W-type Radiant Tube Burner

Abstract:By comparative test on the surface temperature distribution of W-type radiant tube with different burner structure,the main factors having effect on tube temperature uniformity for coaxially parallel jet burner are analyzed. The results show that the temperature of forepart tuber elevates. Meanwhile the temperature of posterior tube decreases with increase of gas speed. At the same time the temperature of forepart tuber decreases while the temperature of posterior tube changes very little with increase of gas speed. When the proportion of second air increases the tuber temperature decreases. However, the proportion of second gas has little effect on it.

Radiant tube
Radiant tube

Based on the principle of indirect heating radiant tube heating technology effectively avoids the heated surface oxidation and decarburization. The protective atmosphere creates the condition for the combustion gases. Consequently the product will not cause pollution to affect product quality. Especially suitable for high quality requirements.

The earliest radiant tube furnace invented and used in Germany in the 1930s. The structure was single straight tube horizontally or vertically through the furnace. Until the early 1950s U-type radiant tubes came out. Furthermore on this basis, develope W-type radiant tube, casing tube type I, as well as exhaust gas recirculation of P and O type, etc.

W-type radiant tube relative to other types of radiant tube has advantages of large burner space. And also has large heat transfer area and high thermal efficiency. But at the same time W-type radiant tube burner also has difficult development problems because of the length of the tube. Many factors influencing the length of the flame tube and the poor temperature uniformity along the length direction of W-type radiant tube.

(To be continue…)

Radiant tube gas heating furnace

Radiant tube gas heating furnace is a kind of gas radiant tube heating device. Gas radiant tube heating device is burning in the sealing sleeve. Furthermore through the sleeve surface heated by thermal radiation as the main form to transfer heat to the heated object. And not with the heated object contact.

Radiant tube
Radiant tube

 

Tube heating furnace gas radiation (gas tube furnace), is a kind of gas radiant tube heating device. Gas radiant tube heating device is burning in the sealing sleeve. Through the sleeve surface heated by thermal radiation as the main form to transfer heat to the heated object. And the object to be heated combustion product of no contact. No combustion atmosphere pollution and affect the quality of products. Similarly control and regulation of atmosphere and the heating temperature for the furnace. In the end very applicable to products of high quality requirements.

Introduction

Radiant tube heating technology originated in Germany in 1936, with the continuous development of heat-resistant materials, the continuous improvement of product quality, continuous improvement of heat treatment technology, USA, Japan and Europe and other countries also widely adopt the indirect heating technology. In recent years, the technology is common in the Chinese metallurgy, machinery, light industry.Radiant tube

Radiant tube heating device is mainly composed of a tube body, the burner and the waste heat recovery device. The tube body is the heat energy of fuel radiation to be key components of the heating object. Due to its inner surface in direct contact with the flame and high temperature flue gas combustion, poor working environment, easy ignition, partial oxidation. If along the length direction of the pipe body there is a big difference. There will produce greater thermal stress. And the impact of airflow during combustion there will produce a certain vibration. Therefore the tube has good heat resistance, high thermal conductivity, high temperature oxidation resistance ability strong. Similarly small coefficient of thermal expansion, high structural strength and good sealing performance.

The burner is radiation core tube heating device, and it controls the power, radiation tube temperature distribution, thermal efficiency and service life. The traditional radiant tube burner common form of parallel flow burner and swirl burner, the two are the diffusion of gas and air temperature or preheat to 200 ~300 fuel mixed combustion. The combustion will produce local high temperature zone. The higher temperature peak combustion, radiant tube along the length direction the higher the obvious difference. Consequently there will cause local high temperature and oxidation corrosion of the radiation tube inner surface. Due to combustion air preheated NOx emission concentration will significantly increase.

Waste heat recovery device is an important part to improve the radiation tube heater thermal efficiency.  Due to the absence of flue gas waste heat recovery device the heat loss is larger. Consequently the thermal efficiency less than 50%. In order to improve the thermal efficiency of radiant tube heating normally arranging the waste heat recovery device in the exhaust tube end. That will recove exhaust heat to preheat the combustion air. But because the waste heat recovery device is used in the ordinary room wall, heat recovery effect is not very ideal, air preheating temperature is 200~300 , flue gas waste heat recovery rate of only about 30%. The traditional gas radiation heat efficiency of heating device is difficult to break through 75%.

Centrifugal casting stainless steel products

 

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Radiant tubes type:

U-type, W-Type, 0-Type, P-type, L-Type, S-Type. Similarly straight-type and also electric radiant tubes.

Application:

One of centrifugal casting stainless steel products. The radiant tubes are working at high temperature environment on average: 800-1200° C. Therefore most of them are used for indirect heating to furnace like CAL (continuous annealing line). Similarly CGL (continuous galvanizing line).

Process:

One of centrifugal casting stainless steel products. First of all centrifugal/spun casting method for tube sections. Furthermore investment casting or sand casting for the bends, hangers. Then welding and finally machining.

Material:

High Nickel and high Chrome heat resistant alloys, Cobalt base alloys. The material like HU, HT, HK, HP, HW, 24/24NbTiZr, 50Cr/50Ni (2.4813), 1.4865, 1.4849, 1.4848, 1.4410, 1.4059, 1.4841, 1.4845, 1.4852, 2.4879 or as per customer’s requirements.

Standard:

ANSI, ASTM, ASME, DIN, GB etc.

20101119102810346

 

 

Stainless steel

roller —Immersion roller, Sink roll, Furnace roller, Bottom roller, Heat resistant roller:

1. Furnace roller

2. Hearth roll

3. immersion roller

4. Heat resistant roller

Application:
One of centrifugal casting stainless steel products.Centrifugal casting stainless steel roll are of good heat, corrosion, wear resistant properties. Almost all working at high temperature environment on average: 800 to 1, 200° C. As a result which are used in the steel mills. Like continuous annealing line, continuous galvanizing line.

Process of centrifugal casting stainless steel products of roll. First of all centrifugal casting for barrel/tube. Furthermore forging for journal/shaft. And static /investment or sand casting for cone/turnings. Then welding and machining and finally grinding.

Material of centrifugal casting stainless steel products of roll: High nickel and high chrome heat resistant alloys, cobalt base alloys. The material like HU, HT, HK, HP, HW, 24/24NbTiZr, 50Cr/50Ni (2.4813), 1.4865, 1.4849, 1.4848, 1.4410, 1.4059, 1.4841, 1.4845, 1.4852, 2.4879 or as per customer’s requirements.