There are several methods for measuring the wind speed of the high and low temperature test chamber, including:
1. The oldest instrument is the wind cup anemometer, which is mostly used in the field of meteorology. The crossed arms of the wind cup rotate slowly and differently under different wind speeds to determine the size of the wind speed and the available range of the wind cup anemometer It is very wide. Nowadays, many sizes of wind cup anemometers can measure the air speed in a small volume such as a test box without using a small anemometer.
2. The cata thermometer is a special type of glass thermometer, which is designed according to the cooling effect of circulation. The measuring principle is based on the need to cool the cata thermometer heated first to a certain temperature (for example, from 38 degrees to 35 degrees). Time to determine the size of the wind speed at this point, but because the thermometer must be reheated after each measurement and then measured, this method is more troublesome.
The measuring principle of the hot wire anemometer and the hot ball anemometer is also designed according to the convection cooling effect. These two anemometers quantify the electrical power of the measuring component during measurement, so that the measuring component reaches a predetermined standard temperature. When air flows through the component, The temperature of the module drops, and the speed of the air can be determined according to the magnitude of the drop of the module. The hot wire measurement module is made of platinum wire, and the measurement module of the hot ball anemometer is in many cases a negative temperature coefficient of resistance. There are components with small size and small heat capacity, so the thermal time constant of the component can be measured very small, and at the same time, the air flow speed on a small cross-sectional area can be measured. This is particularly useful for low wind speeds. The temperature measurement range that has been applied at present Between -30 degrees and 100 degrees, in the hot wire anemometer, the cooling effect of the hot wire component depends on the angle between the spool and the direction of the air flow. When the air flow is equal to the hot wire direction, the cooling effect is the worst, measured by rotating the hot wire anemometer Components can accurately determine the air flow direction.
The wind cup anemometer and cata thermometer can only be used in large-scale test rooms that can be accessed by people, while the hot wire anemometer and hot bulb anemometer can be used in small high and low temperature test chambers.
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