks, there is a danger of explosion and a risk of carbon monoxide poisoning. In addition, incomplete combustion of gas, kerosene, wood, etc. also produces carbon monoxide.
Whether it is natural gas, liquefied gas, or coal-based gas, after leaking for various reasons, when the indoor gas concentration exceeds the lower explosion limit, the fire (lighter, electrical switch, static electricity, etc.) must explode. Why is gas poisoning? Although the composition of artificial coal gas in China's cities is different, they all contain more carbon monoxide. For example, Harbin gas contains carbon monoxide 13, Shanghai gas contains carbon monoxide 19, Qingdao gas contains carbon monoxide 21, and Qinhuangdao gas contains carbon monoxide up to 30. It is well known that carbon monoxide is a highly toxic gas. In a person with carbon monoxide 1 in the air, it produces sputum in 10 minutes and will die in half an hour. Therefore, when coal gas leaks, there is a danger of explosion and there is a danger of carbon monoxide poisoning (direct poisoning). In addition, carbon monoxide poisoning (exhaust poisoning) may occur when a gas water heater or a coal stove is used and ventilation is poor. What is the lower explosion limit? That is, the lowest concentration of the explosion in the air, the alarm concentration is set below 1/4 of the lower explosion limit. For example: methane (main component of natural gas) explosion lower limit of 5.0 (50000ppm) propane (liquefied gas main component) explosion lower limit of 2.0 (20000ppm) hydrogen (coal gas main component) explosion lower limit of 4.0 (40000ppm) gas leakage reasons ? Any family, no matter how you pay attention, may have a case. Among them, the ignition failure, the pot or the wind blows out, the flame is extinguished in the middle, and the total valve is not strict, which accounts for more than 70% of the leakage. Why does the alarm know the gas leak? At the heart of the gas alarm is a gas sensor, commonly known as the "electronic nose." This is a unique resistor. When “smell†to gas, the sensor resistance changes with the gas concentration. When the gas reaches a certain concentration, the sensor can sound and light alarm when the resistance reaches a certain level. What is the sound and light alarm? After the gas leak causes the indoor concentration to reach the alarm concentration, the red indicator of the alarm light is on, and the buzzer emits an alarm sound of “open-up-â€, so it is called sound and light alarm. Why is the gas alarm valid? Sensors that are not of good quality generally lose their performance in 1-2 years, thus losing the safety of the alarm. Alarms in other electronic components (such as transformers, capacitors, transistors, etc.) have a limited life span, so even advanced countries have a valid period of up to five years. To ensure safety, a new alarm must be replaced after five years of expiration.
9 little knowledge
Gas leak alarm principle
Very important gas safety equipment, it is the last protection for safe use of city gas. The gas leak alarm detects the low concentration combustible gas in the surrounding environment through the gas sensor, and transmits the detection signal to the controller or the control circuit through the sampling circuit through the sampling circuit, when the concentration of the combustible gas exceeds the controller or the control circuit. At a fixed value, the controller issues an alarm signal through an actuator or an execution circuit or performs an action such as closing the gas valve. The sensors for detecting combustible gases of combustible gas alarms mainly include oxide semiconductor type, catalytic combustion type, hot line type gas sensor, and a small number of other types, such as chemical battery type sensors. These sensors generate chemical or electrochemical reactions on the sensor surface by adsorption of flammable gases in the surrounding environment, resulting in changes in the electrical and physical properties of the sensor.
Gas leak alarm function
The function can be divided into a leak alarm with only leakage alarm function and a detection alarm that can indicate the detected gas concentration and has an alarm function; it can be divided into a civil gas leak alarm and a commercial alarm from the use place. Civil alarms are usually independent gas alarms used in residential buildings. They are simpler to use; commercial alarms mainly use gas transportation, storage, gas, and factories and public places where gas leaks may occur. The gas code for the basement, semi-basement, closed space on the ground, the pipe well of the building, and the closed meter room shall be installed in the city gas code. Civil gas leak alarms are also recommended for building and gas related codes and regulations.
