Gas leak detection sensor for home. Gas leak sensor with alarm for home: household gas alarm. Consumer Feedback on Useful Features
Heating with fuel-burning units is convenient, economical and efficient. Leakage of combustible gas or combustion products is undesirable during the use of the boiler.
A household gas detector (or sensor) is a device that monitors the quality of the ambient air in the boiler room. When a dangerous concentration of harmful substances in the air accumulates, the signaling device is triggered: it turns on sound and light alarms, turns off the gas supply and stops the combustion of fuel in the boiler.
Installing such a sensor will protect the owners from the accumulation of gas in the room and help to eliminate the leak in time.
The signaling device can send a signal to mobile phone(if there is a GSM module and connected to the subscriber's number).
Gas detectors are installed in rooms where accumulation of harmful substances is possible. Conventional gas analyzers are able to detect accumulation carbon monoxide, propane and natural gas(methane).
Carbon monoxide (CO) is a substance released during the combustion of fuel, and its leakage into indoors can be deadly.
Methane (CH4) is the main element of natural gas, which is supplied through the central gas pipeline. When it accumulates, an explosion and fire can occur (even from the smallest spark).
Propane (C3H8) is the main element of a liquefied propane-butane mixture, which is heavier than air, so even with an open window, gas may accumulate in the lower part of the room.
Design and principle of operation of gas detectors
The operation of gas detectors is based on various sensors: thermomechanical, optical or electromechanical. All gas analyzers consist of certain elements:
- The sensor is a sensitive element that senses and calculates the gas concentration in the ambient air.
- The measuring and indicating module is a system that perceives the signal of the primary converter and compares it with the set value.
- The power supply is a system for providing electrical power to the device.
- Instrument case.
Functionality of gas detectors:
- Light and sound alarm.
- Shut off the gas supply with a solenoid valve.
- Turn on the exhaust device.
- Signaling to a fire or control panel.
If you are planning to build a bath, do not forget about.
Another way to heat a bath is a warm floor, more about it in.
Types of gas detectors
The main difference between gas analyzers is the type of gas captured. The most common household signaling devices are gas analyzers for:
- carbon monoxide;
- methane;
- propane.
Combined gas analyzers capable of capturing several types of gas at once.
Household signaling fans
One of the types of localization of the accumulation of harmful substances in the boiler room is the installation exhaust fan, which turns on at the signal of the gas analyzer and performs forced ventilation.
Shut-off valves
The electromagnetic shut-off valve is used to instantly stop the flow of gas at the signal of the gas analyzer. There are various valves:
- By pipeline diameter.
- Electrical.
- with acceptable pressure.
- Differing in design.
There are 2 types of construction: normally open and normally closed.
They have the following differences:
- The normally open valve is cocked manually, and during operation it is not energized. In the event of a gas analyzer triggering, an electrical impulse is applied to close the valve. The valve is marked - "NA";
- The normally-closed solenoid valve is also manually reset, but for this it is necessary to ensure the supply of electricity. During operation, it is constantly energized, and at the signal of the gas analyzer, the voltage disappears and the valve closes.
Cost of solenoid shut-off valve: type N.A., 220 V, Pmax: 500 mbar:
| Nominal diameter | Cost, rub. |
| Madas Day 15 | 1490 |
| Madas Day 20 | 1515 |
| Gross Dn 20 | 1360 |
| Madas Day 25 | 1950 |
| Gross Dn 25 | 1470 |
Operation of gas detectors
It is better to mount gas analyzers to a vertical plane where gas leakage can occur (near a boiler, furnace, gas meter, gas column).
Do not place the gas analyzer in the following places:
When installing the sensor, consider physical properties gas and its density:
- Methane - not lower than 0.5 m from the floor.
- Carbon monoxide - at a height of 1.8 m from the floor, but not higher than 0.3 m to the ceiling.
- Propane not higher than 0.5 m from the floor.
- Combined sensor for methane and carbon monoxide - in the range of 0.5-0.3 m to the ceiling.
To ensure smooth operation solenoid valves you need to install rechargeable batteries with an automatic switchover system.
The passport of the gas analyzer describes all the functions and requirements for operation, and their observance will allow to achieve reliable operation of the equipment.
Gas analyzer installation
Installation of the device does not require much effort, it can be mounted on dowels or screws. The passport of the device contains a diagram for connecting the electrical power to the device and connecting it to the rest of the equipment.
Installation of solenoid valves on the gas pipeline must be carried out only by a qualified specialist.Periodic examination
At least once a year, it is necessary to conduct a survey of the gas analyzer performance.
