Expanded Applications
As the years went by, applications of the interrupted screw design were expanded beyond slippery and slimy materials. This took place because competing continuous screw presses worked best only under conditions of constant feed, at constant consistency. If either the consistency or the flow rate diminished, squeezing would diminish until it was inadequate for proper moisture removal. At the same time, if the consistency increased, the press could jam. To counteract these tendencies it was necessary to build a very heavy press, frequently with an expensive variable speed drive.
In contrast, it was found that the interruptions in the flighting of the Anderson screw would provide cushion within the press. If consistency went down, compression was still effective. A plug of sufficiently solid material had to build up at each interruption before solids could progress towards the discharge. This self-correcting performance prevents wet material from purging at the cake discharge. It is achieved without varying the speed of the screw.
The economic advantages of these characteristics led to interrupted screw presses being used to dewater fibrous materials that are neither slippery nor slimy. Examples would be alfalfa, corn husk, and, more recently, paper mill fibers.
Read more about this topic: Expeller Pressing
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