US2785142A - Core composition for fire detector element - Google Patents
Core composition for fire detector element Download PDFInfo
- Publication number
- US2785142A US2785142A US535307A US53530755A US2785142A US 2785142 A US2785142 A US 2785142A US 535307 A US535307 A US 535307A US 53530755 A US53530755 A US 53530755A US 2785142 A US2785142 A US 2785142A
- Authority
- US
- United States
- Prior art keywords
- weight
- core composition
- parts
- talc
- manganese dioxide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000000203 mixture Substances 0.000 title claims description 23
- NUJOXMJBOLGQSY-UHFFFAOYSA-N manganese dioxide Chemical compound O=[Mn]=O NUJOXMJBOLGQSY-UHFFFAOYSA-N 0.000 claims description 26
- ZPPSOOVFTBGHBI-UHFFFAOYSA-N lead(2+);oxido(oxo)borane Chemical compound [Pb+2].[O-]B=O.[O-]B=O ZPPSOOVFTBGHBI-UHFFFAOYSA-N 0.000 claims description 12
- 239000000454 talc Substances 0.000 claims description 12
- 229910052623 talc Inorganic materials 0.000 claims description 12
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims description 11
- 239000004020 conductor Substances 0.000 description 6
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 230000005611 electricity Effects 0.000 description 2
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 235000017784 Mespilus germanica Nutrition 0.000 description 1
- 240000002624 Mespilus germanica Species 0.000 description 1
- 235000000560 Mimusops elengi Nutrition 0.000 description 1
- 235000007837 Vangueria infausta Nutrition 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
- H01C7/04—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having negative temperature coefficient
- H01C7/042—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having negative temperature coefficient mainly consisting of inorganic non-metallic substances
- H01C7/043—Oxides or oxidic compounds
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C13/00—Resistors not provided for elsewhere
Definitions
- the present invention relates to fire detector elements
- the invention is concerned with fire detector elements comprising two or more spaced apart conductors of electricity having therebteween a core composition of such a resistance at normal temperatures that, in effect, it insulates the conductors, and of such a resistance at a predetermined higher temperature that it becomes a conductor of electricity between the conductors and enables sufiicient current to pass through the conductors to operate a device for controlling a fire alarm and/or fire extinguishing circuit.
- the elements may be in the form of a cable-like structure adapted to be placed in a space where a fire is to be detected.
- This structure comprises a metallic tube through which electrically conductive wires extend which are separated from each other and the tube by a suitable core composition of the foregoing character.
- the present invention is primarily concerned with improving this core composition in a manner to more accurately predetermine the temperature at which the composition is rendered conductive in response to the heat of a fire whereby current can flow through the conductors to operate an electrical device.
- an object of the present invention is to provide an improved core composition of the character indicated herein.
- Another object is to provide such a composition which becomes electrically conductive practically instantaneously when heated to a predetermined temperature.
- a further object is to provide such a composition which is economical to prepare, is reliable in operation, and is fully adapted for repeated use without change in its responsive characteristic.
- the manganese dioxide, aluminum oxide and talc may be of a chemically pure or technical grade, while the lead borate preferably is chemically pure.
- the tale when used in sufiicient amounts, serves as a body or carrier for the aluminum and manganese oxide in the extrusion thereof and in the final core, while the lead borate serves as a high temperature fiuxing agent to provide good adherence of the core composition to the wires.
- the core had a diameter of .058 inch, and the wires were disposed therein in parallel relation about .010 inch apart throughout their length.
- These sensing elements had an infinite resistance at 70 P. which dropped sharply to about 5,000 ohms when the core composition was heated to 770 F. thereby enabling sufficient direct current or alternating current to flow through the wires to effect operation of an elec trical device for giving an indication that the aforementioned temperature condition existed.
- this formula can be somewhat varied to produce a sharp resistance drop when the core composition is heated to temperatures ranging from about 570 to about 1050 P. which temperatures are in a range quite commonly sought to be detected in practice. This can be accomplished by following substantially the same manufacturing procedure set forth herein to produce an extrudable plastic mass which adheres to the wires and can be fused thereon to provide a durable ceramic-like core.
- a core composition which has a sharp resistance drop at 570 F. is illustrated by the following formula.
- a core composition which has a sharp resistance drop at 1050" F. is illustrated by the following formula.
- a core composition consisting essentially of about 7 25% toabout 40% by weight of manganese dioxide, about 25% to about 40% by weight of aluminum oxide, about 15% to about 40% by weight of talc, and about to about 8% by weight of lead borate.
- a coretcomposition' consisting essentially of about 25% to about 40% by weight of manganese dioxide, about 25 to about 40% by weight of aluminum om'de, about 15% to about 40% by weight of talc, and about 5% to about 8% by Weight of lead borate, the manganese dioxide and aluminum oxide being present in about equal amounts by weight on a chemically pure basis.
