Welker Constant Pressure Cylinders for sampling gas preserve sample integrity by collecting and maintaining process samples at pipeline pressure while being transported for analysis.

Operators can use inert gas to pre-charge the Welker cylinder’s piston prior to being filled with a sample, and then slowly venting the inert gas as the sample is taken. In addition, the cylinders can utilize built in mixers to thoroughly mix and produce a completely representative sample for gas chromatographs and gas analyzers.

The original designs of the Welker constant pressure cylinders were born from an understanding of ideal gas laws which show how changing the  pressure could have a significant effect on analysis, especially if there are heavier hydrocarbons. It is important to maintain the pressure using the precharge end of the cylinder both when extracting a gas sample and also when using it in the lab. Pressure plays a significant role and sometimes temperature is also a consideration- hence the options available for heating the sample cylinder. Welker has decades of experience in helping users maintain sample integrity using constant pressure sample receivers and will be glad to provide consultancy and product training and service with gas and light liquid sampling.

Welker CP Cylinders come in different volumes e.g. standard volumes of 150cc, 300cc and 500cc. Larger validation type cylinders for analyser houses with larger volumes e.g 5L and larger available on request. 

The following presentation was produced by LNG Custody Transfer consultants but is a great example of a typical application for constant pressure gas sampling cylinders which store the vaporized LNG samples. In this case, three custody transfer LNG samples are implemented in the sample system configuration.


Validation Cylinders - Also known as constant pressure receivers and sometimes as a validation tank are being used more often for applications where a reference gas needs to be maintained at a constant pressure as opposed to standard containers. Fabrication of spot sampling systems and complete automatic or manual sampling stations.