Device for the conveyance of bulk material

A device for the conveyance of material, in particular bulk material, comprising at least one trough-type conveyor element with a cyclical drive for transmitting a propelling force periodically to the material present in the trough-type conveyor element at least in the envisaged direction of conveyance, wherein provision is made for at least two parallel, mating trough-type conveyor elements which can move lengthwise relative to each other, and which each have an essentially U-shaped cross section and with their open sides face each other, with the free edges of the side walls essentially resting against each other, so that a closed conveyance space is produced in the form of an oblong conveyor box, and the two trough-type conveyor elements are provided with a cyclical drive which acts both transversely to and in the lengthwise direction of the trough-type conveyor elements, the drive of the two elements when transverse to the lengthwise direction being in phase, and in the lengthwise direction exhibiting a relative phase shift of about 180 degrees.