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  Flame retardant and smoke suppressant composite high performance support-separators and conduit tubesUSPTO Application #: 20070209825Title: Flame retardant and smoke suppressant composite high performance support-separators and conduit tubes Abstract: The present invention includes a high performance communications cable exhibiting reduced cross-talk of any form between transmission media that includes one or more core support-separators having various shaped profiles which define a clearance to maintain a spacing between transmission media or transmission media pairs. The core may be formed of a conductive or insulative material to further reduce cross-talk and improve other electrical properties as well as reduce flame and smoke spread. The cable and separators are comprised of principally polymer blends that include olefin and/or fluoropolymer and/or chlorofluoropolymer based resins with and without inorganic additives such as nano-clay composites. These unique blends offer both flame and smoke suppression while maintaining the characteristics necessary to improve electrical performance and allow for severe cost reduction over conventional separators. The specially shaped core support-separators can be either interior to the cable jacket or be employed singularly without the benefit of a jacket and extend along the longitudinal length of the communications cable. Alternatively, with no jacket for cable completion, a portion of the separator wherein a thin layer of material can act as a type of skin for future mechanical protection is provided. The specially shaped core support-separator has both a central region as well as a plurality of shaped sections that extend outward from the central region that are either solid or partially solid, foamed or foamed with a solid skin surface. In addition, the invention includes the optional incorporation of hollow ducts that can be used to provide optical or metal conductor media either before, during, or after installation of the cable primarily by gas driven means. (end of abstract)
Agent: Guerry L. Grune - Virginia Beach, VA, US Inventor: Charles A. Glew USPTO Applicaton #: 20070209825 - Class: 17411300R (USPTO) The Patent Description & Claims data below is from USPTO Patent Application 20070209825. Brief Patent Description - Full Patent Description - Patent Application Claims
CLAIM TO PRIORITY [0001] This utility application takes priority from provisional application No. 60/534,646 filed Jan. 7, 2004 entitled "FLAME RETARDANT AND SMOKE SUPPRESSANT COMPOSITE HIGH PERFORMANCE SUPPORT-SEPARATORS AND CONDUIT TUBES" the contents of which are hereby expressly incorporated by reference. FIELD OF INVENTION [0002] This invention relates to high performance multi-media communications cables utilizing paired or unpaired electrical conductors or optical fibers that meet stringent flame and smoke suppressant requirements both in the United States under the National Electric Code (NEC) and internationally through the guidelines established by the International Electrotechnical Commission (IEC). More particularly, it relates to cables having a central core defining individual conductor pair channels. The communications cables have interior core support-separators that define a clearance through which conductors or optical fibers may be disposed and these separators are the subject of the present invention. The invention also pertains to conduit tubes that could be used in conjunction with or separately from the separators with the defined clearance channels. These conduit tubes may be round, square, rectangular, elliptical or in any feasible geometric shape that would allow for any communications media conductor to be placed or subsequently blown into place along the length of these tubes. Additionally and concurrently, the present invention relates to composite electrical insulation exhibiting reduced flame spread and reduced smoke evolution, while maintaining favorable electrical properties within the conductors and cables. The present invention also relates to insulated electrical conductors and jacketed plenum cable formed from the flame retardant and smoke suppressant composite insulation(s). BACKGROUND OF THE INVENTION [0003] Many communication systems utilize high performance cables normally having four pairs or more that typically consist of two twisted pairs transmitting data and two receiving data as well as the possibility of four or more pairs multiplexing in both directions. A twisted pair is a pair of conductors twisted about each other. A transmitting twisted pair and a receiving twisted pair often form a subgroup in a cable having four twisted pairs. High-speed data communications media in current usage includes pairs of wire twisted together to form a balanced transmission line. Optical fiber cables may include such twisted pairs or replace them altogether with optical transmission media (fiber optics). [0004] When twisted pairs are closely placed, such as in a communications cable, electrical energy may be transferred from one pair of a cable to another. Energy transferred between conductor pairs is undesirable and referred to as crosstalk. The Telecommunications Industry Association and Electronics Industry Association have defined standards for crosstalk, including TLA/EIA-568 A, B, and C including the most recent edition of the specification. The International Electrotechnical Commission has also defined standards for data communication cable crosstalk, including ISO/IEC 11801. One high-performance standard for 100 MHz cable is ISO/IEC 11801, Category 5. Additionally, more stringent