Introduction to thermal sensitive probe of anemometer
The working principle of the thermal sensitive probe of the anemometer is based on the cold shock airflow carrying away the heat from the heating element. With the help of an adjustment switch, the temperature is kept constant, and the current and flow rate are proportional to each other. When using a thermal sensitive 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 thermal anemometer flow sensor is often higher than that of the rotary probe. The above phenomenon can be observed during pipeline measurement. According to different designs of pipeline turbulence, it may even occur at low speeds. Therefore, the measurement process of anemometer should be carried out during
The straight section of the pipeline is carried out. The starting point of the straight section should be at least 10 × D (D=pipe diameter, in CM) outside the measurement point; The endpoint should be at least 4 × D behind the measurement point. The fluid cross-section must not have any obstruction. (sharp edges, heavy suspensions, etc.).
The rotating probe of the anemometer: The working principle of the rotating probe of the anemometer is based on converting the rotation into an electrical signal. First, it passes through a proximity sensing head to "count" the rotation of the rotor and generate a pulse series. Then, it is converted and processed by the detector to obtain the speed value. The large-diameter probe (60mm, 100mm) of the anemometer is suitable for measuring turbulent flow with medium to low velocities (such as at pipeline outlets). The small-diameter probe of the anemometer is more suitable for measuring airflow in pipelines with a cross-section greater than 100 times that of the probe.
The anemometer measures the relatively balanced distribution of airflow in the pipeline with a large ventilation port during exhaust: a high-speed zone is generated on the surface of the free ventilation port, while the rest of the area is a low-speed zone, 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, a large-diameter rotary anemometer is usually used for measurement. Because a larger diameter can average uneven flow velocity and calculate its average value over a larger range.
