WO1984002048A1 - Self-limiting heater and resistance material - Google Patents

Self-limiting heater and resistance material Download PDF

Info

Publication number
WO1984002048A1
WO1984002048A1 PCT/SE1983/000382 SE8300382W WO8402048A1 WO 1984002048 A1 WO1984002048 A1 WO 1984002048A1 SE 8300382 W SE8300382 W SE 8300382W WO 8402048 A1 WO8402048 A1 WO 8402048A1
Authority
WO
WIPO (PCT)
Prior art keywords
conducting
electrical
heating device
resistance material
electrically
Prior art date
Application number
PCT/SE1983/000382
Other languages
English (en)
French (fr)
Inventor
Wolfgang Bronnvall
Original Assignee
Wolfgang Bronnvall
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Wolfgang Bronnvall filed Critical Wolfgang Bronnvall
Priority to DE8383903611T priority Critical patent/DE3378346D1/de
Priority to JP83503580A priority patent/JPS59502161A/ja
Priority to AT83903611T priority patent/ATE38306T1/de
Publication of WO1984002048A1 publication Critical patent/WO1984002048A1/en
Priority to NO842836A priority patent/NO163430C/no
Priority to FI844891A priority patent/FI80820C/sv

Links

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
    • H01C7/02—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 positive temperature coefficient
    • H01C7/028—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 positive temperature coefficient consisting of organic substances
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/10—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
    • H05B3/14—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
    • H05B3/146—Conductive polymers, e.g. polyethylene, thermoplastics
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/40—Heating elements having the shape of rods or tubes
    • H05B3/54—Heating elements having the shape of rods or tubes flexible
    • H05B3/56—Heating cables

