| 摘要 |
<p>To form a "vapour tap" in the wall of the shell of a valve for a pressurised dispenser such as an aerosol can, the outer surface of the upper end of the open-topped cylindrical shell is offset radially outwards, possibly by simply thickening it to form a rim 14, and an upwardly extending notch 15 formed in the outer surface of this rim and downwardly extending notch 16 in its inner surface cooperate and overlap to define an orifice. There may be several such pairs of such overlapping notches, the outer one being circumferentially wider than the inner one. This formation of the vapour tap orifice by overlapping notches allows the shell to be moulded easily in a simple mould, yet leaves an unbroken upper annular surface 13 of the rim, for engaging the usual gasket. <IMAGE></p> |
