Swagelok Regulators: Always Changing to Meet the Need
by Keith Johns, on Fri, Jul 27, 2012 @ 14:07 PM
Get to know them better, and you'll choose yours with confidence
If someone has tapped a line downstream of the regulator, that changes the flow characteristics. The same is true if someone has added a line. If your plant has been expanded, the distribution system will draw from your main tanks differently. The same regulator that was ideal for the original conditions might now be undersized or oversized. Understanding the changes will help you select the regulators you need now. Download the Pressure Regulators PDF (4.98MB)
If you are used to working with valves, regulators can seem confounding at first. It’s true that there’s a lot more to a regulator and the job that it performs. In this post we’ll go over some basics that will make it easier for you to select the right regulator for each job. We’ll follow up with more detail about some of the Swagelok regulators available to you.
Valves are relatively simple devices. If you know your application needs and the basic pressure and temperature information, you can figure out what valve you need. A regulator, on the other hand, is always changing itself as it reacts to the processes going on around it.
A regulator adjusts the inlet opening to make sure you get a consistent outlet pressure within a certain range of inlet pressures and flow conditions. You need to know not only the inlet pressure, but also the pressure you want on the way out, and how much flow is acceptable. Remember, regulators regulate pressure, not flow.
Each regulator is designed to work best within a certain range of conditions. Bump up against one end of the range, and the pressure will build up enough to close off the inlet. That’s called lockup. Go all the way to the other end of the range, and the regulator will be wide open, and is no longer regulating pressure. That’s called choke flow.
Each regulator has its own optimal flow range between lockup and choke flow.
Obviously, there are some moving parts inside. Some models use an internal spring to control outlet pressure. Others control the outlet pressure by means of pressurized gas in a dome atop the regulator. The sensing mechanisms vary too; from a diaphragm to a piston.
Spring-loaded regulators are a lower-cost option, but the design is more susceptible to temperature, shock, and vibration. Dome-loaded regulators are more rugged, but tend to cost more and take up more space. There are also designs that use a combination of spring loading and dome loading.
Cause and effect
At Swagelok, we’re glad to help customers find the appropriate regulator for each job. But you’ll feel more confident in your choice if you take the time to understand your own systems better, and what you are asking a regulator to do within that system.
Even if you already have a regulator in place, changing conditions may require you to replace it with something slightly different. Here’s why: In any fluid system, you are basically moving a liquid or a gas from Point A to Point B. When changes are made anywhere between those points, the regulator is suddenly required to operate under new conditions.
If someone has tapped a line downstream of the regulator, that changes the flow characteristics. The same is true if someone has added a line. If your plant has been expanded, the distribution system will draw from your main tanks differently.
The same regulator that was ideal for the original conditions might now be undersized or oversized. Understanding the changes will help you select the regulators you need now. Blueprints of your system can help you understand what’s going on, but only if they’ve been updated to track every change since it was built.
Don’t forget the other elements that go along with regulators -- the filters, flange connections, gauges and more. You want all components of the system to match the regulator's performance.
Over the past decade, Swagelok has acquired a pair of companies in order to bring you a full range of regulators for a wide variety of applications. First came Kenmac, now known as the K-Series, and then RHPS. You’ll learn more about them in future posts.