In naval and other maritime vessels, such as aboard ships and submarines, there is a great need to deliver electrical power through spaced apart compartments, each of which can be independently sealed off in a water and air tight manner during emergency situations. Typically, an emergency situation aboard a naval vessel might be a fire in one or more compartments, or water leakage occurring therein, occasioned, for example, during battle.
During such emergency conditions, it is imperative that each compartment in which the emergency condition arises, be sealed off and contained from the rest of the ship. To ensure this, a number of measures are conventionally undertaken.
Firstly, naval power cable with water impenetrable blocking or filler material between the outer jacket and inner conductors, is generally used aboard such vessels. Secondly, electrical power cable extending through adjacent compartments is passed through water blocking cable transits, at which a water and air tight seal is sought between the transits and cable jacket. Thirdly, compartments aboard the vessel through which electrical power cable passes, are capable of being closed shut in a water and air tight manner during emergency situations.
In FIG. 1 of the drawings, a typical prior art multi-conductor power cable for use aboard naval vessels, is illustrated. In general, such prior art power cable 1 comprises a core conductor assembly 2 consisting of triplexed insulated conductors 3, a water blocking layer 4 extruded over the core conductor assembly, a non-uniform layer of binder tape 5 helically wound over the blocking layer, and a jacket layer 6 extruded over the binder tape, as shown. In order to install naval power cable through the various compartments within a vessel, the cable must permit bending at severe angles during cable routing operations.
While it has been possible to satisfy the general requirements of naval power cable, prior art naval power cable of the type described above has nevertheless suffered from several significant shortcomings and drawbacks.
In order to expose the insulated electrical conductors for spreading and connection to electrical equipment in cable spreading rooms, large lengths of water blocking and jacket material must be stripped away to freely expose the core conductor assembly. With such prior art power cable, removal of the water blocking and jacket material requires cutting each layer away bit by bit using sharp cutting tools, the nature of which poses great safety hazards to shipyard workers. In addition to requiring arduous effort and numerous hours and sometimes a day or more to strip away the water blocking and jacket material, often the shipyard workers wielding the sharp cutting tools inadvertently cut into the core conductor assembly, damaging the electrical insulation on the conductors. Frequently, these workers also injure themselves during such stripping operations. For example, workers can cut themselves with the sharp cutting tools. Also they are exposed to the risk of slipping and falling on rubber chips and shavings which fall to the vessel floor during cable stripping operations.
In an effort to avoid damaging the electrical insulation during jacket and blocking material stripping operations, prior art power cable illustrated in FIG. 1 has required the overlapping layer of binder tape to help shipyard workers determine the location of the insulated electrical conductors and the blocking material. Consequently, prior art naval power cable has been generally characterized by surface irregularities in the outer jacket layer due to the underlying helically wound binder tape. These surface irregularities present difficulty in establishing high quality air and water seals desired at the interface of the cable outer jacket and cable transit sealing material. As a result, when a dozen or more of such prior art power cables pass through a cable transit, the risk associated with smoke and water leakage from one compartment to adjacent compartments, is greatly magnified during emergency situations.
Due to the presence of the overlapping binder tape between the water blocking and outer jacket layer, wrinkles often form in the outer jacket of prior art cable as a result of cable bending motion naturally occasioned during installation (i.e., routing) of power cable over cable support hangers, and through conduits and cable transits. Consequently, with such wrinkles, the risk of damage to the outer jacket of prior art naval power cable is substantially increased during the cable installation process.
Thus, there is a great need in the art to provide improved naval power cable and a method of installing the same without the accompanying shortcomings and drawbacks of the prior art.
Accordingly, it is a primary object of the present invention to provide a naval power cable which can be worked through severe bend angles during installation and yet be easily stripped of its water blocking material and outer jacket layer with a substantial reduction in stripping time and an added measure of safety.
Another object of the present invention is to provide such naval power cable, in which the inside surface of the outer jacket is more tenaciously bonded to the outside surface of the water blocking material than with the use of adhesives.
Another object of the present invention is to provide a naval power cable, in which the water blocking material is not internally damaged as the cable is being severely bent during cable working operations.
Another object of the present invention is to provide a naval power cable, in which the water blocking material and outer jacket layer are tenaciously bonded together and can be easily cut without the use of sharp cutting tools so that large lengths of power cable can be quickly and safely stripped aboard a naval vessel, by simply peeling away at most a few integrally bonded strips of water blocking and jacket material.
Another object of the present invention is to provide such naval power cable, in which, the outer jacket is essentially resistant to wrinkling when manipulated during the installation aboard a ship or like naval vessel.
Another object of the present invention is to provide such naval power cable, in which the outer jacket remains essentially uniform over its surface characteristics during installation and while embraced within the sealing material of cable transits, so as to provide improved water and air seals therebetween when subjected to hydrostatic pressures and smoke typically presented during emergency situations.
Yet a further object of the present invention is to provide a novel method of installing electrical power cable through isolatable compartments aboard a naval vessel, in a manner which reduces cable stripping time and provides an additional measure of shipyard worker safety.
An even further object of the present invention is to provide a simpler method of manufacturing such shipboard power cable.
These and other objects will become apparent hereinafter and in the claims.