Abstract: A non-blocking hopper for solids comprising a downwardly convergent hollow frusto-conical bottom part having a maximum radius R and a discharge aperture of diameter D at the narrowest (bottom) end. At least two V-shaped notches are formed symmetrically around the bottom part with their widest ends of width b and open to the discharge aperture, their apices being remote from the periphery of the aperture at a distance r therefrom. The following relationships are observed r.gtoreq. 0.3R; b.gtoreq.0.5D, and the angle between the axis and wall of the frustum is no greater than the angle of repose of the solids.