EXTRUDING DEVICE

PURPOSE:To reduce a resin changing time by disposing a pressure releasing mechanism in a passage of extruded resin and reducing a pressure increase of resin at the time of changing. CONSTITUTION:Kneaded plastic resin 3 flows form an extruder 1 though a changing valve 2 to a passage A. A branched tube 6 is connected between the extruder 1 and the valve 2, and a piston 5 is inserted at this connection part, where the other end of the piston 5 is connected with a cylinder 4 to move right and left. Where the piston 5 is pushed by the cylinder 4, therefore, the resin 3 is prevented from flowing to a passage C in the branched tube 6. For letting the resin 3 flow to a passage B in this condition, if the cylinder 4 is pulled, the passage C opens, where resin 3 goes into the piston part 5, and resin pressure is released. If the valve 2 is rotated clockwise for 90deg. of angle at this time, the valve 2 changes its direction toward the passage B. If the piston 5 is closed then, all the resin 3 flows to the passage B.