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CPC Class Not Allocatable
F23

COMBUSTION APPARATUS; COMBUSTION PROCESSES

Description

Class F23 encompasses mechanical systems and processes for controlled combustion of fuels, including furnaces, boilers, burners, and combustion chambers across industrial, domestic, and specialized applications. It covers fuel supply mechanisms, ignition systems, flame control, exhaust gas handling, and combustion efficiency optimization for solid, liquid, and gaseous fuels. The class includes both stationary combustion apparatus (such as heating systems and power generation equipment) and associated combustion processes, but excludes internal combustion engines (F02), which are classified separately despite their reliance on combustion principles.

Filing statistics

CPC F23 recorded 162,152 patent applications worldwide between 2013 and 2023, summed across its 12 subclasses. Annual filings grew from 12,311 in 2013 to 13,516 in 2023 (+10%), peaking at 18,002 applications in 2020. The most active applicants in class F23 are GE (GENERAL ELECTRIC COMPANY) (2,581 applications), UNITED TECHNOLOGIES CORPORATION (UTC) (1,180 applications) and SIEMENS (1,157 applications).

Source: EPO PATSTAT, worldwide filings

12 direct subcodes

Child Classifications

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Top Applicants

Top 10 applicants by patent filings, 2013–2023, worldwide · Source: EPO PATSTAT

  1. GE (GENERAL ELECTRIC COMPANY) US 2,581
  2. UNITED TECHNOLOGIES CORPORATION (UTC) US 1,180
  3. SIEMENS DE 1,157
  4. GE (GENERAL ELECTRIC COMPANY) 994
  5. XIAN THERMAL POWER RESEARCH INSTITUTE COMPANY 769
  6. MITSUBISHI HEAVY INDUSTRIES JP 701
  7. MITSUBISHI HITACHI POWER SYSTEMS JP 695
  8. RAYTHEON TECHNOLOGIES CORPORATION US 587
  9. NINGBO FOTILE KITCHENWARE COMPANY 543
  10. GENERAL ELECTRIC TECHNOLOGY CH 490