| 摘要 |
<p>A differential fluid pressure indicating device for use in conjunction with a filter body carrying a filter element which provides an exteriorly visible signal when the differential pressure across the filter element exceeds a predetermined amount. The device comprises a housing having a cylindrical chamber in which a rotationally constrained piston is axially slidably disposed and movable between a first and second axial position while resilient means urge the piston towards its first axial position. The inlet fluid pressure communicates with one axial end of the piston while the outlet fluid pressure communicates with the other axial end of the piston. When the differential pressure across the filter element exceeds a predetermined value, the inlet fluid pressure moves the piston from its first to its second axial position and releases a spring loaded exteriorly visible member which rotates from a first to a second rotational position.</p> |
