Hammer mill

The Problem

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

The Solution

• 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 Results

The noise levels were reduced by 8dB.

The Costs

£80 for the full treatment (2005 rates).