PURPOSE: To inspect all quantities of extruded resin and to improve detection sensitivity, by providing a transparent window for detection to a connecting part of the tip end of a cylinder of an extruder and a head and detecting a foreign matter by passing laser light through the resin by using this window.
CONSTITUTION: A transparent window for inspection 6 is provided to a connecting part 5 of the tip end of a cylinder 3 with built in a screw 2 in an extruder 1 and a neck part of a crosshead 4. This window is formed in square e.g. at the part 5 and is attached transparent hard glass (e.g. boric acid glass) 7, 7 etc. having high pressure resistance and also high heat resistance at a part of both side wall faces facing each other and is formed by fixing with plates 8, 8. Further, a scanning device 9 emitting a laser light L is provided at one side of the window 6 and a photodetector 10 receiving the laser light L is provided at the other side of the window 6. For this reason e.g. in case of covering an electrically conductive body 11 with a polyethylene 12 containing a cross-linking agent, the laser light L from the scanning device 9 is irradiated to the polyethylene resin by heating through the window 6 and the transmitted laser light L is received by the photodetector 10.
HASEGAWA SHIYOUICHI
KATAOKA KEIICHIROU
TATENO FUMINORI
| JPS5375993A | 1978-07-05 |