| 摘要 |
PURPOSE:To prevent the ejection of a material through a die in the case of steam blasting accident, by forming an expanded space between the tip of a cylinder and the die to allow the expansion of the space volume when the pressure in the space at the back of the die is increased above the material extrusion pressure. CONSTITUTION:A space B is formed at the back of the die 3 and between the tip of the screw 1 in the cylinder 2 and the die 3 attached in front of the tip of the cylinder 2, and an expanded space 10 composed of a movable ring 4 inserted into the adapter 5 in an axially slidable manner is placed between the tip of the cylinder 2 and the die 3. When steam having abnormally high pressure is flowed from the screw side 1 into the space B during the extrusion operation of the material, the die 3 is shifted together with the movable cylinder 4 to the direction separating from the tip of the cylinder 2. Consequently, the spring 8 is constricted to expand the volume of the space B and drop the vapor pressure and the ejection of the material from the die 3 can be prevented.
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