| 摘要 |
The appts. carriable by a person, samples air-borne particles of pollutive matter. It is of aluminium, comprising two circular plates (1) of 84 mm dia. The plates have 18 circular holes (3) of 8 mm dia., which are covered with a collection substratum for rough particles and an aerosol filter. One plate has 18 smaller holes (6) of 1.8 mm. dia. which control output signals from a reading fork (7). The two discs, together with a worm wheel (8), are fitted on a common shaft supported by ball bearings in a body (9). This body comprises the appts. casing, and also contains a motor (10) and a worm screw (11), a suction mouthpiece (12), an inlet impaction type mouthpiece, and the reading fork (7). The plates are rotated by the motor and worm gear, and sampling air at the rate of 350 cm/min passes through the exchangeable inlet mouthpiece positioned at right-angles to, and at an adjustable distance from the collection substratum of polycarbonate with an Apiezon (RTM) coating. (Provisional Basic advised week K25) |
