An anemometer is an instrument used in meteorology to measure wind speed. At the same time, the mechanisms of action of various types of this device are noticeably different from each other.
The cup anemometer is the oldest and simplest instrument in this category. It consists of four cone-shaped or semicircular containers, which, being fixed on the spokes, form a kind of propeller rotated by the wind in a vertical plane. It was this rotation, or rather, its speed, that served as the basis for measuring the readings of this type of anemometer. This design of the device was invented in 1846 by engineer John Robinson, but it was subsequently improved.
So, the Canadian scientist John Patterson in 1926 proposed to remove one cup, making the anemometer three-bladed, and physicists Brevort and Joyner improved the measurement accuracy given by the device, so that the error obtained in measurements with modern cup anemometers usually does not exceed 3%. Today, anemometers are most often used during high-rise construction work, for example, they are installed on cargo cranes, which makes it possible to determine in time a significant increase in wind and prevent the negative consequences of this atmospheric phenomenon.
The principle of operation of a thermal anemometer is based on the presence of a filament in the composition of this device, which heats up to a certain temperature. In this case, the air flow, which in fact is the wind, cools the heated filament according to the laws of physics. In turn, the degree of this cooling is the basis of the readings of the thermal anemometer. Currently, the main area of application of thermal anemometers is the automotive industry.
The operation of an ultrasonic anemometer is based on the fact that the direction and strength of the wind can change the speed of sound in air. At the same time, depending on the complexity of the design, the sensors installed in this device make it possible to measure various properties of the air flow. So, the simplest ultrasonic anemometers, which are usually called two-dimensional, allow you to establish only the speed and direction of the wind. And more complex models can provide the ability to measure such parameters as the humidity of the air flow, its temperature, and others. Ultrasonic devices are commonly installed in various industrial facilities such as factories and mines.
Ultrasonic anemometers, like other types of these and other measuring devices, are goods subject to mandatory certification on the territory of the Russian Federation.