Introduction to Thermosensitive Probe of Anemometer
The working principle of the thermal sensitive probe of the anemometer is based on the cold impact airflow taking away the heat on the thermal element. With the help of a regulating switch, the temperature is kept constant, and the regulating current is proportional to the flow rate. When using a thermosensitive probe in turbulence, airflow from all directions simultaneously impacts the thermal element, which can affect the accuracy of the measurement results. When measuring in turbulence, the reading of the flow sensor of the thermal anemometer is often higher than that of the rotary probe. The above phenomena can be observed during pipeline measurement. Depending on the different designs of pipeline turbulence, it may even occur at low speeds. Therefore, the anemometer measurement process should be carried out on the straight section of the pipeline. The starting point of the straight section should be at least 10 times before the measurement point × D (D=pipeline diameter, in CM); The endpoint should be at least 4 after the measurement point × Location D. The fluid cross-section must not have any obstruction. (edges, heavy overhangs, etc.).
The working principle of the rotary probe of the anemometer is based on converting the rotation into an electrical signal. First, through a proximity sensing start, the rotation of the rotary wheel is "counted" and a pulse series is generated. Then, after being converted by the detector, the speed value can be obtained. The large-diameter probe of the anemometer (60mm, 100mm) is suitable for measuring turbulence at medium and small flow rates (such as at pipeline outlets). The small caliber probe of the anemometer is more suitable for measuring airflow with a cross-sectional area of more than 100 times that of the probe.
The anemometer measures the relatively balanced distribution of airflow in a pipeline with a large ventilation port during exhaust extraction: a high-speed zone is generated on the surface of the free ventilation port, while the rest are low-speed zones and vortices are generated on the grid. According to different design methods of the grid, the airflow cross-section is relatively stable at a certain distance (about 20cm) in front of the grid. In this case, the measurement is usually carried out using a large-diameter rotary anemometer. Because larger apertures can average uneven flow rates and calculate their average values over a larger range.
