| 摘要 |
<p>The valve of the pressure vessel has a head portion adapted to close the liquid orifice and a stem portion mounted slidably in a guide and defining therewith a variable-volume liquid chamber. A passage is provided between the chamber and an orifice disposed in the vicinity of the head portion. The passage comprise a cylindrical portion in which a ball or other closure member is mounted with a slight clearance, which makes it possible to prevent closure of the valve upon rapid restoration of the liquid in the course of operation, while nonetheless permitting complete emptying of the vessel when the liquid is restored slowly, for example for the purposes of maintenance or inspection.</p> |
