The negative pressure of the coal mill head reflects the flow velocity of the mixture of air and coal powder in the entire head. The higher the velocity, the greater the negative pressure, and vice versa. The main reasons for high negative pressure are as follows:

　　1. There are problems with the layout of process pipelines;

　　2. There are problems with the selection of process fans, with mismatched inlet and outlet air;

　　3. There is a problem with ventilation inside the grinding machine, as poor ventilation leads to excessive negative pressure in the grinding head;

　　4. Accumulation of material in the process pipeline leads to a reduction in the ventilation cross-section of the pipeline, resulting in an increase in negative pressure;

　　5. Operational issues, too much material inside the mill and poor ventilation; Check the above factors that may cause negative pressure to rise, and find corresponding solutions for each different reason.