Simple Diffuser Silencers

Additional Details

The Flo-Dyne Limited HUSH PUP is a non-packed, reactive silencer. It works by expanding the incoming flow through many small holes. This expansion creates a reduction and frequency shift in the vent noise. By correct selection of hole size, spacing and pattern this reduction can be optimized to produce an overall quieting. This simple, yet effective silencing concept has been tested and proven in over thousands of applications as a component part of Flo-Dyne vent and in-line silencers.


The HUSH PUP can be used in any high pressure vent application where a moderate degree of silencing is required. Typical applications include steam relief valve discharge, air compressor vents, boiler blow down lines, gas plant vents and product dump vents

The HUSH PUP will provide a 15 to 20 dB reduction on most vent applications The attenuation curve shown is the actual performance attained on a high pressure air vent test. For more critical silencing application, the Flo-Dyne Limited Vent Silencer is available.

All steel construction allows the handling of high temperature gas or steam. Designed like a pressure vessel, the HUSH PUP can be subjected to high pressure, high impact flow with hush pup attenuation curve no problems. Hole sizes, equal or greater than those of quiet trim valves, prevents clogging problems encountered in some metal type silencers. The all-welded design provides years of non-maintenance, trouble free service.