| 摘要 |
In a pump for hand-held containers, e.g. for cosmetic and pharmaceutical use, of the kind comprising a main piston 3 working in a pump chamber 2 and with delivery controlled by a smaller piston 5 working in a cylinder 15 that forms a co-axial extension of the main chamber, the smaller piston has a flexible lip 16 and in the wall of the cylinder 15 at the position occupied by the smaller piston at the end of the compression stroke there are grooves 17 allowing the space between the pistons to be vented downwardly through a dip tube 4, and furthermore the wall of the cylinder is enlarged in the zone 19 where the small piston 5 lies in the rest position. <IMAGE> |
