| 摘要 |
<p>A pressure regulating unit (4, 40, 80) for maintaining a constant gas or liquid pressure within a pressurised dispensing vessel (1), said unit comprising a sealed chamber (5) delimited by one or more sealed chamber walls (42, 46), a flow passage (13, 19, 20) communicating the sealed chamber (5) to the interior of the dispensing vessel (1), a first one-way valve (30) placed in the flow passage to normally allow flow only into said sealed chamber (5), said first one-way valve (30) including an actable override mechanism (12) for temporarily allowing flow along said passage from said sealed chamber to the interior of the vessel, and actuation means (8, 16) for causing the actuation of the override mechanism (12) when the pressure within the pressurised vessel is instantaneously reduced to below that within the sealed chamber.</p> |
