Cryogenic Air Separation Patents: Top Companies & Trends 2026
- Five companies hold 89.9% of the field. 554 of 616 records in scope sit with the top five assignees, leaving a thin long tail behind them.
- Filing has fallen sharply since the 2018 peak. From 47 records in 2018 to 24 in 2021 and 11 in 2024, a documented -54% drop over that three-year span.
- Claim density is almost entirely inside one IPC subclass. F25J covers 94.8% of records; every other class sits under 14%, which points to where the crowding actually is.
Filing growth compares 2021 (24 records) with 2024 (11) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 616 records in scope (CR5), not by the ranked leaders only.
What this dataset covers
This landscape tracks 616 published records matched against cryogenic air separation and air separation unit energy terms, narrowed to filings that also discuss specific power consumption, distillation column pressure, main heat exchanger design, compressor intercooling, cold box insulation or load flexibility. The scope runs from 2015 through the 2026-07-31 data cut-off, so the most recent one to two years are still being published and will read as understated for some time.
The technology sits almost entirely under gas liquefaction and separation classification, with secondary activity in filtration-type separation processes, inorganic compound production, pumps, catalysis and gas-turbine integration. That concentration is a useful signal on its own: a search string this specific returning nearly all of its records under a single IPC subclass means the field has a well-defined technical core, and the interesting variation is in who owns which piece of it.
Filing trends and technology composition
Two views of the same 616 records: how filing volume has moved year over year, and how those records distribute across IPC subclasses.
Filing activity has declined from a 2018 peak
Records rose to a peak of 47 in 2018, then eased through the early 2020s; the documented span from 24 in 2021 to 11 in 2024 is a -54% move. Because publication lags filing by roughly 18 months, 2025 and 2026 figures are not yet complete and should not be read as a continuation of that decline.
F25J dominates; secondary classes are narrow
F25J (gas liquefaction and separation) appears in 94.8% of the 616 records in scope. B01D, C01B, F04D, B01J, F01K, F02C and C01C each cover a single-digit-to-teens share, marking them as adjacent rather than core to this claim set.
Shares are the percentage of the 616 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Cryogenic Air Separation Energy Efficiency with Eureka
This page is one run against one query. Ask Eureka your own question about cryogenic air separation energy efficiency and every answer comes back with the patent numbers behind it.
Try EurekaThe most-cited records in this field
US6568209B1 — Cryogenic air separation system with dual section main heat exchanger
A cryogenic air separation system having a main heat exchanger for processing feed air, said heat exchanger having a reversing heat exchanger function in an upward feed airflow countercurrent section and having a desuperheating function in a downward feed air flow cocurrent section.Filed by Praxair Technology, Inc., granted 2003-05-27.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5139547A | Production of liquid nitrogen using liquefied natural gas as sole refrigerant | 122 |
| 2 | US5406786A | Integrated air separation – gas turbine electrical generation process | 97 |
| 3 | US5081845A | Integrated air separation plant – integrated gasification combined cycle power generator | 96 |
| 4 | US4533375A | Cryogenic air separation with cold argon recycle | 89 |
| 5 | US5421166A | Integrated air separation plant-integrated gasification combined cycle power generator | 87 |
| 6 | US5049173A | Production of ultra-high purity oxygen from cryogenic air separation plants | 70 |
| 7 | EP1284404A1 | Process and device for recovering a product under pressure by cryogenic air separation | 67 |
| 8 | EP1067345A1 | Process and device for cryogenic air separation | 60 |
| 9 | US5440884A | Cryogenic air separation system with liquid air stripping | 59 |
| 10 | US20070209389A1 | Cryogenic air separation system for enhanced liquid production | 56 |
Citation counts reflect influence within this searched corpus and skew toward older filings; they are not a measure of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three findings from the dataset that change how a freedom-to-operate or whitespace search should be scoped in this field.
The field is a five-way contest, not a crowded market
With 554 of 616 records in scope sitting inside five portfolios, most new entrants are not competing against a broad field of small filers — they are competing against a handful of deep, long-running portfolios. A freedom-to-operate search here gets most of its value from those five, not from the ranked long tail.
Volume is down from the 2018 peak, not from a recent collapse
The peak of 47 records in 2018 has not been matched since; the documented 2021-to-2024 span shows a real decline in new filings. That said, 2025-2026 figures are still filling in under an 18-month publication lag, so this should be read as a multi-year plateau rather than an ongoing freefall.
