| 摘要 |
<p>A vacuum controlled valve mechanism providing two separate one-way valves, one for each of a pair of collapsible fluid containing reservoirs with each valve being in an initial sealed condition preventing flow therethrough until by operation of the pump mechanism a threshold vacuum is exceeded and with the threshold vacuum of a first of the valves being greater than the threshold vacuum of the other, second of the valves. When the threshold vacuum of the first valve is exceeded, that first valve separately permits dispensing of fluid from its reservoir under vacuum conditions less than the threshold vacuum of the first valve and the second valve until the first reservoir is substantially empty after which further operation of the pump mechanism creates a vacuum which exceeds the threshold vacuum for the second valve after which the second valve permits dispensing of fluid from the second reservoir.</p> |
