| 摘要 |
An outer jacket of steel or of plastic impervious to the liquid in the pipeline is placed around at least a part of the length of the pipeline and spaced away from it esp. divided into sections by regularly spaced seals between the pipeline proper and the casing. Within each of these sections there is a port in the casing opening into a stand-pipe within which is a liquid detector; this may be a pressure detector, an ionisation detector of a differential thermistor. Process reduces pollution and fire risk due to leaking pipelines. |
