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CPC technology class · F27

F27D - Details Or Accessories Of Furnaces

Details or accessories of furnaces, kilns, ovens or retorts, in so far as they are of kinds occurring in more than one kind of furnace. 2,695 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.

2,695
US patents granted
#1/3
in F27
55.1%
F27 class share
-17%
5-yr velocity

The verdict

According to USPTO PatentsView, Details Or Accessories Of Furnaces ranks #337 of 670 CPC technology areas - 2,695 US patents granted since 2015, with recorded grant volume down 17% over five years.

#337
of 670 CPC technology areas
2,695
US patents granted, 2015–2025
Molten Metal Equipment…
leading assignee (58)
-17%
grant velocity, last 5 yrs

How F27D's grant cadence moved

Between 2020–2024, F27D recorded 1,064 grants versus 1,282 in 2015–2019 (-17% equal-window velocity). Across complete years, output peaked in 2017 at 287 grants and bottomed in 2021 at 173 (+66% peak-over-trough). Lead assignee Molten Metal Equipment Innovations, LLC holds 2.2% of the class ; the top three share 5.9%.

Leaderboard read

F27D concentration, lead at 2.2%

Molten Metal Equipment Innovations, LLC leads this historical grant record at 2.2% of F27D - foreign corporation assignees hold 65% of class grants (934 of 1,437). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share
2.2%

58 of 2,695 grants

Top three share
5.9%

of the class's recorded grants

Lead over #2
5

more grants than JFE Steel Corporation

Where F27D sits inside F27

Among 3 subclasses in F27 (FURNACES; KILNS; OVENS; Retorts), F27D ranks #1 and holds 55.1% of the parent class's 4,893 recorded grants. Sibling chips below are the other subclasses in the same parent class, not the nationwide volume/lead-share peers further down.

F27B 2,129 F27M 69

Rising assignees active in F27D

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 Ebner Industrieofenbau GmbH 10x 1 → 10 company-wide · 7 in F27D
  2. #2 Zhejiang Hailiang Co., Ltd. 9.00x 0 → 9 company-wide · 5 in F27D
  3. #3 thyssenkrupp Polysius GmbH 6.00x 0 → 6 company-wide · 5 in F27D
  4. #4 HarbisonWalker International Holdings, Inc. 2.50x 2 → 5 company-wide · 6 in F27D
  5. #5 Research Institute OF Industrial Science & Technology 2.20x 15 → 33 company-wide · 7 in F27D

F27D grants by year, peak 2017 (287)

US utility-patent grants per year in F27D, 2015–2025 - recent five years are down 17% versus 2015–2019.

150200250300 20152016201720182019202020212022202320242025 166

Who leads F27D?

The 12 most active assignees in Details OR Accessories OF Furnaces, Kilns, Ovens OR Retorts, IN SO FAR AS They ARE OF Kinds Occurring IN More Than ONE Kind OF Furnace - wider bars mean more grants

patents

What this shows Molten Metal… is the most active filer in F27D, holding 58 of the 2,695 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 F27D
Rank Company Patents in F27D
#1 Molten Metal Equipment Innovations, LLC 58
#2 JFE Steel Corporation 53
#3 Paul Wurth S.A. 47
#4 Novelis Inc. 34
#5 Danieli & C. Officine Meccaniche S.P.A. 31
#6 Outotec (FINLAND) OY 30
#7 Primetals Technologies Austria GmbH 28
#8 Ivoclar Vivadent AG 23
#9 Refractory Intellectual Property GMBH & Co. KG 23
#10 ASM IP Holding B.V. 22
#11 AIR Products AND Chemicals, Inc. 21
#12 Pyrotek, Inc. 20
#13 Outotec Oyj 18
#14 Posco Co., Ltd 16
#15 SMS group GmbH 16
#16 Saint-gobain Centre DE Recherches ET D'etudes Europeen 16
#17 Hatch Ltd. 16
#18 Systems Spray-Cooled, Inc. 16
#19 Suncoke Technology AND Development LLC 14
#20 Inductotherm Corp. 14

Footprint here vs. claim strategy

Each dot is a leading F27D 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 F27D assignees by class footprint. Bubble size = patents in F27D. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 510152025 10203040506070 Patents in F27D Avg claims / patent (company-wide) Molten Metal…Jfe SteelPaul WurthNovelisDanieli & C Officine…Outotec (Finland) OyPrimetals AustriaIvoclar VivadentRefractory Intellectua…Asm Ip Holding B VAir Products And…PyrotekOutotec OyjPosco
Top 14 F27D assignees by class footprint. Bubble size = patents in F27D. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Classes near F27D's 2,695-grant footprint

Nationwide nearest neighbors for F27D (#337 of 670 by volume ; lead share 2.2%) - not the F27 parent-class siblings above.

Nearest by grant volume

E04G 2,717 A62B 2,672 B61L 2,671 F41H 2,723

Nearest by lead-assignee share

F41A 2.2% A61M 2.2% G01G 2.1% B65B 2.2%

Questions about F27D

Which company holds the most patents in F27D?
Molten Metal Equipment Innovations, LLC leads F27D with 58 patents (2.2% of the subclass). By PatentsView assignee type, foreign corporations account for 65% of class grants.
Which F27D assignees grew fastest recently?
Among assignees with ≥5 grants in F27D, Ebner Industrieofenbau GmbH shows the highest company-wide grant multiple (10x: 1 grants in 2019–2021 → 10 in 2022–2024) while holding 7 patents in this subclass. Growth is company-wide, not class-only.
How does F27D compare inside parent class F27?
Inside F27 (FURNACES; KILNS; OVENS; Retorts), F27D ranks #1 of 3 subclasses by grant volume and holds 55.1% of the parent class total. The largest sibling is F27B (2,129 grants).

What to do with this data

F27D in context - here's where to go next.

  • Molten Metal Equipment Innovations, LLC leads F27D with 58 grants in this class. See full portfolio
  • F27D ranks #337 of 670 by grant volume among all tracked CPC technology areas. See the ranking
  • Inside parent class F27, the largest sibling subclass is F27B with 2,129 grants. Explore F27B

Figures reflect USPTO PatentsView grant data through 2026-05-15; pending applications not yet granted are not counted.

Methodology - F27D figures are USPTO PatentsView granted-utility totals for this subclass (2,695 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.