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Publication numberUS2639247 A
Publication typeGrant
Publication dateMay 19, 1953
Filing dateNov 17, 1949
Priority dateNov 17, 1949
Publication numberUS 2639247 A, US 2639247A, US-A-2639247, US2639247 A, US2639247A
InventorsSquier Donald R
Original AssigneeSpecialties Dev Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method of making heat or flame detecting elements
US 2639247 A
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Description  (OCR text may contain errors)

May 19, 1953 D. R; SQUIER- METHOD oF MAKING HEAT 0R FLAME DETECTING ELEMENTS Filed Nov. 17, 1949 tungst- IN VEN TOR j 00A/ALD Rspu/ER rroRA/EY Patented May 19, 1953 METHOD OF MAKING HEAT OR- FLANULl DETECTING ELEMENTS` Donald R. Squier, Pompton Plains, N. J., assignor to Specialties Development Corporation, Belleville, N. J., a corporation of New Jersey Application November 17, 1949, Serial No. 127,845

14 Claims.

The present invention relates to a method of making heat or flame detecting elementsJ and, more particularly, relates to a method of making elements such as illustrated and described in my co-pending application for United States Letters Patent, Serial No. 115,594, led September 14, 1949, now Patent No. 2,587,916.

The invention is primarily concerned with the making of the heat sensitive elements for heat or flame detecting cables of the type generally comprising an elongate tube or housing, one or more electrically conductive Wires disposed in the tube, and a covering of fiber glass yarn on the Wires which is practically non-conductive at normal temperatures but is rendered conductive at much higher temperatures, whereby the wires in effect are insulated from each other and/or the tube at normal temperatures and an electrical circuit is established between the Wires and/or the tube at higher temperatures.

method of making such heat or flame detecting elements.

Another object is to provide a method of the foregoing character which facilitates adjusting the electrical properties of the covering and/or improving its high temperature withstanding qualities.

A further object is to provide a method of the foregoing character for producing covered wires which may be immediately inserted into tubes or may be conveniently stored for use in the future.

Other and further objects of the invention will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment -of the invention in practice.

-to withstand high temperatures, and drying and/ or sintering the treated covering. The elements produced by the foregoing process may be inserted into tubes immediately or may be stored `for use in the future b-y Winding the same on spools or drums or the like.

In the drawing:

Figure l is a diagrammatic flow chart illustrating a method of making the elements in accordance with the present invention.

Figure 2 is a fragmentary elevational view of a length of wire or the like.

Figure 3 is a fragmentary elevational View of the wire having a braided fiber glass yarn covering thereon.

Figure 4 is a fragmentary elevational View of the wire having a spirally Wound fiber glass yarn covering thereon.

Figure 5 is a cross-sectional view illustrating the covering and wire shown in either Figure 3 or Figure 4.

Figure 6 is a cross-sectional View` illustrating the covered wire shown in Figure 5 disposed in a tube.

Figure is a View similar to Figure 6 with the diameter of the tube reduced.

Referring to the drawing, and more particularly to Figure 1 thereof, there is shown a diagrammatic flow sheet illustrating a method of making heat or flame detecting elements in accordance with the invention. An electrical'conductor, such as Wire IB (Figure 2), is supplied from a source such as a spool or drum and is delivered to a machine for providing a fiber glass yarn covering thereon. Such a machine may be of the type which braids the yarn on the wire lil to provide a braided covering Il (Figure 3) or of the typewhich spirally Winds the yarn or a strip or tape of yarn to provide a wound covering I2 (Figure 4). In either instance, a porous fiber glass fabric covering is applied to the wire.

The fiber glass yarn may be of any composition, although yarns made of boro-silicate or barium type glass fibers are preferred because of their relatively high softening point temperatures and thermal endurance without material variation in physical or chemical characteristics upon repeated changes in temperature over a wide range. Such glass compositions have negative temperature coemcients of resistivity which enable the fiber glass covering to act as an insulator at normal atmospheric temperatures and to act as a conductor of electricity upon being subjected to flame or heat produced by flame.

It has also been found suitable to utilize fiber glass yarn which has been treated in a 15% hydrochloric acid solution at about F. Such treatment is believed to remove lead oxide from the glass and thereby raise the softening point temperature of the glass composition.

The covered wire is then delivered to apparatus for applying a material adapted to give the covering desired heat detecting characteristics, such as the ability to withstand temperatures approaching 2000 F. and higher, and/or a predetermined desired negative temperature coefficient.

