Grab Sampling Systems

Grab Sampling Basics

Grab sampling, aka "closed loop sampling", "lab sampling" or "spot sampling", is manual collection of fluid from pipelines, tanks or systems for lab analysis. Routinely analyzing representative fluid samples can:

• Show that your end products meet quality specs ("validate process conditions")
• Confirm your plant's online analyzers are doing their job ("fit for use")
• Check product quality during custody transfers
• Verify your operation's environmental emissions

If you want your analytical instrumentation system to give a reliable picture of the fluid in the process line, you need a good sample. If the sample gets altered anywhere in the process, the data from the analyzer won't be useful.

Deadlegs... permeation... adsorption... all wreak havoc on samples

One challenge is that some chemicals evaporate or fractionate before arriving to a lab, unless they're kept under pressure. And if that happens, the sample isn't representative. Even a sample taken properly at the tap may fall victim to a host of problems, like:

• Dead spaces that create a “static leak,” where fluid from an old sample might bleed or leak into the new sample
• Contamination, permeation, or adsorption
• A phase change that upsets the balance of chemicals
• A chemical reaction

You need a reliable, easy-to-use grab sampling method

Swagelok grab sampling systems provide solutions to satisfy gas and liquid non-slurry sampling service in a consistent, reliable package.