| 摘要 |
<p>A dispensing and dosing pump is provided comprising a cylinder with a top and a bottom wall having an inlet in or near the bottom wall and an outlet in or near the top wall, and a piston which is up- and downwardly movable within the cylinder by means of a piston rod extending through the top wall of the cylinder, the dispensing action of the pump taking place on the up-stroke of the piston, characterized in that a first membrane (10) is fitted to the piston which, on the up-stroke of the piston, is pressed into sliding and sealing contact with the inside wall of the cylinder while on the down-stroke allowing open passage and a second stationary membrane (11) is fitted to or near the top wall of the cylinder, which, on the down-stroke of the piston, is pressed into sliding and sealing contact with the piston rod while, on the up-stroke allowing open passage. A liquid pump is provided which is easy to operate and facilitates repeated dosing of partial operator-adjustable volumes.</p> |
