| 摘要 |
A dispensing valve is provided for being sealingly disposed with respect to, and dispensing a product from, a discharge opening of a container. The preferred form of the valve includes a generally annular marginal portion adapted to be sealingly engaged when the valve is sealingly disposed with respect to the container discharge opening. The valve also includes a central head portion extending from the marginal portion. The head portion has an exterior side with a generally concave shape when viewed from outside the container and has an interior side with (1) a planar central area, and (2) a generally curved, radially outer portion which tapers toward the exterior side such that the periphery of the head portion is preferably thinner than the center of the head portion. The head portion includes at least one normally closed orifice that is defined by at least one slit that extends transversely through the head portion from the exterior side to the interior side to define flaps. The orifice opens by outward displacement of the flaps when the pressure in the interior of the container exceeds the pressure on the exterior of the valve by a predetermined amount.
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