On an anemometer with four cups it is easy to see that since the cups are arranged symmetrically on the end of the arms, the wind always has the hollow of one cup presented to it and is blowing on the back of the cup on the opposite end of the cross. Therefore, counting the turns of the cups over a set time period produced the average wind speed for a wide range of speeds. The air flow past the cups in any horizontal direction turned the cups in a manner that was proportional to the wind speed. These were sent throughout the kingdom as an official. Precipitation Measurement: Who invented the rain gauge 1441 - King Sejong and his son, Prince Munjong, invented the first standardized rain gage. It consisted of four hemispherical cups each mounted on one end of four horizontal arms, which in turn were mounted at equal angles to each other on a vertical shaft. 1846 John Thomas Romney Robinson (Ireland): Invented the first four-cup anemometer, predecessor to modern anemometers for wind measurement. John Thomas Romney Robinson, of Armagh Observatory. First printing of Robinson's new experiments and researches into the constants of the Cup-Anemometer which he invented in 1846 by modifying Whewell's instrument by the introduction of the now-familiar windmill with hemispherical cups.""A simple type of anemometer is the cup anemometer, invented (1846) by Dr. No wrappers as extracted from ""Philosophical Transactions"" 1879 - Vol. It is suitable for the measurement of the positive pressure, negative pressure, and differential pressure of the gas within the pressure range of 3000Pa, as well as the measurement of wind speed and air volume.ĭisadvantages: The use environment is relatively single and not very useful.(London, Harrison and Sons, 1879). According to the differential pressure gauge readings and calculations using related formulas, the measured point can be obtained.Īdvantages: high stability. The small holes on the head and the small holes on the sidewall are connected to two pipelines that are not connected and are respectively connected to the two ends of the differential pressure gauge. These small holes should be perpendicular to the wall and used to feel the static pressure of the fluid during use. At about three times the pipe diameter from the head, several small holes are opened around the pipe wall. At the top of the pitot tube head, facing the incoming flow, a small hole is opened, which is used to feel the total pressure of the fluid. The difference between the total pressure (stagnation pressure) of the flowing air and the static pressure, that is, the dynamic pressure, is used to measure the wind speed. It is composed of a total pressure probe and a static pressure probe. The Pitot tube is named after its inventor and French engineer Henri Pitot. The most commonly used pressure anemometer is the Pitot tube. The time response is fast, the sensitivity is high, and the minimum detection wind speed can reach a few centimeters per second.ĭisadvantages: the installation is more complicated and the price is more expensive. It will be a powerful substitute for mechanical anemometers.Īdvantages: no moving parts, no mechanical wear. Because it overcomes the inherent shortcomings of mechanical anemometers, it can work normally all-weather and for a long time, and it is more and more widely used. The ultrasonic anemometer is a more advanced instrument for measuring wind speed and direction. The air velocity can be obtained by measuring this time difference, that is, the air velocity measurement can be realized by measuring this time difference, which is the working principle of the ultrasonic anemometer. Therefore, within a certain distance, there is a difference between the time required for sound waves to propagate downwind and upwind. The propagation speed of sound waves in the actual atmosphere is equal to the sum of the propagation speed of sound waves in the static atmosphere and the airflow speed in the atmosphere. Secondly, this anemometer is expensive and costly. No special software is required.ĭisadvantages: The hot-wired anemometer is easily affected by the ambient temperature, and its temperature drift is one of the most important sources of error. ![]() Its time constant is only a few hundredths of a second, and it is an important tool for atmospheric turbulence and agrometeorological measurement.Īdvantages: It is a high-speed anemometer, which can be measured even at low speeds. The anemometer has high sensitivity at low wind speeds and is suitable for measuring small wind speeds. The direct heating type is mostly platinum wire, which can directly measure its temperature while measuring the wind speed. The indirect heating type is generally manganese copper wire, its resistance temperature coefficient is close to zero, and its surface is additionally equipped with temperature measuring elements. There are two types of wind speed: indirect heating and direct heating.
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