10 installation steps
installation method
In the selected wall position, corresponding to the two mounting holes on the random mounting plate, the punching mark is made (the hook on the board should be horizontally upward);
Lay the mounting holes, put in the random installation rubber plug, and then fix the mounting plate to the wall with random self-tapping screws;
Align the three holes on the back of the body with the fixing hooks on the mounting plate to hang the body;
After connecting the relevant output signal line, turn on the power.
State test
Normal monitoring status: After the power is warmed up for 3 minutes, the green light is steadyly illuminated, indicating that the alarm is working normally in the monitoring state; during the warm-up process, the alarm may sound “beep...beep†and the red light flashes, and the green light disappears before the light is off. normal.
On-site alarm status: When the gas content in the air around the alarm exceeds the alarm point, the alarm will emit a “beep...beep...†intermittent squeaking of the ear, while the red indicator light flashes to remind the user to do the on-site processing as soon as possible; alarm output status: live sound and light After the alarm lasts for 10 seconds, different types of alarms will output different types of alarm signals, notify the alarm system or activate the corresponding linkage.
11 features
(1) Vent: Gas (natural gas, liquefied petroleum gas, city gas) enters the sensing chamber through the gap between the alarm shell and the bottom casing. To allow the air to circulate properly, do not install the alarm in a dirty, dusty or greasy area.
(2) Sensor: The sensor uses semiconductor technology, which has high sensitivity to flammable gas and avoids false alarms.
(3) Buzzer: The volume is up to 85 decibels, which reminds you of the potential danger. The alarm form is: continuous sound.
(4) Preheating: When the alarm is energized, it needs to be preheated for 2-3 minutes, and no alarm will be given within 2-3 minutes after power on.
Dongguan Hengda Gas Equipment Co., Ltd. is located in Shahukou Village, Changping Town, Dongguan City. It mainly produces: gasifiers, gasifiers, gas fittings, combustible gas alarms, valves, instrumentation, and gas pipeline design and installation. . Companies adhering to the "customer first, forge ahead" business philosophy, adhere to the "customer first" principle to provide our clients with quality services. Welcome patrons! Source of information: http://
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
Gas alarm installation and use
The gas alarm is composed of a detector and an alarm control host. It is widely used in the petrochemical industry where there are toxic gases such as petroleum, gas, chemical, oil depots, etc. It is used to detect the leakage of dangerous places indoors and outdoors, which is important for ensuring production and personal safety. instrument. When there is a toxic gas in the tested place, the detector converts the gas signal into a voltage signal or a current signal and transmits it to the alarm meter. The instrument displays the percentage concentration value of the lower limit of the toxic gas explosion. When the concentration of toxic gas exceeds the alarm set value, an audible and visual alarm signal will be generated, and the on-duty personnel will take safety measures in time to avoid the occurrence of a blasting accident.
1. Precautions during application, once the gas alarm is installed in place, its position is not easy to change. The following points should be considered for specific applications.
(1) Find out the possible leak points of the devices to be monitored, analyze their leakage pressure, direction and other factors, and draw the probe position distribution map, according to the severity of the leakage into three levels I, II, III.
(2) According to the specific factors such as airflow direction and wind direction of the site, determine the leakage direction of toxic gas when a large amount of leakage occurs.
(3) According to the density of the leaking gas (greater or smaller than the air), combined with the trend of air flow, integrated into a three-dimensional flow trend diagram of the leak, and an initial set point scheme is made at the downstream position of the flow.
(4) Study whether the leakage state of the leak point is a micro leak or a spray. If it is a micro leak, set the position of the point close to the leak point. If it is a jet leak, it should be slightly away from the leak. Based on these conditions, a final set-up plan is drawn up. In this way, the quantity and variety that need to be purchased can be estimated.
(5) For places where there is a large toxic gas leak, according to the relevant regulations, a detection point should be set for each distance of 10-20m. For small, non-continuously operating pump rooms that are unattended, attention should be paid to the possibility of toxic gas leakage. Generally, a detector should be installed at the downwind.
(6) For places with hydrogen leaks, the detector should be installed on the plane above the leak point.
(7) For media with a gas density greater than air, the detector should be mounted on a lower surface below the leak point, and pay attention to the surrounding environment. Special attention should be paid to the setting of safety monitoring points for places where toxic gases are easily accumulated.
