Inner flame tube applicable to radiant tube and radiant tube

Abstract

The invention discloses an inner flame tube applicable to a radiant tube and the radiant tube. The inner flame tube is provided with a shrinkage pipe section, a straight pipe section and an expansionpipe section in sequence in the extension direction from the inlet end to the outlet end. After smoke generated by combustion in a nozzle passes through the inner flame tube, high-speed airflow can inject surrounding low-speed airflow through the shrinkage pipe section, the airflows mix and transfer energy, and accordingly an injection area is formed; afterwards, the injecting airflow passes through the straight pipe section to be mixed with the injected airflow so as to form constant-speed and constant-pressure airflow; and finally, the airflow passes through the expansion pipe section, so that the flow speed is reduced and the static pressure is increased. After the inner flame tube is applied to a self preheating nozzle in cooperation with the closed radiant tube with a single-end inlet, backflow of smoke inside can be achieved to the maximum extent, the smoke is mixed with gas and combustion air to form a mixture for a mild and more uniform combustion way, and the temperature uniformity of the surface of the whole radiant tube is improved.

Description

technical field [0001] The invention relates to the field of radiant tubes, in particular to a flame inner tube used in radiant tubes and the radiant tube thereof. Background technique [0002] The radiant tube was officially born in the earlier period (around the 1930s). When the conventional direct flame heating method could not meet certain specific heating environments and specific product production, people came up with an indirect heating tool. [0003] Today, there are two main types of radiant tubes: electric heating radiant tubes and gas-fired radiant tubes, which are often used in industrial heating furnaces and heat treatment furnaces. Among them, gas-fired radiant tubes are more widely used and have higher thermal efficiency. Due to the indirect heating, the radiant tube can meet the requirements of better heating temperature uniformity and atmosphere control in the heating space, and realize the normal production of some specific high-demand products. [0004] ...

AI Technical Summary

Problems solved by technology

[0006] Type I: Standard internal straight flame inner tube, unable to entrain enough smoke to mix and burn, the combustion intensity is intense, the high temperature zone of the flame is obvious, that is, the amount of NOx is generated;

[0007] U and W types: The types developed to improve thermal efficiency, most of them are in the high temperature zone of the flame at and before the first bend, which is prone to local heating. At the same time, the overall length of U and W radiant tubes is relatively large, which is prone to internal stress and has a short service life.

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