Fire resistant coaxial cable for distributed antenna systems
US10726974B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 13, 2019 |
| Grant date | Jul 28, 2020 |
| Priority date | — |
| Expiry date | Dec 13, 2039 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01B3/46
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A fire resistant coaxial cable and method of making includes a 2-part dielectric made of a polymer foam and a ceramifiable silicone rubber. The polymer foam, which can be polypropylene or other polymers, leaves little-to-no residue in the cable that causes electromagnetic loss when upon burning. The polymer foam can be extruded over a center conductor using an inert gas, such as nitrogen, to propagate the foam, ensuring little-to-no residue in the cable. The ceramifiable silicone rubber can be extruded over the polymer foam. The ceramifiable silicone rubber can have a polysiloxane matrix with inorganic flux and refractory particles that ceramify under high heat, such as temperatures specified by common fire test standards (e.g., 1850° F./1010° C. for two hours). The cable is configured to maintain a relatively coaxial relation between a center conductor and an outer conductor even under aforementioned fire tests. Another layer of ceramifiable silicone rubber surrounds the outer conductor and continues to insulate it from the outside if a low-smoke zero-halogen (LSZH) jacket burns away.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.