Patent ID: 6600153
Filing Date: 2003-07-29
Classification: G01V

Abstract:
A dustproof mechanism to control sticking of dust to the minimum in an automatic high-speed counting apparatus comprising:a detector, which has a reflecting mirror, which reflects an optical light in a reverse direction, a light emitter, which irradiates said optical light towards said reflecting mirror, and a light receiver, which receives the optical light reflected by said reflecting mirror and is provided together with said light emitter; a dustproof casing, which accommodates said detector and is provided along a detecting optical path, said detecting optical path is a pathway of said optical light; a detecting position, which is provided at a prescribed position in said dustproof casing, through which substances to be detected pass and intersect said detecting optical path, and a pair of air chambers, which have substantially equivalent capacity and are provided in said dustproof casing so that said detecting position is located therebetween, said pair of air chambers being aligned so that said detecting optical path is adapted to pass through said pair of air chambers, wherein each of said pair of air chambers is defined by at least two adjoining sub-air chambers, and wherein a first sub-air chamber is located adjacent said detecting position and connects with said detecting position via a first opening, and a second sub-air chamber is adjacent said first sub-air chamber opposite said detecting position and connects with said first air chamber via a second opening, said second sub-air chamber having a smaller capacity than said first sub-air chamber.