| 摘要 |
Liquid dispensers are provided including a vacuum relief mechanism with a vacuum relief device and a one-way valve 302,304 in series with the vacuum relief device to prevent flow into and out of a reservoir 18 when a vacuum exists in the reservoir. The vacuum relief device comprises an enclosed chamber 33 having an air inlet 43 open to the atmosphere and a liquid inlet 42 in communication with liquid in the reservoir and in which the liquid inlet opens to the chamber at a height below a height at which the air inlet opens to the chamber. The one-way valve is capable of failure, in which case the vacuum relief device alone provides for pressure relief. The vacuum relief valve permits relief of vacuum from the reservoir without moving parts or valves. The one way valve may comprise a male valve seat 302 and a female valve seat 304 in a flexible cap 32; alternatively the valve may comprise a simple valve (310 fig 24) or a flexible annular flange (320 fig 25). |
