Feed hopper geometry

The design of a storage container for bulk materials is rarely taken in isolation, normally being influenced by various facets of the associated plant or the background of the manufacturer. There are three main steps to selection of storage hopper geometry (i) body configuration (ii) outlet size and shape and (iii) the transformation between the two. 

The second, and crucial decision, is the shape of the outlet. This is determined by the feeder coimection, of a size rated to deliver the output, with an extraction profile and inlet length as selected. The interface connection for a screw feeder is usually a slot form, with a length 

Utilizing this technique requires consideration of the upper dimensions of the diverging section of the flow channel. The reverse wall angle must not unacceptably reduce the length of the flow slot, certainly not to be less 

This is wasteful of headroom a more efficient way is to crank the side walls to facilitate the connection between tapering edges with a flat surface, the faces having to diverge to the same width in differing heights. 

Clearly, the headroom available at the deeper end allows the coimecting edge to be steeper than the opposite end, where less depth is required to attain the same horizontal displacement. The faces of the wall formed by the cranking of the plate follow these inclinations. The crank, or set , in the side wall faces can be made in one of two ways, either crank-in or crank-out , see Fig. 5.24a and b. 

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A special feed hopper design to minimize flow problems was developed by Johanson (1). The geometry of this hopper transitions from a circular cross section to an oval cross section and back to a circular cross section it is called the diamondback hopper (see Fig. 32). 

An overview of feeder design and performance with specific reference to belt and apron feeders is presented. The interfaee geometry of the feed zone is examined in relation to the requirements for the optimum draw-down pattern in the hopper. Relevant aspects of feeder load and drive power determination is reviewed and the need for controlling feeder loads is stressed. The influence of hopper and feeder interface with respect to the shear resistance and feeder slip is outlined. 

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