Dozens of explosions occur every year in Russia due to domestic gas leaks. In particular, a sad record was noted in 2008, when only in January there were 7 powerful explosions in which people were injured and killed. I'm not even talking about destruction and losses. And these are just the cases that made it to the federal news feed. In fact, there are much more gas leaks. Deterioration of equipment, inaccuracy and irresponsibility are the main reasons for such tragedies. There may be fewer of them if more active implementation of gas leak monitoring systems based on inexpensive electrochemical sensors is carried out. One of these devices fell into my hands. The article is devoted to the analysis of the device and possible unsportsmanlike ways of using it. However, the device performs the main function entirely, therefore, after technical bullying, it will be additionally tested in a biogas laboratory, which you can read about, and then donated to Mother, who has gas in her kitchen all her life).
Attention! Age limit of article 18+
And we have gas in the apartment! And you?
In fact, gas is one of the most convenient things to use. Professional chefs prefer to cook on gas stoves. It is fast, convenient, economical, and meat and good steaks, perhaps, can only be cooked on fire. Gas heats millions of people, and modern gas equipment is reliable and safe, provided that you carefully monitor and operate it correctly. Even I, with my not bad level of understanding of technology, studied the device with interest gas boiler from a security point of view. Yes, indeed, such devices are reliable.
This simple drawing shows general principle the operation of the device, the design is actually quite simple. What is mandatory in each such device is the control of gas flow and flame burning. To control it, infrared sensors are used, and at the slightest interruption in the gas supply, the automation reliably turns off the device. Gas equipment must only be installed by a gas service specialist and must be checked regularly.
Despite the reliability of the equipment, the possibility of gas leaks cannot be ruled out. To control such leaks, special odorants are added to the gas - odorants. Their task is to create odor, which is necessary to detect gas leaks, mainly in domestic consumption. To give the gas the required level of odor, the norms for introducing odorants for ethyl mercaptan are set at least 16 g/100 m3 of gas. These are extremely toxic and volatile substances with a disgusting smell. It is this smell that a person regards as a gas leak, while natural gas itself has no color and no smell.
We control leaks
Gas leakage may occur different reasons, but in most cases this is due to human negligence. Milk ran out, the gas was turned off on the stove and it went out, often small children play with gas. There may be main pressure surges in the gas pipe due to freezing gas pipes in severe frosts, as condensation can accumulate in them. Therefore, it is useful to have a gas leak detector that can alert people to a leak, for example, with an additional sound signal. One of these devices I came across to study.
The device is externally made of good plastic, silk-screen printed, however, all inscriptions on English language. Made, of course, in our beloved China. The device plugs directly into a power outlet and does not require batteries. The consumption is scanty (I think a few watts), so it is not able to wind up a lot of electricity. Cleverly thought out design from the point of view of the gas cell. The device has special cutouts so that air can penetrate more freely. However, to install the device, it is better to use a short extension cable and position it as stated in the instructions - for natural main gas closer to the ceiling (methane is lighter than air), and if you use liquefied gas or propane tanks - to the floor, since this gas is heavier than air and spreads down. When turned on, the device emits a short beep and begins to calibrate. This process takes several minutes. At this time, nothing happens and only a dash on the digital indicator flashes. When the device is calibrated, zero appears on the screen. Calibration important point and what she eats is very good. Since an integral sensor is used, the device takes the level of the gas state at the time of calibration as zero, which reduces the likelihood of false positives. This is convenient, for example, in the kitchen, when, in any case, when the gas is ignited, there is a short-term leak and it is better to calibrate the device with all burners and the oven turned on, and after a few minutes turn on the gas leak sensor for calibration so that the device understands the “working” level of air composition and did not beep when not needed. The device was tested in combat conditions in my biogas laboratory, which I talked about in my post, and at the home of Matushka, who has had gas all her life. By the way, such sensors are very useful in old houses where prehistoric gas equipment is installed. Of course, I have repeatedly tried to replace the stove, but it is not so simple. Mom, old school, small kitchen. Therefore, in most old apartments there are such small stoves, although they are made very soundly. Still under Stalin)
Video testing the device in the kitchen with a gas stove
The device is located closer to the floor, since in this case propane is supplied to the apartment, which, if leaked, spreads downward.
Gas is not a toy. Do not repeat such experiments yourself! And if you couldn’t resist, then don’t forget to ventilate the room and turn off the gas!
Opening the device
Of course, I opened the device to study it in detail. It was not a lot of work, since there are no latches in it, everything is on self-tapping screws.
