REFRIGERATION UNITS; FLUID, AIR AND WATER HEATERS AND COOLERS FOR DOMESTIC, COMMERCIAL AND INDUSTRIAL USES; AIR DELIVERY AND HANDLING UNITS FOR COOLING; HEATING AND VENTILATING DOMESTIC, COMMERCIAL AND INDUSTRIAL BUILDINGS, AND FOR USE IN COMMERCIAL PROCESS APPLICATIONS; AIR INDUCTION UNITS; AIR FILTERS, HUMIDIFIERS, VENTILATORS, DIFFUSERS, BLENDERS AND CONVECTORS; REFRIGERANT CONDENSERS, EVAPORATORS AND ABSORBERS; FANS AND BLOWERS; BOILERS; ELECTRIC, GAS, AND OIL FURNACES; HEAT PUMPS; HYDROCARBON FUEL BURNERS, INCINERATORS; HEAT EXCHANGERS FOR USE IN HEAT TRANSFER FOR INDUSTRIAL AND COMMERCIAL USES; SHELL AND TUBE, FIN AND TUBE AND PLATE AND FIN HEAT EXCHANGERS; AND PARTS THEREFOR; ELECTROSTATIC AIR FILTERS; TERMINAL AIR UNITS; VARIABLE AIR VOLUME UNITS; VALVES, TRAPS, VENTS, STRAINERS, PIPE FITTINGS, TUBE FITTINGS AND PARTS THEREOF; FLUID COOLERS, AIR COOLERS, REFRIGERATION MACHINES AND PARTS THEREOF NAMELY, COMPRESSORS, CONDENSERS, EVAPORATORS, ECONOMISERS, HEAT EXCHANGERS, RECEIVERS, MUFFLERS AND STRAINERS; UNIT VENTILATORS, ROOF VENTILATORS; UNIT HEATERS, GAS-FIRED UNIT HEATERS, FURNACES, BOILERS, FANS, CENTRIFUGAL FANS, PROPELLER FANS, GRILLES AND DIFFUSERS
Environmental Control Apparatus