The three-pass boiler refers to a boiler that adopts a three-return structure. In the three pass boiler, the flue gas is discharged outside the boiler after three cycles in the furnace. Generally speaking, a boiler with more passes provides more opportunities for hot gasses to transfer heat to the water in a boiler and operate more efficiently. The three-pass boiler is designed to maximize the time that the flue gas stays in the boiler, minimize the boiler flue gas outlet temperature, and maximize the use of thermal energy. ZBG has WNS series three pass fire tube boiler and DZL series three pass water-fire tube boiler.
WNS series oil and gas boiler are fire tube boilers based on a three-pass design. In the WNS series boiler, The heat generated by the gas (oil) burner is circulated three times in the boiler to completely burn the combustion and improve the thermal efficiency. After years of continuous technical improvement, the structure is very mature. The boiler has large volume and steam chamber height, together with the addition of the drip trap, and the design and smoke tube section as well as the separation between the tubes, the WNS series oil and gas boiler has good internal water recirculation. The WNS series oil and gas boiler is one of the highest performing boilers on the market: according to the pressure and fuel, it can reach 98%.
DZL series biomass/coal fired boiler adopts three-pass structure, compact design and energy-saving space. The air pre-heater and economizer are added to enhance the heating efficiency up to 87% or more. The boiler body has a large heating surface and high thermal efficiency. It has the advantages of compact structure, reasonable water circulation design and quick start. The DZL series boiler adopts the advanced chain grate structure, has reliable work, less fuel leakage, good energy saving effect and reduces the installation and maintenance work of the grate. The grate is equipped with reasonable air, which is conducive to fuel burning and improve the efficiency of the whole machine.