ZOZEN energy-efficient WNS series gas/oil-fired steam boilers have two-pass and three-pass structures. This series of boilers adopt the large-diameter corrugated furnace and threaded smoke tubes with high heat transfer efficiency. With the economizer at the end of the flue gas duct, they can enlarge the boiler's heating surface, lower the exhaust gas temperature to 60℃ and improve the boiler's thermal efficiency to over 98%. ZOZEN WNS 8 tph steam boilers are applied in the food, chemical and heating industries.