Inlet and outlet silencers reduce noise by several decibel levels in typical STP applications by lowering air pulsation within the piping system and airborne noise radiation in the vicinity of the blower. As an added benefit, the reduced air pulsation improves check valve life. Silencers are offered in two styles: chamber and combination absorptive-chamber. The style you choose depends upon the speed at which you’re operating your blower in relationship to its transition speed. Transition speed is defined as the point at which mid and high-frequency amplitude increases dramatically.
The lower-cost chamber style silencers can be used with blowers operating below their transition speed. Chamber style silencers incorporate a series of expansion chambers and acoustically balanced bypass tubes for noise attenuation at low to medium speed ranges.
Premium absorption-chamber style silencers include the same features as chamber style silencers with the addition of an acoustically packed blower connection to reduce objectionable high frequency noises that occur above transition speeds. They are also suitable for use throughout the entire speed range of PD blowers listed in the USABlueBook Catalog.