| 摘要 |
<p>A filter element generally indicated at (10) comprising a spring (11) whose coils are so formed that the filter gaps (12) progressively increase in size from one end (13) of the coil to the other end (14). The increase in the size of the gaps is carefully chosen so that the available deflection for any coil section, when the spring is vertically orientated, is sufficient to develop an upward force which can support the coils in the spring (11) which extend above that particular coil section. Similar results can be achieved by varying the resilience or stiffness characteristics through the filter element.</p> |
