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IPC Main Group
F22B 23/00

Water-tube boilers built-up from sets of spaced double-walled water tubes of return type in unilateral abutting connection with a boiler drum or with a header box, i.e. built-up from Field water tubes comprising an inner tube arranged within an outer unilaterally-closed tube

Introduced: September 1968

Last revised: January 2006

Classification Context

Section:
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Class:
STEAM GENERATION
Subclass:
METHODS OF STEAM GENERATION; STEAM BOILERS

Filing statistics

IPC F22B 23/00 belongs to the parent subclass F22B, which recorded 46,730 patent applications worldwide between 2013 and 2023. Annual filings grew from 2,854 in 2013 to 4,965 in 2023 (+74%), peaking at 5,724 applications in 2020. The most active applicants in class F22 are XIAN THERMAL POWER RESEARCH INSTITUTE COMPANY (922 applications), MIURA COMPANY (416 applications) and HARBIN BOILER COMPANY (390 applications).

Source: EPO PATSTAT, worldwide filings

3 direct subcodes

Child Classifications

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  • F22B 23/02 the water-tube, i.e. Field-tube, sets being horizontal or substantially horizontal
  • F22B 23/04 the water-tube, i.e. Field-tube, sets being vertical or substantially vertical
  • F22B 23/06 Component parts thereof, e.g. Field water tubes

Top Applicants

Top 10 applicants by patent filingsfor class F22, 2013–2023, worldwide · Source: EPO PATSTAT

  1. XIAN THERMAL POWER RESEARCH INSTITUTE COMPANY 922
  2. MIURA COMPANY 416
  3. HARBIN BOILER COMPANY 390
  4. MITSUBISHI HITACHI POWER SYSTEMS 303
  5. XIAN JIAOTONG UNIVERSITY 287
  6. SGCC(STATE GRID CORPORATION OF CHINA) 257
  7. HUADIAN ELECTRIC POWER RESEARCH INSTITUTE 253
  8. SIEMENS DE 247
  9. MIDEA 243
  10. NORTH CHINA ELECTRIC POWER UNIVERSITY 223