Household sensors and gas leak alarms for home and garden. Household gas detectors (sensors) - a way to protect yourself from gas leaks Gas leak detector

Modern apartments, private houses overwhelmingly use this type of fuel as gas for cooking, space heating and providing hot water. In the event of an emergency situation, when any element of the equipment leaks, there is a high probability of an emergency.

To prevent the occurrence of fire, explosion or suffocation of people in the room, a device such as a gas leak detector is used. This device is able to protect property, health and life of people from accidents.

Purpose of the signaling device

The gas leak sensor can be produced in different variations. However, the purpose of such devices is always identical. Similar devices every year they are gaining popularity among owners of private houses and apartments.

The cost of modern signaling devices is relatively low. All devices presented in the open trade must have quality certificates. This device provides round-the-clock monitoring of the content of toxic gases and hazardous components in the air masses inside the premises.

The scope of the presented devices includes methane, propane and carbon monoxide. Installing a signaling device will help to avoid the explosion of combustible gases that have accumulated in the room due to a violation of the integrity of pipelines and equipment systems. Also presented devices can prevent suffocation of people in the house in case of accumulation carbon monoxide when the burner goes out or back draft is formed.

The gas detector can also be used as an additional warning device for the occurrence of a fire of gas origin in the early stages of their formation.

Principle of operation

The gas leak detector (household) has a certain principle of operation. It is based on the movement of air masses through convection. The flows pass through sensitive components that are built into the instrument.

If the concentration threshold of toxic, hazardous substances in the air has exceeded the limit set for the device, an audible signal is triggered. The equipment is disconnected from the supply gas communications. The alarm also includes forced ventilation. The alarm signal is transmitted over the network or via GSM communication channels.

After the cause of the emergency has been eliminated, the gas equipment can be restarted and operated again.

Types of indicators

There are several types of gas leak sensor. First of all, it is necessary to distinguish between household and industrial indicators. For a house, the second option is not suitable for certain reasons.

There are many models of the presented equipment. They can be conditionally divided into 3 main groups. Semiconductor devices absorb gas by the surface of a sensing element made of a special material. It is coated with metal oxide. The equipment compares the readings of the semiconductor with the limit values ​​set in the settings.

The second group includes electrochemical devices. They use an analyzer to take measurements. The third category of signaling devices is based on the principle of air research in the infrared range. Whatever principle of measuring indicators the device uses, it compares the results obtained with the set threshold.

User and expert reviews

Modern gas leakage sensors for the home must have a number of characteristics, regardless of the design of the system. Feedback from users and experts highlights several basic functions and features that the device should have.

First of all, according to consumers and employees of gas services, gas alarms should respond to changes in the level of both carbon monoxide and methane, propane. In this case, a special shut-off valve should operate. A shut-off valve should be responsible for this function. It responds to an electromagnetic pulse sent by the device. If necessary, the gas supply is stopped.

Consumer Feedback on Useful Features

Also, according to user reviews, good model of the presented device, if necessary, includes a ventilation system. Also, advanced equipment can transmit an alarm signal to the owner even at a distance.

User reviews note such a useful feature as autonomous power supply. It is also important that the device performs self-diagnostics. If the device fails, the system will notify the owner. This will allow you to replace faulty equipment in a timely manner.

Shutoff valve

The gas leak sensor, the reviews of which were discussed above, will not be functional without a shutoff system. After all, if a leak occurs, action must be taken as soon as possible. Otherwise, savings when buying a signaling device will turn into serious problems in the future.

Shut-off devices come in different diameters, types and principles of organization of work.

The first group includes normally open (impulse) cutoffs. Enters the coil electricity, this causes the mechanism to move. Such cut-offs are installed more often at enterprises. However, in private homes, their use is also possible. Especially if there are power outages in the house.

The normally closed type of cutter responds to voltage drops. At this moment, the gas consumer is cut off from communications.

Ventilation

Installing gas leakage sensors involves connecting the system to ventilation. In the event of an emergency, the hood will quickly eliminate the accumulated gases from the room. The connection diagram of the signaling device in this case will not require much cost. After all, the hoods connected to common system ventilation, is in almost every home.

