The purpose of adjusting the burner is to change both the combustion speed and the flame shape, which are closely related. Generally, there are the following means: 1. Adjust the total amount and pressure of primary air to ensure that the coal injection pipe has enough thrust. 2. Adjusting the inner diameter of the coal pipe and changing the outlet wind speed are supplementary measures to change the thrust of the coal pipe. 3. Adjust the proportion of internal and external air. The internal wind is swirling wind, which makes the flame shorter and thicker; The external air is axial flow air, which makes the flame thinner and longer. Generally, when the coal injection pipe extends into the pit, the internal air needs to be increased. When the coal injection pipe is pulled out of the pit mouth, the external air needs to be increased. The above is not absolute, and specific analysis is needed.