(8) For open toxic gas diffusion and escape environment, if there is no good ventilation condition, it is easy to make the toxic gas content in a certain part of the air close to or reach the lower explosion limit concentration. These are safety monitoring points that cannot be ignored. . According to the analysis of on-site accidents, more than half of them were caused by incorrect installation and calibration. Therefore, it is necessary to introduce the correct precautions for installation and calibration to reduce malfunctions.
2. Gas alarm installation precautions
(1) The alarm probe is mainly a detecting element that contacts the combustion gas sensor. The platinum wire coil is coated with alumina and a binder to form a spherical shape, and the outer surface thereof is provided with a rare metal such as platinum or palladium. Therefore, be careful when installing to avoid breaking the probe.
(2) The installation height of the alarm should generally be 160-170cm, so that maintenance personnel can carry out routine maintenance.
(3) The alarm device is a safety instrument with sound and light display function. It should be installed in a place that is easy for the staff to see and hear, so as to eliminate hidden dangers in time. (4) There must be no strong electromagnetic fields (such as high-power motors and transformers) that affect the operation of the instrument.
(5) The density of the gas to be measured is different, and the installation position of the indoor probe should also be different. When the measured gas density is less than the air density, the probe should be installed 30cm away from the roof, and the direction is downward; otherwise, the probe should be installed 30cm away from the ground, and the direction is upward. The controller uses a three-core shielded wire to connect with the detector (Note: the single-core wire diameter is not less than 0.75mm national standard wire, depending on the actual distance), and the shielding layer is connected to the controller casing and reliably grounded. When using RVV cables, metal pipes should be worn and the metal pipes should be reliably grounded.
Construction wiring diagram of gas alarm
Refer to the controller and detector wiring diagram, connect the controller to the corresponding terminal of the detector. Connect the input controller terminal to the detector terminal. ◆ Connect the output terminal to the linkage device. ▲. When the inductive device such as the exhaust fan meets When the condition is less than or equal to 5A/220VAV, it can be directly connected to the output terminal, but the load device should be directly connected to the output terminal as much as possible. When the load device is larger than 5A/220VAV, the external transfer device must be connected; ▲. Controller, detector To ensure reliable grounding; ▲. When performing various installation operations, you need to power off first, otherwise the host may be burned out. The detectors used with the controller and the detectors used in conjunction with the controller are: point type gas detectors. Technical parameters: ◆ Detection principle: catalytic combustion, electrochemical ◆ Detection gas: combustible gas, toxic gas ◆ Sampling method: natural diffusion ◆ Indication error: ± 5% F · S / ± 10% / ± 5 × 10mol / mol ◆ Response time: ≤30s ◆ Working voltage: DC12V～30V ◆ Rated power: ≤3W ◆ Temperature: -40°C～60°C ◆ Humidity: ≤95%RH ◆ Connection cable: ≥RVV3×0.75mm (national standard line) ◆ Transmission Distance: ≤1200m ◆ Explosion-proof grade: ExdIICT6 ◆ Installation method: fixed bracket, tube installation, wall installation ◆ Installation screw: G1/2〃 Installation position: The detector should be installed in a gas leaking place, the specific position should be relative to the gas to be tested The proportion of air is determined. When the specific gravity of the detected gas is greater than the specific gravity of the air, the detector should be installed at a distance of 30 to 60 cm from the ground and the sensor portion is downward. When the specific gravity of the detected gas is less than the specific gravity of the air, the detector should be installed at a distance of 30 to 60 cm from the ceiling and the sensor portion is downward. In order to use the detector correctly and prevent the detector from malfunctioning, please do not install it in the following locations: ◆ Where it is directly affected by steam or oil smoke; ◆ Where the air flow, ventilation fan, door, etc. flow is large; ◆ Water vapor and water droplets Place (relative humidity: ≥90%RH); ◆ Temperature below -40 °C or above 55 °C; ◆ Where there is a strong electromagnetic field.
5 treatment methods
edit
1. Please open the door and window immediately, turn off the hazardous gas source, and do not turn on or off any electrical switch.
