Nanjing GIANT Machinery Co.,Ltd.

The fixed dummy block fixed to the working-side end of the twin screw extruder is cooled inside thereof before vacuuming the air from the container and then air in the container is vacuumed with the container being sealed by the seal block disposed on the end surface of the container at the extruding stem side to open and close in the direction perpendicular to the axial direction of the container so that air trapped between the container and the billet can be easily vacuumed as well as the metal flow of the billet is prevented, thereby significantly improving the yield of the end products without blister.

It is an object of the present invention to provide an extruding cycle in which a container is sealed just before air in the container is completely eliminated before extruding a billet in the container, without a step of deaerating before extruding the billet from a die, called as the veep cycle. It is another object of the present invention to provide an single screw extruder which cools a rear end portion of a billet to prevent the metal flow, thereby preventing residual air and impurities from entering into the billet and thus preventing the deterioration of the quality and yield of end products.

For achieving the objects mentioned above, according to a first aspect, an sheet production extruder comprises a cylindrical container into which a billet is loaded; a two-piece seal block disposed on an end surface of the container at an extruding stem side; a vacuum deaerating hole formed in the seal block; and a fixed dummy block, having an internal cooling function, fixed to an end of the extruding stem, wherein the seal block is allowed to be opened and closed in a direction perpendicular to the axial direction of the container and the seal block comes in close contact with an outer surface of the extruding stem and the end surface of the container when the seal block is closed.

According to a second aspect, an twin screw extruder comprises a container having a container liner into which a billet is loaded; a ring-like protrusion disposed on an end surface of the container at an extruding stem side; and a two-piece seal block being opened and closed in a direction perpendicular to the axial direction of the extruding stem; wherein the seal block comes into close contact with an outer surface of the ring-like protrusion and an outer surface of the extruding stem at the same time when the seal block is closed. According to a third aspect, on the basis of the second aspect, the seal block is provided with a vacuum deaerating hole for eliminating residual air in the container wherein the vacuum deaerating hole is connected to a vacuum pump. According to a fourth aspect, on the basis of the second aspect, the seal block is provided with sealing material having heat resistance and resiliency attached to a contact surface of the seal block which come into contact with each other when the seal block is closed.