- a core composition consisting essentially of about parts by weight of manganese dioxide, about 50 parts by weight of aluminum oxide, about parts by weight talc, and about 15 parts by weight lead borate.
- a core composition consisting essentially of about 40 'parts by weight of manganese dioxide, about 40 parts by weight of aluminum 'oxide,"about 15 parts by weight talc, and about 5 'partsby weight lead borate.
- a core composition consisting essentially of about 27.5 parts by weight of manganese dioxide, about 27.5 parts-by weight of aluminum oxide, about 40 parts by weight talc, and about 5 parts by weight lead boratea References Cited in the file of this patent UNITED STATES PATENTS 2,495,867 Peters Jan. 31, 1950 2,526,251 Medlar Oct. 17, 1950 2,587,916 Squier -'Mar. 4, 1952 2,717,946 Peck Sept. 13, 1955 2,720,573 Lundq'vi'st Oct. 11, 1955
Description
nited States Patent 2,785,142 wer CORE COMPOSITION FOR FIRE DETECTOR ELEMENT Ronald M aclntyre, North Arlington, and Raymond E.
Scott, Lincoln Park, N. L, assignors to Specialties Development Corporation, Belleville, N. L, a corporation of New Jersey a I No Drawing. Application September 19, 1955,
Serial No. 535,307 1 5 Claims. (Cl. 252-518) The present invention relates to fire detector elements,
. position in accordance with the present invention:
and, more particularly, to a core composition adapted to be utilized in connection with such elements.
The invention is concerned with fire detector elements comprising two or more spaced apart conductors of electricity having therebteween a core composition of such a resistance at normal temperatures that, in effect, it insulates the conductors, and of such a resistance at a predetermined higher temperature that it becomes a conductor of electricity between the conductors and enables sufiicient current to pass through the conductors to operate a device for controlling a fire alarm and/or fire extinguishing circuit. For example, as shown in United States Letters Patent No. 2,586,252, the elements may be in the form of a cable-like structure adapted to be placed in a space where a fire is to be detected. This structure comprises a metallic tube through which electrically conductive wires extend which are separated from each other and the tube by a suitable core composition of the foregoing character.
More specifically, the present invention is primarily concerned with improving this core composition in a manner to more accurately predetermine the temperature at which the composition is rendered conductive in response to the heat of a fire whereby current can flow through the conductors to operate an electrical device.
Accordingly, an object of the present invention is to provide an improved core composition of the character indicated herein.
Another object is to provide such a composition which becomes electrically conductive practically instantaneously when heated to a predetermined temperature.
A further object is to provide such a composition which is economical to prepare, is reliable in operation, and is fully adapted for repeated use without change in its responsive characteristic.
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.
In accordance with the present invention, it has been found that the foregoing objects can be accomplished by utilizing a core composition comprising manganese dioxide, aluminum oxide, talc and anhydrous lead borate.
The manganese dioxide, aluminum oxide and talc may be of a chemically pure or technical grade, while the lead borate preferably is chemically pure.
The tale, when used in sufiicient amounts, serves as a body or carrier for the aluminum and manganese oxide in the extrusion thereof and in the final core, while the lead borate serves as a high temperature fiuxing agent to provide good adherence of the core composition to the wires.
These materials are admixed together with a suitable binder and/ or lubricant, and sutiicient water is added to I Parts by weight Manganese dioxide 50 Aluminum oxide. 50 Talc Lead borate 15 A core composition was produced from these materials and applied to two-wire. temperature sensing elements in the foregoing described manner. The wires were coniposed of lnconel, and had a length of ten feet and.
a-diameter. of .010 inch. The core had a diameter of .058 inch, and the wires were disposed therein in parallel relation about .010 inch apart throughout their length. These sensing elements had an infinite resistance at 70 P. which dropped sharply to about 5,000 ohms when the core composition was heated to 770 F. thereby enabling sufficient direct current or alternating current to flow through the wires to effect operation of an elec trical device for giving an indication that the aforementioned temperature condition existed.
It further has been found that this formula can be somewhat varied to produce a sharp resistance drop when the core composition is heated to temperatures ranging from about 570 to about 1050 P. which temperatures are in a range quite commonly sought to be detected in practice. This can be accomplished by following substantially the same manufacturing procedure set forth herein to produce an extrudable plastic mass which adheres to the wires and can be fused thereon to provide a durable ceramic-like core.
A core composition which has a sharp resistance drop at 570 F. is illustrated by the following formula.
Parts by weight Manganese dioxide 40 Aluminum oxide 40 Talc 15 Lead borate 5 A core composition which has a sharp resistance drop at 1050" F. is illustrated by the following formula.
