Thank you for drawing attention to this propriatory form of hopper, which has a place in the market.

I am very familiar with the work of Jerry Johanson and a great admirer of his contribution to the field of hopper design, segregation and solids flow problems. His innovation of the diamondback hopper exploits the benefit of plane flow over conical flow, with the additional innovation of focussing a slot with radius ends to a circular outlet. Nevertheless, I would re-iterate that Mass Flow essentially requires relatively steep walls compared with non-mass flow construction. The wall angle can be relaxed slightly by untilising the technique of 'Sigma Two Relief' when terminating at a slot and, with some refined design attention, with a circular outlet.

One point I was trying to bring out is that the selection of a mass flow form of flow may be made for different reasons. The most common reasons that mass flow is chosen are either to avoid dead regions of storage or to secure the flow advantage of passing through smaller outlets. For the latter benefit, an 'expanded flow' construction is usually adequate. There remain many duties for which mass flow is not needed, in which case lower headroom is required for a given storage volume. The choice of flow regime is therefore a crucial, initial decision of hopper design ■