Instrument used to measure wind

An anemometer is a device used to measure the speed of motion of gases and liquids, especially wind. Some anemometers also indicate the direction of movement.

An anemometer that graphically records the speed or direction of the wind is called the anemograph. Currently, anemographs are increasingly supported by computer data recording.

 

Wind speed and flow velocity is an important factor when controlling air conditioning systems, ventilation systems and many other areas. Measurements can be made in open space, as well as in ventilation, air-conditioning and exhaust systems, and wherever the medium is being tested. Flow rate / volume flow means the quantity (quantity) of gases (or liquids) that flow through a certain area (section) within one second.

Weather tool that measures wind speed

This means that an anemometer can measure the flow (ie the amount of cubic meters of air escaping through the shaft ventilation outlet in a matter of a second or a minute). In most cases, they are additionally equipped with humidity and temperature meters: thermometers (measurement up to 60 ° C, with a switch for values ​​expressed in ° F) or pyrometers for measuring the ambient temperature, often with precise laser sights.

Weather tool that measures wind speed

Most measurements in shafts and ventilation systems are made using a vane anemometer with the use of appropriate accessories. Flow measurement can also be carried out indoors, for example to determine drafts.

 

Manufacturers of measuring instruments offer many types of anemometers, i.e. devices that measure flow velocity and air flow. There are anemometers available on the market with wings of small and large diameter, anemometers with thermo-resistance probes, with Pitot tubes and so-called. balometry. Large selection of meters and a wide range of prices causes that many future users have a problem with choosing the right instrument for their needs. In this article we will try to explain the differences, indicate the advantages of different solutions and help in choosing the right instrument.

 

Windmill anemometers

Windmill anemometers (also known as wing or fan anemometers) are the most popular group of flow measurement devices. Windmills (blades) are embedded permanently or in a casing and connected with a cable to the rev counter. Such a construction provides greater flexibility and convenience in taking measurements. These anemometers are very well suited for measuring very low speeds.

 

Thermomagnetic anemometer

The measured medium flows and cools the heated heating element in the probe. Using the change in the heat pickup of an electrically heated element (electrical resistance of the heating element), a measurement is made. On this basis, the meter is able to determine the air velocity very accurately.

 

Pressure anemometer (Pitot tube)

For the measurement uses the pressure change in the moving fluid. The measurement is performed based on the principle of Pitot tube operation. The tube is bent at the end at an angle of 90 °, the tube face is perpendicular to the direction of flow. This type of probe is placed in the cable axis and connected to the differential manometer. The pressure, which will be measured with a pressure gauge, is the sum of the pressure in the pipe (static) and the pressure accumulation caused by the stagnation of the stream (dynamic). The measured pressure is therefore the total pressure.

 

Sound or ultrasonic anemometer

Wind speed measurement consists in sending acoustic pulses, which are then received by a miniature receiver. Ultrasonic anemometers measure the time required by the ultrasonic pulse to travel from one sensor (transducer) to another. They belong to devices that do not have moving parts and are resistant to temperature fluctuations and icing. They are also more durable mechanically than the bowl models, thanks to which they are perfect for mounting on wind turbines.