Accurate Natural Gas Sampling Starts at the Source
Welker's GSS-4 Composite Gas Sampler delivers accurate, representative natural gas sampling for wet, dry, clean, or sour gas applications. Designed with Welker's Vanishing Chamber™ positive displacement pump and self-purging technology, the GSS-4 captures fresh composite samples directly from the flowing pipeline for reliable analysis. Compatible with single-cavity and constant-pressure cylinders, and compliant with all major industry sampling standards.
Where to Use
Composite SamplingNatural gas pipelines — wet, dry, clean, or sour
Custody TransferBilling-quality measurement at sales points
Fully displaces every sample grab into the connected cylinder — no residual gas left in the collection cup — so each sample is complete, uncontaminated, and ready for analysis.
Fresh Sample System™ — Self-Purging Design
Automatically purges stale gas from the sample path before each actuation, ensuring every grab reflects current pipeline conditions — not the previous cycle.
Direct Probe-Mount Installation
Mounts directly to the pipeline via a Welker Sample Probe — eliminating long sample tubing runs that delay sample capture and compromise representativeness.
Center-Third Pipeline Sampling
The probe extends into the center one-third of the pipeline cross-section — the zone required by API 14.1 — capturing a truly representative sample of the flowing gas stream.
Wet Gas Compatible with LE-2SSKO Liquid Eliminator
For wet gas applications, the patented Welker LE-2SSKO probe-mounted liquid eliminator knocks free liquids out of the sample stream and returns them to the pipeline — keeping the sample in the gas phase.
Compatible with Single Cavity & Constant Pressure Cylinders
Works with both Welker SC single cavity cylinders for dry gas and CP-2 constant pressure cylinders for wet or liquids-rich streams — covering the full range of natural gas sampling applications.
Cylinder Manifold & Bracket Included
Ships standard with a manifold for single cavity cylinders (keeping them vertical for correct filling and purging) and a mounting bracket for constant pressure cylinders — no additional hardware required.
Flexible Actuation — PLC, Analog, or Digital Signal
Connect to a PLC or SCADA system, or use the optional Welker 4P Sample Frequency Controller on analog or digital signal. An optional AC-to-DC converter covers sites without a direct current power supply.
Resilient Chamber Material for Long Service Life
The Vanishing Chamber™ is made from durable, resilient material that reliably springs back to its original shape actuation after actuation — delivering consistent grab volume over the full service life of the sampler.
API 14.1, GPA 2166 & ISO 10715 Compliant
Meets all major natural gas sampling standards — so the samples you collect satisfy custody transfer documentation requirements and stand up to audit review without modification or exception.
CP-2
The Welker CP-2 Constant Pressure Cylinder is designed for safe collection, transport, and containment of accurate natural gas and light liquid hydrocarbon samples for laboratory analysis.
SC Cylinder
A DOT 3E cylinder, the Welker SC Single Cavity Cylinder is designed for the safe collection and transportation of natural gas and light liquid hydrocarbon samples.
