Industrial Fluid Systems Blog

Swagelok Sample Probe Modules: Welded or Retractable?

Either way, our team can make the whole assembly to your specifications


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Do you know the difference between welded and retractable probes? Download the catalogue and user manual for more Sample Probe Module information here.

 


A crucial step in oil and gas processing is measuring the concentration of key components in the gas and liquid streams. That means grabbing some representative samples. It must be done quickly and cleanly to make sure that the sample that gets into the analyzer really represents what's in the pipes.

To do the job right for any pipe larger than 50 mm in diameter, you need a sample probe in conjunction with sample probe valves. A probe allows you to extract a sample precisely from the middle third of the pipe's cross-section. If you draw the fluid from too high up, you might hit turbulent flow. If you draw the sample from too low, you may pick up more sludge or particulates from the sides or bottom.

Welded or retractable

Edmonton Valve & Fitting can do more than just provide the parts. We can build the whole sample probe module as one of our Pre-Engineered Subsystems. You pick out the type of probe you need (welded or retractable), and we pair it up with a block-and bleed sample probe valve.

Welded sample probes are best suited for use with double block-and-bleed valves. We also can add a mechanical interlock between the primary block valve and the bleed valve.

Retractable sample probes are best used with single block-and-bleed valves, which include safety features that do not allow the valve to actuate while the probe is in service. 

Probe design

Welded probes have very heavy, sturdy walls, and they are designed to be permanently installed. They are a good choice for liquids that carry dirt and sediment, as the relatively slow flow speed allows some particles to fall out of the probe instead of getting into the analytical sample system. Our welded probes also may be the right choice for low-pressure gas systems. Our probes can be welded to a variety of flanges from 3/4 inch to two inches.

But for a clean, small-volume environment, you may want to use our retractable probe.  Smaller retractable probes are not as strong as welded probes, but their smaller internal volume provides faster flow speeds to the analyzer. You also have the option of including a locking bracket so the probe can't be retracted until you say so.

The probe itself can come in lengths from 8 to 36 inches, including custom lengths. But why so long? We have to measure from the lowest supported point to the middle third of the pipe. For instance, in our retractable probes the lowest supported point is where the Conax® fitting seals the probe, not where the tubing exits the bottom of the valve.

Did you know that both our welded and retractable probes, with a tip-cut of 45 degrees, has a symbol etched on the side? This etching matches the direction of the tip, which assists in lining up probe in the correct direction. A 45-degree tip greatly reduces the amount of particulate extracted into the sample system.

Facts and figures

When you need a probe but aren't sure about the particulars, call your local account manager here at Edmonton Valve or at either of our branches, and they will be happy to help you with your decision. You will need to supply information such as temperature, flow rate, and pipe diameter for your system, along with whether you want a retractable or welded probe. Our team here can help you run the calculations by filling in the system’s parameters.

Sample probe modules are relatively inexpensive assemblies, especially compared to the sensitive analyzer systems they feed into. Now you have the opportunity to get exactly what you need without having to assemble parts yourself.

There's plenty more to learn online with our Sample Probe Module Application Guide and User's Manual - download both here!

 


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