device for the intermittent output of very little vetskemengder, serskilt hŸ2oŸ2

摘要

In an apparatus for the pulse-wise dispensing of very small amounts of liquid controlled with a measuring instrument. The measuring instrument comprises an ejector for the pulse-wise ejection of a desired amount of liquid and a measuring vessel having a volume greater than the volume of the liquid to be ejected for each pulse. The measuring vessel has an outlet connected to the ejector and a cross-section of the vessel is adapted to the amounts of liquid to be controlled. A sensing apparatus has an upper and lower sensing device positioned at the vessel and responsive to the level of the liquid therein with an accuracy of about from 1 to 5 amounts of liquid to be ejected and which generates a signal when the upper and lower sensing devices are activated. A pulse generator is synchronized with the ejector and a counter receives counting pulses from the pulse generator and is activated to start by the upper sensing device and to stop by the lower sensing device whereby the known volume in the vessel, divided by the number of pulses counted by the counter, measures the amount of liquid ejected by the ejector for each pulse.