| 摘要 |
<p>An apparatus for sealing a clearance between a host pipe and a liner pipe. The liner pipe is fed into the host pipe and includes a tubular element forming a leading end of the liner pipe. It also includes a compressible seal which is adapted when compressed longitudinally to expand radially and is mounted on the tubular element when in use. The seal moves freely with the element in the direction of feeding of the liner pipe. But when the liner pipe is retracted counter to the direction of feeding, the seal movement is arrested and the seal compressed longitudinally by the element so that the seal expands radially to engage the internal wall of the host pipe and seal the clearance.</p> |
