The invention discloses an indoor drainage
system for preventing back flow of
sewage, which is applicable to residential buildings, office buildings, commercial buildings, hotels, auditoriums, etc. The indoor drainage
system mainly comprises a drainage stand
pipe and a stack vent thereof, a cross junction, a drainage
elbow of 90 degrees, a
discharge pipe, an overflow
pipe (the pipe bottom is about 150mm lower than the indoor
ground level), an indoor overflow horizontal pipe, an overflow drainage tee, a blind
flange (positioned at staircases or outdoors), a transparent observation pipe, an overflow telemetering
light control probe, an
electrical control probe, an overflow
discharge pipe, a horizontal drainage
branch pipe, sanitary ware, an overflow stand pipe and a stack vent thereof. When some place of the drainage stand pipe or the
discharge pipe is blocked, the
sewage is automatically discharged from the overflow pipe and not returned indoors. When the pipe is cleared, the blind
flange is taken off, a spring soft shaft of an electric cleaning
machine is rotatably inserted into the pipe
mount and the pipe can be cleaned in short time. As the cleaning
machine is not arranged indoors, the pipe can be periodically cleaned for blockage prevention. The telemetering device can timely discover blockage of the drainage pipe.