摘要 |
<p>A coupling for a pressure or vacuum fluid system having a bowl and filter head (10, 26) that connect together by relative rotation to engage bayonet coupling formations (32, 34, 94) thereof. When connected together the bowl (10) and filter head (26) have outer walls (16, 104) overlapping with an intervening seal (22) therebetween. A pressure relief valve (38) is provided in one of the members (10). A latch (36, 108) engages at an angular position of said members (10, 26) where the bayonet coupling is established to prevent relative rotation of said members (10, 26) and is prevented from engagement at other angular positions. The latch (36) is decoupled from the valve (38) when in its engaged state but is operatively coupled to the valve (38) when in a disengaged state to open said valve (38), fluid flow therethrough providing an audible warning when a pressure differential exists across the valve (38).</p> |