It is necessary to solder the wire from the relay contacts to the switch button in parallel. Also in this case, you can use the cap clamps. They are fixed on the wire, creating a good contact.

But in such a situation, if there is not enough experience, it is better to contact a professional electrician. He will do such a good job. In the arrangement gas alarm independent connection could be very costly in the future.

Installing the signaling device

Modern gas leakage sensors (household) may have a simple or complex structure. Whatever type of device would not be chosen by the consumer, the installation cannot be done independently. It is also not worth resorting to the help of inexperienced craftsmen. After all, the safety of people living in an apartment or house depends on the correct connection of such devices.

The installation of the presented equipment can only be carried out by professional master who has a license for the right to perform such work. This is the only way to be sure of the well-functioning operation of the unit in accordance with the characteristics of the gas equipment installed in the room.

An ordinary user will not be able to take into account all the nuances of the heating or household appliances. Even the average user will not be able to choose the right place for installing the signaling device without knowledge of the relevant SNiP. Therefore, such work is entrusted exclusively to a specialist.

A few installation rules

To understand the seriousness of the presented installation, it is necessary to general development read a few rules from official documents. They state that a gas leak detector with an alarm for the house must be located in close proximity to heating or household equipment. At the same time, the list of equipment that is included in this list includes, in addition to the boiler, a column, a stove and a counter. From all these devices, the signaling device should be located no further than 4 m.

The device must be at least 1 m away from sources of open fire. It is strictly forbidden to mount the detector above the stove. Also, the presented equipment cannot be installed in places where fat, ash and dirt accumulate. In such conditions, the device will quickly become unusable.

The signaling device should not be located close to windows, ventilation systems. Otherwise, if a leak occurs, it will not be able to catch the increased concentration of gas in the room.

These are the basic rules. There are many more nuances in choosing a location for the sensor. Therefore, it is almost impossible to determine it on your own.

Rules for determining the position of the sensor

In addition to the features that a gas leak sensor with an alarm has, it is necessary to take into account the properties of those flammable substances that it detects.

The detector should not be placed higher than 1.8 m from the floor in the room. But even lower than 0.3 m, it also cannot be installed. This is due to the lighter weight of the carbon monoxide mixture compared to air.

Heavy gas (methane) settles in the floor area. To determine the high concentration of methane, the detector must be located no more than 0.5 m from the ceiling.

If the detector's sensor is designed as a combination sensor, it detects the presence of methane and carbon monoxide in the room. It must be installed at a level of 0.3-0.5 m from the ceiling.

The natural gas leak sensor is very easy to attach to the wall. There are corresponding holes in the case. However, before the master installs the device, the owners must move the detector to a warm room. If the device long time stored in a cold room, his testimony will be untrue. Before installation, the device must be warmed up at room temperature.

After installation, the owners can clean the device from dust and dirt with a dry cloth. It is forbidden to perform other actions with the signaling device. It is strongly not recommended to independently check the health of the system. It is impossible to bring burning matches, lighters, paper to the signaling device. Otherwise, the sensitive elements of the equipment fail. This could turn into a tragedy in the future.

Before using the gas detector, carefully read the manufacturer's instructions. Compliance with all its rules is mandatory.

Using a device such as a gas leak sensor, you can protect yourself and your home from accidents associated with fuel leakage from the system.

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 feed. federal news. 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, main function the device performs completely, therefore, after technical bullying, it will be additionally tested in a biogas laboratory, which you can read about, and then donated to Matushka, 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 for 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 with my not bad level of understanding of technology, I studied with interest the device of a gas boiler from the point of view of safety. 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 he himself natural gas has no color and 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 very coldy as condensation may accumulate. Therefore, it is useful to have a gas leak sensor that can alert people about a leak, for example, by 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 cord 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 as zero gas state at the time of calibration, 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); // let's 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. Passes inside the tube a heating element, which heats the sensitive layer to a temperature at which it begins to react to the gas being detected. 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, a short time recovery. 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. No wonder. 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.

