F01K STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES (gas-turbine or jet-propulsion plants F02; nuclear power plants, engine arrangements therein G21D)
Description
F01K covers steam engine plants and power generation systems utilizing steam as the working fluid, including boiler-turbine combinations, auxiliary equipment, and thermal efficiency improvements. It encompasses steam accumulators (pressure vessels for storing thermal energy), and engine plants employing non-conventional working fluids or thermodynamic cycles not covered by other F01 subclasses, such as organic Rankine cycles or supercritical fluid systems. This classification includes complete power plant configurations, control systems, and integration of multiple components, but excludes individual components (turbines, compressors, pumps) classified elsewhere in F01 unless presented as an integrated plant system. F01K serves as a residual category for specialized or emerging engine technologies that do not fit standard internal combustion or specific turbomachinery classifications.
Filing statistics
CPC subclass F01K recorded 27,100 patent applications worldwide between 2013 and 2023. Annual filings declined from 2,583 in 2013 to 2,181 in 2023 (-16%), peaking at 2,897 applications in 2016. The most active applicants in class F01 are GE (GENERAL ELECTRIC COMPANY) (9,989 applications), UNITED TECHNOLOGIES CORPORATION (UTC) (8,110 applications) and SAFRAN AIRCRAFT ENGINES (6,248 applications).
Source: EPO PATSTAT, worldwide filings
14 direct subcodes
Child Classifications
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- F01K 1/00 Steam accumulators (use of accumulators in steam engine plants F01K3/00)
- F01K 11/00 Plants characterised by the engines being structurally combined with boilers or condensers
- F01K 13/00 General layout or general methods of operation of complete plants
- F01K 15/00 Adaptations of plants for special use
- F01K 17/00 Using steam or condensate extracted or exhausted from steam engine plant (for heating feed-water F01K7/34; returning condensate to boiler F22D )
- F01K 19/00 Regenerating or otherwise treating steam exhausted from steam engine plant ( plants characterised by use of means for storing steam in an alkali to increase steam pressure F01K5/00; returning condensate to boiler F22D)
- F01K 21/00 Steam engine plants not otherwise provided for
- F01K 23/00 Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
- F01K 25/00 Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for
- F01K 27/00 Plants for converting heat or fluid energy into mechanical energy, not otherwise provided for
- F01K 3/00 Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein (regenerating exhaust steam F01K19/00)
- F01K 5/00 Plants characterised by use of means for storing steam in an alkali to increase steam pressure, e.g. of Honigmann or Koenemann type
- F01K 7/00 Steam engine plants characterised by the use of specific types of engine (F01K3/02 takes precedence); Plants or engines characterised by their use of special steam systems, cycles or processes (reciprocating-piston engines using uniflow principle F01B17/04); Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating
- F01K 9/00 Plants characterised by condensers arranged or modified to co-operate with the engines (by condensers structurally combined with engines F01K11/00; steam condensers per se F28B)(F01K23/04 takes precedence)
Top Applicants
Top 10 applicants by patent filingsfor class F01, 2013–2023, worldwide · Source: EPO PATSTAT
- GE (GENERAL ELECTRIC COMPANY) US 9,989
- UNITED TECHNOLOGIES CORPORATION (UTC) US 8,110
- SAFRAN AIRCRAFT ENGINES FR 6,248
- HYUNDAI MOTOR COMPANY KR 4,530
- SIEMENS DE 4,461
- FORD GLOBAL TECHNOLOGIES US 4,029
- RAYTHEON TECHNOLOGIES CORPORATION US 3,947
- TOYOTA MOTOR CORPORATION JP 3,734
- GE (GENERAL ELECTRIC COMPANY) 3,415
- SCHAEFFLER TECHNOLOGIES & COMPANY DE 3,063