Definitions

  • This invention relates to self-regulating electrical heating devices with electrical resistance materials the resistivity of which is changed by more than a power of 10 within a pre ⁇ determined narrow temperature interval.
  • Known electrical heating devices which, after reaching a cri- tical temperature, rapidly decrease their output without the help of thermostati ⁇ regulation are based on two or more con ⁇ ductors and an intermediate resistance material, the resisti ⁇ vity of which starts to increase steeply at the critical tem ⁇ perature.
  • Such materials are called PTC-materials (Positive Temperature Coefficient).
  • PTC-materials for self-limiting heating devices consist of crystalline polymers with conducting particles distributed therein.
  • the polymers can be thermoplastic or crosslinked.
  • the steep increase of the resistivity is ex ⁇ plained by the expansion of the polymer leading to interrup ⁇ tion of the contact between the conducting particles.
  • USP 3.673.121 the PTC effect is claimed to be due to phase changes of crystalline polymers with narrow molecular weight distri- bution.
  • OMPI freely choose the temperature interval for the steep increase of the resistivity.
  • the present invention relates to a self-limiting electrical heating device with an electrical resistance material, the re- sistivity of which is changed by more than a power of 10 with ⁇ in a pre-determined narrow temperature interval and which is arranged between electrical conductors connectable to a voltage source, the conductor and the resistance material being en ⁇ closed in an electrically insulating cover.
  • the device is cha- racterized in that the electrical resistance material con ⁇ sists of 1) an electrically, relatively non-conducting crys ⁇ talline, monomeric substance which melts within or near the predetermined narrow temperature interval and which forms the outer phase, 2) particles of one or several electrically con- r ducting materials distributed in the non-conducting substance,
  • the weight ratio between the components 1) and 3) shall be between 10:90 and 50:50.
  • the invention also relates to the electrical resistance mate- rial as such.
  • the change in resistivity per degree Celsius for the electri ⁇ cal resistance material according to the invention is smaller at lower temperatures than within the predetermined narrow tem- perature interval.
  • the resistivity of the previously known com ⁇ positions of meltable onomeric substances and conducting par ⁇ ticles is not constant within temperature ranges above the interval where the resistivity is rapidly increasing, but drops from its maximum by up to a power of 10 per 20°C.
  • the slope below the critical temperature interval is less steep and the decrease above is only very small if the mixtures contain one or several non-conducting fillers which are insoluble in the non-conducting material. It is-, important that this decrease above is as small as possible, since a large decrease may cause the resistivity to be so low that the device will develop power again. / ' > r
  • the power development in the compositions should not exceed 5 watts per cm 3 , preferably not
  • the resis ⁇ tivity values of the compositions should be greater than 0 ohm cm, preferably greater than 10 ohm cm.
  • compositions accor ⁇ ding to the invention have higher thermal conductivity than previously known compositions.
  • composition according to the invention may be a case in which the filler is present in such a amount and shape that the mixture below the swit ⁇ ching point is composed of separate particles surrounded by the components 1) and 2). This facilitates the design of hea- ting devices in which it is desired to change the shape of the device.
  • Substances with a melting point interval of a maximum of 10°C are preferred; preferably the melting point interval shall not exceed 5°C. It is advantageous if the molecular weight of the substances is less than 1000, preferably less than 500.
  • Especially suitable and preferred substances are organic com ⁇ pounds or mixtures of such compounds which contain polar groups, e.g. carboxyli ⁇ or alcohol groups.
  • Suitable polar organic com- pounds which are excellent to use as relatively n ⁇ ' n-conduc- ting meltable substances according to the present invention, are, for example, carboxyli ⁇ acids, esters or alcohols.
  • particles of one or several electrically con- ' ducting materials such particles of metal, e.g. copper, are used.
  • particles of electrically con ⁇ ducting metal compounds e.g. oxides, sulfides and carbides, and particles of carbon, such as soot or graphite, which can be amorphous or crystalline, silicon carbide or other elect ⁇ rically conducting particles.
  • the electrically conducting par ⁇ ticles may be in the form of grains, flakes or needles, or they may have other shapes. Several types of conducting par- tides can also be used as a mixture.
  • Particles of carbon have proved to be suitable.
  • a particularly suitable electrically conducting carbon material is carbon black with a small ac ⁇ tive surface.
  • the amount of component 2 is determined by the desired resistivity range. Generally the component 2 is used in amounts between 5 and 50 parts by weight per- 100 parts by weight of component 1. When metal powder is used, it may be necessary to use larger amounts than 50 parts by weight per 100 parts by weight of component 1.
  • non-conducting powdered, flake-shaped or fibrous fillers which are insoluble in the non-conducting substance, there are used, for example, silica quartz, chalk, finely dis ⁇ persed silica, such as Aerosil R , short glass fibres, polyme ⁇ ric materials insoluble in component 1 ,or other inert, inso- luble fillers.
