| 摘要 |
<p>The invention concerns an apparatus for dispensing measured quantities of a liquid or liquefied material, comprising first pumping means (3), capable of delivering a continuous flow of material, second pumping (13) downflow from said first pumping means, said second pumping means being capable of delivering less than the amount fed thereto by said first pumping means, a recirculation line (8), connected to the line (6) connecting said first and said second pumping means, said recirculation line being provided with a valve and means for compensating excess of material fed by said first pumping means, which means (10) for compensating excess material are present in said connecting line, and can activate a switch for opening said valve. In order to obviate possible problems concerning contaminating, and to provide longer production runs, the invention is characterized in that said means for compensating excess material comprise membrane (11) which is impermeable for said liquid or liquefied material.</p> |
