Cleaning of internal or external surfaces of heat-exchange or heat-transfer conduits

Official title: 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)

F28G (Cleaning of internal or external surfaces of heat-exchange or heat-transfer conduits) appears on 1,463 US grants and 1,078 published applications in this corpus.