Automatic ignition nozzle employing ultraviolet (UV) flame monitoring for W-shaped radiant tube

Abstract

The invention relates to an automatic ignition nozzle employing ultraviolet (UV) flame monitoring for a W-shaped radiant tube. The nozzle mainly comprises an air distribution plate, a main gas pipe, air channels, a flame monitoring pipe, an electrode and an electrode pipe; the disc-shaped air distribution plate is positioned at the tail end of the nozzle; a flame monitoring hole, a gas circulation hole and 6-8 circles of circular seam shaped combustion supporting air channels are arranged on the air distribution plate; the flame monitoring pipe is obliquely inserted into the flame monitoring hole in the air distribution plate along the air channels; the position and the angle of the flame monitoring pipe can be adjusted; a head end of the flame monitoring pipe is provided with a UV flame monitor; and combustion air is layered through circular seam and mixed with main gas step by step. Due to the adoption of a multi-stage air combustion technology, the combustion effect is greatly improved, and the content of NOx in a combustion product is greatly reduced; and by reasonable adjustment on the position and the angle of the flame monitoring pipe, the UV flame monitor can stably monitor flame within full adjustment range of the nozzle.

Description

technical field [0001] The invention relates to the technical field of combustion devices, in particular to a combustion device for heating a radiant tube used in conjunction with a W-shaped radiant tube. Background technique [0002] At present, W-shaped radiant tubes have been well promoted and applied in large-scale continuous strip steel heat treatment furnaces due to their large effective heating area, high fuel utilization rate, and relatively simple system control operation. In order to meet the requirements of the production process, the temperature uniformity of the entire radiant tube surface must be ensured when the radiant tube burner burns. At the same time, the flame is required to have good stability and the NOx content in the combustion products must be strictly controlled. Usually, the radiant tube burner with automatic ignition must contain two parts: ignition device and flame monitor. Ignition is mainly realized by connecting the electrodes of the ignitio...

AI Technical Summary

Problems solved by technology

When using UV monitoring, the flame signal is easily affected by the ignition spark, adjacent and opposite flame signals

[0003] The W-type radiant tube has the characteristics of long tube length, large combustion space, and large effective heating area. The traditional radiant tube burner has the disadvantage of excessive temperature difference along the direction of the radiant tube body due to the inaccurate control of the mixing speed. , there are often local overheating areas on the surface of the radiant tube, and the temperature gradient on the entire radiant tube surface is relatively large. Due to thermal stress, the surface of the radiant tube is prone to cracks, which affects the service life of the radiant tube

At the same time, the automatic ignition W-type radiant tube burner used in China, in order to ensure the stability of flame monitoring, often deliberately speeds up the mixing speed, and concentrates the combustion area at the air gas nozzle. The length of the flame is too short, resulting in an increase in the temperature difference on the surface of the radiant tube. Affect the service life of the radiant tube

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