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In order to pay only for the water you use, it is necessary to install a water meter in the apartment or, as they say, water meters. What water meters are and which ones are suitable for domestic 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: non-volatile (using mechanical processes) and volatile (requiring electricity).
In general, there are four types of counters:
Tachometric water meters with impeller Tachometric (turbine or vane). Relate to mechanical devices (non-volatile). The main working part is a small turbine or impeller that is in the water. The amount of water is calculated by the number of revolutions that the impeller makes. The revolutions of the impeller axis cause the mechanical counter to move. Works with any water (hard, high iron, etc.), but the accuracy of the readings is not very high, it is likely that after a few years the impeller will grow and begin to rotate more slowly. But it may happen that it will spin faster than it should. In general, the option is inexpensive and this type of meters is mainly installed in apartments.
- Induction or electromagnetic. This appliance requires electricity to operate. The operation 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, it gives accurate data. Since clear water and the ideal condition of the pipeline are not about our networks, they rarely install it.
Electromagnetic (induction) water meter - Ultrasonic. They also require a power supply. The principle of operation is to compare the speed of propagation of ultrasound “along” and “against” the flow. The accuracy is high, but also only on clean pipes. The price is even higher, although the service life is around 15 years.
- Vortex. They analyze the speed of formation of a vortex street behind a specially shaped obstacle. The behavior of the water vortex is analyzed by an electronic device (power supply is also required). They work normally only with clean water without impurities, the service life is 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 basically installed.
How to choose polypropylene pipes read here.
Types of tachometric counters
Mechanical counters are good in that no additional conditions are required for their operation. There is a stream of water – they work, there is no it – they stop. But they don’t really like long downtime – due to the presence of salts in the water, the impeller or turbine may stop rotating. This means that you will need to change the meter.
Water temperature classification
Water meters (this is the official name) are for cold and hot water. They differ in the operating temperature range:
- for cold, the maximum is +30°C;
- for hot +130°C;
- universal — operating temperature range — up to +90°C.
Even if the water meters are of the same type and they have the same manufacturer, the difference in price is noticeable. But it is justified – heat-resistant materials are used for hot water supply, and they are much more expensive. To make them easy to distinguish outwardly, the cases are painted in different colors – counters for cold water are usually blue, for hot – red, universal ones are orange.
By the principle of action
With the general principle of operation, this type of water meters has several varieties. First, there are two principles of operation:
- Single-jet – water flows in a single stream and enters the impeller. In this case, vortex flows arise, which adversely affect the measurement accuracy.
- Multi-jet. The flow is broken into several separate jets, which reduces the turbulence of the flows, increasing the accuracy of measurements.
Multi-jet water meter has a different look
But not everything is so simple: multi-jet tachometric water meters are available only for large pipe diameters (more than 40 mm in diameter). They are not suitable for apartments.
According to the installation method of the counting and rotating mechanism
More relevant for us is the division according to the method of installing the counting mechanism. On this basis, water meters are divided into dry and wet. In wet counting mechanism stands in the water, so it quickly fails. In dry type devices, the counting mechanism is separated from the water by a plate and they work longer.
There is another type of tachometric meters – valve. In such a water meter, a shut-off valve is additionally installed, which allows shutting off the water. It is difficult to say why this may be needed, because when installing a shut-off valve is required in front of the water meter. It is needed in case you need to change or check the meter, with this tap, if necessary, they turn off the water.
Inside the tachometric counters there is a turbine or an impeller, respectively, they are divided into turbine and vane ones. The whole difference is in the location of the axis of rotation. In vaned ones, it is perpendicular to the flow, in turbine ones it is parallel, although the shape of the rotating wheel is identical for them. Vane water meters are more sensitive and can measure weak water flows, but they have a drawback – they almost completely block the passage of water, which reduces the throughput of the water supply. The second minus is that in the event of a malfunction (if the impeller stops rotating), the flow is almost completely blocked.
| Name | For what water | A type | Bore diameter | installation length | Min/max flow | Connecting dimensions | Price |
|---|---|---|---|---|---|---|---|
| SVK-15-3-2 “Arzamas” | universal | paddle dry-propelled | 15mm | 110 mm | 0,06 – 3 m3/hour | thread G3/4 | 600 rub |
| VSHN DN 25 | cold water | vaned single-jet | 25 mm | 260 mm | 0,07-7 m3/hour | thread 1” 1/4” | $72 |
| VSGN-25 DN | hot water | vaned single-jet | 25 mm | 260 mm | 0,14-7,3 m3/hour | thread 1” 1/4” | $87 |
| VALTEC VLF-R-L | universal | paddle dry-propelled | 15 mm | 110 mm | 0,01-3 m3/hour | thread 1/2″ | 800 rub |
| ITELMA IS.160005 (vertical installation is allowed) | hot water | paddle dry-propelled | 15 mm | 110 mm without fittings | up to 3 m3/hour | G3/4” | 890 rub |
| PULSE 15-X (vertical installation is allowed) | cold | Winged, dry | 15 mm | 80 mm without spurs | up to 3 m3/hour | thread 1/2″ | 730 rub |
To combine the advantages of both types of rotating elements, a combined tachometric water meter was invented. It has both a turbine and an impeller. With a low flow rate of water, it is fed to the impeller, with a large flow – to the turbine. But the cost of this type of equipment is already quite high.
One more thing: turbine water meters are produced with diameters of 40 mm or more, so there is actually no choice for apartment owners. We have to install vane water meters – others simply do not fit.
How to install a water meter read here.
Additional features
To automate the process of taking readings, there are special overlays (based on reed switches or with radio transmission). They are not compatible with all devices, so water meters are usually sold immediately with such additions.
There are vane DHW water meters with the ability to control the temperature; they can also be called multi-tariff, as they calculate the amount of water consumed with different temperatures. They are relevant for those countries in which a recalculation mechanism has been developed. Russia, also belongs to them (Decree of the Government of the Russian Federation of August 27, 2012 No. 354).
Multi-tariff hot water meters have a small processor and memory, and most often operate from a rechargeable battery. Since only a few sensors, a microprocessor and memory require power, the consumption is very small. One power element is enough for 5-8 years.
The temperature data is stored in the microprocessor memory, from where it can be retrieved. The memory is periodically cleared, so it is necessary to check periodically.