Unpowered apparatus for preventing backflow

Abstract

The present invention relates to an unpowered apparatus for preventing backflow, comprising: a tubular main body having a stepped portion, wherein the main body has an inlet port for the inflow of sewage, an outlet port for discharging the sewage, and a communication port which is inclined toward the outlet port and which puts the inlet port and the outlet port in communication; an opening/shutting door having a door body rotatably hinged to the inside of the main body so as to open/shut the communication port, and a pair of blocking plates extending from either side of the door body so as to block the space between the stepped portion and an inner wall of the main body; a floating part which is arranged in the opening/shutting door, the interior of which is empty such that the floating part can float on a water surface, and which provides the opening/shutting door with buoyancy and operates the opening/shutting door so as to close the communication port when the sewage flows back toward the outlet port; and a guide interposed between the stepped portion and a bottom surface of the main body so as to guide the sewage introduced from the inlet port such that the sewage flows toward the outlet port via the communication port.

Dependencies are inferred from the claim text.