| 摘要 |
<p>Fluid-flow control apparatus is disclosed by which magnetically-positionable elements (39,25) within a rigid body (9) can be externally manipulated using a controlling source (39) of magnetic flux. The relative attractive forces which bias internal magnetic elements into normally-closed sealing engagement are substantially alterd by repositioning the magnetic elements in response to the controlling magnet flux. Complete sealing or isolation against back flow through the valve under conditions of net positive outlet pressure is inhibited by the internal double-acting sealing elements (23,24) which respond in unified manner to the controlling magnetic flux. Sealing surfaces (54,56) on the elements are dome-shaped to limit the effect of horizontal forces imposed thereon. The elements are biased into floating relation and reduced in dimension to inhibit contact with internal sidewalls of the valve body.</p> |
