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 steady seller to the plastics recycling industry for dewatering wash tank sludge. Recent applications include pressing cranberries, 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. Recently our seventh production was completed. 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.

The 4" screw of the press is driven by a hollow shaft gearbox with a 1-1/2 hp motor. The screw is gripped by taper-lock bushings, a recent improvement. As with the original prototype, the screen is profile bar with 0.020" slot width, with four stationary resistor teeth.

A new option being offered is an air cylinder actuator for the discharge cone. This replaces the spring actuator used in some earlier versions. The standard discharge arrangement uses counterweights to push the cone against the material being pressed.

The latest CP-4 looks quite different from all predecessors. Previously a side yoke was used to support the tail bushing (or bearing). The new units have an overhung arm support. The advantage is better visibility of the pressing operation, with less opportunity for the press cake to hang-up at the discharge.

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 available. Gearboxes can be changed for different screw speeds; and the pan can be modified for a bottom (instead of side) drain. Various screw options, including hardsurfaced, are offered. On occasion the press is made vapor-tight, with an explosion proof motor.