Special flavors are mixed with household gases, which allow you to detect a leak by smell. However, if there is tight closed doors or a room far from the living rooms with gas boiler the situation can become critical very quickly.

If a gas leak alarm is installed, then the probability of a timely response of people to the danger increases many times over. Loud - about 85 dB - the alarm signal of the gas leak alarm system will attract everyone's attention, wake up the sleepers and be heard even on the street.

In some cases, for example, during the initial installation of gas equipment (columns), the presence of a gas leak sensor with an alarm for the house is mandatory.

How does a gas leak detector work?

The gas leak alarm operates from a 220 V network and is a domestic gas analyzer, a sound speaker and a system of light and digital indicators that display the gas level in the room.

The reliability and accuracy of the household gas leak detector is determined by the design of the main element - the analyzer sensor. It is a silicon wafer coated with a metal oxide film with a certain level of resistance, which in this case is designed for exposure to household gas. When the gas concentration rises, the film absorbs the gas from the air and changes resistance. The magnitude of the change in resistance directly depends on the concentration.

Since the metal oxide film is an active element, a gas leak sensor with this type of alarm has a regulated service life of 3 years. When the resource is exhausted, the household signaling device must be disconnected from the network and replaced with a new one.

How to use the gas leak detector?

1. After being connected to the network, the household signaling device analyzes the gas level (the sensor is configured specifically for household gas) and displays the value on the digital display in the range of 0-2 when the green indicator is on. This means that there is no gas leakage.
2. In case of a slight leak, the value on the display of the household signaling device goes into the range from 3 to 6, the light indication changes to yellow, and the sound speaker begins to emit a constant signal of medium volume. It is necessary to shut off the gas supply and check the serviceability of the equipment.
3. At a high and explosive concentration of gas, the value on the display of the household alarm is in the range of 7–9, the emergency red light indication turns on, and the audible speaker of the gas leak alarm starts emitting a sharp intermittent signal at a maximum volume of 85 dB. It is necessary to shut off the gas supply, leave the premises and contact specialized services.

Almost every day there are explosions and various degrees of fires that occur when gas enters the room. To avoid such situations, it is necessary to use a gas leak sensor. It serves to establish its content in the air. At critical indicators, the device notifies the surrounding personnel of a serious leak. gas can have in its configuration various shut-off valves that serve to shut off the flow of fuel. Most simple models determine the concentration of a particular gas. And if the allowable limit exceeds the norm, it signals this. Externally, this is a compact mobile equipment that can be installed anywhere. Typically used for security living conditions. But other models used in industrial premises are also widespread on the market.

What are leak sensors?

They are of two kinds. Wired and wireless. Looking at their name, we can say that they differ from each other in the source of power. The first type is connected to a household power supply, with a voltage of 200 V.

The second type works with the help of special batteries. The latter are located in the sensor itself.

Also, the gas leak sensor is classified according to the method for determining the concentration of fuel entering the environment. So there are the following types. Semiconductor, infrared and catalytic.

The first type functions with the help of semiconductors, the principle of which is to absorb gas oxide heated to a certain temperature. Devices of the following type resemble explosive lamps in their design.

Its work is carried out on the basis of gas combustion, while decomposing it into two components: water and devices of the latter type determine the concentration of fuel, due to the absorption of a medium that is within the infrared spectrum.

Features of leakage sensors

As mentioned earlier, all sensors are divided into two types - wired and wireless. Now let's take a closer look at their features. The wired gas leak detector functions from a conventional consumer electrical network, with a voltage of 220 V.

Most people believe that this species is unsafe. With a high gas content in environment any short circuit will lead to an explosion. But this idea is considered wrong. The device is assembled using special technologies. Therefore, the occurrence of an explosion due to a short circuit does not threaten. Gas leakage sensors for a wired type house have low cost and also quite easy to handle. Them negative side is a large consumption of electricity, which is required for the functioning of various sensors.

