A conveyor system may include a pipe conveyor with a head end, a tail end, and an inclined section. The conveyor system may also include a conveyor belt including a first portion and a second portion. The conveyor belt may form a pipe shape when the first and second portions of the conveyor belt are overlapped. The pipe shape may extend from a pipe closing point to a pipe opening point and may enclose two or more longitudinally spaced-apart centering structures. The centering structures may allow for self-bridging of a bulk material carried in a pipe volume above each centering structure. Means of implementing this material-transport principle within a pipe conveyor system are described.