F28 HEAT EXCHANGE IN GENERAL
Description
Covers apparatus and methods for transferring thermal energy between fluids or between a fluid and a solid surface, including heat exchangers, condensers, evaporators, and cooling devices. Encompasses various heat transfer mechanisms such as direct contact, indirect contact through walls, and phase-change processes, with designs ranging from simple tube-and-shell configurations to complex multi-stage systems. Includes control systems, accessories, and manufacturing techniques specific to heat exchange equipment, but excludes specialized applications assigned to other classes (such as refrigeration systems in F25 or internal combustion engine cooling in F01).
Filing statistics
CPC F28 recorded 194,580 patent applications worldwide between 2013 and 2023, summed across its 5 subclasses. Annual filings grew from 15,115 in 2013 to 16,234 in 2023 (+7%), peaking at 20,904 applications in 2020. The most active applicants in class F28 are VALEO SYSTEMES THERMIQUES (1,945 applications), MITSUBISHI ELECTRIC CORPORATION (1,518 applications) and MAHLE INTERNATIONAL (1,120 applications).
Source: EPO PATSTAT, worldwide filings
5 direct subcodes
Child Classifications
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- F28B STEAM OR VAPOUR CONDENSERS (condensation of vapours B01D5/00; steam engine plants having condensers F01K; liquefaction of gases F25J; details of heat-exchange and heat-transfer arrangements of general application F28F)
- F28C HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA COME INTO DIRECT CONTACT WITHOUT CHEMICAL INTERACTION (safety devices in general F16P; fluid heaters having heat generating means F24H; with an intermediate heat-transfer medium coming into direct contact with heat-exchange media F28D15/00 - F28D19/00; details of heat-exchange apparatus of general application F28F)
- F28D HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of general)
- F28F DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION (water and air traps, air venting F16)
- F28G CLEANING OF INTERNAL OR EXTERNAL SURFACES OF HEAT-EXCHANGE OR HEAT-TRANSFER CONDUITS, e.g. WATER TUBES OR BOILERS (cleaning pipes or tubes in general B08B9/02; devices or arrangements for removing water, minerals, or sludge from boilers while the boiler is in operation, or which remain in position while the boiler is in operation, or are specifically adapted to boilers without any other utility F22B37/48; removal or treatment of combustion products or combustion residues F23J; removing ice from heat-exchange apparatus F28F17/00)
Top Applicants
Top 10 applicants by patent filings, 2013–2023, worldwide · Source: EPO PATSTAT
- VALEO SYSTEMES THERMIQUES FR 1,945
- MITSUBISHI ELECTRIC CORPORATION JP 1,518
- MAHLE INTERNATIONAL DE 1,120
- ALFA LAVAL SE 1,085
- HANON SYSTEMS KR 939
- DENSO CORPORATION JP 900
- LG ELECTRONICS KR 861
- HAMILTON SUNDSTRAND US 795
- DAIKIN INDUSTRIES JP 608
- DENSO CORPORATION 537