Test Fixture for Detecting the Presence of Water in Buoyant Cables.

摘要

A simple low-frequency technique for determining the presence of water or moisture in buoyant cables has been developed. It is used primarily a diagnostic tool for rejecting cables containing traces of sea water. The method makes use of test fixture in the form of a curved-plate capacitor. The plate configuration of the capacitor was designed in such a manner that its sensitivity to low levels of moisture (less than 0.1 ounce per foot) is accompanied by large percentage increases in capacitance from the nominal dry value. Typical increases in capacitance for such levels have been observed in the range of 12% to 25%, with fully saturated cables exhibiting maximum changes as large as 70%. A mathematical expression for volume of water present in a cable as a function of the percentage increase in capacitance was derived and has been shown to agree with experimental data.