Several Testing Methods of Digital Anemometer
Digital anemometer testing includes testing of average wind speed and testing of turbulent components (wind turbulence 1-150KHz, different from variations). The methods for testing average wind speed include thermal, ultrasonic, impeller, and pitot tube methods
This method is to test the resistance change caused by the cooling of the sensor due to wind when it is powered on, and thus test the wind speed. Unable to obtain information on wind direction. In addition to being easy and convenient to carry, it has a high cost performance ratio and is widely used as a standard product for anemometers. The elements of the thermal anemometer include platinum wire, thermocouple, and semiconductor, but our company uses platinum winding wire. The material of platinum wire is physically stable. Therefore, it has advantages in long-term stability and temperature compensation.
The wind direction sensor of the photoelectric anemometer uses a low inertia light metal wind vane to respond to the wind direction, driving the coaxial encoder to rotate. This encoder encodes according to the Gray code and scans with photoelectrons to output electrical signals corresponding to the wind direction.
The photoelectric wind speed sensor adopts a low inertia wind cup, which rotates with the wind to drive the coaxial cutting disc to rotate. It uses photoelectrons to scan and output a pulse train, and outputs the corresponding value of pulse frequency corresponding to the number of revolutions, which is easy to collect and process. High intensity, good starting, in line with national meteorological measurement standards;
The wind direction sensor is equipped with an electronic compass that automatically locates the direction angle. It can be installed in fixed locations or in mobile locations such as special vehicles, ships, drilling platforms, etc
Wheel type probe of anemometer
The working principle of the rotary probe of the digital 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-sectional area greater than 100 times that of the exploration head.
Positioning of Digital Anemometer in Air Flow
The correct adjustment position of the anemometer's rotary probe is that the airflow direction is parallel to the rotary axis. When the probe is gently rotated in the airflow, the reading will change accordingly. When the reading reaches the maximum value, it indicates that the probe is in the correct measurement position. When measuring in a pipeline, the distance from the starting point of the straight part of the pipeline to the measurement point should be greater than 0XD. Turbulence has a relatively small impact on the thermal sensitive probe and pitot tube of the anemometer.
Digital anemometer for measuring airflow velocity inside pipelines
Practice has proven that the 16mm probe of the anemometer has the widest range of applications. Its size ensures good permeability and can withstand flow velocities up to 60m/s. The measurement of airflow velocity inside pipelines is one of the feasible measurement methods, and the indirect measurement protocol (grid measurement method) is applicable to air measurement.
