Abstract: A pneumatic tubular conveyor pipeline is provided for conveying solid products, for example, in granular or chunk form. The conveyor pipeline comprises an outer impervious pipe and a smaller-diameter inner porous pipe. The inner pipe has longitudinally-spaced, uni-directional pressure responsive vents dividing the inner pipe into chambers. A gas pressure source is connected to the upstream portion of the inner pipe. A feed apparatus is connected to the feed end of the outer pipe for injecting the product into and propelling same through the outer pipe. The chambers vent consecutively through the vents in the downstream direction at a rate determined by the product flow through the outer pipe, as the surrounding portions of the outer pipe become filled with the product.