Nearly everything sits in one IPC subclass
Secondary classes such as B01D (13.1%), C01B (7.6%) and F04D (5.5%) show where energy-efficiency claims spill into adjacent separation, compound-production and pump technology, but the technical center of gravity is single-subclass concentrated.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to cryogenic air separation energy efficiency, with the prior art for and against each one.
| Assignee | Co-assignee | Shared families |
|---|---|---|
| PROSSER NEIL M | KROMER BRIAN R | 19 |
| PROSSER NEIL M | HANDLEY JAMES R | 18 |
| HANDLEY JAMES R | KROMER BRIAN R | 17 |
| PROSSER NEIL M | LUO YANG | 14 |
| HOWARD HENRY E | SCHWARZ CARL L | 12 |
| HOWARD HENRY E | ROSEN LEE J | 12 |
| HOWARD HENRY E | ABDELWAHAB AHMED F | 12 |
| HOWARD HENRY E | DEGENSTEIN NICK J | 11 |
Ten co-assignee pairs appear in the dataset; the strongest pairings recur across multiple filings, indicating stable inventor teams rather than one-off collaborations.
Who holds the claim space
The ranking covers 49 companies counted in records — the full set the data endpoint returns, not a top-50 or top-100 cut. The leader alone accounts for 312 records; by the fifth position that figure is down to 14, and by tenth position just 3.
One portfolio dominates the ranked field
The leading assignee's 312 records is more than the next four ranked competitors combined, which makes its claim scope the first reference point for any new filing strategy in this space.
Concentration falls off a cliff after the leader
The gap between first and fifth position (312 records versus 14) is far steeper than the gap between fifth and tenth (14 versus 3), showing the field has one dominant player, a small group of established competitors, and then a long, thin tail.
Recent-year activity has slowed across the board
Several of the most active historical filers show zero records in the latest year or year-over-year declines in the -50% to -100% range. Given the publication lag, this reads more as a reporting gap than as firms exiting the space outright.
| Assignee | Recent year | YoY |
|---|---|---|
| Linde AG | 1 | -50% |
| Prosser Technologies Co., Ltd. | 0 | -100% |
| Air Products and Chemicals, Inc. | 0 | — |
| PROSSER NEIL M | 0 | — |
| L'Air Liquide, Société Anonyme pour l'Étude et l'Exploitation des Procédés Georges Claude | 0 | -100% |
| HANDLEY JAMES R | 0 | — |
| KROMER BRIAN R | 0 | — |
| HOWARD HENRY E | 0 | -100% |
Where to take this analysis
The dataset points to a concentrated core and a thin edge of adjacent activity. These are the natural next steps for a team acting on it.
Map claims against the leading five portfolios
Since 89.9% of records sit with five assignees, a claim-by-claim comparison against those five portfolios will surface most freedom-to-operate risk before a broader search is needed.
Explore assignee portfolios in EurekaCheck the under-claimed branches before drafting
Compressor intercooling, cold box insulation and load flexibility all show meaningfully lower filing density than the F25J core, which may leave room for a defensible first claim.
Run a whitespace search in EurekaRe-check 2025-2026 figures as they publish
Because publication lags filing by roughly 18 months, the apparent decline since 2018 should be revisited once the most recent two years finish filling in.
Track filing trends in EurekaCommon questions on this field
The assignee ranking for this dataset covers 49 companies, and it is heavily top-weighted: the leading assignee alone holds 312 of the 616 records in scope, and the top five combined account for 89.9% of all records. That leaves a long tail of smaller filers with only a handful of records each. Any competitive review of this space should start with those five portfolios before looking further down the ranking.
No — filing volume peaked in 2018 at 47 records and has declined since, with a documented drop from 24 records in 2021 to 11 in 2024, a -54% change over that span. However, because publication typically lags filing by around 18 months, the 2025 and 2026 figures in any such dataset are still incomplete and should not yet be read as confirming a continued decline. The safer conclusion is a multi-year plateau below the 2018 peak, pending later data.
The overwhelming majority of records, 94.8% of 616, fall under IPC subclass F25J, covering gas liquefaction and separation. Secondary activity appears in separation processes and filtration (13.1%), inorganic compound production (7.6%), non-positive-displacement pumps (5.5%), catalysis (3.9%), and gas-turbine and steam-plant integration (each under 3%). Because a single record can carry multiple IPC classes, these shares add up to more than 100%, and they should be read as overlapping technical themes rather than mutually exclusive categories.
US6568209B1, assigned to Praxair Technology, Inc. and granted in 2003, covers a cryogenic air separation system with a main heat exchanger split into a reversing-function countercurrent section and a desuperheating-function cocurrent section for feed air processing. Its blocking effect is narrow: it covers that specific dual-section heat exchanger architecture, not main heat exchangers or cryogenic air separation generally. A new filing that uses a different heat exchanger sectioning approach, or that does not rely on that reversing/desuperheating split, would sit outside its literal claim scope, though a formal freedom-to-operate opinion would need to check the full claim set and any related family members.
The clearest gaps sit outside the dominant F25J core: compressor intercooling optimization, cold box insulation systems, load-flexibility and turndown control, gas-turbine integrated air separation unit cycles, and catalytic pre-purification stages all show materially lower filing density than the core distillation and heat-exchanger claims. These branches appear in the dataset's secondary IPC classes (F04D, F01K, F02C, B01J) at single-digit shares of the 616 records, which suggests less-crowded claim space for a first-mover filing, though a targeted prior-art search in each branch is still needed before drafting.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.