What are the common wind speed sensors?
1. Propeller type wind speed sensor We know that the electric fan is driven by the motor to rotate the fan blades, and a pressure difference is generated between the front and back of the blades to promote the air flow. The working principle of the propeller anemometer is just the opposite. The blade system aligned with the airflow is affected by the wind pressure, and a certain torque is generated to rotate the blade system. Usually, the propeller speed sensor measures the wind speed by rotating a group of three-bladed or four-bladed propellers around the horizontal axis. The propellers are generally installed at the front of a wind vane so that the plane of rotation is always facing the direction of the wind, and its speed is proportional to the wind speed. .
2. Wind cup wind speed sensor The wind cup wind speed sensor is a very common wind speed sensor, which was first invented by Robinson in England. The induction part is composed of three or four conical or hemispherical empty cups. The hollow cup shell is fixed on the three-pointed star-shaped brackets at 120° or on the cross-shaped brackets at 90° with each other. The concave surfaces of the cups are arranged in one direction, and the entire cross-arm frame is fixed on a vertical rotation axis.
3. Thermal wind speed sensor The thermal wind speed sensor uses a hot wire (tungsten wire or platinum wire) or a hot film (platinum or chromium thin film) as a probe, exposed to the measured air, and connects it to Whiston The electric bridge detects the flow velocity of the air in the measured section through the resistance or current balance relationship of the Wheatstone bridge. The hot film of the hot film wind speed sensor is coated with a very thin quartz film insulation layer to insulate the fluid and prevent pollution. It can work in the airflow with particles, and its strength is higher than that of the metal heating wire.
4. Pitot tube wind speed sensor Pitot tube, also known as "pitot tube", "wind speed tube", is a tubular device that measures the total pressure and static pressure of the airflow to determine the airflow velocity. It was named after the invention of H. Pitot in France .
5. Ultrasonic wind speed and direction sensor: The working principle of the ultrasonic wind speed sensor is to use the ultrasonic time difference method to measure the wind speed. Due to the propagation speed of sound in the air, it will superimpose with the airflow speed in the wind direction. If the ultrasonic wave travels in the same direction as the wind, its speed will increase; conversely, if the ultrasonic wave travels in the opposite direction to the wind, its speed will slow down. Therefore, under fixed detection conditions, the speed of ultrasonic waves propagating in the air can correspond to the wind speed function. Accurate wind speed and wind direction can be obtained through calculation. Since the speed of sound waves is greatly affected by temperature when they propagate in the air; the wind speed sensor detects two opposite directions on two channels, so the effect of temperature on the speed of sound waves is negligible.
