How to choose the right wind gauge and anemometer?
Square cross-section grid, measuring common specifications
Circular cross-section grid, measuring centre-axis specification
Circular cross-section grid, measuring range linear specifications
Measurement of anemometers in exhaust ventilation
The air vent can greatly change the relative balance of airflow distribution in the pipe: it generates a high speed zone on the exterior of the air vent and low speed zones in other parts of the pipe, and produces vortices on the grille. Depending on the design of the grille, at a certain interval in front of the grille (about 20cm), the airflow cross-section is more stable. In this case, usually use a large anemometer calibre rotor to stop measuring. Because of the larger calibre can be unbalanced flow rate to stop uniform, and in a wide range of calculation of its uniform value.
Anemometers use a volumetric flow funnel to measure at the extraction hole:
Even if there is no grid interference at the extraction, the path of air activity has no direction and its airflow cross-section is extremely uneven. The reason for this is that part of the vacuum in the pipeline to funnel the air out of the air chamber, even at the interval of pumping very close to the region, there is not a position to meet the measurement conditions to stop measuring operations. If the grid measurement method with the function of calculating the uniform value is used to stop measurement, and the volume flow rate method is used to stop measurement, and the volume flow rate is used to determine the volume flow rate, etc., only the pipe or the funnel measurement method can provide repeatable measurement results. In this case, different sizes of measurement funnels can meet the application requirements. The application of the measurement funnel can be generated at a certain interval in front of the sheet valve to meet the conditions of flow velocity measurement of a fixed cross-section, measured to locate the centre of the cross-section and fixed cross-section, measured to locate the centre of the cross-section and fixed cross-section, measured to locate the centre of the cross-section and fixed here. The measured value obtained by the flow rate probe is multiplied by the funnel coefficient to calculate the volume flow rate of the pumping. (e.g. hopper factor 20)
Test methods for wind speed
Wind speed test has a uniform wind speed test and turbulence component (wind turbulence 1 ~ 150KHz, different from the change) of the test. Methods for testing uniform wind speed include thermal, ultrasonic, impeller, and skin.
Thermal wind speed test method
This method tests the resistance change of the sensor when it cools down due to wind in the energised state, and thus tests the wind speed. It does not provide information on wind direction. In addition to being easy and convenient to carry, it has a high cost/performance ratio and is commonly adopted as a standard product for anemometers. Thermal anemometers use platinum wires, thermocouples, and semiconductors, but we use platinum coiled wires. Platinum wire is materially stable. Therefore, it has advantages in long-term stability and temperature compensation.
