| 摘要 |
This invention is a vent valve suitable for an electric storage battery in which a movable valve member 16 co-operating with a valve seat 14 is caused to move by being attached to or integral with a rubber annulus 19 one side of which is exposed to ambient pressure while the other side is exposed to the pressure within the battery. The area of the annulus 19 is substantial compared with the size of the valve member so that a small pressure difference across it can be sufficient to open the vent. Alternatively (Fig. 7) a corrugated annulus 19 may be provided which forms a seal with a post 42 depending from a closure 23. Motion of the annulus under influence of pressure causes the inner edge to encounter recesses 43, allowing escape of gas past the annulus. In a further embodiment (Fig. 9) a flexible disc 19 seals against shoulder 116 and unseals when the disc 19 distorts under the influence of pressure. <IMAGE> |
