One industrial gas company holds a clearly dominant position in this dataset, with 251 records in a 37-company ranking versus 11 for the fifth-ranked filer. That gap is unusually steep rather than a gradual taper, meaning freedom-to-operate work in this field should start with that single filer's portfolio before moving to the long tail of smaller filers and individual inventors. The concentration is measured in patent family records within the ranked set, not as a percentage of all published documents.

No. Filing volume peaked in 2018 at 31 records and has not returned to that level since, sitting at 19 by the 2022 midpoint of the trend. Because publication typically lags filing by around 18 months, the final year or two in any trend understates true activity, but the multi-year plateau visible before that lag window is a genuine signal that filing has flattened rather than accelerated.

US10018413B2, assigned to Praxair Technology, Inc. and published in 2018, covers a method and apparatus for increasing argon recovery by separating an impure argon stream within a cryogenic air separation unit and purifying it using an integrated, multi-stage pressure swing adsorption system. It is a representative example of how PSA integration has been used to lift argon recovery yields rather than a foundational or singularly blocking patent. Anyone designing an integrated argon-PSA recovery process should review its specific claim scope directly rather than relying on the abstract alone.

Based on IPC composition in this dataset, control-system integration with ASU turndown, combustion-linked heat recovery from waste streams, and catalytic pretreatment ahead of molecular sieve beds all show thin representation relative to the core gas-separation claims. These overlaps each account for a small single-digit percentage of the 408 records in scope, suggesting lighter claim density there than in core distillation and argon-purification claims. That said, thin representation in a search corpus is a starting hypothesis for a design search, not a guarantee of open white space.

The five most-cited records in this corpus are all argon purification or argon-enriched stream patents, several originating in the 1980s and 1990s, including US4477265A and US6240744B1. Argon recovery from cryogenic air separation is a narrower, more technically constrained problem than bulk oxygen or nitrogen separation, so early foundational solutions tend to accumulate citations from every subsequent improvement. This is a signal of historical influence within the searched corpus, not necessarily of current commercial relevance.