A manufacturer of tube fittings made extensive use of vibratory bowl feeders to move metal products around and to transfer them from a hopper to the next stage of a production process. The noise level associated with this was 96dB.
The inside surfaces of the bowl feeder were faced with a 3mm thick layer of shotblast rubber held in place with a contact adhesive.
The noise level was reduced by at some 5dB to 91dB.
£70 per bowl feeder (including adhesive, and in house labour).