Abstract: In a belt conveyor, the belt parts are carried by a gas. Each belt run moves over a trough bottom with apertures allowing gas to enter between the trough bottom and the belt run to carry it with low friction. The invention, aiming at optimum operating conditions, proposes to draw in the gas from the environment by a compressor through the apertures for the return, non loaded run of the belt and to blow gas by the same or another compressor to the apertures in the trough bottom for the upper, loaded run of the belt and to choose the apertures for the lower run so that there are at least 2 and at most 40 per meter length of the belt and that the total surface area of these apertures is at least 1.5 cm.sup.2 and at most 20 cm.sup.2 per m.sup.2 belt surface area.

Abstract: For belt conveyors in which the loaded part of the belt is supported by a gas layer in a trough, the energy needed to drive the belt is lower if the belt is more fully out of contact with the trough. But much energy is needed to compress the gas carrying the belt. The invention proposes to provide for measuring the power for these two purposes and to alter the gas flow into the trough so that the total power requirement is at a minimum. The latter may be performed in steps and as soon as a step appears to result in an increase of power required, this step may be undone. Drives of the belt (1) and of a compressor (6) by electric motors (5, 8) make measurement of electric power supplied thereto preferable. A control member (14) receives signals of power measurements and issues signals to change the power for drive of the compressor. Instead of separate measurements added by the control member (14) the latter may be fed with a measurement of the total power supplied for both purposes.

Abstract: The invention relates to a conveyor comprised of an arcuate endless belt, a stationary trough below the belt and a device including perforations in the trough for introducing a fluid under pressure between the trough and the belt to support the belt. The belt is flexible in planes perpendicular to its length to shape itself to the contour of the trough by virtue of its own weight.