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Restriction Orifice Design
Pressure Control · Flow Control · Cavitation & Choked Flow Management
A restriction orifice (RO) is a plate, similar in construction to a measuring orifice plate, installed in a pipeline purely to create a defined, controlled pressure drop — not to measure flow. It is used to limit flow rate, protect downstream equipment from excess pressure, or reduce pressure ahead of a control valve or vessel, without the cost and complexity of a control valve.
Because ROs are sized for pressure control rather than measurement accuracy, the design emphasis shifts toward managing the consequences of a large, deliberate pressure drop: cavitation in liquids, choked (sonic) flow in gases, high fluid velocity through the bore, noise generation, and erosion at the downstream edge.
Design Considerations
No moving parts and far lower cost than a control valve for applications needing a fixed pressure drop rather than variable control.
Passive mechanical design with nothing to actuate, minimising failure modes in critical pressure protection duties.
Fits within a standard flange or spool piece with minimal additional space or piping modification required.
Provides a hard physical limit on maximum flow rate through a line, independent of upstream pressure fluctuations.
Our engineers will size an RO for your required pressure drop while checking cavitation, choking, velocity, and noise limits.
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