CPC technology class · F23

F23D - Burners

Burners. 2,623 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.

Compiled by PlainPatent · May 15, 2026

2,623
US patents granted: #2/12
in F23: 17.2%
F23 class share: -14%
5-yr velocity

The verdict

According to USPTO PatentsView, Burners ranks #342 of 670 CPC technology areas - 2,623 US patents granted since 2015, with recorded grant volume down 14% over five years.

#342
of 670 CPC technology areas: 2,623
US patents granted, 2015–2025: General Electric
leading assignee (186): -14%
grant velocity, last 5 yrs

How F23D's grant cadence moved

Between 2020–2024, F23D recorded 1,116 grants versus 1,291 in 2015–2019 (-14% equal-window velocity). Across complete years, output peaked in 2019 at 301 grants and bottomed in 2024 at 175 (+72% peak-over-trough). Lead assignee Delavan Inc. holds 2.4% of the class ; the top three share 6.3%.

Leaderboard read

F23D concentration, lead at 2.4%

Delavan Inc. leads this historical grant record at 2.4% of F23D - us corporation assignees hold 53% of class grants (663 of 1,257). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share: 2.4%
Top three share: 6.3%
Lead over #2: 8

Where F23D sits inside F23

Among 12 subclasses in F23 (Combustion APPARATUS; Combustion Processes), F23D ranks #2 and holds 17.2% 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 F23N 1,763 F23C 1,571 F23J 1,082 F23G 1,073 F23L 922 F23K 754 F23M 568

Rising assignees active in F23D

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 · 22 in F23D
#2 Collins Engine Nozzles, Inc. 74x 0 → 74 company-wide · 17 in F23D
#3 Zeeco, Inc. 4.00x 1 → 4 company-wide · 7 in F23D
#4 Bekaert Combustion Technology B.V. 3.00x 0 → 3 company-wide · 5 in F23D
#5 Rheem Manufacturing Company 2.26x 80 → 181 company-wide · 22 in F23D

F23D grants by year, peak 2019 (301)

US utility-patent grants per year in F23D, 2015–2025 - recent five years are down 14% versus 2015–2019.

Delavan

62
Haier Us Appliance…

54
Clearsign Combustion

48
Rinnai

45
Pro-iroda Industries

43
Mitsubishi Hitachi…

35
Lennox Industries

35
EberspÄCher Climate…

29
Air Products And…

27
Kyungdong Navien

27
Clearsign

25
Bsh Hausgeräte

23

What this shows General Electric is the most active filer in F23D, holding 186 of the 2,623 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 F23D
Rank	Company	Patents in F23D
#1	Delavan Inc.	62
#2	Haier US Appliance Solutions, Inc.	54
#3	Clearsign Combustion Corporation	48
#4	Rinnai Corporation	45
#5	Pro-iroda Industries, Inc.	43
#6	Mitsubishi Hitachi Power Systems, Ltd.	35
#7	Lennox Industries Inc.	35
#8	EBERSPÄCHER Climate Control Systems GMBH	29
#9	AIR Products AND Chemicals, Inc.	27
#10	Kyungdong Navien Co., Ltd.	27
#11	ClearSign Technologies Corporation	25
#12	BSH Hausgeräte GmbH	23
#13	Rheem Manufacturing Company	22
#14	Doosan Enerbility Co., Ltd.	22
#15	Alstom Technology Ltd	20
#16	Lamplight Farms Incorporated	20
#17	Noritz Corporation	17
#18	8 Rivers Capital, LLC	17
#19	Collins Engine Nozzles, Inc.	17
#20	Webasto SE	16

Footprint here vs. claim strategy

Each dot is a leading F23D 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 F23D assignees by class footprint. Bubble size = patents in F23D. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Classes near F23D's 2,623-grant footprint

Nationwide nearest neighbors for F23D (#342 of 670 by volume ; lead share 7.1%) - not the F23 parent-class siblings above.

Nearest by grant volume

F41G 2,623 H02B 2,655 F26B 2,656 G07D 2,578

Nearest by lead-assignee share

B60Q 7.1% F21L 7.1% F24F 7.1% A61N 7.1%

Questions about F23D

Which company holds the most patents in F23D?

General Electric Company leads F23D with 186 patents (2.4% of the subclass). By PatentsView assignee type, us corporations account for 53% of class grants.

Which F23D assignees grew fastest recently?

Among assignees with ≥5 grants in F23D, Doosan Enerbility Co., Ltd. shows the highest company-wide grant multiple (121x: 0 grants in 2019–2021 → 121 in 2022–2024) while holding 22 patents in this subclass. Growth is company-wide, not class-only.

How does F23D compare inside parent class F23?

Inside F23 (Combustion APPARATUS; Combustion Processes), F23D ranks #2 of 12 subclasses by grant volume and holds 17.2% of the parent class total. The largest sibling is F23R (4,138 grants).

What to do with this data

F23D in context - here's where to go next.

Delavan Inc. leads F23D with 62 grants in this class. See full portfolio
F23D ranks #342 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 - F23D figures are USPTO PatentsView granted-utility totals for this subclass (2,623 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.