Edmonton Valve & Fitting Blog

Weekly posts for northern and central Alberta engineers, plant operators, and buyers.

Edmonton Valve Makes Analysis Easier with Stream Selector Systems

by Taryn Hardes, on Tue, Oct 22, 2013 @ 15:10 PM

A modular assembly designed for process analyzer sampling systems that can accommodate multiple process streams. 


Stream selector small

swagelok parts Download the Stream Selector System For Process Analyzer Applications Catalogue

Delivering a fluid to an analyzer system can be a little trickier than it may look. Samples must get to the analyzer from different sources, and they must arrive without picking up contamination.

At one time, companies used to fashion their own double block and bleed valves out of various parts on hand. That would get the job done, after a fashion, but it required a lot of do-it-yourself time and effort. Then the industry developed more modular designs. But that still meant a lot of O-rings that were prone to leaks, and that meant big maintenance headaches.

Beats the competition

You'll find some of our competitors sell devices that use "cascading flow," where each outlet in a line of valves sends the sample through the bleed ports of all the valves in front of it. This is done to get rid of the previous fluid from the other streams and avoid contamination, but it also changes the flow coefficients with each stream. In other words, the further you get from the outlet, the lower the flow rates.

Swagelok solved that problem with its Stream Selector System. The device is based on a single block, meaning the number of O-rings has been greatly reduced. It uses a common flow path. If you have two or five or a dozen valves, they all send their samples through the same loop. That means you'll get the same flow rate from each valve. And it has a vented air gap to prevent air in the actuator from mixing with system media.

Our Stream Selector System also has a handy visual indicator. Every time one of the modules is cycled, a colored ring on the top of the valve pops up about a quarter-inch. It's easy to see which stream is running at any given time. You can even select the ring color for each valve.

It's also worth noting that Swagelok's Stream Selector System complies with the ANSI/ISA SP76 standard for miniature modular platforms. Some other companies say their products will sit on the platform, but the footprint doesn't actually fit.


Our Stream Selector System comes with options such as an integrated atmospheric reference vent positioned prior to the analyzer and attached to the outlet of the stream selector system. It is designed to equalize the sample loop pressure to atmospheric pressure just prior to the sample injection. This ensures a constant sample pressure in repetitive analyses.

You also can get an optional Modular Platform Components-compatible interface for up to 10 streams.

Get ready…

As with the selection of any other precision part, it helps to gather some information before calling Edmonton Valve & Fitting. It's always good to have a list showing the fluid that will go through the system, the pressure range, and the temperature range. Check out more details online. Then give us a call at 780-437-0640.

Topics:ValvesSample Systems

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