REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES

Introduced: September 1968

Classification Context

Section:: MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Class:: COMBUSTION APPARATUS; COMBUSTION PROCESSES
Subclass:: REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES

Description

F23J covers technologies for managing exhaust gases, particulates, and residual matter generated by combustion processes, along with the flue systems that transport these byproducts. This includes dust collectors, ash removal equipment, scrubbers, and related treatment systems for both solid and gaseous combustion residues. The classification encompasses flue design, draft control, and ancillary equipment that processes or directs combustion products from furnaces, boilers, and other combustion apparatus. Related dust separation and air pollution control measures are included where integral to combustion residue management.

Filing statistics

IPC subclass F23J recorded 62,845 patent applications worldwide between 2013 and 2023. Annual filings grew from 2,090 in 2013 to 7,638 in 2023 (+265%), peaking at 9,395 applications in 2020. The most active applicants in class F23 are GE (GENERAL ELECTRIC COMPANY) (2,124 applications), XIAN THERMAL POWER RESEARCH INSTITUTE COMPANY (1,369 applications) and NINGBO FOTILE KITCHENWARE COMPANY (1,363 applications).

Source: EPO PATSTAT, worldwide filings

In class comparison

F23J ranks 1st of 12 subclasses with filings in F23, with 62,845 applications between 2013 and 2023, 20.9% of the class. Annual filings grew 265% from 2013 to 2023, above the class as a whole (+76%).

Top 10 of 12 subclasses of class F23 by patent applications, 2013–2023
Rank	Subclass	Title	Applications	Share
1	F23J	Removal or Treatment of Combustion Products or Combustion Residues; Flues	62,845	20.9%
2	F23G, Cremation Furnaces; Consuming Waste or Low Grade Fuels by Combustion	Cremation Furnaces; Consuming Waste or Low Grade Fuels by Combustion	62,605	20.8%
3	F23D, Burners	Burners	48,008	15.9%
4	F23L, Supplying Air or Non-Combustible Liquids or Gases to Combustion Apparatus in General; Valves or Dampers Specially Adapted for Controlling Air Supply or Draught in Combustion Apparatus; Inducing Draught in Combustion Apparatus; Tops for Chimneys or Ventilating Shafts; Terminals for Flues	Supplying Air or Non-Combustible Liquids or Gases to Combustion Apparatus in General; Valves or Dampers Specially Adapted for Controlling Air Supply or Draught in Combustion Apparatus; Inducing Draught in Combustion Apparatus; Tops for Chimneys or Ventilating Shafts; Terminals for Flues	24,279	8.1%
5	F23C, Methods or Apparatus for Combustion Using Fluid Fuel or Solid Fuel Suspended in Air	Methods or Apparatus for Combustion Using Fluid Fuel or Solid Fuel Suspended in Air	19,304	6.4%
6	F23R, Generating Combustion Products of High Pressure or High Velocity, e.g. Gas-Turbine Combustion Chambers	Generating Combustion Products of High Pressure or High Velocity, e.g. Gas-Turbine Combustion Chambers	17,458	5.8%
7	F23K, Feeding Fuel to Combustion Apparatus	Feeding Fuel to Combustion Apparatus	17,228	5.7%
8	F23N, Regulating or Controlling Combustion	Regulating or Controlling Combustion	15,400	5.1%
9	F23Q, Ignition; Extinguishing Devices	Ignition; Extinguishing Devices	12,442	4.1%
10	F23B, Methods or Apparatus for Combustion Using Only Solid Fuel	Methods or Apparatus for Combustion Using Only Solid Fuel	9,943	3.3%

Source: EPO PATSTAT, worldwide filings

Related Keywords

removing ASH(ES) from combustion apparatusremoving CINDERS from combustion apparatusCLEANING fire-gratesremoving CLINKER from combustion apparatusFLUES for combustion apparatusremoval or treatment of FUMES in combustion apparatusPRICKERS for fire-gratesraking of fire-gratesremoving SLAG from combustion apparatusremoval or treatment of SMOKE in combustion apparatusremoving SOOT from fluesTRAP(S) for combustion residues

8 direct subcodes

Child Classifications

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F23J 1/00 Removing ash, clinker, or slag from combustion chambers
F23J 11/00 Devices for conducting smoke or fumes, e.g. flues
F23J 13/00 Fittings for chimneys or flues
F23J 15/00 Arrangements of devices for treating smoke or fumes
F23J 3/00 Removing solid residues from passages or chambers beyond the fire, e.g. from flues by soot blowers
F23J 7/00 Arrangement of devices for supplying chemicals to fire
F23J 9/00 Preventing premature solidification of molten combustion residues
F23J 99/00 Subject matter not provided for in other groups of this subclass

Top Applicants

Top 10 applicants by patent filingsfor class F23, 2013–2023, worldwide · Source: EPO PATSTAT

GE (GENERAL ELECTRIC COMPANY) US 2,124
XIAN THERMAL POWER RESEARCH INSTITUTE COMPANY 1,369
NINGBO FOTILE KITCHENWARE COMPANY 1,363
SIEMENS DE 997
UNITED TECHNOLOGIES CORPORATION (UTC) US 937
GE (GENERAL ELECTRIC COMPANY) 898
VATTI 815
CHINESE ACADEMY OF SCIENCES 719
RINNAI COMPANY 708
MITSUBISHI HITACHI POWER SYSTEMS 670