Compressor Stall and Surge Control Patents: Top Companies & Trends 2026
- 40.1% concentration. The five leading assignees account for 1,340 of the 3,341 records in scope — filing is concentrated at the top, with a long tail of single-digit filers behind them.
- Filing has cooled from its 2017 peak. Annual filings ran from 209 in 2017 down to 73 by 2024, a 42% drop across 2021-2024, though 2025-2026 figures are still filling in as publication catches up with filing.
- Gas-turbine and pump classifications dominate. F02C and F04D each cover roughly two-fifths of all records, while control-systems classes like G05B and F02D sit under 5% — a gap between mechanical hardware claims and control-software claims.
Filing growth compares 2021 (125 records) with 2024 (73) — 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 3,341 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Compressor stall and surge control spans the mechanisms that keep axial and centrifugal compressors operating away from their instability boundary: variable stator vanes, inlet guide vanes, bleed valve scheduling, casing treatments, tip injection and the stall-inception sensing that triggers them. The search set combines these mechanism terms with the aerodynamic phenomena they manage, so the corpus captures both hardware claims — vane geometries, bleed-valve arrangements, casing profiles — and control-logic claims that schedule those mechanisms against a stall margin.
The dataset covers 3,341 published records filed or published between 2015 and mid-2026, drawn primarily from jet-engine and industrial gas-turbine assignees, with receiving offices led by the United States, the European Patent Office and the United Kingdom.
Filing trend and technology composition
Two views of the same 3,341-record corpus: how filing activity has moved year over year, and which IPC subclasses carry the claim density.
Filing trend: a 2017 peak, then a multi-year pullback
Annual filings peaked at 209 in 2017. By 2021 the annual count had settled to 125, and by 2024 — the most recent year with a complete publication window — it had fallen to 73, a 42% decline across that three-year span. 2025 and 2026 figures are still incomplete because publication typically lags filing by around 18 months, so those years should not yet be read as a continued decline.
Technology composition: gas-turbine and pump hardware lead
F02C (gas-turbine plants) and F04D (non-positive-displacement pumps) each touch roughly two-fifths of the 3,341 records, and F01D (turbines and non-positive engines) covers close to a third. Control and regulating classifications — G05B and F02D — sit under 5% each, and aircraft-equipment class B64D sits at 5.0%. Because a single record can carry several IPC classes, these shares do not sum to 100% and should be read against the full record count, not against each other.
Shares are the percentage of the 3,341 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Compressor Stall and Surge Control with Eureka
This page is one run against one query. Ask Eureka your own question about compressor stall and surge control and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative filing
US20080279676A1 — Turbine Anti-Rotating Stall Schedule
A method of starting up a turbine with a compressor having an inlet guide vane, a number of bleed valves, and a number of blades so as to limit the duration in a rotating stall window. The method includes starting rotation of the blades, increasing rotational speed, closing one or more bleed valves to shift the rotating stall window to a higher rotational speed, partially opening the inlet guide vane to a position outside that window, and opening the bleed valves while partially closing the inlet guide vane so the blades pass through the rotating stall window.Filed by GE Infrastructure Technology, this record ties bleed-valve and inlet-guide-vane scheduling together as a single start-up sequence rather than treating each mechanism independently.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20150185716A1 | Methods and systems for enhancing control of power plant generating units | 492 |
| 2 | US5915917A | Compressor stall and surge control using airflow asymmetry measurement | 442 |
| 3 | US5809772A | Turbofan engine with a core driven supercharged bypass duct | 273 |
| 4 | US20160281607A1 | Methods and systems for enhancing operation of power plant generating units and systems | 262 |
| 5 | US20020024332A1 | Methods and apparatus for controlling electric appliances during reduced power conditions | 260 |
| 6 | US4031407A | System and method employing a digital computer with improved programmed operation for automatically synchroni… | 256 |
| 7 | US4455614A | Gas turbine and steam turbine combined cycle electric power generating plant having a coordinated and hybridi… | 239 |
| 8 | US4151725A | Control system for regulating large capacity rotating machinery | 224 |
| 9 | US6891478B2 | Methods and apparatus for controlling electric appliances during reduced power conditions | 208 |
| 10 | US20080243352A1 | Methods and Systems for Model-Based Control of Gas Turbines | 207 |
Citation counts inside a searched corpus skew toward older filings simply because they have had longer to accumulate citations — read them as a signal of influence on later filers, not as a ranking of current technical importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the concentration and trend numbers mean for filing strategy
The record counts point to a field where hardware claim space is heavily occupied at the top but the control-logic layer is comparatively open.
Filing is concentrated, not fragmented
The five leading assignees hold 1,340 of the 3,341 records in scope, and the top ten extend that to 52.2%. That leaves a long tail of the remaining ranked assignees each holding a modest share — new entrants are filing into gaps rather than displacing the leaders.
