CPC technology class · F23

F23K - Feeding Fuel To Combustion Apparatus

Feeding fuel to combustion apparatus. 754 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.

Compiled by PlainPatent · May 15, 2026

754
US patents granted: #8/12
in F23: 4.9%
F23 class share: -2%
5-yr velocity

The verdict

According to USPTO PatentsView, Feeding Fuel To Combustion Apparatus ranks #488 of 670 CPC technology areas - 754 US patents granted since 2015, with recorded grant volume down 2% over five years.

#488
of 670 CPC technology areas: 754
US patents granted, 2015–2025: General Electric
leading assignee (76): -2%
grant velocity, last 5 yrs

How F23K's grant cadence moved

Between 2020–2024, F23K recorded 350 grants versus 356 in 2015–2019 (-2% equal-window velocity). Across complete years, output peaked in 2017 at 83 grants and bottomed in 2018 at 56 (+48% peak-over-trough). Lead assignee NOX II, Ltd. holds 2.0% of the class ; the top three share 4.6%.

Leaderboard read

F23K concentration, lead at 2.0%

NOX II, Ltd. leads this historical grant record at 2.0% of F23K - us corporation assignees hold 61% of class grants (145 of 239). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share: 2.0%
Top three share: 4.6%
Lead over #2: 5

Where F23K sits inside F23

Among 12 subclasses in F23 (Combustion APPARATUS; Combustion Processes), F23K ranks #8 and holds 4.9% 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.

F23R 4,138 F23D 2,623 F23N 1,763 F23C 1,571 F23J 1,082 F23G 1,073 F23L 922 F23M 568

Rising assignees active in F23K

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 Rinnai Corporation 0.54x 50 → 27 company-wide · 6 in F23K
#2 VRC Technology, LLC 0.50x 2 → 1 company-wide · 6 in F23K
#3 Copreci, S.COOP. 0.42x 12 → 5 company-wide · 7 in F23K
#4 Grand Mate Co., Ltd. 0.41x 34 → 14 company-wide · 6 in F23K
#5 Ada-es, Inc. 0.38x 16 → 6 company-wide · 10 in F23K

F23K grants by year, peak 2017 (83)

US utility-patent grants per year in F23K, 2015–2025 - recent five years are down 2% versus 2015–2019.

Nox Ii

15
Delavan

10
Ada-es

10
Ener-core Power

8
Progreen Labs

8
Copreci S Coop

7
Rinnai

6
Grand Mate

6
Vrc Technology

6
The Babcock & Wilcox

5
Bill & Melinda Gates…

5
EberspÄCher Climate…

4

What this shows General Electric is the most active filer in F23K, holding 76 of the 754 patents in this class. Concentration at the top signals how contestable this technology area is for new entrants.

View data table

Top patent holders in CPC subclass F23K
Rank	Company	Patents in F23K
#1	NOX II, Ltd.	15
#2	Delavan Inc.	10
#3	Ada-es, Inc.	10
#4	Ener-Core Power, Inc.	8
#5	Progreen Labs, LLC	8
#6	Copreci, S.COOP.	7
#7	Rinnai Corporation	6
#8	Grand Mate Co., Ltd.	6
#9	VRC Technology, LLC	6
#10	The Babcock & Wilcox Company	5
#11	Bill & Melinda Gates Foundation	5
#12	EBERSPÄCHER Climate Control Systems GMBH	4
#13	Hyliion Inc.	4
#14	Robertshaw Controls Company	4
#15	GE Energy Products France SNC	4
#16	Babcock Power Services, Inc.	4
#17	SIT S.P.A.	4
#18	Getas Gesellschaft für thermodynamische Antriebssysteme mbH	4
#19	University of Leeds	3
#20	Precision Combustion, Inc.	3

Footprint here vs. claim strategy

Each dot is a leading F23K 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.

Top 14 F23K assignees by class footprint. Bubble size = patents in F23K. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Classes near F23K's 754-grant footprint

Nationwide nearest neighbors for F23K (#488 of 670 by volume ; lead share 10.1%) - not the F23 parent-class siblings above.

Nearest by grant volume

C13K 754 F01B 754 C05C 753 C25C 753

Nearest by lead-assignee share

B41N 10.0% F01L 10.0% B60W 10.2% A41D 9.9%

Questions about F23K

Which company holds the most patents in F23K?

General Electric Company leads F23K with 76 patents (2.0% of the subclass). By PatentsView assignee type, us corporations account for 61% of class grants.

Which F23K assignees grew fastest recently?

Among assignees with ≥5 grants in F23K, Rinnai Corporation shows the highest company-wide grant multiple (0.54x: 50 grants in 2019–2021 → 27 in 2022–2024) while holding 6 patents in this subclass. Growth is company-wide, not class-only.

How does F23K compare inside parent class F23?

Inside F23 (Combustion APPARATUS; Combustion Processes), F23K ranks #8 of 12 subclasses by grant volume and holds 4.9% of the parent class total. The largest sibling is F23R (4,138 grants).

What to do with this data

F23K in context - here's where to go next.

NOX II, Ltd. leads F23K with 15 grants in this class. See full portfolio
F23K ranks #488 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 - F23K figures are USPTO PatentsView granted-utility totals for this subclass (754 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.