| 摘要 |
PURPOSE:To prevent the back flow of a molten resin into gas piping and to smoothly inject compressed gas into the molten resin by providing a slidable pin to the tip of a gas injection nozzle and combining the pin, a housing and an air permeable member to constitute a valve. CONSTITUTION:A gas injection nozzle has a gas inflow part 8 using a pin 9 at the leading end thereof and a stainless steel air permeable member (sintered metal) 19 provided on the upstream side in a gas flow direction. A valve is constituted by combining the pin 9, a housing 24 and the air permeable member 19. The pin 9 does not retreat by the filling pressure of the molten resin 12 flowing in a gas emitting part by the spring force of a spring to make it possible to prevent the back flow of the molten resin. The piston in the gas injection nozzle and the pin 9 retreat toward an upstream region by the pressure of gas at the time of the inflow of gas and the gas inflow part 8 is opened to introduce gas into the molten resin from the gas inflow part 8 through a gas conduit, the piston and the air permeable member 19. |
