PURIFIER OF BATHTUB

摘要

PURPOSE:To effectively purify the filter material in a biological filter tank. CONSTITUTION:The water suction port 2 and water emitting port 3 of a bathtub 1 are connected by a circulating passage 4. A biological filter tank 5 is arranged on the way of the circulating passage 4 and the filter materials 6 in the biological filter tank 5 are provided in a multistage fashion. At the time of backwashing, by whirling the filter materials 6 of respective stages upwardly to wash the same, the filter materials 6 can be effectively washed.