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In order to pay only for the water you use, you need to install a water meter or, as they say, water meters in your apartment. What are the water meters and which of them are suitable for household use and we will understand.

Types and types of water meters

There are several types of water meters, but all of them can be divided into two main groups: energy-independent (using mechanical processes) and energy-dependent (need the presence of electricity).

In general, there are four types of meters:

• 

  Tachometric (turbine or impeller). They are mechanical devices (non-volatile). The main working part is a small turbine or impeller, which is in the water. The amount of water is counted by the number of revolutions that the impeller makes. The revolutions of the impeller axis make the mechanical meter move. Works with any water (hard, with high iron content, etc.), but the accuracy of the readings is not very high, there is a chance that after a few years the impeller will become overgrown and will rotate slower. But it may happen that it will rotate faster than it should. In general, the option is inexpensive and this type of meters are mostly put in apartments.

• Induction or electromagnetic. Electricity is required for the operation of this device. The action of the device is based on the ability of water to conduct electricity. The device is expensive, the service life is long – more than 10 years, in the absence of foreign inclusions in the water and rust / scale in the pipes gives accurate data. Since clear water and perfect condition of the pipeline – this is not about our networks, it is not often put.

  

• Ultrasonic. Also require the presence of power supply. The principle of operation – comparing the speed of ultrasound propagation “on” and “against” the flow. Accuracy is high, but also only on clean pipes. The price is even higher, although the service life is in the neighborhood of 15 years.
• Vortex. They analyze the rate of vortex track formation behind a specially shaped obstacle. The behavior of the water vortex is analyzed by an electronic device (also requires power supply). They work normally only with clean water without impurities, service life – about 8 years.

From all of the above it turns out that in our real conditions – old pipes and not the cleanest water – only tachometric meters are suitable. They are mostly installed.

How to choose pipes from polypropylene read here.

Types of tachometric meters

Mechanical meters are good in that they do not require any additional conditions for their work. There is a flow of water – they work, there is no it – they stand. But only long downtime they are not very fond of – due to the presence of salts in the water, the impeller or turbine can stop rotating. This means that you will need to change the metering device.

Classification by water temperature

Metering devices for water consumption (this is the official name) are for cold and hot water. They differ in the range of operating temperatures:

• for cold maximum is +30°C;
• for hot water +130°C;
• universal – the working temperature range is up to +90°C.

Even if the water meters are of the same type and the manufacturer is the same, the difference in price is noticeable. But it is justified – for DHW, heat-resistant materials are used, and they cost much more. To make them easy to distinguish, the cases are painted in different colors – meters for cold water are usually blue, for hot water – red, universal have orange coloring.

According to the principle of operation

With the general principle of operation, this type of water meter has several varieties. First, there are two principles of action:

But not everything is so simple: multi-jet tachometric water meters are only for large pipe diameters (more than 40 mm in diameter). For apartments, they are not suitable.

According to the method of installation of the counting and rotating mechanism

More relevant for us is the division by the method of installation of the counting mechanism. According to this feature, water meters are divided into dry and wet. In wet meters, the counting mechanism stands in water, so it quickly fails. In devices of dry type the counting mechanism is separated from water by a plate and they work longer.

There is another type of tachometer meters – valve. In such a water meter, a shut-off valve is additionally installed, which allows you to shut off the water. For what it may be necessary, it is difficult to say, because when installing in front of the water meter necessarily put a shut-off valve. It is needed in case it is necessary to change or verify the meter, this is the tap, if necessary, and shut off the water.

Inside the tachometer meters is a turbine or impeller, respectively, they are divided into turbine and impeller. The difference lies in the location of the axis of rotation. In the impeller it is perpendicular to the flow, in the turbine – parallel, although the shape of the rotating wheel in them is identical. Wing water meters are more sensitive and can measure weak water flows, but they have a disadvantage – they almost completely block the passage of water, which reduces the capacity of the water pipe. The second disadvantage – in case of malfunction (if the impeller stops rotating), the flow is almost completely blocked.

To combine the advantages of both types of rotating elements, the combined tachometer was invented. It has both a turbine and an impeller. At low water flow rate it is fed to the impeller, at high flow rate – to the turbine. But the cost of this type of equipment is already quite high.

Another point: turbine water meters are available in diameters from 40 mm, so that for apartment owners there is actually no choice. You have to put wing water meters – the others simply do not fit.

How to install a water meter read here.

Ďalšie funkcie

To automate the process of taking readings, there are special overlays (based on reed switches or with transmission via radio channel). They are not compatible with all devices, so usually water meters are sold immediately with such additions.

There are wing water meters for DHW with the possibility of temperature control, they can also be called multitariff, because they calculate fix the amount of water consumed with different temperatures. They are relevant for those countries that have developed a recalculation mechanism. Russia, too, belongs to them (Resolution of the Government of the Russian Federation of August 27, 2012 № 354).

Multi-tariff hot water meters have a small processor and memory capacity, most often work from a rechargeable battery. Since only a few sensors, microprocessor and memory require power, the consumption is very small. One power cell lasts for 5-8 years.

Temperature data is recorded in the microprocessor memory, from where it can be retrieved. The memory is periodically cleared, so it should be checked periodically.