that need weighing up towards each other preferably the first opposing segments 17 18 and the second opposing segments 19 20 do not meet on the lower edge 7 but the intermediate segment 21 22 23 24 is intermediate also on the lower edge 7 thus shaping round corners 13 14 15 16 of the lower edge 7 for an optimal flow the friction of the inner wall 33 in the conical part 4 should preferably be as low as possible e g stainless steel will work the friction of the inner wall in the cylindrical part 2 is less critical and may be higher not only the shape of the bin 1 but also the rotary pocket feeder 40 for discharging the material affects the result in order to have a uniform flow of the material the rotary pocket feeder 40 should preferably feed the material uniformly from the whole cross section of the lower edge 7 or there is a risk that stagnant zones will occur in the simplest form of the invention could the rotary pocket feeder include only one rotating feeder means in the preferred embodiment disclosed in drawings the rotary pocket feeder 40 comprises two rotating means 41 42 see fig4 a h it is an advantage to have two rotating means 41 42 that are counter rotating because the symmetry will increase the probability for a uniform feeding of the material from the whole cross section of the lower edge 7 the opening formed in the lower edge of the bin forms a rectangular shape with a ratio of the first long sides 9 10 to the.