What is an Air Chute?

An air chute is a continuous pneumatic conveying device for inclined downward transportation of dry powdered materials. It is widely used in industries like cement, electric power, and chemical engineering, typically for conveying cement, raw meal, fly ash, flour, talc powder, and phosphate rock powder. As a dense-phase fluidized conveying equipment, it features low power consumption, low production costs, and effective production efficiency improvement.

In terms of structure, an air chute mainly consists of upper/lower trough bodies, an air-permeable layer, an air inlet, a feed inlet, a discharge outlet, an air shut-off valve, and an inspection window. The trough body is usually pressed from ~3mm steel plates into a rectangular cross-section; each standard section is 2m long, with flat iron flanges at both ends for connecting sections to meet different conveying length needs. The air-permeable layer is a key component, commonly available in canvas or porous plate types, which allows uniform air penetration to fluidize materials. The air inlet is formed by connecting a cylindrical air duct to the lower trough’s bottom plate, through which high-pressure air from a blower is blown into the lower trough. The feed inlet is on the upper trough’s top (rectangular or circular), with a porous plate above the air-permeable layer here to reduce material impact. Discharge outlets include end and intermediate ones—intermediate outlets are on the upper trough’s side, equipped with gate plates for easy unloading at different positions. The air shut-off valve precisely controls air volume for different conveying conditions; the inspection window (on the upper trough’s side) lets operators monitor material flow and detect blockages promptly.

Unveiling the Working Principle

The air chute operates based on fluidization technology and gravity. Before startup, dry powdered materials are fed onto the air-permeable layer of the upper trough via the feed inlet. When the system starts, a high-pressure centrifugal fan blows air (with specific pressure and flow rate) into the lower trough through the air inlet. The air in the lower trough passes evenly through the air-permeable layer into the material layer. Here, the air-permeable layer plays a critical role—its dense, uniform, and continuous pores ensure even air penetration, achieving uniform material fluidization and avoiding eddy currents.

When air enters the material layer, it forms an air cushion between particles, separating them, reducing internal friction, and making the material exhibit fluid-like properties (this is material fluidization). At this point, the fluidized material flows from the upper trough’s higher end to the lower end along the air-permeable layer (like a liquid), driven by the component of its gravity along the chute, and is finally discharged from the outlet. Excess air overflowing the material layer is released into the atmosphere through the upper trough’s top filter; if higher air quality is required, this air can be directed to dust removal equipment for purification before discharge to meet environmental standards.

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