| 摘要 |
The bore of a gas service pipe is temporarily of permanently blocked by forcing a resilient ball 6 along the pipe 5 from the gas meter tap end of the pipe 5 by gas pressure, the ball 6 forming a force fit sufficient to resist any attempt to dislodge it by the pressure of gas in the pipe 5. The ball 6 is forced to a position where it is outside the gas consumer's premises 1. A releasable cable 7 may be attached to the ball 6. <IMAGE> |
