Negative pressure fans are divided into three negative pressure fans: A, B and C, among which A type is installed on the bracket and the wind is down. B type is mounted on a bracket with the wind upward. The C type is placed on the ground, with the wind heading upward. The equipment has low noise, uniform air volume, good cooling effect, and easy installation and disassembly. All models are customized, and the surface colors are also customizable. The CE certified motor can be used if required, and the PLC control interface can be set according to customer requirements. The fan parameters are as follows: