This is a Hollander Beater. This one was designed and built by Mark Landers of Christchurch, New Zealand.

Small pieces of cotton fabric are placed in the beater, with water, and then macerated as the cloth passed between the stainless steel ribs on the grinding wheel and the ribbed plate in the bottom.

A 1/2 Horsepower motor drives the grinding wheel and causes the mixture of fiber and water to circulate.

After an hour of beating, you can see the fibers pulling apart.

A close-up of the fabric before beating.

The beating process causes the cells in the cotton strands to expand and bond with the hydrogen, creating pulp. This process is the origin of the saying, "beaten to a pulp."