A successful application for a Vincent screw press has been found at a diaper factory.

Diapers, and similar sanitary products, used to be rectangular. Today, they are hourglass shaped. This configuration can either be achieved by using a water jet to cut the pattern from a continuous strip or band of material, or it can be die-cut. It is in the former process that a screw press is valuable.

Manufacture starts by continuously unwinding large rolls of woven inner liner, cellulose fiber or matting (with SAP – super absorbent powder), and waterproof outer liner. These layers are sandwiched together. The laminate band produced is fed through high pressure rolls to form crease marks, checkered patterns, and the hourglass shape.

Next, the water jet cuts the material on the outlined crease marks. The water jet uses high pressure water, at 50,000 to 60,000 psi, to cut the desired shape. The cutting water passes into a tank under the cutting table. This tank is fed additional water to cushion the jets and to dilute the flow.

It is the water from this tank that is fed to the Model KP-6 screw press. Featuring a wedgewire screen and rotating cone, this press separates the solids from the water. The solids, mostly paper fiber, with some SAP and liner material, come out very hard and dry. They go to landfill, while the press liquor is clean enough for the sewer system.

The flow has a very high degree of freeness. The KP-6 easily handles a 30-gpm flow from four diaper lines.

July 2008 Update

We thought we were on to a neat market niche. Unfortunately the diaper industry has moved on to using a die-cutting procedure for cutting out the diapers. If the diapers aren’t wet, a screw press can’t do anything with them.