First introduced in 1994, the little Model CP-4 screw press has proven a steady seller.  The largest single market is laboratories, although most sales fall in a wide range of miscellaneous.  Until the advent of the Model KP-6, the press was a popular in the plastics recycling industry for dewatering wash tank sludge.  Recent applications include pressing cranberries, egg shells, nutraceuticals, crumb rubber, sludge from sidehill screens, fish waste, alfalfa, and orange juice pulp.

With each production run a review is made for possible improvements.  We are now in our 52nd production release! Looking back, we see that the press has gradually become more powerful, safer, and more reliable. Just like automobiles.

The CP-4 is extremely handy to use because it can be plugged into any 110-volt wall outlet.  Also, the capacity is such that it can be conveniently fed from 5-gallon pails.  We have forty-eight of these in our rental fleet today, so there is almost always something available.

The 4″ screw of the press is driven by a hollow shaft gearbox.  Motors ranging from 0.5 to 7.5 hp can be supplied, although 1-1/2 hp is most common.  As with the original prototype, the screen is profile bar with 0.015″ slot width, with four stationary resistor teeth.

To regulate the moisture content of the press cake, an air cylinder actuator is used to position the discharge cone.  This replaces the weight arm and spring actuators used in some earlier versions.

The latest CP-4 looks quite different from predecessors.  The press liquor collection pan is now, for easy cleaning, made in an inverted pyramid configuration.  And the bronze discharge cone has been switched to UHMW plastic.

The inlet hopper features a vertical wall on one side and a sloped wall on the other.  The vertical wall is used to minimize bridging of material in the inlet hopper, while the sloped wall is employed to maximize hopper capacity.

Units are frequently customized.  Stands with wheels are also available.  VFD’s which accept single phase power are used to allow variable speed operation.  Gearboxes can be changed for different screw speeds.  Various screw options, including hardsurfaced, notched, and conical, are offered.  On occasion the press is made vapor-tight, with an explosion proof motor.

Originally published January 16, 2002
Updated June 2010
Updated July 2018