The wireless gas leak detector works with a battery built directly into the housing. Thanks to him, you can install devices anywhere. They also consume a fair amount of electricity. Therefore, they are not used in industrial areas. In addition, the cost of devices is quite high.

gas with valve

Currently, devices with a valve or other shutoff valves. Their design includes a sensitive element. With a high gas content in the room, it transmits a signal to the electrical circuit, and it closes. Then the valve closes, and the flow of fuel into the room stops. As a rule, the device is installed in front of any gas equipment, for example, a filter, a burner, a column, etc. The installation of such elements must be carried out by a special master. He installs valves in the pipe and checks its performance. The valve has long term operation and does not require an electrical connection. To return the valve to its original position, you must turn it manually. Thanks to automatism, the household gas leak detector with a valve has become the most popular.

Characteristics of the device with alarm

Wireless communication elements are installed in current devices, thanks to which signaling parts can be used. If the amount of gas has passed normal performance, then the sensitive element is triggered. Then the signal goes to the owner on a regular phone.

Therefore, the owner can independently decide to eliminate this problem. The gas leak sensor with alarm has a special device. It can be used for the security system of other elements. For example, they are important element cozy home.

How Sensors Work

They are divided into three types: semiconductor, catalytic and infrared. Elements work differently, so you need to understand each type.

1. catalytic. The principle of operation of this type is the splitting of gas into elements such as water and carbon dioxide during the combustion process. A small amount of air great content fuel flows through the sensor. There is a combustion process. In this case, the resistance in the coil changes. Also in the device there is another coil, which serves to determine the rise in temperature. The greater the gas content in the room, the higher the resistance will be. To ensure that the coil is not subjected to any influences, thermal balls are placed at its ends. The latter are covered with a layer of glass. Such a device serves as a compensator. Information about the content of gas particles in the air comes in a matter of milliseconds.
2. semiconductor sensors. Their principle of operation is similar to that used in a catalytic device. A silicon wafer serves as a sensitive element. Metal oxide is applied to its surface. This method is also applied to the production of computer parts. In the case of contact with such a surface of gas particles, a change in resistance occurs, which corresponds to the concentration harmful substances in the surrounding air. Such devices are widely used in everyday life. They cannot be used for industrial purposes, since the concentration of some fuels is quite difficult to determine. One of negative qualities is a slow response, and long time recovery requiring personnel supervision.
3. infrared. They are used for industrial purposes to determine the gas content in the room. When compared with the catalytic type, significant advantages stand out. These include fast turn-on times and low power consumption. The principle of operation is to analyze gas particles using light. The light waves are located in the infrared range. So, in the analysis, two waves are used: the reference and the studied. Two media pass through a certain light source and return back. Further, the device analyzes the corresponding signals and shows the amount of fuel in the room.

Installation of gas leakage sensors

Their location depends on the type of gas produced. For example, if its mass is greater than air, then the devices are installed in the lower parts of the wall. If used, the location is reversed, i.e. the element is mounted under the ceiling.

When installing equipment, you must adhere to some rules:

• do not install sensors near various gas appliances;
• it is impossible to install them on gas appliances;
• installation takes place in a room where air does not penetrate;
• can not be installed near windows and doors;
• do not install devices in rooms with a high content of ammonia.

Service

When buying a household gas leak sensor, it is already configured. Therefore, during installation, it is not necessary to make any preparatory work. After installing it, you should watch it for a while.

In addition, it is necessary to clean the surrounding areas of the device from dust and other contaminants. In this case, you should not overdo it so as not to disable the sensitive element.

Another important point is the performance check. To do this, apply gas to the sensor. You can do this with a regular lighter. After the sensor has been triggered, you need to pay attention to It must be loud enough to be heard by the whole service staff. After the weathering of the gas, the device recovers itself. If the devices are equipped with shut-off valves, then the performance is checked manually.

Price

The price of the sensor depends on the concentration of which type of gas you need to determine.

The type of equipment also affects this indicator. Wireless devices cost much more than wired devices. The price for them is in the range from eight hundred rubles to four thousand.