| 摘要 |
A rapid shut-off device, for piping which is accessible at only one end, comprises an obturator propelled by pressure into the piping, the novelty being that the obturator (1) has a device for jamming the obturator in the piping (6), whe actuated by the difference in pressure at opposite sides of the obturator, and is secured to a cable (3) passing through the accessible end of the piping. Also claimed is a rapid shut-off process using the above device, the process involving: (a) creating a pressure difference at opposite sides of the obturator (1) and freeing the cable (3) to propel the obturator into the piping; (b) securing the cable when the obturator has reached the shut-off location; (c) increasing the pressure difference across the obturator to operate the jamming device; (d) reducing the pressure difference to unjam the obturator; and (e) using the cable to raise the obturator to the accessible end of the piping, all the above steps being carried out automatically in sequence by means of an electromechanical servo-system, controlled opt. by microprocessor. When the piping is a prodn. tube of a pressurised gas storage cavity, the pressure of the stored gas is used to raise the obturator to the accessible end of the tube. The jamming device is located between two discs which are coaxial with the piping (6) and which have a diameter similar to that of the piping, each disc having a seal which slides in the piping. The cable (3) is attached to the lower of the two discs. The jamming device is a flexible plastics or rubber torus which is filled with gas under pressure. USE/ADVANTAGE - The device is used esp. for emergency shut-off of a prodn. tube of a subterranean activity used to store hydrocarbons under pressure. Conventional pipeline pig and packer technology can be applied to emergency tube shut-off using an energy-efficient, robust and reliable device.
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