HG-type Rotary grid machine is composed of a unique rake teeth Assembly into a set of rotating grille chain. Driven by a Motor reducer, rake teeth chain for inverse direction of flow the rotation, the scum floating on the water fishing, rake teeth chain when running to the upper part of the device, due to the sheave and curved track-oriented, so that each group between Harrow teeth have relatively clear movement, the vast majority of solids by gravity down. Others rely on the reverse movement of the cleaning stuff stuck on the rake teeth clean.