The principle and usage method of hot ball anemometer
1. Construction principle
It is an instrument capable of measuring low wind speeds, with a measurement range of 0.05-10m/s. It consists of two parts: a hot ball probe and a measuring instrument. The probe has a glass ball with a diameter of 0.6mm, surrounded by a nickel chromium wire ring for heating the glass ball and two series connected thermocouples. The cold end of the thermocouple is connected to a phosphor copper pillar, directly exposed to the airflow. When a certain amount of current passes through the heating coil, the temperature of the glass ball increases. The degree of increase is related to the wind speed, and the degree of increase is greater when the wind speed is low; On the contrary, the degree of increase is small. The magnitude of the increase is indicated on the meter by a thermocouple. Based on the reading of the electricity meter, check the calibration curve to determine the wind speed (m/s).
2. Usage
① Before use, observe whether the pointer of the meter points to zero. If there is any deviation, gently adjust the mechanical adjustment screw of the meter to make the pointer return to zero;
② Place the calibration switch in the off position;
③ Insert the measuring rod plug into the socket, place the measuring rod vertically upwards, press the plug tightly to seal the probe, place the "calibration switch" in the full degree position, and slowly adjust the "full degree adjustment" knob to make the meter pointer point at the full degree position;
④ Set the "calibration switch" to the "zero position", slowly adjust the "coarse adjustment" and "fine adjustment" knobs, so that the meter pointer points to the zero position;
⑤ After following the above steps, gently pull the plug to expose the probe of the measuring rod (length can be selected according to needs), and make the red dot on the probe face the wind direction. Based on the reading of the electricity meter, refer to the calibration curve to check the measured wind speed;
⑥ After measuring several points (about 10 minutes), steps ③ and ④ above must be repeated once to standardize the current inside the instrument;
⑦ After the measurement is completed, the "calibration switch" should be placed in the off position.
3. Precautions
① This instrument is a more precise instrument that is strictly protected from collision and vibration. It should not be used in places with excessive dust content or corrosive properties.
② The instrument is equipped with four batteries, divided into two groups. One group is connected in series with three batteries, and the other group is a single battery. When adjusting the "full scale adjustment" knob, if the meter cannot reach full scale, it indicates that a single battery has been exhausted; When adjusting the "coarse adjustment" and "fine adjustment" buttons, if the meter pointer cannot return to zero, it indicates that 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 instrument maintenance, it must be recalibrated.
