The wind speed of unidirectional flow is basically stable, and the direction of air flow is basically the same. There is little difference between the wind speed near the air inlet and the wind speed on the working face. Moreover, the wind speed in the whole dust-free workshop is good, and the uniformity of wind speed is generally not needed to be considered.

The wind speed and direction of each part of the non-unidirectional flow are not the same, and the wind speed uniformity of the whole dust-free workshop is poor, so it is necessary to consider the uniformity of the wind speed, and sometimes it is necessary to measure the wind speed of each part separately. When measuring the wind speed, it is necessary to judge the wind direction in advance, because the probe of the general anemometer has directivity, so it is necessary to recognize the direction when measuring the wind speed.

Because the air flow in the inlet is divergent, it is generally necessary to add a hood to measure the wind speed in the inlet.

(1) It is a common method to measure wind speed with hot-bulb anemometer and hot-bulb anemometer. Generally, the sensitivity of the hot-sphere anemometer is higher, but the stability is poor. Therefore, attention should be paid to the drugstore when measuring the wind speed with a hot-ball anemometer: check whether the appearance and working state of the anemometer are normal; Calibrate the zero position of the anemometer before measurement; When correcting the zero position, the probe should be in the state of no wind; The windward side of the anemometer probe should be perpendicular to the wind direction when measuring the wind speed. Wait for the display to be stable before reading; Care should be taken to prevent the probe of the anemometer from touching other objects.

(2) use rotor anemometer to measure the wind speed. The rotor anemometer's rotating shaft has a certain friction force, so the early rotor anemometer is less sensitive, people do not like to use. With the neck of the technology, the sensitivity of the rotor anemometer is getting higher and higher, and more and more people are using the rotor anemometer. Points should be paid attention to when measuring wind speed with rotor anemometer: check whether the appearance and working state of anemometer are normal; Check whether the friction of the rotating shaft is normal; When measuring the wind speed, the direction of the airflow should be clearly recognized; The rotation plane of the rotor should be perpendicular to the wind direction; The rotor should be all in the air duct; Wait until the display stabilizes before starting the reading.

(3) The wind speed was measured by pitot tube combined with micromanometer. Standard pitot tube combined with micromanometer is used to measure static pressure and total pressure, according to the static pressure and total pressure to calculate the force pressure, and then according to the dynamic pressure to calculate the output wind speed. In general, the wind speed measured by standard pitot tube is more reliable. The standard wind speed in the wind tunnel is measured using a standard pitot tube combined with a micromanometer. However, the operation of this measurement method is more troublesome, and the sensitivity and accuracy of the micromanometer. The following matters should be noted when measuring wind speed with pitot tube: check whether the air inlet of standard pitot tube is damaged; Check whether there is blockage in the standard pitot tube; Check whether the pipe connecting the pitot tube is patchy; Check whether the display of the micro pressure gauge is normal; Standard pitot tubes should be placed in an accurate direction.