After the heat transfer of the flue gas of the fire tube steam boiler through the smoke chamber into the human tube (the first return smoke tube), the smoke temperature is low to the front smoke box (generally around: 450℃), making the structure of the front smoke box simple, generally with steel structure lined with heat insulation material. The “wet back” structure can adapt to high temperature, good sealing, and its volume is much smaller than the “dry back” type of smoke chamber. Wet back steam boiler can prolong the normal operation cycle of the boiler and reduce the maintenance cost. So it is widely used.

Wet back steam boiler

This series of steam boiler refers to the fully automatic fuel oil (gas) steam boiler, using horizontal internal combustion full wet back, high efficiency screw pipe, equipped with perfect insulation outsourcing design, boiler thermal efficiency up to 85%. The series of boiler products are novel in design, reasonable in structure and good in process performance, which make the products have outstanding quality. Horizontal internal combustion three return full wet back steam boilers. Full waveform furnace with good thermal scalability. Full pull edge butt welding technology reduces temperature difference stress of furnace body. The pipe and tube-sheet connection adopts the form of expansion before welding, which eliminates the corrosion problem and prolongates the service life of the boiler. The heat transfer coefficient of the boiler is increased by the threaded smoke tube. The product has beautiful appearance, high thermal efficiency, low fuel consumption, stable output, short installation period, convenient maintenance and high degree of automation.

Wet back steam boiler furnace space is large, can store more steam, strong load adaptability. The series WNS series boiler has an elastic corrugated fire cylinder in the horizontal drum, and a chain grate is arranged in the fire cylinder. The left and right sides of the drum and the upper part of the fire cylinder are arranged with smoke pipes. The fire tube and the smoke tube are immersed in the water volume of the drum, the upper part of the steam boiler about 1/3 space is the steam volume, the fire tube wall above the grate is the main radiation heating surface, and the smoke tube for convection heating surface.

Fire tube steam boiler flue gas in the steam boiler is three return flow, so it is also called three return steam boiler. After combustion, the flue gas flows in the reverse direction in the fire simple, which is the first return journey of the flue gas. The flue gas flows to the front of the furnace through the left and right smoke pipes of the rear smoke box, which is the second return journey. After the flue gas collects in the front smoke box, it flows backward into the smoke pipe on the upper part of the fire cylinder, which is the third return journey. Finally, it is discharged into the chimney by induced draft fan through the economizer.

Fire tube steam boiler

Wet back steam boiler reasonable price, quality assurance, is your purchase of the boiler of choice. Zozen Boilers produces and manufactures fire tube Boilers including oil burners, boiler bodies, insulation and shells, pipe valves, instruments, economizers, condensers, and smoke ducts. The design of this boiler mainly considers the principle of boiler maintenance and stability. The mixing device is set in the backwater inlet of the boiler. The backwater first scour the tube bundle of the smoke pipe and then touches the furnace chamber, which improves the water temperature of the backwater contacting the furnace chamber. The phenomenon of local supercooled boiling is avoided. Furnace water flows in the lower layer of the high temperature part of the combustion flue gas, and the lower temperature flows in the upper part. Optimal structural design has been achieved in terms of thermal convection. The steam boiler also achieves the maximum vaporization space, and the rear plate is added to cause the circulating water to flow through the high temperature surface of the backcombustion chamber, so that the heat transfer is reasonable and uniform. Ensure the safe operation of the tube sheet in the backcombustion chamber.