  • suitable fillers are fillers which are good thermal conductors, e.g. magnesium oxide.
  • the mixtures of the components 1) , 2) and 3) can be made in various types of mixers, e.g. in a Brabender mixer,or a rol- ling mill.
  • the mixing process is suitably performed at a tem ⁇ perature above the melting point for component 1) .
  • One or se ⁇ veral heat treatments of the mixtures after the mixing pro ⁇ cess to temperatures above the melting point of the meltable substance, causes the temperature-resistivity curves after re- peated measurements to coincide to a greater extent than with ⁇ out heat treatments.
  • the electrical conductors connectable to a voltage source in the self-limiting electrical heating device according to the invention may be of copper, aluminium or other electrical con ⁇ ductor materials and they may be tinned, silver-coated or sur ⁇ face treated in other ways to improve the contact properties, the corrosion resistance and the heat resistance.
  • the conduc ⁇ tors can be solid with round, rectangular or other cross-sec ⁇ tional shape. They can also exist in the form of strands, foils, nets, tubes, fabrics or other non-solid shapes.
  • the narrow temperature interval within which the resistivity of the electrical resistance material is drasticly changed is a temperature range of about 50°C at the most, preferably of about 20°C at the most.
  • spacers are used in order to maintain the distance between the electrical conductors connectable to a voltage source, when the electrically non-conducting material is in the molten state, there can be used elements of electrically non-conduc- ting materials, such as glass, asbestos or other inorganic ma ⁇ terials, cotton, cellulose, plastics, rubber or other natural or synthetic organic materials.
  • the distance elements can be incorporated in the electrical r resistance material in the form of wire, yarn, net,- lattice or foam material.
  • the incorporated distance elements have such a shape or/and packing degree that they alone, or together with the insulating cover,prevent the electrical conductors con ⁇ nectable to a voltage source from changing their relative po- sition when the electrically relatively non-conducting resis ⁇ tance material is in the molten state.
  • the insu ⁇ lating cover alone may constitute the distance element by the electrical conductors being attached' to the cover or by the insulating cover being so shaped that it prevents relative movement between the electrical conductors.
  • the insulating cover can be of plastic, rubber or consist of other insulating materials, e.g. polyethylene, crosslinked po- lyethylene, polyvinylchloride polypropylene, natural rubber, synthetic rubber or other natural or synthetic polymers.
  • fig. 1 shows a cross-section of a heating cable according to the present invention, where the distance between the electrical conductors (1), between which an electrical resistance material (2) is positioned, is main ⁇ tained permanently by an insulating cover (3) which forms the spacer;
  • Fig. 2 shows a cross-section of a heating cable according to the invention, where the spacer in the form of glass fibre fab ⁇ ric is incorporated in the electrical resistance material (4) .
  • Fig. 3 shows a cross-section of a heating cable according to the invention, where the outer conductor (6) is formed by a copper foil and where the spacer in the form of glass fibre fabric has been incorporated in the electrical resistance ma ⁇ terial (4) ; and J 'r.
  • Fig. 4 shows a cross-section of a heating cable according to the invention, where a plastic profile (5) forms the spacer.
  • Figures 5 and 6 show curves which have been measured in the examples 1-14 for the relationship resistivity - temperature.
  • Example 7 Stearyl alcohol 100 parts by weight Polymamide 11 powder 600 - " - Printex 300 17,5 - " -
  • Example 10 Stearic acid 100 parts by weight Printex 300 15 - " -
  • Example 11 (comparison) Paraffin, melting point 48-52°C 100 parts by weight Flammruss 101 20 - " -
  • Example 12 Stearic acid 100 parts by weight Silica quartz powder 150 - # - Polyamide 11 powder 100 - * - Printex 300 17,5 - '" -
  • Example 13 Stearic acid 100 parts by weight Silica quartz powder 300 - " - Grafit W-95 20 - " - Printex 300 8 - " - '
  • the current intensity was 0,5 A when switching on the cable.
  • the cable was put into a heating chamber with a temperature of 60°C.
  • the current intensity was less than 1 mA, showing that the resistance between the con ⁇ ductors in the cable had risen to above 200,000 ohms, the re ⁇ sistivity of the resistance material had increased by about 500 times its value at room temperature.
  • Printex 17 - " The switching temperature, that is the temperature of which the resistivity changes by leaps, was determined.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Ceramic Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Resistance Heating (AREA)
  • Thermistors And Varistors (AREA)
PCT/SE1983/000382 1982-11-12 1983-11-08 Self-limiting heater and resistance material WO1984002048A1 (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
DE8383903611T DE3378346D1 (en) 1982-11-12 1983-11-08 Self-limiting heater and resistance material
JP83503580A JPS59502161A (ja) 1982-11-12 1983-11-08 自己制御電気加熱装置
AT83903611T ATE38306T1 (de) 1982-11-12 1983-11-08 Selbstbegrenzender erhitzer und widerstandsmaterial.
NO842836A NO163430C (no) 1982-11-12 1984-07-11 Elektrisk motstandsmateriale med pct-egenskaper.
FI844891A FI80820C (sv) 1982-11-12 1984-12-11 Självreglerande elektrisk uppvärmningsanordning

