The Evolution of the Grizzly Screen
A grizzly screen provides a simple, initial sorting method for rough materials. Grizzly screens are mainly used in mining and other sorting industries where it is necessary to sort materials by size. Grizzly screens were first used several hundred years ago, when mining first became industrialized. Since the early invention of grizzly screens, the machine has changed several times to evolve into a machine that works with modern manufacturing and mining processes.
The earliest grizzly screen was simply a series of metal bars that miners used to separate different materials back in the 1800s. Miners used the bars to separate the unwanted materials from the smaller blocks of rocks and stones that they wanted to collect from the mine. These initial bars were operated by hand, and workers simply spread the rocks over the bars to separate the material.
About 100 or so years later, the grizzly screen became automated. The bars still were designed to separate materials, but a motor-run vibrator helped separate the materials automatically. This flat design was used for many years, but lacked the efficiency of the latest design.
Most modern grizzly screens incorporate a sloping design into the hopper. The materials are spread onto the hopper and the slope combined with the vibrations of the machine help separate the materials. Other units also have multiple screening sections to filter out materials of various sizes. Some units rely on gravity only to filter the materials rather than a vibrating machine.
Grizzly screens have come a long way since their invention over 200 years ago, but the modern design still uses the same original idea as the very first units. Depending on the manufacturer, you can find screens capable of handling small or large loads of loose stone and dirt.