Reversible overflow gate device for large grit chamber

The invention provides a reversible overflow gate device for a large grit chamber. The height of the top of an overflow gate can be adjusted randomly, and when materials are fed, the height of the overflow gate is adjusted to the maximum value, the just-fed materials which are not clarified can be prevented from directly crossing the upper end of the overflow gate and then entering the discharging port end, after the sand-containing materials are clarified for a period of time, the height of the top of the overflow gate is reduced, and the clear supernatant water is allowed to flow cross the top of the gate and flow into the discharging port end and then is pumped out by a submersible sewage pump 12, the height of the top of the overflow gate is reduced at regular intervals, a step-by-step sedimentation overflow method is adopted, so that the water content of the silt 13 at the feeding port end of the grit chamber is less and less, and finally a grabbing machine is used for grabbing sand out of the device. The reversible overflow gate device is composed of an electric transmission assembly 1, a transmission assembly supporting seat 2, the overflow gate 3, an overflow gate hinge seat 4, an overflow gate bottom circular shaft 5, a bottom circular shaft supporting seat 6, a manual transmission assembly 7, a side swing assembly 8, a connecting rod 9, a pin shaft 10 and the like.