| 摘要 |
<p>The powder is located in a hopper, and volumetric dosing is achieved by a moving piston rod fitted with a fixed upper piston (2) and a lower piston (3) sliding axially along the rod. When the rod is lifted, the distance between the two pistons increases until a collar on the bottom of the rod butts against piston (3); but when the rod is lowered, piston (2) moves towards piston (3), and pushes a dose of powder into a dosing chamber (8). Piston (3) is pref. fitted with a sealing lip (7) so a force of min. 3p/mm3 of the vol. of chamber (8) is needed to press it downwards from its raised position. In mfg. medicine tablets, e.g. vitamin C tablets, there are strict tolerances on the wt. of each tablet made in presses. The invention provides a doser producing accurate volumetric dosing of flowable powders and thus reliable and consistent wts.</p> |
