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 filing trajectory.

2,854
US patents granted
F01
Parent CPC class
20
Active assignees
-14%
5-yr velocity

The verdict

Steam Engine Plants ranks #326 of 670 CPC technology areas - 2,854 US patents granted since 2015, with filing down 14% over five years.

#326
of 670 CPC technology areas
2,854
US patents granted, 2015–2025
General Electric
leading assignee (233)
-14%
filing velocity, last 5 yrs
Top assignee: General Electric Company (233 patents)

CPC subclass F01K - STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES - covers 2,854 US utility patents granted between 2015 and 2025 according to USPTO PatentsView records, within the broader CPC class F01 (MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES). See our CPC classification guide for how the system works.

The competitive landscape in F01K is shaped by 20 distinct companies actively filing in this space. General Electric Company leads with 233 patents, followed by General Electric Technology Gmbh at 66 grants and ICE Thermal Harvesting, Llc at 49.

Filing activity in F01K is down 14% over the past five years versus 2015-2019, a relatively steady filing pace. All counts come directly from USPTO PatentsView and reflect US granted utility patents only.

Is F01K innovation accelerating?

US utility-patent grants per year in F01K, 2015–2025 - recent five years are down 14% 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

About This Class

CPC subclass F01K belongs to class F01.

2,854 patents were granted in this class between 2015 and 2025.

20 companies actively patent in this space.

Classification System

Cooperative Patent Classification (CPC) is a hierarchical patent classification system used by the USPTO and EPO.

← All Technology Classes Technology Rankings →

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).

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 Po…General Electric Tech…Ice Thermal HarvestingMaltaRondo EnergyMitsubishi Power8 Rivers CapitalDoosan Heavy Industri…Echogen Power SystemsAlstom TechnologySiemens Energy Global…Orcan EnergyMitsubishi Heavy Indu…Uop
Top 14 F01K assignees by class footprint. Bubble size = patents in F01K. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Frequently Asked Questions

What is CPC class F01K?
CPC subclass F01K covers STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES. It belongs to CPC class F01 (MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES), with 2,854 US utility patents granted since 2015.
How many patents have been filed in F01K?
2,854 US utility patents were granted in CPC subclass F01K between 2015 and 2025, based on USPTO PatentsView data.
Which company holds the most patents in F01K?
General Electric Company leads F01K with 233 patents, making it the most active assignee in this technology area.
How is patent data for F01K collected?
Patent data comes from USPTO PatentsView, a public research dataset maintained by the United States Patent and Trademark Office. It covers all US granted utility patents and assigns CPC codes based on the technology described in each patent.
What is the difference between CPC class and subclass?
A CPC class (e.g., F01) is a broad technology category. Subclasses like F01K provide finer granularity within that category. PlainPatent organizes data at the subclass level (4-character codes) for the most useful view of technology domains.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from USPTO PatentsView - official U.S. government patent data. See our methodology for computation details. Retrieved and formatted by PlainPatent Editorial

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.