High-pressure pneumatic loops periodically need to return some of their pressurised air to the atmosphere to stay balanced. Whether they’re lifting, pushing, or holding, pneumatic exhausts and outlets help keep the internal psi levels in valves, cylinders, and pipelines stable and safe.
However, unprotected venting creates mechanical stress if not managed carefully. Rapidly pushing excess air through a narrow port creates strong vibrations – resulting in unwanted noise. Pneumatic exhaust noise pollution can be hazardous as well as unpleasant, posing a risk to hearing. Ambient ‘buzz’ can wear down nearby unprotected eardrums over time, leading to tinnitus and deafness.
You can minimise waste noise by installing a noise-limiting silencer over a machine’s pneumatic exits before starting work.
What Is A Pneumatic Silencer?
A pneumatic silencer (or ‘muffler’) is a specialised exit valve filter that seals neatly over each air exhaust. By passing air through a fine mesh trap, airflow is slowed and depressurised before it exits the loop. You’ll often find silencers used at multiple points in a single system to help spread the strain of depressurisation. Some silencer valves include manual throttles and locks to better aid airflow control.
How Do Pneumatic Silencers Work?
A pneumatic silencer is a classic example of an active inertial dampener. It doesn’t arrest all gas motion, as that would block the vent! Instead, the valve controls and limits the spread and flow of kinetic energy. Dense, interwoven grids absorb and contain the waves of kinetic force generated by pressurised air moving and colliding against solid barriers on the way out. The range of nearby ambient noise lowers from a potentially risky 80-120 dB (i.e. heavy industry shopfloor levels) to a far safer 40-80 dB (i.e. soft person-to-person speaking).
Which Materials and Shapes Do Pneumatic Silencers Use?
Most silencers use exposed blocks of sintered brass, plastic, or stainless steel mounted on a bolt-on solid brass and rubber sealed attachment. Silencer filter blocks often look sponge-like due to their micromesh construction. You can buy many types and shapes of silencer. The most popular pneumatic valve variants are brass-mounted cone (direct vertical) and circular flat (wide).
Find Out More
At Hydrastar, we provide a range of silencers from Festo and other leading pneumatic manufacturers. To find out more, or to discuss noise-reduction strategies with one of our team, please get in touch today.