| 摘要 |
<p>The casing for a filter comprises at least two body portions defining a chamber for the filter means. The body portions are relatively movable between a closed position in which fluid cannot escape between them, and an open position in which fluid can escape between them. An increase in pressure in the chamber tends to urge the body portions to their open position, but there is resilient means which resists that and only permits the portions to part when the pressure in the chamber reaches a predetermined value.</p> |
