GSS-4PM Composite Gas Sampling System

The unrivaled accuracy of Welker’s GSS-4PM Gas Sampling System is world-famous. Its unparalleled decades-long history of representative sampling, repeatability, and accuracy have made the GSS-4PM the composite sampling system for natural gas—wet or dry, clean or dirty.

Probe-mounted and self-purging, the GSS-4PM is a self-contained system compatible with single cavity and constant pressure cylinders. With the Vanishing Chamber™ collection cup at the heart of the positive displacement pump, there’s no doubt your samples will be as representative and accurate as the results of an online analyzer.

The GSS-4PM’s claim to fame is the Vanishing Chamber™ collection cup. This compressible collection cup captures set volumes of sample. Each actuation of the sample pump voids the collection cup, fully displacing the sample into the connected sample cylinder. Made from resilient material, the Vanishing Chamber™ bounces back to provide repeatable results actuation after actuation.

Mounted on a Welker Sample Probe, the GSS-4PM installs directly to the pipeline. There are no long tubing runs to impact sample timeliness and representativeness. Extending into the center one-third of your pipeline, the GSS-4PM captures samples representative of the flowing stream and leaves free liquids behind.

For wet gas sampling applications, swap the standard Welker Sample Probe for a Welker LE-2SSKO. The patented design of our probe-mounted liquid eliminator effectively knocks free liquids out of the sample stream and returns them to the pipeline.

The GSS-4PM features Welker’s Fresh Sample System™. This self-purging design ensures a fresh, representative sample grab during each sample cycle.

Don’t let residual impurities distort your sample. Air or previous samples can impact sample accuracy if not properly removed. Purge your sample cylinder before each collection period as recommended using the GSS-4PM’s integrated purge manifold.

The inline relief protects sample representativeness during fluctuations in pipeline pressure. Acting as a check valve, the inline relief keeps your samples in the sample cylinder. If pipeline pressure drops, rest assured sample won’t flow from your cylinder back to the pipeline.

No need to add a cylinder holder to your order—each GSS-4PM comes standard with a manifold for a single cavity cylinder and a bracket with mounting hardware for a constant pressure cylinder. The manifold keeps your single cavity cylinder vertical for proper filling and purging. The bracket provides the horizontal support your constant pressure cylinder requires and keeps it close for short tubing connections.