| 摘要 |
<p>A portable fluid pumping device includes a valve assembly having a pair of one-way umbrella valves (316) controlling the flow of air to produce a positive pressure at one port and a negative pressure at another port. Each umbrella valve includes a valve stem (316c) having a neck (316b) received within the mounting opening (10a), and an umbrella skirt (316a) integrally joined to the neck (316b) to overlie the valve opening (10a). The umbrella skirt (316a) is relatively thin for its complete extent, and the juncture (316a) between the umbrella skirt (316a) and neck (316b) of the valve stem (316c) is of frusto-conical configuration increasing in diameter from the neck (316b) to the umbrella skirt (316a).</p> |