2. Report to the gas management department immediately and have it checked and handled by professionals.
3. After being handled by professionals, the alarm should be ventilated.
6 emergency treatment
When the detector leaks due to gas leakage and uses the automatic cut-off device, do not turn on the light or turn on any electrical switch; immediately open the window for ventilation, and wait for the red alarm indicator of the detector to go out, find the cause of the gas leak (cannot When confirming the cause, you should contact the relevant gas company for processing) and eliminate it. Confirm that the detector does not continue to alarm (the gas does not continue to leak), press the manual switch to turn on the automatic cut-off device to recover the gas. Do not touch the power of the household gas alarm at will to prevent the detector from working properly.
7 technical parameters
Voltage selection: AC 220V/AC110; DC9V-16V
Low power alarm static power consumption:
High power alarm static power consumption: <3.3W (calculated by 220VAC)
Alarm concentration: combustible gas: liquefied gas 0.1% to 0.5%; natural gas 0.1% to 1%; city gas (H2) 0.1% to 0.5%; carbon monoxide: 1‰ to 0.4‰
Adopting the US imported PIC 16F676 is one of the best ICs in the world.
Gas response, recovery time: ≤30S Carbon monoxide response, recovery time: ≤200S Alarm volume: ≥70dB
Working environment: Humidity ≤97%RH Temperature: -15°C-+50°C
8 unique features
The automatic shut-off manipulator automatically closes the main ball valve when the gas alarm occurs. This makes it possible to fully realize the 24-hour alarm alarm function.
(1) Added sensor drift automatic compensation function, which can prevent false alarms and false negatives according to the drift of the sensor. At present, this technology is the first in China.
(2) The alarm fault prompt function, the sensor damage is automatically prompted for the user to replace and repair, preventing the report from being reported.
(3) MCU full control, working temperature is -40 degrees to 80 degrees. The robot can be automatically reset, no need to manually reset, to ensure timely management in the first time
Combustible gas and carbon monoxide harm to human body
1. When the concentration of flammable gas exceeds the lower limit of explosion, explosion occurs in case of fire (lighter, electrical switch, static electricity, etc.), causing injury.
2, carbon monoxide is a colorless and odorless highly toxic gas, inhaled through the respiratory tract and human hemoglobin, causing the body to be hypoxic and poisoned.
3. The city gas itself contains a large amount of carbon monoxide. Therefore, when the gas leaks, there is a danger of explosion and a risk of carbon monoxide poisoning. In addition, incomplete combustion of gas, kerosene, wood, etc. also produces carbon monoxide.
Whether it is natural gas, liquefied gas, or coal-based gas, after leaking for various reasons, when the indoor gas concentration exceeds the lower explosion limit, the fire (lighter, electrical switch, static electricity, etc.) must explode. Why is gas poisoning? Although the composition of artificial coal gas in China's cities is different, they all contain more carbon monoxide. For example, Harbin gas contains carbon monoxide 13, Shanghai gas contains carbon monoxide 19, Qingdao gas contains carbon monoxide 21, and Qinhuangdao gas contains carbon monoxide up to 30. It is well known that carbon monoxide is a highly toxic gas. In a person with carbon monoxide 1 in the air, it produces sputum in 10 minutes and will die in half an hour. Therefore, when coal gas leaks, there is a danger of explosion and there is a danger of carbon monoxide poisoning (direct poisoning). In addition, carbon monoxide poisoning (exhaust poisoning) may occur when a gas water heater or a coal stove is used and ventilation is poor. What is the lower explosion limit? That is, the lowest concentration of the explosion in the air, the alarm concentration is set below 1/4 of the lower explosion limit. For example: methane (main component of natural gas) explosion lower limit of 5.0 (50000ppm) propane (liquefied gas main component) explosion lower limit of 2.0 (20000ppm) hydrogen (coal gas main component) explosion lower limit of 4.0 (40000ppm) gas leakage reasons ? Any family, no matter how you pay attention, may have a case. Among them, the ignition failure, the pot or the wind blows out, the flame is extinguished in the middle, and the total valve is not strict, which accounts for more than 70% of the leakage. Why does the alarm know the gas leak? At the heart of the gas alarm is a gas sensor, commonly known as the "electronic nose." This is a unique resistor. When “smell†to gas, the sensor resistance changes with the gas concentration. When the gas reaches a certain concentration, the sensor can sound and light alarm when the resistance reaches a certain level. What is the sound and light alarm? After the gas leak causes the indoor concentration to reach the alarm concentration, the red indicator of the alarm light is on, and the buzzer emits an alarm sound of “open-up-â€, so it is called sound and light alarm. Why is the gas alarm valid? Sensors that are not of good quality generally lose their performance in 1-2 years, thus losing the safety of the alarm. Alarms in other electronic components (such as transformers, capacitors, transistors, etc.) have a limited life span, so even advanced countries have a valid period of up to five years. To ensure safety, a new alarm must be replaced after five years of expiration.
