How Does a Tub Grinder Work?

Tub grinders are equipment used for grinding down large pieces of wood. Construction companies and clean-up crews use tub grinders to clear parcels of land or to clean up after a storm in which branches or trees are blown down.

Another name for a tub grinder is wood chipper, but the term "tub grinder" refers specifically to pieces of equipment utilizing a tub-like shape. Tub grinders can turn large trees, brush and wood into wood chips that can then be sold to gardening centers, stores and individuals. A tub grinder has a large metal rotating tub into which large pieces of wood are fed. Depending on the type of tub grinder, the wood can be fed using a front-end loader that scoops up wood and drops it in the grinder or by a claw that is attached to the grinder.

Components

A tub grinder is divided into upper and lower sections. The upper section houses the tub grinder, while the lower section contains a hammer mill. A conveyor belt extends away from the tub grinder and expels the chipped wood. The hammer mill has rods that extend through the hammer and rotor plates. The hammer works to break up the pieces of wood so that the grinder’s blades can chip it into small pieces. A tub grinder provides a variety of sizes of wood pieces, from short chips to longer stringy pieces of wood.

Process

Once the wood enters the machine and the hammer mill breaks it up, it is chipped into small pieces in the grinder and then moves onto a conveyor belt. The conveyor belt may be in a chute that points at an angle to shoot the wood chips into a large pile, or it may be a belt that slides the chips into a collection bucket. Tub grinders are portable, allowing them to move around a work site easily, reducing large pieces of wood into easily portable wood chips.