The concentrator of the dewatering machine is composed of a fixed ring and a floating ring, and the screw shaft is formed through the filtering device, and the former is the condensing part and the latter part is the dewatering part.The sludge is concentrated by the gravity part and transported to Dehydration Department, in the process of advancing with the pitch and the pitch becomes smaller, as well as the role of the back pressure plate block, resulting in great internal pressure, the volume is shrinking, to achieve the purpose of full dehydration.