The device was made by hardworking Chinese girls (boys), soldered by hand and not even washed from rosin. However, everything is done soundly and even checked by the Chinese Quality Control Department). Of course, it was interesting for me on which sensor the device was made and how it was washed down according to the scheme. A priori, I believed that the device uses an MQ series sensor and was not mistaken. I did not find any details more familiar to me (I'm talking about controllers, of course). The device is supplied with mysterious Chinese microcircuits, and the device itself is designed with obvious redundancy. After all, the MQ series sensor can be launched on a penny Attiny or ATmega in a few microseconds. And if the arduinka is lying around, then even faster. We connect the signal output of the sensor to any analog port, for example, A0, apply power and receive data in a minute):
int sensorValue; void setup() ( Serial.begin(9600); // then open the port ) void loop() ( sensorValue = analogRead(0); // what is it measuring for us there? Serial.println(sensorValue, DEC); // let's get the numbers on the screen, don't be shy! delay(1000); // smoke for 1 sec to wake up the sensor)
It's not even a code. By the way, well done arduinists, they collected everything about these sensors very conscientiously on the site. Link .
But back to our device under study. Most likely, the circuit is designed so that it can be used in various sensors and devices, by replacing the sensor and flashing it. Fine! Everything else is standard. Of course, I would put an additional fuse in the power supply circuit, but this is more for cowards than for bold Chinese engineers. Even in the device, I was surprised by the 85 dB signaling device. Gently poured liquid nails at the gas sensor.
Maybe 85 dB is not there, but it squeaks loudly and rather disgustingly. Thus, the notification in the device is implemented soundly. By the way, the loud siren does not turn on immediately. The device first starts beeping when the reading on the screen becomes more than three units, and if more than 9, a loud siren turns on. By car type. Maybe even the neighbors can hear it.
A little about the gas sensor. I have the same one in my collection. This is Henan Hanwei Electronics MQ series sensor. A popular sensor from a series of electrochemical sensors, the manufacturing technology of which is well developed. The principle of operation of the gas detection sensor is based on the property of changing the conductivity of a thin-film layer of tin dioxide SnO2 when it comes into contact with the gas to be determined. Sensitivity to different kind gases is achieved by doping various impurities into the sensitive layer of the sensor. The sensitive element of the sensor itself consists of a ceramic microtube coated with Al2O3 and a sensitive layer of tin dioxide deposited on it. A heating element passes inside the tube, which heats the sensitive layer to a temperature at which it begins to react to the gas to be determined. When gas enters the sensor, gas absorption occurs and, as a result, the resistance of the sensor drops. For a couple of hundred rubles, you can purchase the desired one from the sensors of the MQ series.
The sensor needs heat to operate. However, this is all miniature, so you will not feel any noticeable heating of the sensor. The signal is, of course, analog. The sensors are reliable and quite durable when not used in harsh environments. Good performance, short recovery time. However, such sensors do not have very good selectivity, and they also require calibration. But this makes it possible to have fun with it is not standard!
Not sport use. 18+
This use happened thanks to the birthday of one of the employees, which we decided to slightly celebrate in a narrow circle. We gathered in a small meeting room at the end of the working day. A company of four people drank cognac. Approximately an hour later, in the room where alcohol had already been decently drunk at that moment, the signals of the device that was plugged into the outlet began to be heard. This cheered up those present. However, any approach of a drunk person with a desire to blow on the device instantly caused a siren and roaring laughter. Thus, a breathalyzer can also be made from the device. This is not surprising. MQ series sensors are more or less sensitive to different gases. This is well illustrated by a graph of the sensitivity of sensors for various gases.For the timely detection of leaks in domestic, liquid and natural gas. The device is easy to use and easy to install. It is a reliable and economical solution for modern home. The detector detects the leakage of dangerous combustible gases, such as natural, household and liquefied gases. In the event of a leak, the device gives light and sound signals. The device can be used as self equipment as well as in the security system.
The sensors of the device react to the spread of gas in the air and cause a signal. When the gas content in the air reaches the set value, the device emits a loud alarm, which indicates the need to take measures to eliminate the gas leak.
Gas Leak Detector Installation Instructions
The gas leak detector is mounted on a wall or cabinet within a radius of 1.5 meters from the gas source. For liquefied gas sources, the distance from the floor should be about 30 cm. For natural gas sources, the sensor is installed at a distance of 30 cm below the ceiling.
Please note that the detector is for indoor use only. The detector should not be installed outdoors or in damp rooms as well as in ventilation systems.
Features of gas leak detector
- Easy to install and use;
- Automatic fault detection;
- Identifies natural and liquefied gas;
- Microprocessor control;
- Sound and light alarm.
Characteristics
- Rated power: ≤3W;
- Working temperature: -10 degrees + 50 degrees;
- Power supply: 110V-220V;
- Working voltage: 100mA;
- Permissible humidity: 95% RH;
