Wind speed probe is a sensitive part. When a constant current flows through its heating coil, the temperature of the sensitive part rises and reaches a certain value in still air. At this time, the thermocouple in the measuring element generates the corresponding thermoelectric potential, which is transmitted to the measuring indication system. This thermoelectric potential and the reference back electromotive force generated in the circuit cancel each other, so that the output signal is zero and the instrument pointer points to zero accordingly. If the heat-sensitive part at the end of the wind speed probe is exposed to the air flow, the thermoelectric potential of the thermocouple will change due to heat exchange, which will generate a weak difference signal compared with the reference back electromotive force. After being amplified by the measurement indication system, the watt-hour meter will be pushed, and the pointer can read the measured wind speed.

Thermal anemometer

(1) Place the instrument horizontally so that the direct key switch is in the original position (upward).

(2) Adjust the mechanical zero point of the electric meter so that the pointer of the electric meter points to the zero point.

(3) Place the probe rod vertically upward, so that all heat-sensitive components are pressed into the rod tube, and insert the plug of the wind speed probe into the "probe" socket.

(4) Press the "power" key (the first one from the left) to adjust the "amplifier zero point", and the potentiometer makes the pointer point to zero.

(5) Press the "1m/s" direct key switch (second from the left) to adjust the "zero point adjustment" potentiometer so that the pointer points to zero point.

(6) Preheat for 10 minute, and repeat the above steps before measurement.

(7) After preheating and calibration in the low wind speed section (0.05 ~ 1m/s), the heat-sensitive part at the end of the measuring rod of the wind speed probe can be pulled out and exposed to the airflow to be measured. Pay attention to make the measuring rod vertical and make the top wire face the direction of quasi-airflow (as shown in Figure 3), so that the wind speed can be read from the indicated value of the electric meter.

(8) When the wind speed exceeds lm/s in the high wind speed section (1m/s ~ 30m/s), press "30m/s" and "10m/s".

(9) After use, all keys of the direct key switch should be reset from left to right in turn. Press the pull-out part of the measuring rod of the temperature-sensitive part of the wind speed probe into the measuring rod tube completely, remove the plug and put it in the original position of the instrument box.

(10) battery installation;

When using the built-in battery, be sure to pay attention to the polarity when installing.

When using external power supply, pay attention to the correct plug connection and insertion, and the power supply voltage should meet the requirements of 4.5V ~ 6V.

experimental data

According to the actual measured wind speed, the tester selects the low-speed or high-speed adjustment button for at least three times, removes the rough data, and takes the average value as the final wind speed value.