US 5,469,752 AGranted

Apparatus for automatically inspecting powdery products for the presence of foreign substances

AssigneeShin-Etsu Chemical Co., Ltd.

InventorsHajime Kitamura, Masaru Takeuchi, Hideo Yoshikoshi, Mikio Kitai, Takashi Chino, Yuji Nogami, Hajime Yashiro, Keisuke Kato

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Abstract

An apparatus for automatically and continuously inspecting a powdery product for the presence of foreign substances as contaminants, which permits highly precise inspection of powdery products, comprises static charge eliminator 10 for eliminating electrostatic charges generated on a powdery sample supplied to the apparatus; hopper 41 for receiving and storing the powdery sample whose electrostatic charges have been eliminated and dropped onto the hopper through static charge eliminator 10; conveyor 42 for conveying the powdery sample, as a subject to be photographed, discharged from hopper 41 and spread over conveyor 42 in the form of a layer having a uniform thickness; and video camera 43 for photographing, over a predetermined visual field, the powdery sample on the subject-conveyor. Images taken by video camera 43 do not include those originated from dark spots due to unevenness of the powdery sample distribution, but includes only those originated from foreign substances even when inspecting a powdery sample which is liable to be electrically charged such as a vinyl chloride resin, since the powdery sample is not agglomerated.

Claims7

Dependent claims

An apparatus for automatically inspecting a powdery material for presence of foreign substances, comprising:

a static charge eliminator for eliminating electrostatic charges generated on a powdery sample supplied to the apparatus, said static charge eliminator comprising a funnel having a shutter, a first rotary drive unit means for rotating the funnel, a first knocker for tapping said funnel, an agitator for agitating the powdery sample in said funnel, said agitator comprising a screw-agitator which has a rotation axis approximately parallel to an inclined inner wall of the funnel and a second rotary drive unit means for rotating the screw-agitator in a direction opposite to a rotation direction of the funnel, and a source for supplying static-charge eliminator liquid to the powdery sample in said funnel;
a hopper for receiving and storing the powdery sample from said static charge eliminator, said hopper including a second knocker for tapping the hopper;
a conveyor for conveying the powdery sample from the hopper;
a spreader for spreading the powdery sample over the conveyor in the form of a layer having a uniform thickness;
and
a video camera for photographing, over a predetermined visual field, the powdery sample on the conveyor.

3 more elements

Dependencies are inferred from the claim text.