| 摘要 |
The plug increases in dia. on encountering fluid so as to improve the sealing effect. It has an expanding component enclosed by a sealing body, and mechanical means causing expansion and functioning when a material, soluble in the fluid, is dissolved. The body is of fibrous compressed and absorbent material. Alternatively the body can be of flexible, elastic and watertight material, such as an elastomer. The expanding component can comprise an expanding outer vessel and a coaxial rigid gas-filled inner one. The two are connected together to allow gas to flow between them. A flexible diaphragm is held by a soluble tablet against a semi-rigid wall between it and the inlet to the inner vessel so as to shut off the connection, via an intermediate piece of calibrated thickness. Means for delivering fluid to the tablet are included. |
