Determination of wind speed Commonly used instruments are cup anemometer, wing anemometer, catastat thermometer and hot bulb anemometer. The wing and cup anemometers are easy to use, but have a high inertia and mechanical friction resistance and are only suitable for measuring large wind speeds.

Hot ball electric anemometer

1. Construction principle It is an instrument capable of measuring low wind speed, and its measurement range is 0.05-10m/s. It consists of two parts: a hot ball type probe and a measuring instrument. The probe has a glass ball of 0.6 mm in diameter surrounded by a nickel-chromium wire loop for heating the glass ball and two thermocouples connected in series. The cold end of the thermocouple is attached to the phosphor bronze pillar and is directly exposed to the gas stream. When a certain amount of current passes through the heating coil, the temperature of the glass ball rises. The degree of elevation is related to the wind speed, and the degree of increase in wind speed is large; on the contrary, the degree of elevation is small. The degree of elevation is indicated on the meter by a thermocouple. According to the reading of the meter, check the calibration curve to find out the wind speed (m/s).
2. How to use

1 Before using, observe whether the pointer of the meter points to zero. If there is any offset, you can gently adjust the mechanical adjustment screw of the meter to return the pointer to zero point;
2 Place the calibration switch in the off position;
3 Insert the measuring rod plug into the socket, the measuring rod is placed vertically upwards, the screw plug is pressed tightly to seal the probe, the “correction switch” is placed at the full position, and the “full adjustment” knob is slowly adjusted to make the meter pointer Full position
4 Put the “correction switch” in “zero position”, and slowly adjust the “coarse adjustment” and “fine adjustment” two knobs to make the meter pointer point at the zero point;
5 After the above steps, gently pull the screw plug to expose the probe (the length can be selected as needed), and make the red dot on the probe face the wind direction. According to the meter reading, check the calibration curve. The measured wind speed;
6 After measuring a few points (about 10 minutes), the above steps 3 and 4 must be repeated to standardize the current in the meter; 7 After the measurement, the “correction switch” should be placed in the off position.
3. Precautions
1 This instrument is a relatively precise instrument, which is strictly resistant to collision vibration and should not be used in places with excessive dust or corrosiveness.
2 The instrument is equipped with 4 batteries, which are divided into two groups and are connected in series, and one group is single-section. When adjusting the “Full Degree 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” knob, if the meter pointer cannot return to zero, the explanation The three batteries have been exhausted; when replacing the battery, open the small door at the bottom of the instrument and connect it in the correct direction.
3 After the instrument is repaired, it must be recalibrated.