... gas boiler, industrial furnace, resident building, medium and low pressure small direct fired equipmentMedianatural gas, manufactured coal gas, LPG, air, ... 1 Regulators used indoor, buildings, medium and low pressure small direct-fired machine etc. 2.2 Kinds of regulators( ... used indoor, buildings, medium and low pressure small direct-fired machine etc.2.4 Pressure regulator cabinets and device (used in ...