| 摘要 |
A hydrant 51 is used to gain access to a water pipe 50 to perform a maintenance operation on the pipe 50. The method is particularly suited for stopping water flow through a section of pipe by the insertion of an inflatable stopping bag 54 into the pipe 50 through the hydrant 51. A pressure regulator 60 is used so that the pressure in the inflatable bag 54 is proportional to the pressure in the pipe 50. A section of water main may be bypassed (figure 8) by blocking the main through two hydrants, and connecting the sections with a bypass pipe (70a, figure 8) that extends through the inflatable bags 54. |
