| 摘要 |
<p>A dosing device for dispensing liquid from a container (5), comprises an outlet passage for the liquid and an obturator (20, 40, 125, 144) adapted to be driven to block the outlet passage, once a quantity of liquid has been dispensed, under the influence of liquid flowing from the container through a small aperture (34, 91, 93, 111) into a space behind the obturator in a chamber (13, 43, 113) in which the obturator is movable. The outlet passage has a convoluted configuration whereby flow of liquid through it is directed at least partly back towards the obturator (20, 40, 125, 144) to exert a back-pressure thereon, the obturator being of a dimension such that is may be acted on by liquid in part of the passage in which the flow is thus directed back. This tends to control the advance of the obturator so as to obtain a more consistent dose that is less dependent on the pressure applied to the container. The chamber may have a movable wall portion that opens up a large aperture to allow rapid restoration of the obturator to its start position.</p> |
