Identification marking during the manufacture and refurbishment of beer barrels can result in A-weighted noise levels of 105dB. During marking, barrels are imprinted with a series of numbers and letters naming the owners and indicating the type and serial number of each batch.
Modern methods now use machines for large batches. Early designs used pneumatic impact cylinders to make an impression on the empty barrels. Acoustic screens limited noise radiation to neighbouring workers but did not reduce the exposure of the operators.
The new machinery combines pneumatics and hydraulics to control the impactive strike. The pneumatics accelerate the die towards the barrels but stop it short of the actual point of impact. The hydraulic compression finishes the impression stroke by applying a force of 15 tonnes over the last 3 mm of the die movement.
About £3000 per machine. (1995)
A noise reduction of about 20 dB. An additional benefit has been an improvement in the quality of definition in the lettering and numbering.
The photograph was supplied by Alumasc-Grundy Limited.