The covering may be improved to resist high temperature by coating or impregnating the saine with a slurry of refractory material or compositions of two or more refractory materials. Such materials may be complexes or compounds of aluminum oxide, aluminum silicate, calcium oxide, chromic oxide, chromite, magnesium oxide, magnesium silicate, silicon carbide, titanium xide, zirconium oxide and'zirconium carbide and the like.

These materials or compositions thereof may contain other compounds in small percentages Without materially aiecting the refractory properties thereof. For example, small amounts of carbonatos are no-t objectionable, but, to the contrary, are desirable to provide a iluxing action in the event it is desired to sinter the refractory materials and the glass libers.

Various commercially available prepared refractory type cements may be utilized to good advantage for improvingthe yarn to withstand high temperatures.

Graphite of the refractory type may be also utilized, but, due to its relatively high electrical conductivity, its use in small amounts or in mixtures comprising a major proportion oi less conductive refractory materials is recommended.

Since refractory materials have negative temperature coefficients of resistivity, they may also be applied to the covering for the purpose of modifying the resistivity thereof whereby the covering becomes relatively conductive at predetermined temperatures.

The resistivitl7 of the covering, either with or without application of the refractory material, may be modined or adjusted to a predetermined value by the application of materials having thermistor-like properties. Such materials may be oxides of barium, beryllium, cadmium, cerium, cobalt, copper, iron, lead, manganese, nickel, strontium, tin and tungsten and the like. These materials may be applied in slurry form or may be incorporated in the slurry o f refractory materials. Alternatively, suitable salts of these metals in a solvent may be applied to. the covering or may be incorporated with the refractory material, which thereafter are converted into the oxide of the, metal.

The so treated covered wire is then delivered to a drying zone Where the liquid or solvent of the slurry or solution is removed by the application of heat at a temperature well above the boiling point of Water.

The Wire (Figure 5) is `finally delivered to. a zone maintained at temperatures adapted to effeot sintering of the refractory material and glass bers and/or the conversion of metallic salts to oxides of the metals. `Sintering apparently produces a glass-refractory composition which may be alternately and repeatedly subjected to temperatures varying between about 70 F. and about 2000 F. Without any material variation in temperature coeflicient of resistivity.

The element' produced by the foregoing described method is now ready to be cut in lengths and inserted into a tube lll havingan inner diameter which is greater than the diameter of the element (Figure 6), and the tube may then be :reduced in diameter, for example, by redrawing the same to snugly house lthe element (Figure '1).

4 Alternatively, the element may be wound on a drum or spool or the like, and stored for future use in a compact and convenient manner.

From the foregoing description, it will be seen that the present invention provides a simple, economical and practical process for producing heat or flame detecting elements wherein all of the steps may be performed in line sequence from the bare Wire to the insertion of the treated covered Wire into the tube or housing. The method of this invention has great utility because it can be carried out in a minimum amount ofY oor space and at all times leaves the Wire in a iiexible condition to facilitate handling and storage thereof.

As. various changes may be made without departing from the spirit and scope of the invention and without sacricing any of its advantages, it is to be understood that all matter herein is to be interpreted as illustrative and not in any limiting sense.

I claim:

l. A method of making continuous flexible heat or name detecting elements of the class described, which comprises applying a continuous flexible covering of ber glass yarn to an electrically conductive flexible Wire, and applying a material to the covering adapted to. give thecovering desired heat detecting characteristics said material being a substance selected from the group consisting of aluminum oxide, aluminum silicate, calcium oxide, chromic oxide, chromite, inagnesiuzn oxide, magnesium silicate, silicon carbide, titaniumk oxide, zirconium oxide and zirconium carbide.

2. A method of making continuous flexible heat or aine detecting elements of the class described, vvhich comprises applying a continuous exible covering of liber glass. yarn to; an electrically conductive ilexible wire applying a ma,- `terial to thev covering adapted to,y give the covering desired heat. detecting characteristics, and drying the covering said material being; a. Sub,.- stance selected from the group Consisting; of aluminum oxide, aluminum silicate, calcium oxide, chromic oxide, chrorrite,l maeglsiumoxide, magnesium silicate, silicon carbide, titanium oxide, zirconium oxide and; zirconium carbide.

3. A method of making continuous exible heat 0r flamcvdctectine elements cf the class described, which comprises applying a continuous exible covering of fiber glass to anelecl'fricall-yl con-- ductive flexible wire, applying a material to- `the covering adapted t give the covering desired heat detecting characteristics, and winding the coveredwire said material being al substance se,- lected from the group, consisting of aluminum oxide, aluminum silicate, calciumox'ide, chromic oxide, chrrnite, magnesium oxideL magnesium silicate, silicon carbide, titanium Oxide, Zirconium oxide and zirconium Carbide.

