Importance

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Abstract

A screw press comprising a flywheel rotatable continuously in one direction and a pneumatically operated coupling, selectively operable to couple the flywheel to the screw for a working stroke, wherein the coupling has a pressure chamber supplied by way of a one-way valve and dischargeable by the action of an inertial mass which rotates with the screw during its working stroke and inertially relative to the screw at the end of the working stroke to open a discharge orifice of the pressure chamber. A valve piston is moveable axially of the screw in a cylindrical recess, serving as an input chamber for supply air, which valve piston projects into a second chamber, connected to the atmosphere and having an opening, coverable by the valve piston, for supply and discharge of the pressure chamber. The valve piston is provided with at least one through passage having a one-way valve for feeding air from the cylindrical recess input chamber to the pressure chamber, and having a servo-valve operable by the inertial movement of the inertial mass to discharge the input chamber to the atmosphere, the resulting pressure differential across the valve piston causing it to open the pressure chamber discharge orifice.

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First Claim