| 摘要 |
<p>FIBER OPTIC CABLE A fiber optic cable contains large diameter optical fibers for directly transmitting visible signals, such as those produced by water level indicators, within a steam boiler. The fibers are each sheathed in an extruded layer of polymeric material that remains soft over an operable temperature range of the cable, and the sheathed fibers are cabled in a long lay length about an axial core member that has a coefficient of thermal expansion similar to that of the optical fibers in order to restrain the sheaths, which generally have significantly different thermal coefficients of thermal expansion, from excessively expanding or contracting relative to the fibers. The cabled, sheathed fibers are wrapped in tape, and an inner jacket, which holds the sheathed fibers in compression, is extruded around the tape. Tensile strength is provided by braided yarn surrounding the inner jacket, and crush strength is provided by an outer jacket surrounding the braided yarn.</p> |
