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Safely & Correctly Select and Size Your Next Regulator

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Safely & Correctly Select and Size Your Next Regulator

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We’ve covered a lot in our series on Pressure Regulators – the basic make up and function of a pressure regulator, regulator troubleshooting, and regulators for specialty applications – but we’ve yet covered the hard and fast criteria for selecting and sizing a pressure regulator for your unique application. The process of selecting the correct regulator requires definition of the application according to pressure requirements, flow rate, gas/liquid composition and temperature.

Rule of Thumb

When selecting a regulator, look for the right size as well as the correct set of capabilities, which is a function of the regulator’s design. The best way to select a regulator for your application is to examine its flow curve, which is often provided by the manufacturer. Have trouble with interpreting flow curves? Our whitepaper on Pressure Regulator Selection explains flow curve interpretation in greater detail:

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Regulators should be sized based on the largest possible flow and the smallest change in pressure. In the event your requirements approach the limit of the regulator you’re selecting, consider using the next largest regulator available for your application.

A Note on Valve Sizing

Valve sizing means determining how much flow can pass through the pressure regulator, not the size of the end connections. Since gases are compressible and liquids are not, significant differences exist when sizing for gas and liquid regulators. We discuss consideration for gas and liquid flow, and specific gravity correction factors for gases, in our recent blog: Keep Ahead of the Curve.

Selecting a Regulator

Safely and correctly selecting a regulator requires project-specific information – no two conversations around pressure regulators are the same.

Information Needed to Quote a Regulator:

Regulator Function	Pressure-reducing, back-pressure, specialty, etc.
Inlet Pressure	What are the minimum and maximum pressures, including units?
Outlet Pressure	How accurate do you require an outlet pressure reading (provide a range)? In what units?
Flow	At what inlet and outlet pressure do you require flow? In what units? Use flow curves to help you determine this, or contact us for assistance.
Medium	Composition of fluid – is it a gas or liquid?
System Compatibility	Consider the materials of construction required including the valve body, seat and diaphragm materials as well as o-rings.
Loading mechanism	Spring- or dome-loaded? External feedback?
End Connections	Specify size, spec, and pressure class.
Surface finish and lubrication	Specify surface finish Ra value if needed and what lubricants are preferred.
Options	Detail all special requirements such as certification of material, special testing, etc. as well as any additional options you require (handles, hoses, isolation valves, etc.).
Temperature range	Include fluid minimum and maximum temperatures as well as environmental minimum and maximum temperatures.

All our Regulator Resources – One Click Away

With many variables to consider, selecting the correct regulator can be an intimidating task. At Swagelok, we want to ease the pressure on you. If you have unanswered questions, or are unsure how to proceed with correct product selection, our regulator subject matter experts are here to field your call.

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