The principle of the paper tape filter: the paper tape filter relies on the gravity of the liquid itself to filter the cloth to isolate the sundries, so as to achieve the purpose of purifying the liquid. The chain and the wire mesh of the transmission mechanism form a certain depth of the liquid pool, and the filter cloth is laid on the chain and the wire mesh. When the dirty liquid carrying impurities flows through the water flow buffer device to the non-woven fabric during operation, the impurities are separated by the filter cloth to form a filter cake, the filter cake becomes thicker and thicker, the liquid level of the dirty liquid rises, and the floating liquid level controller sends a message. The reducer starts, drags the filter cloth, and the dirt and dirty cloth fall into the dirty carton, thereby realizing the automatic replacement of the filter cloth; after the filter cloth is updated, the liquid level of the dirty liquid drops, the reducer stops rotating, and the machine enters the next filtration cycle. The filtered pure liquid is delivered to the main unit by a liquid pump.