standards are being implemented for higher frequency cables including Category 6 and Category 7, which includes frequencies of 200 and 600 MHz, respectively and the most recent proposed industrial standard raising the speeds to 10 Gbit over copper with Ethernet or other cable designs. Industry standards cable specifications and known commercially available products are listed in Table 1 and a set of updated standards for Category 6, including alien crosstalk proposals are included in Tables 2 A-G. TABLE-US-00001 TABLE 1 INDUSTRY STANDARD CABLE SPECIFICATIONS ANIXTER ANIXTER XP6 XP7 TIA CAT 6 R3.00XP R3.00XP ALL DATA AT TIA DRAFT 10 November November 100 MHz CAT 5e Nov. 15, 2001 2000 2000 MAX TEST 100 MHz 250 MHz 250 MHz 350 MHz FREQUENCY ATTENTUATION 22.0 db 19.8 db 21.7 db 19.7 db POWER SUM 32.3 db 42.3 db 34.3 db 44.3 db NEXT ACR 13.3 db 24.5 db POWER SUM 10.3 db 22.5 db 12.6 db 23.6 db ACR POWER SUM 20.8 db 24.8 db 23.8 db 25.8 db ELFEXT RETURN LOSS 20.1 db 20.1 db 21.5 db 22.5 db [0005] TABLE-US-00002 TABLE 2A Return Loss Requirements for Category 6 Cable Return loss @ 20.degree. C. .+-. 3.degree. C. (68.degree. F. .+-. 5.5.degree. F.), worst pair for a length of 100 m (328 ft) Frequency MHz Category 6 dB 1 .ltoreq. f .ltoreq. 10 20 + 5 log (f) 10 .ltoreq. f .ltoreq. 20 25 20 .ltoreq. f .ltoreq. 250 25 - 7 log (f/20) [0006] TABLE-US-00003 TABLE 2B Insertion Loss Requirements for Category 6 Cable Insertion loss @ 20.degree. C. .+-. 3.degree. C. (68.degree. F. .+-. 5.5.degree. F.), worst pair for a length of 100 m (328 ft) Frequency MHz Category 6 dB .772 1.8 10.0 6.0 250.0 32.8 [0007] TABLE-US-00004 TABLE 2C Near End Crosstalk Requirements For Category 6 Cable Horizontal cable NEXT loss @ 20.degree. C. .+-. 3.degree. C. (68.degree. F. .+-. 5.5.degree. F.), worst pair-to-pair, for a length of 100 m (328 ft) Frequency MHz Category 6 dB 0.150 86.7 10.0 59.3 250.0 38.3 [0008] TABLE-US-00005 TABLE 2D Power Sum Near End Crosstalk Requirements for Category 6 Cable PSNEXT loss @ 20.degree. C. .+-. 3.degree. C. (68.degree. F. .+-. 5.5.degree. F.), for a length of 100 m (328 ft) Frequency MHz Category 6 dB 0.150 84.7 10.0 57.3 250.0 36.3 [0009] TABLE-US-00006 TABLE 2E Equal Level Near End Crosstalk Requirements for Category 6 Cable ELNEXT loss @ 20.degree. C. .+-. 3.degree. C. (68.degree. F. .+-. 5.5.degree. F.), worst pair-to-pair for a length of 100 m (328 ft) Frequency MHz Category 6 dB .772 70.0 10.0 47.8 250.0 19.8 [0010] TABLE-US-00007 TABLE 2F Power Sum Equal Level Near End Crosstalk Requirements for Category 6 Cable PSELNEXT loss @ 20.degree. C. .+-. 3.degree. C. (68.degree. F. .+-. 5.5.degree. F.), for a length of 100 m (328 ft) Frequency MHz Category 6 dB .772 67.0 10.0 44.8 250.0 16.8 [0011] TABLE-US-00008 TABLE 2G Proposed Requirements for Alien Near-end Cross-talk for Category 6 Cable Proposed Requirement for Channel Power Sum Alien Near-End Cross-talk Frequency Category 6 dB PSANEXT .gtoreq. 60-10log(f) 1 .ltoreq. f .ltoreq. 100 MHz PSANEXT .gtoreq. 60-15log(f) 100 .ltoreq. f .ltoreq. 625 MHz [0012] In conventional cable, each twisted pair of conductors for a cable has a specified distance between twists along the longitudinal direction. That distance is referred to as the pair lay. When adjacent twisted pairs have the same pair lay and/or twist direction, they tend to lie within a cable more closely spaced than when they have different pair lays and/or twist direction. Such close spacing increases the amount of undesirable cross-talk that occurs. Therefore, in many conventional cables, each twisted pair within the cable has a unique pair lay in order to increase the spacing between pairs and thereby to reduce the cross-talk between twisted pairs of a cable. Twist direction may also be varied. Along with varying pair lays and twist directions, individual solid metal or woven metal air shields can be used to electro-magnetically isolate pairs from each other or isolate the pairs from the cable jacket. [0013] Shielded cable, although exhibiting better cross-talk isolation, is more difficult, time consuming and costly to manufacture, install, and terminate. Individually shielded pairs must generally be terminated using special tools, devices and techniques adapted for the job, also increasing cost and difficulty. [0014] One popular cable type meeting the above specifications is Unshielded Twisted Pair (UTP) cable. Because it does not include shielded pairs, UTP is preferred by installers and others associated with wiring building premises, as it is easily installed and terminated. However, UTP fails to achieve superior cross-talk isolation such as required by the evolving higher frequency standards for data and other state of the art transmission cable systems, even when varying pair lays are used. [0015] Some cables have used supports in connection with twisted pairs. These cables, however, suggest using a standard "X", or "+" shaped support, hereinafter both referred to as the "X" support. Protrusions may extend from the standard "X" support. The protrusions of these prior inventions have exhibited substantially parallel sides. [0016] The document, U.S. Pat. No. 3,819,443, hereby incorporated by reference, describes a shielding member comprising laminated strips of metal and plastics material that are cut, bent, and assembled together to define radial branches on said member. It also describes a cable including a set of conductors arranged in pairs, said shielding member and an insulative outer sheath around the set of conductors. In this cable the shielding member with the radial branches compartmentalizes the interior of the cable. The various pairs of the cable are therefore