CPC technology class · F27

F27B - Furnaces

Furnaces, kilns, ovens or retorts in general; open sintering or like apparatus. 2,129 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.

Compiled by PlainPatent · May 15, 2026

2,129
US patents granted: #2/3
in F27: 43.5%
F27 class share: -14%
5-yr velocity

The verdict

According to USPTO PatentsView, Furnaces ranks #363 of 670 CPC technology areas - 2,129 US patents granted since 2015, with recorded grant volume down 14% over five years.

#363
of 670 CPC technology areas: 2,129
US patents granted, 2015–2025: Jfe Steel
leading assignee (42): -14%
grant velocity, last 5 yrs

How F27B's grant cadence moved

Between 2020–2024, F27B recorded 844 grants versus 978 in 2015–2019 (-14% equal-window velocity). Across complete years, output peaked in 2017 at 228 grants and bottomed in 2021 at 146 (+56% peak-over-trough). Lead assignee JFE Steel Corporation holds 2.0% of the class ; the top three share 5.4%.

Leaderboard read

F27B concentration, lead at 2.0%

JFE Steel Corporation leads this historical grant record at 2.0% of F27B - foreign corporation assignees hold 71% of class grants (758 of 1,061). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share: 2.0%
Top three share: 5.4%
Lead over #2: 0

Where F27B sits inside F27

Among 3 subclasses in F27 (FURNACES; KILNS; OVENS; Retorts), F27B ranks #2 and holds 43.5% 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.

F27D 2,695 F27M 69

Rising assignees active in F27B

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 Ebner Industrieofenbau GmbH 10x 1 → 10 company-wide · 9 in F27B
#2 Eisenmann GMBH 8.00x 1 → 8 company-wide · 5 in F27B
#3 thyssenkrupp Polysius GmbH 6.00x 0 → 6 company-wide · 5 in F27B
#4 Onejoon GMBH 5.00x 0 → 5 company-wide · 5 in F27B
#5 Quantumscape Battery, Inc. 3.54x 13 → 46 company-wide · 6 in F27B

F27B grants by year, peak 2017 (228)

US utility-patent grants per year in F27B, 2015–2025 - recent five years are down 14% versus 2015–2019.

Jfe Steel

42
Paul Wurth

42
Ivoclar Vivadent

32
Danieli & C Officine…

28
Outotec (Finland) Oy

26
Screen Holdings

20
Primetals Austria

20
Asm Ip Holding B V

17
Sms group

16
Molten Metal…

15
Outotec Oyj

14
Thyssenkrupp…

13

What this shows Jfe Steel is the most active filer in F27B, holding 42 of the 2,129 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 F27B
Rank	Company	Patents in F27B
#1	JFE Steel Corporation	42
#2	Paul Wurth S.A.	42
#3	Ivoclar Vivadent AG	32
#4	Danieli & C. Officine Meccaniche S.P.A.	28
#5	Outotec (FINLAND) OY	26
#6	Screen Holdings Co., Ltd.	20
#7	Primetals Technologies Austria GmbH	20
#8	ASM IP Holding B.V.	17
#9	SMS group GmbH	16
#10	Molten Metal Equipment Innovations, LLC	15
#11	Outotec Oyj	14
#12	Thyssenkrupp Industrial Solutions AG	13
#13	IHI Machinery AND Furnace Co., Ltd.	13
#14	Terra CO2 Technology Holdings, Inc.	13
#15	AIR Products AND Chemicals, Inc.	12
#16	Pyrotek, Inc.	12
#17	Hatch Ltd.	12
#18	Inductotherm Corp.	12
#19	Leco Corporation	11
#20	Mattson Technology, Inc.	10

Footprint here vs. claim strategy

Each dot is a leading F27B 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 F27B assignees by class footprint. Bubble size = patents in F27B. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Classes near F27B's 2,129-grant footprint

Nationwide nearest neighbors for F27B (#363 of 670 by volume ; lead share 2.0%) - not the F27 parent-class siblings above.

Nearest by grant volume

D03D 2,141 B24D 2,145 G09C 2,112 H01C 2,105

Nearest by lead-assignee share

G01B 2.0% G01M 2.0% C12N 1.9% C07C 2.0%

Questions about F27B

Which company holds the most patents in F27B?

JFE Steel Corporation leads F27B with 42 patents (2.0% of the subclass). By PatentsView assignee type, foreign corporations account for 71% of class grants.

Which F27B assignees grew fastest recently?

Among assignees with ≥5 grants in F27B, Ebner Industrieofenbau GmbH shows the highest company-wide grant multiple (10x: 1 grants in 2019–2021 → 10 in 2022–2024) while holding 9 patents in this subclass. Growth is company-wide, not class-only.

How does F27B compare inside parent class F27?

Inside F27 (FURNACES; KILNS; OVENS; Retorts), F27B ranks #2 of 3 subclasses by grant volume and holds 43.5% of the parent class total. The largest sibling is F27D (2,695 grants).

What to do with this data

F27B in context - here's where to go next.

JFE Steel Corporation leads F27B with 42 grants in this class. See full portfolio
F27B ranks #363 of 670 by grant volume among all tracked CPC technology areas. See the ranking
Inside parent class F27, the largest sibling subclass is F27D with 2,695 grants. Explore F27D

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

Methodology - F27B figures are USPTO PatentsView granted-utility totals for this subclass (2,129 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.