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Pressair uses airlift technology to raise mixtures and solids above water. The principle is as simple as it is efficient, and takes advantage of an elementary physical law using the least mechanical effort.
A pipe (delivery pipe) is vertically stuck into water with one end above water level. Through a second pipe of smaller diameter air is pushed into the lower end of the delivery pipe. There, air de-compresses and expands. Consequently, an underpressure occurs in the delivery pipe, pulling in water and solids independent of shape, size or gravity, raising it up to the surface. So much for the principle.

In fact, for efficient dredging and mining it needs much more. Air volume, pressure, feed and control need to be well managed. That's Pressair's know-how and that's why Pressair received patents and awards in all major industrial countries and is considered a technology leader.
It is obvious that the Pressair-system needs few mechanical components and that they are not exposed to excessive wear caused by solids. The solids concentration is important, and oversize of up to 350 mm (14") diameter can be handled easily. Theoretically there is no limit to dredging depth.To remove compacted deposits or to penetrate hard layers, Pressair's delivery heads are fitted with a hydraulically powered cutterhead. A cross-section of a Pressair delivery head (right)
shows the driving and air control system. Sensors inside the head monitor all important data and service intervals for display on the operator’s control panel.
The life of a delivery head is infinite, as all wearing parts can easily be replaced.