separated from each other, but each is only partially shielded, which is not so effective as shielding around each pair and is not always satisfactory. [0017] The solution to the problem of twisted pairs lying too closely together within a cable is embodied in three U.S. Pat. No. 6,150,612 to Prestolite, U.S. Pat. No. 5,952,615 to Filotex, and U.S. Pat. No. 5,969,295 to CommScope incorporated by reference herein, as well as an earlier similar design of a cable manufactured by Belden Wire & Cable Company as product number 1711A. The prongs or splines in the Belden cable provide superior crush resistance to the protrusions of the standard "X" support. The superior crush resistance better preserves the geometry of the pairs relatives to each other and of the pairs relative to the other parts of the cables such as the shield. In addition, the prongs or splines in this invention preferably have a pointed or slightly rounded apex top which easily accommodates an overall shield. These cables include four or more twisted pair media radially disposed about a "+"-shaped core. Each twisted pair nests between two fins of the "+"-shaped core, being separated from adjacent twisted pairs by the core. This helps reduce and stabilize crosstalk between the twisted pair media. U.S. Pat. No. 5,789,711 to Belden describes a "star" separator that accomplishes much of what has been described above and is also herein incorporated by reference. [0018] However, these core types can add substantial cost to the cable, as well as excess material mass which forms a potential fire hazard, as explained below, while achieving a crosstalk reduction of typically 3 dB or more. This crosstalk value is based on a cable comprised of a fluorinated ethylene-propylene (FEP) conductors with PVC jackets as well as cables constructed of FEP jackets with FEP insulated conductors. Cables where no separation between pairs exist will exhibit smaller cross-talk values. When pairs are allowed to shift based on "free space" within the confines of the cable jacket, the fact that the pairs may "float" within a free space can reduce overall attenuation values due to the ability to use a larger conductor to maintain 100 ohm impedance. The trade-off with allowing the pairs to float is that the pair of conductors tend to separate slightly and randomly. This undesirable separation contributes to increased structural return loss (SRL) and more variation in impedance. One method to overcome this undesirable trait is to twist the conductor pairs with a very tight lay. This method has been proven impractical because such tight lays are expensive and greatly limits the cable manufacturer's throughput and overall production yield. An improvement included by the present invention to structural return loss and improved attenuation is to provide grooves within channels for conductor pairs such that the pairs are fixedly adhered to the walls of these grooves or at least forced within a confined space to prevent floating simply by geometric configuration. This configuration is both described here within and referenced in U.S. Pat. No. 6,639,152 filed Aug. 25, 2001 as well as PCT/US02/13831 filed at the United States Patent and Trademark Office on May 1, 2002. [0019] A "rifling" or "ladder-like" separator design also contributes to improved attenuation, power sum NEXT (near end cross talk), power sum ACR (attenuation cross-talk ratio) and ELFEXT (equal level far end cross-talk) by providing for better control of spacing of the pairs, adding more air-space, and allowing for "pair-twinning" at different lengths. Additional benefits include reduction of the overall material mass required for conventional spacers, which contributes to flame and smoke reduction. [0020] In building designs, many precautions are taken to resist the spread of flame and the generation of and spread of smoke throughout a building in case of an outbreak of fire. Clearly, the cable is designed to protect against loss of life and also minimize the costs of a fire due to the destruction of electrical and other equipment. Therefore, wires and cables for building installations are required to comply with the various flammability requirements of the National Electrical Code (NEC) in the U.S. as well as International Electrotechnical Commission (EIC) and/or the Canadian Electrical Code (CEC). [0021] A broad range of electrical conductors and electrical cables are installed in modern buildings for a wide variety of uses. Such uses include data transmission between computers, voice communications, as well as control signal transmission for building security, fire alarm, and temperature control systems. These cable networks extend throughout modern office and industrial buildings, and frequently extend through the space between the dropped ceiling and the floor above. Ventilation system components are also frequently extended through this space for directing heated and chilled air to the space below the ceiling and also to direct return air exchange. The space between the dropped ceiling and the floor above is commonly referred to as the plenum area. Electrical conductors and cables extending through plenum areas are governed by special provisions of the National Electric Code ("NEC"). Continue reading... Full patent description for Flame retardant and smoke suppressant composite high performance support-separators and conduit tubes Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Flame retardant and smoke suppressant composite high performance support-separators and conduit tubes patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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