WNS series horizontal internal combustion boiler is classic *-pass wetback oil/gas fired boiler. After fuel is atomized by burner, flame is full of the wave furnace and transfer heat via furnace wall, called 1st pass; the high temperature flue gasses are collected in reversal chamber and then enter 2nd pass, which is grooved tube bundle area through heat convection, air temperature gradually falls and flows to front smoke box and enter 3rd pass, which is done in the smooth tube bundle area, and then through back smoke box lead to chimney and exhausted to the atmosphere.

• The key processes including material cutting, rolling, drilling are made by advanced CNC machining process to reduce the assembly stress and extend boiler working lifetime. 
• The front and back smoke chamber plates are cut by CNC plasma cutting machine with tidy and beautiful look.

• 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.

• 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.
• Longitudinal and girth joint adopt advanced automatic submerged-arc welding for good welding quality. All longitudinal and girth joint are test by radiographic inspection.
• 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.

• High quality aluminum silicate fiber is used with fire clay insulation, to control the boiler body temperature below *5℃ and reduce heat lost.
• Sufficient steam storage room and heating area to generate high quality steam and high thermal power.
• Condenser is added to recycle the waste heat of the exhausted smoke to increase feeding waters temperature and reduce flue gas emission temperature and increase the thermal efficiency over *8% and save operating cost.

  Model	Rated thermal power（MW）	Rated working pressure（Mpa）	Rated output water temperature（℃）	Rated feeding water temperature（℃）
  WNS0.**0.7/*5/**- Y(Q)	0.7	0.7	*5	*0
  WNS1.**0.7/*5/**- Y(Q)	1.4	0.7	*5	*0
  WNS2.**0.7/*5/**- Y(Q)	2.1	0.7	*5	*0
  WNS2.**0.7/*5/**- Y(Q)	2.8	0.7	*5	*0
  WNS3.**0.7/*5/**- Y(Q)	3.5	0.7	*5	*0
  WNS4.**1.0/**5/**- Y(Q)	4.2	1.0	**5	*0
  WNS**1.0/**5/**- Y(Q)	5.6	1.0	**5	*0
  WNS**1.0/**5/**- Y(Q)	7	1.0	**5	*0
  WNS*0.**1.0/**5/**- Y(Q)	*0.5	1.0	**5	*0
  WNS***1.0/**5/**- Y(Q)	*4	1.0	**5	*0