The working principle of pressure fan is when the motor through the coupling or pulley drives the driving shaft to rotate is arranged on the driving wheel gear drives the driven wheel gear in the opposite direction of the rotor meshing with synchronous rotation, rotation, so that the shell and a rotor to form a space, the gas from the inlet into the space. This gas will be compressed and rotor extrusion outlet, and the other one is to the rotor and the first rotor position relative to the compression began, and the shell on the other side of the formation of a new space, a new gas enters the space, be squeezed out. To achieve the goal of continuous motion.