Page 68 - Energize April 2022

TECHNICAL

Figure 4: The modal suppressor consists of cylindrical chambers of varying sizes surrounding a full bore perforated tube. Each chamber generates destructive
interference over a small range of frequencies to provide significant noise reduction across a broad spectrum.

A new option for noise reduction References
The modal suppression WhisperTube is a simple, passive device offering a 10 dB average 1. Lighthill’s Law – see https://bit.
noise reduction across a broad range of frequencies (Figure 5). This new design is full-bore ly/35HQjlL
and generates no pressure drop. When combined with a full ported ball valve, the device can 2. Vena contracta is the point in a fluid
provide a noise suppressed pipeline control system that can be pigged without additional pig stream where the diameter of the
catching and bypass equipment. Less expensive butterfly valves can also be paired with this stream is the least, and fluid velocity is
device to provide a lower cost option as compared to a typical globe control valve with low at its maximum – https://en.wikipedia.
noise trim. org/wiki/Vena_contracta
Finally, the self-draining version can be utilised for steam and two-phase flow
applications where liquid accumulation would adversely affect many other noise abatement Acknowledgement
designs. This article was first published by
Hydrocarbon Engineering and is
Conclusion republished here with permission.
It may have been nearly 40 years in the making, but additive manufacturing and some
diligent engineering have finally brought full-bore noise reduction to reality. Applicable to Contact Jacqueline Marie Moreno,
either gas or steam, the new product offers new possibilities for pipeline applications, as well Emerson Automation Solutions,
as high noise control valve applications in a variety of services. jacqueline.moreno@emerson.com

Figure 5: Concentric rings of various sizes create broadband noise reduction as shown in this chart. Generated noise and rejected frequencies tend to shift higher
as pipe size is reduced, so the suppressor is well matched to the typical application.

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