Impeller Anemometer - What is the function of an anemometer?
Commonly used instruments for measuring wind speed include cup anemometers, wing anemometers, catarrhal thermometers and hot bulb electric anemometers. Wing-shaped and cup-shaped anemometers are easy to use, but their inertia and mechanical friction resistance are large, and they are only suitable for measuring larger wind speeds.
1.Construction principle
It is an instrument that can measure low wind speed, and its measuring range is 0.05-10m/s. It consists of two parts: a hot ball rod probe and a measuring instrument. The probe has a glass ball with a diameter of 0.6mm, and a nickel-chromium wire ring for heating the glass ball and two series-connected thermocouples are wound around the ball. The cold end of the thermocouple is connected to a phosphor bronze support and is directly exposed to the air flow. When a certain amount of current passes through the heating ring, the temperature of the glass ball increases. The degree of increase is related to the wind speed. When the wind speed is small, the degree of increase will be greater; otherwise, the degree of increase will be smaller. The magnitude of the rise is indicated on the meter by a thermocouple. According to the reading of the electric meter, the wind speed (m/s) can be found by checking the calibration curve.
2. How to use
① Before use, observe whether the pointer of the meter points to the zero point. If there is deviation, gently adjust the mechanical adjustment screw of the meter to return the pointer to the zero point;
② Place the calibration switch in the off position;
③Insert the measuring rod plug into the socket, place the measuring rod vertically upward, tighten the screw plug to seal the probe, place the "calibration switch" in the full-scale position, and slowly adjust the "full-scale adjustment" knob to make the meter pointer point at full position;
④Set the "calibration switch" to the "zero position" and slowly adjust the "coarse adjustment" and "fine adjustment" knobs so that the meter pointer points to the zero position;
⑤After the above steps, gently pull the screw plug to expose the measuring rod probe (the length can be selected according to your needs), and make the red dot on the probe face the wind direction. According to the meter reading, check the calibration curve. Output the measured wind speed;
⑥After measuring for several minutes (about 10 minutes), the above steps ③ and ④ must be repeated once to standardize the current in the meter;
⑦ After the measurement, the "calibration switch" should be placed in the off position. 3. Precautions ① This instrument is a relatively precise instrument. It must be strictly protected against collision and vibration. It cannot be used in places with excessive dust or corrosiveness. ② The instrument is equipped with 4 batteries, divided into two groups, one group of three cells connected in series, and one group of single cells. When adjusting the "full adjustment" knob, if the meter cannot reach full scale, it means that the single battery has been exhausted; when adjusting the "coarse adjustment" and "fine adjustment" knobs, if the meter pointer cannot return to zero, it means that Three batteries have been exhausted; when replacing the batteries, open the small door at the bottom of the instrument and connect them in the correct direction. ③After the instrument is repaired, it must be recalibrated.
