11 COMMERCIAL AND INDUSTRIAL STEAM AND POWER INDUSTRY SYSTEMS COMPRISING FURNACE BOILERS, STOKERS, CASINGS, BURNERS, REFRACTORY FURNACES, SOOT BLOWERS, FUEL CONVEYERS, FUEL COLLECTORS, ASH HANDLING EQUIPMENT, NAMELY, CONVEYERS, FEEDWATER EQUIPMENT, NAMELY, PIPING, WATER TREATMENT APPARATUS, AND PUMPS, AND ENVIRONMENTAL CONTROL EQUIPMENT, NAMELY, DUST COLLECTORS, ELECTROSTATIC PRECIPITATORS, AND MECHANICAL COLLECTORS, ALL SOLD TOGETHER AS A UNIT; AND BOILERS, STOKERS, AND REFRACTORY FURNACES SOLD SEPARATELY