F22D PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS
Introduced: September 1968
Description
F22D covers the preheating, supply, and control systems for feed-water in steam generation plants, along with devices that enhance water circulation within boilers. This includes economizers and feed-water heaters that raise inlet water temperature before entry into the boiler, feed-water supply equipment and regulation systems, water-level control mechanisms, and internal circulation-promoting devices such as baffles or circulation tubes. The class encompasses both the thermodynamic efficiency improvements from preheating and the operational safety and stability features related to water management in steam boiler systems. Related auxiliary equipment for steam generation itself is classified elsewhere under F22B-F22C.
IPC and CPC are identically structured here. All 5 subcodes exist in both systems.
1 shared codes have differing titles between IPC and CPC.
Child Classifications
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- F22D 1/00 Feed-water heaters, i.e. economisers or like preheaters +2 CPC IPC+CPC Available in IPC and CPC
- F22D 11/00 Feed-water supply not provided for in other main groups +2 CPC IPC+CPC Available in IPC and CPC
- F22D 5/00 Controlling water feed or water level; Automatic water feeding or water-level regulators 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