The hydraulic power pack of a 250 tonne billet hydraulic guillotine was found to be generating A-weighted noise levels of between 90 and 95 dB. Noise was generated through vibration transmission from the motor pump unit to the machine frame (and through rigid pipework to the remainder of the machine) and impacts from the valve bank. An acoustic enclosure was unsuitable because its effectiveness would have been limited by the transmission of vibration through the pipework.
It was decided to reduce the noise by isolating the noise sources from the guillotine. This solution was considerably cheaper than an enclosure and did not affect access.
The motor and pump units were mounted on a rigid frame, isolated from the machine. The rigid pipework was interspersed with flexible couplings. The valve bank was isolated from the machine frame using a cork-rubber composite.
A noise reduction of at least 17 dB.
Photographs courtesy of Joseph Rhodes Limited. Acoustic consultants were Industrial Noise and Vibration Centre.