Hammer mill

The Problem

The Hammer Mill is used in the preparation of animal feeds and produces 93dB at 1.2m.

An enclosure was constructed from a frame built from 50 x 50 mm wooden battens and clad in 19 mm plywood sheeting, glued and screwed together. The enclosure was designed to be self-standing and allowed a minimum gap of 100 mm between the motor and the internal surfaces.
Air vents were left at the front and rear (motor end) of the enclosure to ensure airflow over the motor, with a stepped-baffle fitted to the rear air vent to minimise any noise seepage.
The only adjustments that had to be made on site during installation was the addition of a clearance hole to the bottom of the sliding door for the electricity supply and a clearance hole for the ducting running up the grain input pipe.
A 25mm thick sheet of fire retardant acoustic foam was glued to the inside face of the enclosure.

The noise levels were reduced by 8dB.

£80 for the full treatment (2005 rates).