摘要 |
<p>A device for the selection, metering and delivery of treatment liquids for industrial laundry washers comprising a plurality of pumping units without positive displacement of pumping members. The pumping action is performed by a correlated combination of applications of pressure and vacuum on columns of the liquid that must be pumped. The delivery or pumping rate may be adjusted by setting on each pumping unit the quantity of the displaced material by sensing the displaced volume.</p> |