Learn to distinguish the differences between different anemometers
There are three main types of on-site anemometer measurements based on their principles: differential pressure type, impeller type, and hot bulb type
Differential pressure is a classic method for measuring flow velocity in fluid mechanics, mainly relying on pitot tubes and differential pressure gauges to measure dynamic pressure, and then calculating flow velocity based on the Bernoulli equation. The advantages of this method are low detection limit and high sensitivity, but it requires high uniformity of the flow field. When measuring in the environment, it is easy to be inaccurate due to uneven flow field. Therefore, the pressure difference method is mainly used to measure wind speed in air ducts.
The main principle of the hot ball type is that the probe is set to a constant temperature, and air flowing through the probe will take away heat. At this time, the probe will be heated to the set temperature, and an electrical signal will be collected by the instrument during this process, and the wind speed will be calculated accordingly. The advantages of this method are high sensitivity, large range, and adaptability to environmental measurement. The disadvantage is that the platinum wire connecting the hot ball in the probe is relatively fragile, and if used accidentally, it can easily cause damage to the probe and cannot be repaired. At present, the domestic hot ball anemometer is still an old-fashioned anemometer. The Air Conditioning Institute of the Construction Research Institute has a more advanced alternative technology, which replaces the hot ball with a ceramic hot column, which has much better strength than the hot ball.
The impeller is mainly driven by wind to rotate and generate electromagnetic signals for measurement. The advantage of this method is that the instrument is relatively durable and commonly used for long-term measurement. The three cup anemometer used in meteorological observation also follows the same principle, but the disadvantage is slightly lower sensitivity.
Wind speed instruments belong to the category of safety protection and environmental monitoring measuring instruments, and are mandatory calibration measuring instruments stipulated by China's Metrology Law. Requirements for safe use of anemometers:
If the anemometer emits abnormal odors, sounds, or smoke during use, or if liquid flows into the interior of the anemometer, please immediately shut down and remove the battery. Otherwise, there is a risk of electric shock, fire, and damage to the anemometer.
2. Do not expose the probe and anemometer body to rain. Otherwise, there may be risks of electric shock, fire, and personal injury.
3. Do not touch the sensor area inside the probe.
When the anemometer is not in use for a long time, please remove the internal battery. Otherwise, the battery may leak and cause damage to the anemometer.
5. Do not place the anemometer in places with high temperature, high humidity, high dust, and direct sunlight. Otherwise, it will result in damage to internal components or deterioration of anemometer performance.
6. Do not use volatile liquids to wipe the anemometer. Otherwise, it may cause deformation and discoloration of the anemometer housing. When there are stains on the surface of the anemometer, a soft fabric and neutral detergent can be used to wipe it off.
7. Do not drop or heavily press the anemometer. Otherwise, it will cause malfunction or damage to the anemometer.
8. Do not touch the sensor part of the probe when the anemometer is live. Otherwise, it will affect the measurement results or cause damage to the internal circuit of the anemometer.
