PlainPatent

CPC technology class · F01

F01K - Steam Engine Plants

Steam engine plants; steam accumulators; engine plants not otherwise provided for; engines using special working fluids or cycles. 2,854 US utility patents granted 2015–2025, with the leading assignees and year-by-year grant trajectory.

2,854
US patents granted
#6/8
in F01
5.3%
F01 class share
-24%
5-yr velocity

The verdict

According to USPTO PatentsView, Steam Engine Plants ranks #326 of 670 CPC technology areas - 2,854 US patents granted since 2015, with recorded grant volume down 24% over five years.

#326
of 670 CPC technology areas
2,854
US patents granted, 2015–2025
General Electric
leading assignee (233)
-24%
grant velocity, last 5 yrs

How F01K's grant cadence moved

Between 2020–2024, F01K recorded 1,124 grants versus 1,472 in 2015–2019 (-24% equal-window velocity). Across complete years, output peaked in 2017 at 339 grants and bottomed in 2024 at 191 (+77% peak-over-trough). Lead assignee Mitsubishi Hitachi Power Systems, Ltd. holds 2.8% of the class ; the top three share 6.9%.

Leaderboard read

F01K concentration, lead at 2.8%

Mitsubishi Hitachi Power Systems, Ltd. leads this historical grant record at 2.8% of F01K - foreign corporation assignees hold 53% of class grants (623 of 1,170). Figures describe granted US utility patents in this CPC subclass, not current investment or legal strength.

Leader's share
2.8%

81 of 2,854 grants

Top three share
6.9%

of the class's recorded grants

Lead over #2
15

more grants than General Electric Technology GMBH

Where F01K sits inside F01

Among 8 subclasses in F01 (Machines OR Engines IN GENERAL; Engine Plants IN GENERAL; Steam Engines), F01K ranks #6 and holds 5.3% of the parent class's 53,585 recorded grants. Sibling chips below are the other subclasses in the same parent class, not the nationwide volume/lead-share peers further down.

F01D 24,492 F01N 12,144 F01L 4,152 F01P 4,129 F01M 3,398 F01C 1,662 F01B 754

Rising assignees active in F01K

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 Doosan Enerbility Co., Ltd. 121x 0 → 121 company-wide · 14 in F01K
  2. #2 GE Infrastructure Technology LLC 80x 2 → 160 company-wide · 9 in F01K
  3. #3 ICE Thermal Harvesting, LLC 45x 1 → 45 company-wide · 49 in F01K
  4. #4 Rondo Energy, Inc. 36x 0 → 36 company-wide · 42 in F01K
  5. #5 Energy Dome S.P.A. 8.00x 0 → 8 company-wide · 9 in F01K

F01K grants by year, peak 2017 (339)

US utility-patent grants per year in F01K, 2015–2025 - recent five years are down 24% versus 2015–2019.

100150200250300350 20152016201720182019202020212022202320242025 137

Who leads F01K?

The 12 most active assignees in Steam Engine PLANTS; Steam ACCUMULATORS; Engine Plants NOT Otherwise Provided FOR; Engines Using Special Working Fluids OR Cycles - wider bars mean more grants

patents

What this shows General Electric is the most active filer in F01K, holding 233 of the 2,854 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 F01K
Rank Company Patents in F01K
#1 Mitsubishi Hitachi Power Systems, Ltd. 81
#2 General Electric Technology GMBH 66
#3 ICE Thermal Harvesting, LLC 49
#4 Malta Inc. 42
#5 Rondo Energy, Inc. 42
#6 Mitsubishi Power, Ltd. 36
#7 8 Rivers Capital, LLC 35
#8 Doosan Heavy Industries & Construction Co., Ltd. 30
#9 Echogen Power Systems, LLC 28
#10 Alstom Technology Ltd 27
#11 Siemens Energy Global GmbH & Co. KG 25
#12 Orcan Energy AG 20
#13 Mitsubishi Heavy Industries Compressor Corporation 17
#14 UOP LLC 16
#15 Mitsubishi Power Americas, Inc. 15
#16 Doosan Enerbility Co., Ltd. 14
#17 Ormat Technologies Inc. 14
#18 Sanden Corporation 13
#19 Emerson Process Management Power & Water Solutions, Inc. 12
#20 Toshiba Energy Systems & Solutions Corporation 11

Footprint here vs. claim strategy

Each dot is a leading F01K 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 F01K assignees by class footprint. Bubble size = patents in F01K. Source: USPTO PatentsView (claim depth is company-wide across all classes). Scatter plot of 14 data points (bubble-sized by third dimension). 010203040 020406080100 Patents in F01K Avg claims / patent (company-wide) Mitsubishi Hitachi…General Electric…Ice Thermal HarvestingMaltaRondo EnergyMitsubishi Power8 Rivers CapitalDoosan Heavy…Echogen Power SystemsAlstom TechnologySiemens Energy Global…Orcan EnergyMitsubishi Heavy…Uop
Top 14 F01K assignees by class footprint. Bubble size = patents in F01K. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Classes near F01K's 2,854-grant footprint

Nationwide nearest neighbors for F01K (#326 of 670 by volume ; lead share 8.2%) - not the F01 parent-class siblings above.

Nearest by grant volume

B23D 2,856 A63H 2,847 D01D 2,869 A23B 2,807

Nearest by lead-assignee share

B60T 8.1% D10B 8.1% B04B 8.1% F01N 8.1%

Questions about F01K

Which company holds the most patents in F01K?
General Electric Company leads F01K with 233 patents (2.8% of the subclass). By PatentsView assignee type, foreign corporations account for 53% of class grants.
Which F01K assignees grew fastest recently?
Among assignees with ≥5 grants in F01K, Doosan Enerbility Co., Ltd. shows the highest company-wide grant multiple (121x: 0 grants in 2019–2021 → 121 in 2022–2024) while holding 14 patents in this subclass. Growth is company-wide, not class-only.
How does F01K compare inside parent class F01?
Inside F01 (Machines OR Engines IN GENERAL; Engine Plants IN GENERAL; Steam Engines), F01K ranks #6 of 8 subclasses by grant volume and holds 5.3% of the parent class total. The largest sibling is F01D (24,492 grants).

What to do with this data

F01K in context - here's where to go next.

  • Mitsubishi Hitachi Power Systems, Ltd. leads F01K with 81 grants in this class. See full portfolio
  • F01K ranks #326 of 670 by grant volume among all tracked CPC technology areas. See the ranking
  • Inside parent class F01, the largest sibling subclass is F01D with 24,492 grants. Explore F01D

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

Methodology - F01K figures are USPTO PatentsView granted-utility totals for this subclass (2,854 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.