A Pneumatic silencer’s function is to vent pressurized air after it has performed work at a safe noise level and to prevent contaminants from exiting (if it is combined with a filter). Excessive noise may be produced as the pressurized air is released to the environment. Noise is the result of turbulent air which is produced when the fast-moving air released from the vent collides with the static air of the environment. Typically, silencers are installed directly at the exhaust port of a valve and diffuse the released air through a larger surface area which reduces turbulence and thus decreases noise levels. Pneumatic exhaust silencers are commonly designed with a porous material to increase the surface area of the exhaust port which it covers. They can also be installed on hoses. A pneumatic silencer is used to vent pressurized air to the atmosphere. They are commonly installed on pneumatic 5/2-way solenoid valves, pneumatic cylinders, or fittings. Depending on the flow and pressure of the air coming out of the exhaust port, the pneumatic air exiting the device could produce noise that is potentially harmful to workers in the surrounding environment or cause noise issues in the application (theatre applications). In addition to noise, the exhaust air may emit contaminants during operation. Using a silencer exhaust cleaner can prevent harmful contaminants from entering the environment. Standards defined by organizations such as OSHA (Occupational Health and Environmental Control Agency) are enforced by governments to help protect workers from harmful noise and contaminant exposure
Sintered brass is a lower cost option for a durable metal housing. An example of a sintered brass silencer this material is suitable for non-corrosive and neutral environments.
Throttle valves are commonly included with silencers and are commonly just called adjustable pneumatic silencers or flow control silencers. Adjustable pneumatic silencers are an inexpensive method for pneumatic flow control to control the speed at which air exits the valve. For example, by controlling the exhaust speed of a pneumatic cylinder you can control how quickly the piston is able to extend and/or retract. The flow rate of air is typically adjusted by rotating a knob to change the flow speed, like a needle valve. The position of the screw will increase or decrease the size of the valve orifice and thus adjust the flow rate of the air exiting the valve