Smooth guide rail, with self cleaning function of the scraper, to ensure the smooth operation of the equipment, less residual material. Discharge door can be in any position, and can be manual, pneumatic or electric control, to achieve a multi-point discharge, unloading clean completely, no residue. With the scraper chain tension detection device to ensure the normal operation of the equipment. The tail floating adjustable structure, and a tail end product material automatic cleaning device to eliminate the residual.