DIFF Subgroup
F22B 21/04 involving a single upper drum and a single lower drum, e.g. the drums being arranged transversely
Introduced: September 1968
Full Title
Water-tube boilers of vertical or steeply-inclined type, i.e. the water-tube sets being arranged vertically or substantially vertically > built-up from substantially-straight water tubes > involving a single upper drum and a single lower drum, e.g. the drums being arranged transversely
IPC and CPC are identically structured here. All 3 subcodes exist in both systems.
Child Classifications
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- F22B 21/06 the water tubes being arranged annularly in sets, e.g. in abutting connection with drums of annular shape +1 CPC IPC+CPC Available in IPC and CPC
- F22B 21/08 the water tubes being arranged sectionally in groups or in banks, e.g. bent over at their ends +5 CPC IPC+CPC Available in IPC and CPC
Top Applicants
Top Applicants (IPC)
Class F22,2013–2023, worldwide · Source: EPO PATSTAT
- XIAN THERMAL POWER RESEARCH INSTITUTE COMPANY 922
- MIURA COMPANY 416
- HARBIN BOILER COMPANY 390
- MITSUBISHI HITACHI POWER SYSTEMS 303
- XIAN JIAOTONG UNIVERSITY 287
- SGCC(STATE GRID CORPORATION OF CHINA) 257
- HUADIAN ELECTRIC POWER RESEARCH INSTITUTE 253
- SIEMENS DE 247
- MIDEA 243
- NORTH CHINA ELECTRIC POWER UNIVERSITY 223
Top Applicants (CPC)
Class F22,2013–2023, worldwide · Source: EPO PATSTAT
- XIAN THERMAL POWER RESEARCH INSTITUTE COMPANY 544
- SIEMENS DE 306
- PHILIP MORRIS PRODUCTS CH 258
- GENERAL ELECTRIC TECHNOLOGY CH 254
- MITSUBISHI HITACHI POWER SYSTEMS JP 235
- XIAN JIAOTONG UNIVERSITY 214
- MITSUBISHI HEAVY INDUSTRIES JP 195
- MITSUBISHI HITACHI POWER SYSTEMS 169
- HARBIN BOILER COMPANY 166
- VALMET TECHNOLOGIES FI 155