WNS series gas-fired (oil-fired) hot water boiler

WNS series horizontal internal combustion boiler is a boiler shell type 3 passes wetback oil/gas fired boiler. After fuel is being atomized by burner, flame is full of the wave furnace and transfer heat via furnace wall, this is 1st pass; the high temperature smoke is collected in reversal chamber and then enters 2nd pass which is grooved tubes bundle area; after heat convection, air temperature gradually falls and goes to front smoke box and turn to 3rd pass, which is smooth tubes bundle area, and then enters chimney passing back smoke box and exhausted to the atmosphere.


0.35-14 MW


0.7-1.25 Mpa


Nature gas, coke oven gas, biogas, methanol, liquid propane gas, diesel, heavy oil, light oil, crude oil, etc.


Heat supplying, hospital, hotel

wns oil-fired boiler1
wns oil-fired boiler2

Easy operation and maintenance

Fully intelligent operation, with automatic adjustment and protection of burning, water level, temperature and steam pressure. The smoke box door uses the hinge structure for easy inspection, inventory and cleaning.

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Long service life

(a) The way to weld Smoke tube and tube sheet is to first expand to eliminate the gap between them, then adopt automatic argon arc welding to relief the stress and expand boiler service life.
(b) Longitudinal and girth joint adopt advanced automatic submerged-arc welding for good welding quality. All longitudinal and girth joint are test by radiographic inspection.
(c) Fin tube uses ND steel or stainless-steel material to avoid corrosion in the low temperature . Inspection stops are set up to guarantee the sequence of expanding and welding to avoid cracking of the tube sheet holes.

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Less fuel consumption

(a) High quality aluminum silicate fiber is used with fire clay insulation, to control the boiler body temperature below 45℃ and reduce heat lost.
(b) Sufficient steam storage room and heating area to generate high quality steam and high thermal power.
(c) Condenser is added to recycle the waste heat of the exhausted smoke to increase feeding water’s temperature and reduce flue gas emission temperature and increase the thermal efficiency over 98% and save operating cost.

ASME(American Society of Mechanical Engineers)

It has been estimated that over 100 countries accept the ASME BPVC as a means of meeting their government safety regulations. ZBG holds ASME certification, with large-scale power station boiler project total package qualification can provide customers a full range of products and services.

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