PlainPatent

CPC technology class · F23

F23J - Removal Or Treatment Of Combustion Products Or Combustion…

Removal or treatment of combustion products or combustion residues; flues. 1,082 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.

1,082
US patents granted
#5/12
in F23
7.1%
F23 class share
-41%
5-yr velocity

The verdict

According to USPTO PatentsView, Removal Or Treatment Of Combustion Products Or Combustion… ranks #446 of 670 CPC technology areas - 1,082 US patents granted since 2015, with recorded grant volume down 41% over five years.

#446
of 670 CPC technology areas
1,082
US patents granted, 2015–2025
General Electric Technology
leading assignee (39)
-41%
grant velocity, last 5 yrs

How F23J's grant cadence moved

Between 2020–2024, F23J recorded 354 grants versus 599 in 2015–2019 (-41% equal-window velocity). Across complete years, output peaked in 2017 at 130 grants and bottomed in 2024 at 54 (+141% peak-over-trough). Lead assignee General Electric Technology GMBH holds 3.6% of the class ; the top three share 8.4%.

Leaderboard read

F23J concentration, lead at 3.6%

General Electric Technology GMBH leads this historical grant record at 3.6% of F23J - foreign corporation assignees hold 58% of class grants (293 of 504). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share
3.6%

39 of 1,082 grants

Top three share
8.4%

of the class's recorded grants

Lead over #2
10

more grants than Mitsubishi Hitachi Power Systems, Ltd.

Where F23J sits inside F23

Among 12 subclasses in F23 (Combustion APPARATUS; Combustion Processes), F23J ranks #5 and holds 7.1% 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 F23G 1,073 F23L 922 F23K 754 F23M 568

Rising assignees active in F23J

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. #1 Next Carbon Solutions, LLC 7.00x 2 → 14 company-wide · 5 in F23J
  2. #2 Fuel Tech, Inc. 3.00x 2 → 6 company-wide · 7 in F23J
  3. #3 Membrane Technology and Research, Inc. 2.00x 3 → 6 company-wide · 5 in F23J
  4. #4 Valmet Technologies Oy 1.52x 29 → 44 company-wide · 9 in F23J
  5. #5 Kyungdong Navien Co., Ltd. 1.44x 39 → 56 company-wide · 6 in F23J

F23J grants by year, peak 2017 (130)

US utility-patent grants per year in F23J, 2015–2025 - recent five years are down 41% versus 2015–2019.

406080100120140 20152016201720182019202020212022202320242025 58

Who leads F23J?

The 12 most active assignees in Removal OR Treatment OF Combustion Products OR Combustion RESIDUES; Flues - wider bars mean more grants

patents

What this shows General Electric… is the most active filer in F23J, holding 39 of the 1,082 patents in this class. Concentration at the top signals how contestable this technology area is for new entrants.

Source USPTO PatentsView, granted utility patents As of 2015–2025 grant years
View data table
Top patent holders in CPC subclass F23J
Rank Company Patents in F23J
#1 General Electric Technology GMBH 39
#2 Mitsubishi Hitachi Power Systems, Ltd. 29
#3 Noritz Corporation 23
#4 Ada-es, Inc. 23
#5 Alstom Technology Ltd 18
#6 NOX II, Ltd. 15
#7 The Babcock & Wilcox Company 14
#8 8 Rivers Capital, LLC 12
#9 Mitsubishi Heavy Industries Engineering, Ltd. 9
#10 Valmet Technologies Oy 9
#11 Clearsign Combustion Corporation 7
#12 Fuel Tech, Inc. 7
#13 Kyungdong Navien Co., Ltd. 6
#14 EBERSPÄCHER Climate Control Systems GMBH 6
#15 Itea S.P.A 6
#16 VRC Technology, LLC 6
#17 The Lubrizol Corporation 5
#18 Chiyoda Corporation 5
#19 Membrane Technology and Research, Inc. 5
#20 The Kansai Electric Power Co., Inc. 5

Footprint here vs. claim strategy

Each dot is a leading F23J 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 F23J assignees by class footprint. Bubble size = patents in F23J. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 010203040 01020304050 Patents in F23J Avg claims / patent (company-wide) General Electric…Mitsubishi Hitachi…NoritzAda-esAlstom TechnologyNox IiThe Babcock & Wilcox8 Rivers CapitalMitsubishi Heavy…Valmet OyClearsign CombustionFuel TechKyungdong NavienEberspÄCher Climate…
Top 14 F23J assignees by class footprint. Bubble size = patents in F23J. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Classes near F23J's 1,082-grant footprint

Nationwide nearest neighbors for F23J (#446 of 670 by volume ; lead share 3.6%) - not the F23 parent-class siblings above.

Nearest by grant volume

A01P 1,084 C10K 1,080 A47D 1,075 F23G 1,073

Nearest by lead-assignee share

G01H 3.6% F21S 3.6% Y10S 3.6% B21C 3.6%

Questions about F23J

Which company holds the most patents in F23J?
General Electric Technology GMBH leads F23J with 39 patents (3.6% of the subclass). By PatentsView assignee type, foreign corporations account for 58% of class grants.
Which F23J assignees grew fastest recently?
Among assignees with ≥5 grants in F23J, Next Carbon Solutions, LLC shows the highest company-wide grant multiple (7.00x: 2 grants in 2019–2021 → 14 in 2022–2024) while holding 5 patents in this subclass. Growth is company-wide, not class-only.
How does F23J compare inside parent class F23?
Inside F23 (Combustion APPARATUS; Combustion Processes), F23J ranks #5 of 12 subclasses by grant volume and holds 7.1% of the parent class total. The largest sibling is F23R (4,138 grants).

What to do with this data

F23J in context - here's where to go next.

  • General Electric Technology GMBH leads F23J with 39 grants in this class. See full portfolio
  • F23J ranks #446 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 - F23J figures are USPTO PatentsView granted-utility totals for this subclass (1,082 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.