Multi-stage heat sensing cable and emergency communication system
US4157526A · kind A · utility
Inventor
Key dates
| Filing date | Feb 22, 1977 |
| Grant date | Jun 5, 1979 |
| Priority date | — |
| Expiry date | Feb 22, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG08B17/06
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A heat sensing cable is provided for use in an alarm and/or fire extinguishing system, which is capable of responding to the presence of fire, or excessive heat, and to sound an alarm, actuate fire extinguishing sprinkling equipment, operate other fire extinguishing means, or to perform other emergency functions. The heat sensing cable of the invention comprises two or more multi-strand single conductor plastic coated insulated wires twisted together in a spiral manner, and which are placed under tension when in use. Each insulated wire in the multi-conductor heat sensing cable of the invention consists of a single multi-strand conductor of low electrical resistance, formed of copper or other suitable conductive material, and having any particular gage to suit any particular application. The conductor of each insulated wire is coated with a prescribed thickness of selected thermal-responsive plastic material which softens at a predetermined temperature and which, due to its softening, causes the wire conductor in each single conductor cable of like insulation to cut through the plastic and make contact with the conductor or conductors of the other cable having similar insulated wir…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.