Vane Anemometer - What is the function of an anemometer?
Determination of wind speed The commonly used instruments are cup anemometer, wing anemometer, katar thermometer and hot bulb electric anemometer. Wing-shaped and cup-shaped anemometers are easy to use, but their inertia and mechanical friction resistance are relatively large, so they are only suitable for measuring large wind speeds. Hot bulb electric anemometer
1. Structural principle It is an instrument capable of measuring low wind speed, and its measuring range is 0.05-10m/s. It is composed of two parts: a thermal ball probe and a measuring instrument. The probe has a glass ball with a diameter of 0.6mm, and the ball is wound with a nickel-chromium coil for heating the glass ball and two thermocouples connected in series. The cold junction of the thermocouple is attached to a phosphor-bronze post exposed directly to the air flow. When a certain amount of current passes through the heating ring, the temperature of the glass bulb rises. The degree of increase is related to the wind speed, and the degree of increase is large when the wind speed is small; otherwise, the degree of increase is small. The magnitude of the rise is indicated on the meter by means of a thermocouple. According to the reading of the electric meter, check the calibration curve to find out the wind speed (m/s).
2. How to use
① Before use, check whether the pointer of the meter is at the zero point. If there is any deviation, you can gently adjust the mechanical adjustment screw of the meter to make the pointer return to the zero point;
②Place the correction switch in the OFF position;
③Insert the plug of the measuring rod into the socket, place the measuring rod vertically upward, press the screw plug tightly to seal the probe, put the "calibration switch" at the full position, and slowly adjust the "full scale adjustment" knob so that the pointer of the meter points to the Full position;
④Place the "calibration switch" in the "zero position", and slowly adjust the two knobs of "coarse adjustment" and "fine adjustment", so that the pointer of the ammeter points to the zero position;
⑤ After the above steps, gently pull the screw plug to expose the probe of the measuring rod (the length can be selected according to the needs), and make the red point on the probe face the wind direction. According to the reading of the meter, check the calibration curve, and you can check Measured wind speed;
⑥ After 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 test, the "calibration switch" should be placed in the off position.
3. Precautions
① This instrument is a relatively precise instrument, strictly guarded against collision and vibration, and cannot be used in places with excessive dust content or corrosiveness.
②The instrument is equipped with 4 batteries, which are divided into two groups, one group is three cells connected in series, and one group is single cell. When adjusting the "full scale adjustment" knob, if the ammeter cannot reach the full scale, it means that the single battery has been exhausted; The 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.
③ After the instrument is repaired, it must be recalibrated.
