PURPOSE: To detect a fine foreign object in a fluid by applying light from the direction of axis line of a fluid passage so that the passage is surrounded and observing the scattering light due to the foreign object inside the fluid from the direction which is nearly vertical to the direction of channel at the part of a transparent body which is constituted at one part of the passage.
CONSTITUTION: A fluid passage 1 of a high-temperature melted resin from an extruder to a mold is bent at right angle and its partial passage 1a is constituted of a transparent body 3 such as crystal glass with the section being circular and the outer section being square as an observation part. A projection light 2 impinges on the transparent body 3 from the direction of axis line of the passage 1 from a flexed part so that the passage 1 is surrounded. A CCD camera 4 is provided in a direction which is nearly at right angle to the passage 1 and is set to capture the side light scattering due to a foreign object inside the fluid. The foreign object ranging from several μm to several mm inside the melted resin causes light to be scattered and can be observed from the side with the camera 4. Also, the transparent body 3 is in hexagonal shape, three cameras 4 are provided, and then the opposite surface is a light-absorbing surface, thus enabling the visual field of the camera 4 to cover the entire region of the passage 1 and achieving 100%, detection.
KONAKA HIROYUKI
YAMASHITA MAKOTO
YASUOKA OTOTAKE
KATO SHIGERU
YONETANI TOSHIO
