When the environmental protection equipment is running, the barrel is evacuated by multistage high-pressure fans and other equipment, so that the negative pressure rises rapidly. High negative pressure makes air flow into the bucket through the air inlet, and the bucket passes through the dust brush and dust pipe. The flowing air carries the solid particles to be collected and treated into the barrel, and the filter bag is connected with the air inlet, so that the solid particles are attached to the inner surface of the filter bag. After filtration, the air filtered once passes through the gap of the filter bag and then filtered by the filter element, so that the air reaches the discharge standard. The higher the negative pressure, the stronger the suction, the wider the diameter of the suction port, the higher the flow rate, the smaller the corresponding negative pressure and the smaller the suction. By choosing the appropriate model, the negative pressure can be kept in a constant range to adapt to the absorption and treatment of different materials. For details, please consult 4001168 = 88/178.