Venturi tube is a short venturi tube, the venturi effect of the principle is the barrier when the wind blows, the barrier on the leeward side port near the surface of a relatively low pressure, and the resulting adsorption causes the air flow. Venturi principle is very simple, it is to air from coarse to fine, in order to accelerate the gas flow rate, the gas outlet at the rear side of the venturi tube to form a "vacuum" area. It can be used to achieve the powder conveying airflow. Effect on the lot, mainly using its fire-suction effect, such as vacuum cleaners, powder delivery, coolers, flow meters, dryers, etc. Chemical industry, fire-suction pump is the principle, so the material applied mainly to see the place, and there are iron, aluminum, plastic, all kinds of nylon.