Prevent stifled water drainage tank

The utility model provides a prevent stifled water drainage tank, including the first cell body that connects gradually, second cell body and third cell body, first cell body, second cell body and third cell body are the upper end opening, the structure that the lower extreme is sealed, first cell body and third cell body are the cell body of cross section for the U -shaped, the one end of secondcell body is kept away from to first cell body and the second cell body was kept away from to the third cell body one end feeds through with indoor sewer pipe respectively, it is little that the second cell body is the upper end, the toper cell body that the lower extreme is big, the inner wall of second cell body passes through the cambered surface transitional coupling with the inner wall of first cell body and the inner wall of third cell body respectively, outside arch is distinguished to the lateral wall to the double -phase of second cell body, the bottom surface of second cell body is the cambered surface of un