Why WNS Natural Gas Boilers Design With Corrugated Furnace

Why WNS Natural Gas Boilers Design With Corrugated Furnace?

Before you buy a natural gas steam boiler, you need to know more about its design and why its hearth is designed the way it is.

The furnace design of a gas steam boiler is the key to its stable operation. After the burner emits a flame, the flame needs a space to burn.

How big this space is designed and what it looks like will directly affect the combustion of the fuel, as well as the transfer of heat, directly affecting the overall performance of the boiler you buy.

Next, we understand the following aspects of the steam boiler hearth structure, function, features, and the production process of corrugated hearth liner.


1. Design Structure Of The Hearth

The furnace chamber is made of high temperature resistant and corrosion-resistant boiler steel plate Q345R. It can withstand the heat load brought about by combustion at relatively high temperatures. We design the shape, size and arrangement of the furnace chamber, taking into account the heat transfer efficiency, structural strength and stability of the boiler. This effectively ensures the strength and durability of your furnace liner, and also effectively extends the service life of the equipment.

2. Design Of The Materials Used

In the furnace chamber, you will see WNS using high-quality alloy steel Q235B or Q345R material. These steel plates have good resistance to high temperatures, corrosion resistance, and can withstand high pressure. The specific material composition of the boilerplate is as follows:

Q245B is a commonly used carbon structural steel, and its specific chemical composition and mechanical properties make it suitable for a variety of structural components.


The following is the specific composition of Q245B steel:

Chemical composition

The chemical composition of Q245B is approximately as follows (in mass percent)

Carbon (C): ≤0.20%

Silicon (Si): ≤0.35%

Manganese (Mn): ≤0.30-0.70%

Phosphorus (P): ≤0.045

Sulfur (S): ≤0.045

Mechanical properties

The mechanical properties of Q245B are as follows:

Yield strength (σs): ≥245 MPa

Tensile strength (σb): 375-500 MPa

Elongation (δ5): ≥21% (thickness ≤ 16mm)

Impact toughness (αkv J/cm²): temperature 0 ℃ ≥ 27


Of course, the length as well as the thickness of the materials used in the furnace chamber will change with the pressure and temperature. There are several main factors that affect the thickness of the furnace chamber.

The first is the difference in the type of fuel used. This boiler is generally uses fuel oil and gas, if fuel oil and gas their heat loads, the wall thickness of the furnace chamber will be different.

The second factor is the working pressure and working temperature, this is the absolute factor affecting the thickness, the higher the pressure, the thicker the wall thickness.

The third factor is the performance of the material, When the pressure used is high, the wall thickness needs to be thick, so we will use better boilerplate Q345R. and better high temperature and corrosion-resistance treatment.

Corrugated Furnace

3. Principles Of Furnace Design

Many customers want to understand clearly the design principle of the furnace chamber of the WNS industrial gas boiler. The initial idea is to achieve the maximum combustion and utilization of natural gas or diesel fuel within the limited space.

Let us describe the design rationale in detail through the following aspects:

Heat exchange efficiency:

We designed the shape as cylindrical, and corrugated so that we can extend a little bit of flue gas in the furnace chamber to stay longer. The corresponding flexure surface can also increase the contact area with the hot gas, as well as water, which will increase the heating surface.

Mechanical strength and stability:

Just like the spring we are familiar with, the spring folds and bends, so it has good elasticity, the same corrugated furnace also has good elasticity, and this elasticity can be a good response to thermal expansion and contraction. Especially when your boiler will start and stop frequently, this will help you to extend the life of the equipment.

The working environment is decisive:

Suppose the corrugated furnace chamber is completely immersed in the water environment, surrounded by water. In that case, that is to say, the entire back of this boiler is wet. This design can better transfer heat to the water, to prevent overheating, in the smoke exhaust, reduce the temperature of the flue gas, and to improve the overall natural gas steam boiler efficiency.

4. Furnace Production Process

The production process of corrugated furnace liner. There are mainly the following:

First: the procurement of raw materials should be from the factory with a certificate of conformity to purchase the appropriate steel products, the raw materials of small factories can not meet the high-quality needs of the core components.

Secondly, the second is to carry out the barrel rolling. The material will be rolled into the shape of a pot cylinder, and the two ends are permeable. Welding is also carried out when the length is not enough, and finally, proof rounding is carried out.

Third, the third step is suspension molding. The furnace body is slowly molded by heating the chamber at a high temperature while rotating it on a rotary press. The furnace body is cooled down at any time after molding. This process, the requirements of mechanical equipment is relatively high, so only the strength of the factory can carry out spinning production.

Fourth, after a series of production, the corrugated furnace liner should be quality tested to ensure that its production meets the design requirements.

Corrugated Furnace Production

5. Working Process And The State Of Presentation

How do we determine the boiler in the combustion process presents the appropriate state?

First, look at the color of the flame. Pay attention to the color of the burner flame, if the flame in the hearth presents a light blue, the fire is strong, and the height of the flame size is uniform and consistent. This state shows that your fuel and air mixing ratio is appropriate, combustion is sufficient, and this is an optimal combustion state. Then,  our furnace chamber provides space with enough capacity to support the fuel as much as possible.

Second, look at the presence of soot. Observation of smoke from the boiler, if there are no black smoke emissions and no particulate matter, proves that the combustion is more complete, the emission of pollutants is relatively small, especially in recent years, the application of low-NOx burners, and its particulate matter emissions can be as low as 30mg. ordinary burners as low as 150mg.

Third, the length and shape of the flame.

The length of the flame should be moderate—not too long, not too short. If it is too short, it proves that the fuel is not burned sufficiently, and the proportion of air may be insufficient. But if the flame length is too long, it will cause heat loss. The best flame condition is a relatively stable flame, which can form a relatively stable thermal field inside the furnace chamber to ensure the efficient transfer of heat.

Corrugated Furnace Firing


It can be said that in the gas steam system, the furnace chamber is a key part of it. However, thanks to the corrugated structure and the high quality of the raw materials used, it is possible to ensure that the boiler can deliver efficiently in some of the harsher environments.

If you need to use the boiler at different operating temperatures and pressures, and want to extend its life, you can contact us, our engineers can give you precise technical specifications according to your specific needs. We will do our best to meet the heat needs of different users. You can rest assured that the oil and gas natural boiler you purchase will be well-designed for stable and efficient operation.

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