4. A method of Amaking continuous ilexible heat or flame detectingelements otA the class described, Whlch comprises. applying a continuous iiexible covering of ber glass, yarn to .an electrically conductive flexible Wire, applying a materiall ,17.0, .the covering adapted to give the, covering desired heat detectingv characteristics, drying the cove-ring, and Winding the covered Wire said material being a substance yselected from the grou-pconsisting of aluminum oxide, `alu-mimirn silicate, calcium oxide., chromic oxide, chromite, magnesium oxide, masnesiumsilicate, silicon carbide, titanium oxide, zirconium oxide and zirconium carbide.

5. A method of making continuous flexible heat or liarne detecting elements of the class described, which comprises braiding a continuous flexible covering of ber glass yarn on an electrically conductive flexible wire, and applying a material to the covering adapted to give the covering the desired heat detecting characteristics said material being a substance selected from the group consisting of aluminum oxide, aluminum silicate, calcium oxide, chromic oxide, chromite, magnesium oxide, magnesium silicate, silicon carbide, titanium oxide, zirconium oxide and zirconium carbide.

6. A method of making continuous flexible heat or flame detecting elements of the class described, which comprises spirally winding a continuous flexible covering of fiber glass yarn on an electrically conductive flexible wire, and applying a material to the covering adapted to give the covering the desired heat detecting characteristics said material being a substance selected from the group consisting of aluminum oxide, aluminum silicate, calcium oxide, chromic oxide, chromite, magnesium oxide, magnesium silicate, silicon carbide, titanium oxide, zirconium oxide and zirconium carbide.

7. A method of making continuous exible heat or flame detecting elements of the class described, which comprises applying a continuous exible covering of fiber glass yarn on an electrically conductive flexible wire, and applying a material having a nega-tive temperature coefficient of resistivity to the covering said material being a substance selected from the group consisting of aluminum oxide, aluminum silicate, calcium oxide, chromic oxide, chromite, magnesium oxide, magnesium silicate, carbide, titanium oxide, zirconium oxide and zirconium carbide.

8. A method of making continuous flexible heat or flame detectingelements of the class described, which comprises applying a continuous flexible covering of fiber glass yarn on an electrically conductive exible wire, and applying a slurry of refractory material to the covering to enable the covering to withstand relatively high f temperatures said material being a substance selected from the group consisting of aluminum oxide, aluminum silicate, calcium oxide, chromic oxide, chromite, magnesium oxide, magnesium silicate, silicon carbide, titanium oxide, zirconium oxide and zirconium carbide.

9. A method of making continuous flexible heat or flame detecting elements of the class described, which comprises applying a continuous flexible covering of fiber glass yarn on an electrically conductive flexible wire, and impregnating the covering with a thermistor-like material said material being a substance selected from the group consisting of aluminum oxide, aluminum silicate, calcium oxide, chromic oxide, chromite, magnesium oxide, magnesium silicate, silicon carbide, titanium oxide, zirconium oxide and zirconium carbide.

10. A method of making continuous fiexible heat or flame detecting elements of the class described, which comprises applying a continuous flexible covering of fiber glass yarn on an electrically conductive flexible Wire, impregnating the covering with a thermistor-like material, and coating the covering with a refractory material said material being a substance selected from the group consisting of aluminum oxide, aluminum silicate, calcium oxide, chromic oxide, chromite, magnesium oxide, magnesium silicate, silicon carbide, titanium oxide, zirconium oxide and zirconium carbide.

11. A method of making continuous flexible heat or flame detecting elements of the class described, which comprises applying a continuous flexible covering of fiber glass yarn on an electrically conductive flexible wire, applying a slurry of refractory material to the covering, and sintering the covering and material to produce a composition adapted to withstand relatively high temperatures said material being a substance selected from the group consisting of aluminum oxide, aluminum silicate, calcium oxide, chromic oxide, chromite, magnesium oxide, magnesium silicate, silicon carbide, titanium oxide, zirconium oxide and zirconium carbide.

l2. A method of making continuous flexible heat or flame detecting elements of the class described, which comprises applying a refractory material to a continuous flexible fiber glass yarn covering on an electrically conductive flexible wire, and sintering the refractory material and the ber glass yarn to produce a composition adapted to withstand relatively high temperatures said material being a substance selected from the group consisting of aluminum oxide, aluminum silicate, calcium oxide, chromic oxide, chromite, magnesium oxide, magnesium silicate, silicon carbide, titanium oxide, zirconium oxide and zirconium carbide.