Activity has pulled back from its 2017 peak
Annual filings fell from 125 in 2021 to 73 in 2024. That is a real decline over a complete measurement window, though the 2025-2026 figures are still incomplete due to publication lag and should not be read as confirming a continued drop.
Gas-turbine hardware carries the claim density
F02C and F04D between them touch a large majority of records, reflecting how much of this field's IP sits in mechanical hardware — vanes, bleed valves, casings — rather than in the control software that schedules them.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to compressor stall and surge control, with the prior art for and against each one.
Who is filing, and where the gaps sit
The ranked leaders are dominated by jet-engine OEMs and industrial gas-turbine makers, with recent-year momentum mostly flat or negative rather than accelerating.
A single OEM dominates the ranking
The leading assignee's 591 records outstrip the fifth-place holder's 126, a gap wide enough that the leader alone accounts for close to a fifth of all 3,341 records in scope.
A cluster of major OEMs fills the mid-ranks
From fifth to tenth place, holdings taper from 126 down to 59 records, a group made up largely of established jet-engine and turbine manufacturers rather than new entrants.
Recent-year activity has gone flat across the leaders
Several of the most prolific historical filers show zero or negative year-over-year change in the latest year, with the two largest showing -100% YoY. This likely reflects publication lag rather than an actual halt in filing.
| Assignee | Recent year | YoY |
|---|---|---|
| Rolls-Royce plc | 1 | 0% |
| Honeywell International Inc. | 1 | 0% |
| General Electric Company | 0 | -100% |
| Pratt & Whitney Canada Corp. | 0 | -100% |
| United Technologies Corporation | 0 | — |
| Ford Global Technologies, LLC | 0 | — |
| Westinghouse Electric Corporation | 0 | — |
| Hitachi, Ltd. | 0 | — |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, competitive tracking or identifying open claim space.
Map claim boundaries around the leader's portfolio
With one assignee holding 591 of 3,341 records, a freedom-to-operate check for any new bleed-valve or vane-scheduling mechanism should start by mapping that portfolio's claim boundaries directly.
Explore assignee portfolios in EurekaTrack the control-logic gap
G05B and F02D classifications sit well under the hardware classes, suggesting control-software claims around stall-margin scheduling are comparatively open — worth a dedicated search before filing.
Run a white-space search in EurekaWatch for the 2025-2026 publication catch-up
Because publication lags filing by roughly 18 months, the apparent 2025-2026 slowdown will fill in over the next reporting cycles — re-run the trend query rather than treating the current dip as final.
Set a monitoring alert in EurekaCommon questions on this landscape
The assignee ranking is led by one company with 591 of the 3,341 records in scope, a wide margin over the fifth-place holder's 126. The leading names are dominated by jet-engine OEMs and industrial gas-turbine manufacturers rather than component suppliers or software firms. The top five assignees together account for 40.1% of all records, so the field is concentrated but not monopolised — a long tail of smaller filers still holds meaningful ground.
Filing peaked in 2017 at 209 records and has since declined, falling from 125 in 2021 to 73 in 2024 — a 42% drop over that three-year window, which is the most recent period that can be treated as complete. The years 2025 and 2026 currently show far lower counts, but that reflects publication lag of roughly 18 months rather than an actual halt in filing activity. Any conclusion about the very latest trend should wait for those years to fill in before being treated as reliable.
This GE Infrastructure Technology filing claims a start-up method that coordinates inlet guide vane positioning with sequential bleed-valve closing and opening to shift a compressor's rotating stall window to a higher rotational speed and limit the time spent inside it. It ties two mechanisms — bleed valves and inlet guide vanes — into a single scheduled sequence rather than claiming either independently. Anyone designing a start-up scheduling method that coordinates these two mechanisms in a similar sequence should review this filing's claim scope directly rather than relying on this summary.
Control and regulating classifications such as G05B and F02D each cover under 5% of the 3,341 records, well below the 45.2% and 39.9% shares held by the gas-turbine and pump hardware classes F02C and F04D. That gap suggests control-logic claims — adaptive bleed-valve scheduling, sensor-fusion approaches to stall inception, or cross-mechanism surge-margin control loops — are comparatively under-claimed relative to the mechanical hardware they operate. Casing treatment for centrifugal (rather than axial) stages also appears thinner in the record set.
The top five assignees hold 1,340 of 3,341 records, or 40.1% of the corpus, and the top ten extend that to 52.2%. That level of concentration means new filers are competing for claim space against a handful of large incumbent portfolios rather than a fragmented field. It also means that citation leaders and top assignees overlap heavily, since several of the most-cited records in the corpus originate from the same companies that dominate the filing count.
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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.