FAQ Knowledge management

FAQ Pressure regulators - Your questions, our answers!

Swagelok offers an extensive range of pressure regulators for a variety of applications in a wide range of industries.
But which pressure regulator is the right choice for your application? We try to answer frequently asked customer questions about pressure regulators in our FAQ.

1. How do I select a pressure regulator?

When selecting products, the entire system design must be considered to ensure safe, trouble-free operation. The following points should be considered:

• Media in the system
• Pressure reduction (pressure reducing regulator) or pressure monitoring (back pressure regulator)
• Load type of pressure regulator (spring, simple and inexpensive, dome with high accuracy but two regulators, or remote-controlled with electric motor)- Resistance to the medium used (e.g. seal or body material)
• Connections
• Maximum inlet pressure
• Outlet pressure range
• System temperature: The temperature range in which our regulators can be used depends on the material of the O-rings, diaphragm and seat.
• Flow rates (volume flows)
• Pressure gauge or pressure sensors
• Flow direction (e.g. right to left): This is important for pressure gauges, as they should not be upside down (legibility).
• Shut-off valve (at inlet or outlet)
• Protection of the outlet side using an overflow valve: The maximum permissible operating pressure of the regulator should never be exceeded. On the outlet side, the maximum permissible pressure is 1.5 times the set outlet pressure. We therefore recommend using overflow valves and setting them so that slight fluctuations in the outlet pressure do not trigger a blow-off.
• Installation position of the pressure regulator: The Swagelok regulators of the RHPS series should be installed horizontally with the spring housing facing upwards. Vertical installation is generally possible, but can lead to inaccuracies in the control behaviour and increased wear
• Self-venting
• Certificates (e.g. 3.1 material certificate, FDA, etc.)
• Particles: If the medium is contaminated with particles, filters should be installed. Pressure regulators are normally leak-tight. Particles in the system often lead to damage to the seat and thus to leaks. Regulators for industrial applications do not need to be leak-tight. If this is required, additional shut-off valves must be used. The use of good system filters is also recommended.

We define the dimensioning of the pressure regulators by means of calculations based on your specifications and use the flow curves in the catalogues.

2. What is the difference between a pre-pressure regulator and a pressure regulator?

The classic pressure reducer or pressure regulator reduces an inlet pressure to the desired control or outlet pressure. Swagelok offers you a wide range of options. Back-pressure regulators regulate the inlet pressure upstream of the pressure regulator. Swagelok offers a wide range of inlet pressure regulators in many pressure control ranges. The pressure regulators offer the following options:

• Spring- or dome-loaded
• Diaphragms or pistons as sensor element
• Connections from ¼ to 4 inch thread, welding connections, DIN and ANSI flanges, VCR and Swagelok connections
• Cv values from 0.02 to 73
• Pressure control ranges from 0-0.01 bar up to 0-700 bar- Gas cylinder switching stations
• Tank- Overlay pressure regulators (tank blanketing)

3. Why are there pressure regulators with piston or diaphragm control?

As you can see from the title, the control mechanism of the pressure regulator is described here. The control element is the component that separates the force of the spring/dome from the system force. The control element can react to a change in pressure and restore the desired set pressure.

Piston control
A piston is a cylindrical metal component that is usually used to regulate a high control pressure that is too high for a diaphragm control. Pistons are also more resistant to damage caused by pressure surges.

Diaphragm control
The diaphragm is a large, flat disc made of plastic or metal, depending on the application. A diaphragm is normally used for low control pressure applications in spring-loaded pressure regulators and in all dome-loaded pressure regulators.

You can download a comprehensive pressure regulator FAQ here.

Didn't find the answer to your question?

We will be happy to help you. Simply send us your question by e-mail to info@arborag.ch or call us on +41 56 485 61 61.