Parts by weight Manganese dioxide 27.5 Aluminum oxide -a 27.5 Talc 40 Lead borate 5 Thus, on a one hundred part by weight basis the formula may be varied within the following approximate ranges to produce core compositions having sharp resistance drops at temperatures ranging from about 570 to 1050 F.
Percent by weight Manganese dioxide 25 to 40 Aluminum oxide 25 to 40 Talc 15 to 40 Lead borate 5 to 8 V 3 It will be understood that the details and examples hereinbefore set forth are illustrative only and that the invention as broadly described and claimed is in no 1. A core composition consisting essentially of about 7 25% toabout 40% by weight of manganese dioxide, about 25% to about 40% by weight of aluminum oxide, about 15% to about 40% by weight of talc, and about to about 8% by weight of lead borate.
, 2. A coretcomposition' consisting essentially of about 25% to about 40% by weight of manganese dioxide, about 25 to about 40% by weight of aluminum om'de, about 15% to about 40% by weight of talc, and about 5% to about 8% by Weight of lead borate, the manganese dioxide and aluminum oxide being present in about equal amounts by weight on a chemically pure basis.
3. A core composition consisting essentially of about parts by weight of manganese dioxide, about 50 parts by weight of aluminum oxide, about parts by weight talc, and about 15 parts by weight lead borate.
4. A core composition consisting essentially of about 40 'parts by weight of manganese dioxide, about 40 parts by weight of aluminum 'oxide,"about 15 parts by weight talc, and about 5 'partsby weight lead borate. v
5.- A core composition consisting essentially of about 27.5 parts by weight of manganese dioxide, about 27.5 parts-by weight of aluminum oxide, about 40 parts by weight talc, and about 5 parts by weight lead boratea References Cited in the file of this patent UNITED STATES PATENTS 2,495,867 Peters Jan. 31, 1950 2,526,251 Medlar Oct. 17, 1950 2,587,916 Squier -'Mar. 4, 1952 2,717,946 Peck Sept. 13, 1955 2,720,573 Lundq'vi'st Oct. 11, 1955
Claims (1)
1. A CORE COMPOSITION CONSISTING ESSENTIALLY OF ABOUT 25% TO ABOUT 40% BY WEIGHT OF MANGANESE DIOXIDE, ABOUT 25% TO 40% BY WEIGHT OF ALUMINUM OXIDE, ABOUT 15% TO ABOUT 40% BY WEIGHT OF TALC, AND ABOUT 5% TO ABOUT 8% BY WEIGHT OKF LEAD BORATE.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US535307A US2785142A (en) | 1955-09-19 | 1955-09-19 | Core composition for fire detector element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US535307A US2785142A (en) | 1955-09-19 | 1955-09-19 | Core composition for fire detector element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2785142A true US2785142A (en) | 1957-03-12 |
Family
ID=24133634
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US535307A Expired - Lifetime US2785142A (en) | 1955-09-19 | 1955-09-19 | Core composition for fire detector element |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2785142A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3093598A (en) * | 1957-09-13 | 1963-06-11 | English Electric Co Ltd | Electrically conductive glasses |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2495867A (en) * | 1948-01-14 | 1950-01-31 | Petcar Res Corp | Method of manufacturing fire detector and like elements |
| US2526251A (en) * | 1950-01-10 | 1950-10-17 | Fox Prod Co | Thermally responsive impedance unit |
| US2587916A (en) * | 1949-09-14 | 1952-03-04 | Specialties Dev Corp | Heat detecting cable |
| US2717946A (en) * | 1950-10-14 | 1955-09-13 | Sprague Electric Co | Electrical resistance elements |
| US2720573A (en) * | 1951-06-27 | 1955-10-11 | Dick O R Lundqvist | Thermistor disks |
-
1955
- 1955-09-19 US US535307A patent/US2785142A/en not_active Expired - Lifetime
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2495867A (en) * | 1948-01-14 | 1950-01-31 | Petcar Res Corp | Method of manufacturing fire detector and like elements |
| US2587916A (en) * | 1949-09-14 | 1952-03-04 | Specialties Dev Corp | Heat detecting cable |
| US2526251A (en) * | 1950-01-10 | 1950-10-17 | Fox Prod Co | Thermally responsive impedance unit |
| US2717946A (en) * | 1950-10-14 | 1955-09-13 | Sprague Electric Co | Electrical resistance elements |
| US2720573A (en) * | 1951-06-27 | 1955-10-11 | Dick O R Lundqvist | Thermistor disks |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3093598A (en) * | 1957-09-13 | 1963-06-11 | English Electric Co Ltd | Electrically conductive glasses |
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