摘要 |
<p>A drinking cup has a cover which is formed with a drinking spout at one side and a vent at the other. Elements extend down from under the spout and the vent. A flow control element is provided and made of elastomeric material having a pair of spaced cavities on one side, each cavity having a floor at the bottom thereof. The cavities receive in frictional engagement respectively the lower ends of the elements. This engagement supports the flow control element with the floor of each cavity in sealed relation to its element. Each floor has a passage which is normally closed but opens on the occurrence of a pressure differential on opposite sides of the floor.</p> |