From Control Valves

Valve Features to Reduce Noise

Silencers and Diffusers

A diffuser is a pressure reducing device that is installed downstream from a control valve. The total pressure drop needed for flow control of a flow control loop is divided between the valve and diffuser. This enables the valve to operate at a lower pressure ratio (?p/p1) and greatly reduce the control valve noise level generated by steam, gas or vapor flow. A properly selected diffuser valve combination can result in up to a 40 dBA noise reduction.

The diffuser or silencer differs from other types of path treatments because it does actually absorb some of the noise energy. For control valve applications operating at high pressure ratios (?p/p1 greater than 0.8), a series approach, which splits the total pressure drop between the control valve and a fixed restriction such as a diffuser, downstream from the valve, can effectively minimize the noise.

The diffuser must be designed for each unique installation so that the noise levels generated by the valve and diffuser are equal. Valve manufacturers that offer diffusers will design for the conditions. Diffuser and silencer design are covered in Chapter 8.


Vent Diffusers

Control applications venting to...

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Products & Services
Control Valves
Control valves or proportional valves are power-operated devices used to modify fluid flow or pressure rate in a process system.
Hydraulic Valves
Hydraulic valves contain and transfer the flow and pressure of hydraulic fluid in hydraulic power systems. They range from simple shutoff valves to precision control valves.
Valve Actuators
Valve actuators mount on valves and, in response to a signal, move a valve to a desired position using an outside power source.
Manual Valve Actuators
Manual valve actuators do not require an outside power source. They use a handwheel or lever to drive a series of gears whose ratio results in a higher output torque compared to the input (manual) torque.
Pneumatic Valve Actuators
Pneumatic valve actuators adjust valve position by converting air pressure into linear or rotary motion.

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