13. A method of making continuous flexible heat or flame detecting elements of the class described, which comprises impregnating a continuous iiexible fiber glass yarn covering on an electrically conductive flexible wire with a thermistor-like material said material being a substance selected from the group consisting of aluminum oxide, aluminum silicate, calcium oxide, chromic oxide, chromite, magnesium oxide, magnesium silicate, silicon carbide, titanium oxide, zirconium oxide and zirconium carbide.

14. A method of making continuous flexible heat or flame detecting elements of the class described, which comprises impregnating a con- 'tinuous flexible fiber glass yarn covering on an electrically conductive flexible wire with a thermistor-like material and a refractory material, and sintering the refractory material and the glass yarn covering to produce a composition adapted to withstand relatively high tempera-x tures said material being a substance selected from the group consisting of aluminum oxide, aluminum silicate, calcium oxide, chromic oxide, chromite, magnesium oxide, magnesium silicate, silicon carbide, titanium oxide, zirconium oxide and zirconium carbide.

DONALD R. SQUIER.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,370,046 Keyes Feb. 20, 1945 2,372,840 Mattern Apr. 3, 1945 2,390,039 Slayter et al. Nov. 27, 1945 2,427,507 Powell et al. Sept. 16, 1947 2,487,526 Dahm Nov. 8, 1949

Patent Citations
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US2370046 *Mar 20, 1942Feb 20, 1945Westinghouse Electric & Mfg CoInsulated electrical conductor
US2372840 *Nov 6, 1942Apr 3, 1945Honeywell Regulator CoTemperature responsive resistance element
US2390039 *Nov 13, 1941Nov 27, 1945Owens Corning Fiberglass CorpInsulated electrical conductor
US2427507 *Apr 11, 1944Sep 16, 1947Carbide & Carbon Chem CorpMethod of producing sealed cables
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2799608 *Jul 13, 1951Jul 16, 1957Int Standard Electric CorpElectric cables
US2859271 *Apr 18, 1955Nov 4, 1958Gen ElectricHigh voltage bushing
US2978363 *Oct 11, 1956Apr 4, 1961DegussaInsulated electrical conductors
US3030257 *Dec 2, 1957Apr 17, 1962Rea Magnet Wire Company IncHeat resistant insulated electrical components and process of making
US3060923 *Jan 7, 1959Oct 30, 1962Teca CorpCoaxial electrode structure and a method of fabricating same
US3232782 *Aug 5, 1960Feb 1, 1966Owens Corning Fiberglass CorpHigh temperature resistant vitreous material and method of producing same
US3269818 *Oct 29, 1964Aug 30, 1966Owens Corning Fiberglass CorpDevitrifying a glass about glass fibers on a conductor
US3448222 *Dec 7, 1967Jun 3, 1969Greber HenryAerial conductor
US3620861 *Oct 27, 1969Nov 16, 1971Wiswell George C JrCable protection and method
US4491822 *Nov 2, 1981Jan 1, 1985Xco International, Inc.Heat sensitive cable
US4540972 *Aug 29, 1984Sep 10, 1985Xco International, Inc.Heat sensitive cable
US4614024 *Aug 29, 1984Sep 30, 1986Xco International, Inc.Filling sheath with heat treated manganese dioxide and thermoelectrical conductor
US4638107 *May 23, 1985Jan 20, 1987Xco International, Inc.Heat sensitive tape and method of making same
US4647710 *May 23, 1985Mar 3, 1987Xco International, Inc.Heat sensitive cable and method of making same
US4906308 *Mar 29, 1989Mar 6, 1990Lestox, Inc.Method of making electric cable with improved burn resistance feature
US4910361 *Mar 29, 1989Mar 20, 1990Lestox Inc.Electric cable with burn resistant features
US5008495 *Feb 12, 1990Apr 16, 1991Lestox, Inc.Electric cable with burn resistant characteristics and method of manufacture
US5483414 *Mar 30, 1993Jan 9, 1996Vaisala OyElectrical impedance detector for measurement of physical quantities, in particular of temperature
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Classifications
U.S. Classification156/53, 156/280, 174/124.00R, 338/214, 428/377, 338/26
International ClassificationH01B7/10, G08B17/06, H01C7/04
Cooperative ClassificationG08B17/06, H01B7/102, H01C7/04
European ClassificationH01C7/04, H01B7/10B, G08B17/06