TIP: Enclosure of machines. Use of Akustikabsorber and Vibrabsorber+Sylomer® products. Reduction noise level according the isolation technique.

Akustikabsorber® noise attenuating composites are often installed in industrial machinery to absorb, insulate and damp airborne noise.

Vibrabsorber+Sylomer® spring vibration isolators are often installed beneath industrial machinery to isolate structural noise.

This article aims to inform people of the expected typical improvements in noise reduction per frequency band of industrial machinery. For a more detailed view on reduction figures an acoustic engineer should be contacted.

Let’s imagine that we have a rotating machine that generates a noise level as seen below.

If we add Vibrabsorber + Sylomer® vibration isolators which provide a low natural frequency suspension and also assume that the ground is infinitely stiff , we will correct the noise level within the low frequency band. This is demonstrated on the graph below.

If we have no vibration isolators in place and add only an enclosure that is rigid and correctly sealed, we will correct the higher frequencies but have almost no impact/improvement on the low frequencies.

Combining the Vibrabsorber+Sylomer® vibration isolators and the sealed enclosure we will reduce both the high and low frequency bands as shown below.

Within the same enclosure if we add Akustikabsorber® soundproofing composites, we will further increase the noise insulation at higher frequencies.

If we provide a secondary step of isolation (double mass isolation system) comprising of an additional layer of Vibrabsorber+Sylomer® and Akustikabsorber, we can expect a further reduction of low, mid and high frequencies as shown below.

This kind of installation must be correctly studied taking in account the stiffness and damping per axis of the vibration isolators. It is also important to consider the weight of the intermediary frame as this plays a key role in achieving good results. More information on this topic can be found on the following article: VIBRATION ISOLATION ON INDUSTRIAL MACHINERY.

Do not hesitate to contact our technical department if you require help on this topic.