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 filing trajectory.

1,082
US patents granted
F23
Parent CPC class
20
Active assignees
-31%
5-yr velocity

The verdict

Removal OR Treatment OF Combustion Products OR Combustion… ranks #446 of 670 CPC technology areas - 1,082 US patents granted since 2015, with filing down 31% over five years.

#446
of 670 CPC technology areas
1,082
US patents granted, 2015–2025
General Electric Tech…
leading assignee (39)
-31%
filing velocity, last 5 yrs
Top assignee: General Electric Technology Gmbh (39 patents)

CPC subclass F23J - REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES - covers 1,082 US utility patents granted between 2015 and 2025 according to USPTO PatentsView records, within the broader CPC class F23 (COMBUSTION APPARATUS; COMBUSTION PROCESSES). See our CPC classification guide for how the system works.

The competitive landscape in F23J is shaped by 20 distinct companies actively filing in this space. General Electric Technology Gmbh leads with 39 patents, followed by Mitsubishi Hitachi Power Systems, Ltd. at 29 grants and Noritz Corporation at 23.

Filing activity in F23J is down 31% over the past five years versus 2015-2019, a notable slowdown that may signal a maturing field. All counts come directly from USPTO PatentsView and reflect US granted utility patents only.

Is F23J innovation accelerating?

US utility-patent grants per year in F23J, 2015–2025 - recent five years are down 31% 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 Tech… 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

About This Class

CPC subclass F23J belongs to class F23.

1,082 patents were granted in this class between 2015 and 2025.

20 companies actively patent in this space.

Classification System

Cooperative Patent Classification (CPC) is a hierarchical patent classification system used by the USPTO and EPO.

← All Technology Classes Technology Rankings →

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).

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 Tech…Mitsubishi Hitachi Po…NoritzAda-esAlstom TechnologyNox IiThe Babcock & Wilcox8 Rivers CapitalMitsubishi Heavy Indu…Valmet OyClearsign CombustionFuel TechKyungdong NavienEberspÄCher Climate C…
Top 14 F23J assignees by class footprint. Bubble size = patents in F23J. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Frequently Asked Questions

What is CPC class F23J?
CPC subclass F23J covers REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES. It belongs to CPC class F23 (COMBUSTION APPARATUS; COMBUSTION PROCESSES), with 1,082 US utility patents granted since 2015.
How many patents have been filed in F23J?
1,082 US utility patents were granted in CPC subclass F23J between 2015 and 2025, based on USPTO PatentsView data.
Which company holds the most patents in F23J?
General Electric Technology Gmbh leads F23J with 39 patents, making it the most active assignee in this technology area.
How is patent data for F23J collected?
Patent data comes from USPTO PatentsView, a public research dataset maintained by the United States Patent and Trademark Office. It covers all US granted utility patents and assigns CPC codes based on the technology described in each patent.
What is the difference between CPC class and subclass?
A CPC class (e.g., F23) is a broad technology category. Subclasses like F23J provide finer granularity within that category. PlainPatent organizes data at the subclass level (4-character codes) for the most useful view of technology domains.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from USPTO PatentsView - official U.S. government patent data. See our methodology for computation details. Retrieved and formatted by PlainPatent Editorial

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.