9 little knowledge
Gas leak alarm principle
Very important gas safety equipment, it is the last protection for safe use of city gas. The gas leak alarm detects the low concentration combustible gas in the surrounding environment through the gas sensor, and transmits the detection signal to the controller or the control circuit through the sampling circuit through the sampling circuit, when the concentration of the combustible gas exceeds the controller or the control circuit. At a fixed value, the controller issues an alarm signal through an actuator or an execution circuit or performs an action such as closing the gas valve. The sensors for detecting combustible gases of combustible gas alarms mainly include oxide semiconductor type, catalytic combustion type, hot line type gas sensor, and a small number of other types, such as chemical battery type sensors. These sensors generate chemical or electrochemical reactions on the sensor surface by adsorption of flammable gases in the surrounding environment, resulting in changes in the electrical and physical properties of the sensor.
Gas leak alarm function
The function can be divided into a leak alarm with only leakage alarm function and a detection alarm that can indicate the detected gas concentration and has an alarm function; it can be divided into a civil gas leak alarm and a commercial alarm from the use place. Civil alarms are usually independent gas alarms used in residential buildings. They are simpler to use; commercial alarms mainly use gas transportation, storage, gas, and factories and public places where gas leaks may occur. The gas code for the basement, semi-basement, closed space on the ground, the pipe well of the building, and the closed meter room shall be installed in the city gas code. Civil gas leak alarms are also recommended for building and gas related codes and regulations.
10 installation steps
installation method
In the selected wall position, corresponding to the two mounting holes on the random mounting plate, the punching mark is made (the hook on the board should be horizontally upward);
Lay the mounting holes, put in the random installation rubber plug, and then fix the mounting plate to the wall with random self-tapping screws;
Align the three holes on the back of the body with the fixing hooks on the mounting plate to hang the body;
After connecting the relevant output signal line, turn on the power.
State test
Normal monitoring status: After the power is warmed up for 3 minutes, the green light is steadyly illuminated, indicating that the alarm is working normally in the monitoring state; during the warm-up process, the alarm may sound “beep...beep†and the red light flashes, and the green light disappears before the light is off. normal.
On-site alarm status: When the gas content in the air around the alarm exceeds the alarm point, the alarm will emit a “beep...beep...†intermittent squeaking of the ear, while the red indicator light flashes to remind the user to do the on-site processing as soon as possible; alarm output status: live sound and light After the alarm lasts for 10 seconds, different types of alarms will output different types of alarm signals, notify the alarm system or activate the corresponding linkage.
11 features
(1) Vent: Gas (natural gas, liquefied petroleum gas, city gas) enters the sensing chamber through the gap between the alarm shell and the bottom casing. To allow the air to circulate properly, do not install the alarm in a dirty, dusty or greasy area.
(2) Sensor: The sensor uses semiconductor technology, which has high sensitivity to flammable gas and avoids false alarms.
(3) Buzzer: The volume is up to 85 decibels, which reminds you of the potential danger. The alarm form is: continuous sound.
(4) Preheating: When the alarm is energized, it needs to be preheated for 2-3 minutes, and no alarm will be given within 2-3 minutes after power on.
Dongguan Hengda Gas Equipment Co., Ltd. is located in Shahukou Village, Changping Town, Dongguan City. It mainly produces: gasifiers, gasifiers, gas fittings, combustible gas alarms, valves, instrumentation, and gas pipeline design and installation. . Companies adhering to the "customer first, forge ahead" business philosophy, adhere to the "customer first" principle to provide our clients with quality services. Welcome patrons! Source of information: http://
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
Digital Electronic Precision Scale
Shanghai Liuyuan Trading Co. , Ltd. , https://www.ly-weighing.com