CPC technology class · F23
F23C - Methods Or Apparatus For Combustion Using Fluid Fuel Or S…
Methods or apparatus for combustion using fluid fuel or solid fuel suspended in ; a carrier gas or; air. 1,571 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.
- 1,571
- US patents granted
- #4/12
- in F23
- 10.3%
- F23 class share
- -37%
- 5-yr velocity
The verdict
According to USPTO PatentsView, Methods Or Apparatus For Combustion Using Fluid Fuel Or S… ranks #401 of 670 CPC technology areas - 1,571 US patents granted since 2015, with recorded grant volume down 37% over five years.
- #401
- of 670 CPC technology areas
- 1,571
- US patents granted, 2015–2025
- General Electric
- leading assignee (85)
- -37%
- grant velocity, last 5 yrs
How F23C's grant cadence moved
Between 2020–2024, F23C recorded 542 grants versus 864 in 2015–2019 (-37% equal-window velocity). Across complete years, output peaked in 2019 at 185 grants and bottomed in 2024 at 85 (+118% peak-over-trough). Lead assignee Clearsign Combustion Corporation holds 4.1% of the class ; the top three share 8.6%.
Leaderboard read
F23C concentration, lead at 4.1%
Clearsign Combustion Corporation leads this historical grant record at 4.1% of F23C - foreign corporation assignees hold 51% of class grants (388 of 758). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.
- Leader's share
- 4.1%
- Top three share
- 8.6%
- Lead over #2
- 23
65 of 1,571 grants
of the class's recorded grants
more grants than General Electric Technology GMBH
Where F23C sits inside F23
Among 12 subclasses in F23 (Combustion APPARATUS; Combustion Processes), F23C ranks #4 and holds 10.3% of the parent class's 15,279 recorded grants. Sibling chips below are the other subclasses in the same parent class, not the nationwide volume/lead-share peers further down.
Rising assignees active in F23C
Company-wide grant multiples (2022–2024 vs 2019–2021) among assignees with ≥5 patents in this subclass. Growth is company-wide; class patent counts are subclass-specific.
- #1 Doosan Enerbility Co., Ltd. 121x 0 → 121 company-wide · 5 in F23C
- #2 Collins Engine Nozzles, Inc. 74x 0 → 74 company-wide · 5 in F23C
- #3 Zeeco, Inc. 4.00x 1 → 4 company-wide · 5 in F23C
- #4 Membrane Technology and Research, Inc. 2.00x 3 → 6 company-wide · 6 in F23C
- #5 Hyper Fryer, LLC 1.67x 3 → 5 company-wide · 8 in F23C
F23C grants by year, peak 2019 (185)
US utility-patent grants per year in F23C, 2015–2025 - recent five years are down 37% versus 2015–2019.
Who leads F23C?
The 12 most active assignees in Methods OR Apparatus FOR Combustion Using Fluid Fuel OR Solid Fuel Suspended IN ; A Carrier GAS OR; AIR - wider bars mean more grants
- Clearsign Combustion
Clearsign Combustion Corporation
65 patents
- General Electric…
General Electric Technology GMBH
42 patents
- Ansaldo Energia…
Ansaldo Energia Switzerland AG
28 patents
- Exxonmobil Upstream… 24
Exxonmobil Upstream Research Company
24 patents
- Ifp Energies Nouvelles 21
IFP Energies Nouvelles
21 patents
- Alstom Technology 21
Alstom Technology Ltd
21 patents
- Ener-core Power 19
Ener-Core Power, Inc.
19 patents
- Air Products And… 17
AIR Products AND Chemicals, Inc.
17 patents
- Clearsign 17
ClearSign Technologies Corporation
17 patents
- 8 Rivers Capital 15
8 Rivers Capital, LLC
15 patents
- Delavan 14
Delavan Inc.
14 patents
- EberspÄCher Climate… 13
EBERSPÄCHER Climate Control Systems GMBH
13 patents
What this shows General Electric is the most active filer in F23C, holding 85 of the 1,571 patents in this class. Concentration at the top signals how contestable this technology area is for new entrants.
View data table
| Rank | Company | Patents in F23C |
|---|---|---|
| #1 | Clearsign Combustion Corporation | 65 |
| #2 | General Electric Technology GMBH | 42 |
| #3 | Ansaldo Energia Switzerland AG | 28 |
| #4 | Exxonmobil Upstream Research Company | 24 |
| #5 | IFP Energies Nouvelles | 21 |
| #6 | Alstom Technology Ltd | 21 |
| #7 | Ener-Core Power, Inc. | 19 |
| #8 | AIR Products AND Chemicals, Inc. | 17 |
| #9 | ClearSign Technologies Corporation | 17 |
| #10 | 8 Rivers Capital, LLC | 15 |
| #11 | Delavan Inc. | 14 |
| #12 | EBERSPÄCHER Climate Control Systems GMBH | 13 |
| #13 | The Babcock & Wilcox Company | 10 |
| #14 | Total Raffinage Chimie | 10 |
| #15 | Sumitomo SHI FW Energia Oy | 10 |
| #16 | Total SA | 9 |
| #17 | GAS Technology Institute | 9 |
| #18 | Linde GmbH | 8 |
| #19 | Noritz Corporation | 8 |
| #20 | Valmet Technologies Oy | 8 |
Footprint here vs. claim strategy
Each dot is a leading F23C assignee, placed by how many patents it holds in this class (horizontal) against its company-wide average claims per patent (vertical) - a read on whether the class is led by broad-but-shallow filers or focused deep-claim players.
Classes near F23C's 1,571-grant footprint
Nationwide nearest neighbors for F23C (#401 of 670 by volume ; lead share 5.4%) - not the F23 parent-class siblings above.
Nearest by grant volume
Questions about F23C
Which company holds the most patents in F23C?
Which F23C assignees grew fastest recently?
How does F23C compare inside parent class F23?
What to do with this data
F23C in context - here's where to go next.
- Clearsign Combustion Corporation leads F23C with 65 grants in this class. See full portfolio
- F23C ranks #401 of 670 by grant volume among all tracked CPC technology areas. See the ranking
- Inside parent class F23, the largest sibling subclass is F23R with 4,138 grants. Explore F23R
Figures reflect USPTO PatentsView grant data through 2026-05-15; pending applications not yet granted are not counted.
Methodology - F23C figures are USPTO PatentsView granted-utility totals for this subclass (1,571 grants in the tracked window).
Every figure on PlainPatent is rendered directly from USPTO source data, no number is typed in by an editor. This page draws directly on USPTO source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.