PlainPatent

CPC technology class · F23

F23L - Supplying Air Or Non-combustible Liquids Or Gases To Comb…

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

922
US patents granted
#7/12
in F23
6.0%
F23 class share
-23%
5-yr velocity

The verdict

According to USPTO PatentsView, Supplying Air Or Non-combustible Liquids Or Gases To Comb… ranks #470 of 670 CPC technology areas - 922 US patents granted since 2015, with recorded grant volume down 23% over five years.

#470
of 670 CPC technology areas
922
US patents granted, 2015–2025
General Electric
leading assignee (33)
-23%
grant velocity, last 5 yrs

How F23L's grant cadence moved

Between 2020–2024, F23L recorded 359 grants versus 465 in 2015–2019 (-23% equal-window velocity). Across complete years, output peaked in 2017 at 112 grants and bottomed in 2023 at 60 (+87% peak-over-trough). Lead assignee L'Air Liquide, Societe Anonyme Pour l'Etude et l'Exploitation des Procedes Georges Claude holds 3.4% of the class ; the top three share 8.4%.

Leaderboard read

F23L concentration, lead at 3.4%

L'Air Liquide, Societe Anonyme Pour l'Etude et l'Exploitation des Procedes Georges Claude leads this historical grant record at 3.4% of F23L - us corporation assignees hold 53% of class grants (224 of 423). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share
3.4%

31 of 922 grants

Top three share
8.4%

of the class's recorded grants

Lead over #2
6

more grants than Noritz Corporation

Where F23L sits inside F23

Among 12 subclasses in F23 (Combustion APPARATUS; Combustion Processes), F23L ranks #7 and holds 6.0% 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 F23K 754 F23M 568

Rising assignees active in F23L

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 Rheem Manufacturing Company 2.26x 80 → 181 company-wide · 9 in F23L
  2. #2 Membrane Technology and Research, Inc. 2.00x 3 → 6 company-wide · 7 in F23L
  3. #3 Kyungdong Navien Co., Ltd. 1.44x 39 → 56 company-wide · 12 in F23L
  4. #4 8 Rivers Capital, LLC 1.35x 31 → 42 company-wide · 21 in F23L
  5. #5 L'Air Liquide, Societe Anonyme Pour l'Etude et l'Exploitation des Procedes Georges Claude 1.15x 273 → 315 company-wide · 31 in F23L

F23L grants by year, peak 2017 (112)

US utility-patent grants per year in F23L, 2015–2025 - recent five years are down 23% versus 2015–2019.

406080100120 20152016201720182019202020212022202320242025 49

Who leads F23L?

The 12 most active assignees in 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 - wider bars mean more grants

patents

What this shows General Electric is the most active filer in F23L, holding 33 of the 922 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 F23L
Rank Company Patents in F23L
#1 L'Air Liquide, Societe Anonyme Pour l'Etude et l'Exploitation des Procedes Georges Claude 31
#2 Noritz Corporation 25
#3 8 Rivers Capital, LLC 21
#4 Praxair Technology, Inc. 18
#5 Regal Beloit America, Inc. 16
#6 AIR Products AND Chemicals, Inc. 14
#7 Rinnai Corporation 13
#8 Kyungdong Navien Co., Ltd. 12
#9 Field Controls, LLC 11
#10 Rheem Manufacturing Company 9
#11 American Air Liquide, Inc. 9
#12 Clearsign Combustion Corporation 9
#13 Ener-Core Power, Inc. 9
#14 Biochar Now, LLC 8
#15 GAS Technology Institute 7
#16 Membrane Technology and Research, Inc. 7
#17 Itea S.P.A 7
#18 Taiyo Nippon Sanso Corporation 6
#19 Arvos Ljungstrom LLC 6
#20 HER Majesty THE Queen IN Right OF Canada AS Represented BY THE Minister OF Natual Resources 4

Footprint here vs. claim strategy

Each dot is a leading F23L 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 F23L assignees by class footprint. Bubble size = patents in F23L. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 010203040 010203040 Patents in F23L Avg claims / patent (company-wide) L'air Liquide Societe…Noritz8 Rivers CapitalPraxair TechnologyRegal Beloit AmericaAir Products And…RinnaiKyungdong NavienField ControlsRheem ManufacturingAmerican Air LiquideClearsign CombustionEner-core PowerBiochar Now
Top 14 F23L assignees by class footprint. Bubble size = patents in F23L. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Classes near F23L's 922-grant footprint

Nationwide nearest neighbors for F23L (#470 of 670 by volume ; lead share 3.6%) - not the F23 parent-class siblings above.

Nearest by grant volume

F15D 924 A23J 927 F04F 906 F42C 944

Nearest by lead-assignee share

Y10S 3.6% A23K 3.6% F21S 3.6% G10K 3.6%

Questions about F23L

Which company holds the most patents in F23L?
General Electric Company leads F23L with 33 patents (3.4% of the subclass). By PatentsView assignee type, us corporations account for 53% of class grants.
Which F23L assignees grew fastest recently?
Among assignees with ≥5 grants in F23L, Rheem Manufacturing Company shows the highest company-wide grant multiple (2.26x: 80 grants in 2019–2021 → 181 in 2022–2024) while holding 9 patents in this subclass. Growth is company-wide, not class-only.
How does F23L compare inside parent class F23?
Inside F23 (Combustion APPARATUS; Combustion Processes), F23L ranks #7 of 12 subclasses by grant volume and holds 6.0% of the parent class total. The largest sibling is F23R (4,138 grants).

What to do with this data

F23L in context - here's where to go next.

  • L'Air Liquide, Societe Anonyme Pour l'Etude et l'Exploitation des Procedes Georges Claude leads F23L with 31 grants in this class. See full portfolio
  • F23L ranks #470 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 - F23L figures are USPTO PatentsView granted-utility totals for this subclass (922 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.