| 摘要 |
<p>A cylindrical filter, closed at one end, is held in posn against a seating in a sleeve by a spring, so that when blockage causes excessive perssure drop, the filter holder is displaced, permitting by-pass flow, and comes into contact with a conductor, to complete an electrical warning circuit. The cylindrical sleeve has an axial inlet, and the valve may be at this inlet, or alternatively may be a sliding valve at side outlet, closed during normal operation. The electrical signal may alternatively be produced by breaking an electrical circuit closed when filter holder is in operating posn. The device is compact.</p> |
