The invention relates to the
water treatment industry, in particular to advanced purification of drinking water. The invention discloses a drainage method for assembling and disassembling a
filter element of a
backwashing water purifier. The
backwashing water purifier is equipped with a water inlet pipeline, a water outlet pipeline, a drainage pipeline and a waterway switcher, wherein, the water inlet pipeline is equipped with a water
inlet valve; a drainage port of the waterway switcher is connected with the drainage pipeline, a water inlet of the waterway switcher is connected with the water inlet pipeline, a water outlet of the waterway switcher is connected with the water outlet pipeline, and the water outlet and the drainage port are alternatively opened; a controlled water inlet and a controlled water outlet of the waterway switcher are respectively butted with the water inlet and the water outlet and connected with the water inlet pipeline and the water outlet pipeline of the
filter element to form a filtering channel; when the waterway switcher is located in a
backwashing switching position, the controlled water inlet and the controlled water outlet of the waterway switcher are respectively butted with the drainage port and the water inlet to form a backwashing channel of the
filter element; when the water
inlet valve is opened, water entering the backwashing water purifier is discharged from the drainage pipeline; and when the water
inlet valve is closed, water in the backwashing water purifier is discharged from the drainage pipeline in a gravity drop manner. The drainage method of the invention has the advantages of clean, sanitary and
pollution-free filter element replacing process, and high-grade products.