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE8206442A SE433999B (sv) 1982-11-12 1982-11-12 Sjelvbegrensande elektrisk uppvermningsanordning och elektriskt motstandsmaterial

Publications (1)

Publication Number Publication Date
WO1984002048A1 true WO1984002048A1 (en) 1984-05-24

Family

ID=20348565

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1983/000382 WO1984002048A1 (en) 1982-11-12 1983-11-08 Self-limiting heater and resistance material

Country Status (8)

Country Link
US (1) US4629869A (sv)
EP (1) EP0140893B1 (sv)
JP (1) JPS59502161A (sv)
CA (1) CA1207467A (sv)
DE (1) DE3378346D1 (sv)
FI (1) FI80820C (sv)
SE (1) SE433999B (sv)
WO (1) WO1984002048A1 (sv)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0169019A1 (en) * 1984-07-11 1986-01-22 RAYCHEM CORPORATION (a Delaware corporation) Method for converting a fluid tracing system into an electrical tracing system
EP0338552A2 (en) * 1988-04-22 1989-10-25 Thermon Manufacturing Company Flexible, elongated positive temperature coefficient heating assembly and method

Families Citing this family (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5148005A (en) * 1984-07-10 1992-09-15 Raychem Corporation Composite circuit protection devices
US5089688A (en) * 1984-07-10 1992-02-18 Raychem Corporation Composite circuit protection devices
US5064997A (en) * 1984-07-10 1991-11-12 Raychem Corporation Composite circuit protection devices
JPS62131065A (ja) * 1985-12-03 1987-06-13 Idemitsu Kosan Co Ltd 高分子正温度特性組成物
US4849611A (en) * 1985-12-16 1989-07-18 Raychem Corporation Self-regulating heater employing reactive components
FR2603133B1 (fr) * 1986-08-21 1990-04-06 Electricite De France Element chauffant autoregulant et son procede de preparation
JPH0777161B2 (ja) * 1986-10-24 1995-08-16 日本メクトロン株式会社 Ｐｔｃ組成物、その製造法およびｐｔｃ素子
US5250226A (en) * 1988-06-03 1993-10-05 Raychem Corporation Electrical devices comprising conductive polymers
US5925276A (en) * 1989-09-08 1999-07-20 Raychem Corporation Conductive polymer device with fuse capable of arc suppression
US5045673A (en) * 1990-04-04 1991-09-03 General Signal Corporation PTC devices and their composition
US5198639A (en) * 1990-11-08 1993-03-30 Smuckler Jack H Self-regulating heated mirror and method of forming same
US5558794A (en) * 1991-08-02 1996-09-24 Jansens; Peter J. Coaxial heating cable with ground shield
US5749118A (en) * 1993-02-05 1998-05-12 Holland; Dewey T. Heated wiper blade
US5556576A (en) * 1995-09-22 1996-09-17 Kim; Yong C. Method for producing conductive polymeric coatings with positive temperature coefficients of resistivity and articles made therefrom
DE10325517A1 (de) * 2003-06-05 2004-12-23 Hew-Kabel/Cdt Gmbh & Co. Kg Elektrische Heizleitung oder Heizband
US20050167134A1 (en) * 2004-02-02 2005-08-04 Philippe Charron Heating cable substantially free from electromagnetic field
US20080000039A1 (en) * 2006-06-28 2008-01-03 Eugene Higgs Heated Wiper Assembly
JP5278316B2 (ja) * 2007-01-22 2013-09-04 パナソニック株式会社 面状発熱体
US10959295B2 (en) 2016-05-10 2021-03-23 Nvent Services Gmbh Shielded wire for high voltage skin effect trace heating
US11006484B2 (en) 2016-05-10 2021-05-11 Nvent Services Gmbh Shielded fluoropolymer wire for high temperature skin effect trace heating
DE102019132997A1 (de) * 2019-12-04 2021-06-10 Eichenauer Heizelemente Gmbh & Co. Kg Behälterheizung
DE102021213401A1 (de) * 2021-11-09 2023-05-11 Robert Bosch Gesellschaft mit beschränkter Haftung Wischblatt, insbesondere für ein Kraftfahrzeug
US11904815B1 (en) 2022-11-17 2024-02-20 Robert Bosch Gmbh Wiper blade, in particular for a motor vehicle

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE85642C1 (sv) *
GB675752A (en) * 1947-11-24 1952-07-16 Standard Telephones Cables Ltd Improvements in or relating to electrical resistors
DE2103319B2 (de) * 1970-01-27 1974-01-31 Texas Instruments Inc., Dallas, Tex. (V.St.A.) Elektrisches Heizelement aus einem Polymer mit elektrisch leitenden Teilchen
DE2634931A1 (de) * 1975-08-04 1977-05-26 Raychem Corp Gegenstaende mit ptc-verhalten, verfahren zu ihrer herstellung sowie formmassen zur herstellung dieser gegenstaende

Family Cites Families (5)

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Publication number Priority date Publication date Assignee Title
CH181635A (de) * 1933-11-25 1935-12-31 Rca Corp Verfahren zur Herstellung eines elektrischen Widerstandsmaterials.
US3243753A (en) * 1962-11-13 1966-03-29 Kohler Fred Resistance element
US4388607A (en) * 1976-12-16 1983-06-14 Raychem Corporation Conductive polymer compositions, and to devices comprising such compositions
US4200973A (en) * 1978-08-10 1980-05-06 Samuel Moore And Company Method of making self-temperature regulating electrical heating cable
US4304987A (en) * 1978-09-18 1981-12-08 Raychem Corporation Electrical devices comprising conductive polymer compositions

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE85642C1 (sv) *
GB675752A (en) * 1947-11-24 1952-07-16 Standard Telephones Cables Ltd Improvements in or relating to electrical resistors
DE2103319B2 (de) * 1970-01-27 1974-01-31 Texas Instruments Inc., Dallas, Tex. (V.St.A.) Elektrisches Heizelement aus einem Polymer mit elektrisch leitenden Teilchen
DE2634931A1 (de) * 1975-08-04 1977-05-26 Raychem Corp Gegenstaende mit ptc-verhalten, verfahren zu ihrer herstellung sowie formmassen zur herstellung dieser gegenstaende

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0169019A1 (en) * 1984-07-11 1986-01-22 RAYCHEM CORPORATION (a Delaware corporation) Method for converting a fluid tracing system into an electrical tracing system
US4661687A (en) * 1984-07-11 1987-04-28 Raychem Corporation Method and apparatus for converting a fluid tracing system into an electrical tracing system
EP0338552A2 (en) * 1988-04-22 1989-10-25 Thermon Manufacturing Company Flexible, elongated positive temperature coefficient heating assembly and method
EP0338552A3 (en) * 1988-04-22 1991-04-10 Thermon Manufacturing Company Flexible, elongated positive temperature coefficient heating assembly and method

Also Published As

Publication number Publication date
CA1207467A (en) 1986-07-08
SE433999B (sv) 1984-06-25
FI80820B (fi) 1990-03-30
EP0140893B1 (en) 1988-10-26
DE3378346D1 (en) 1988-12-01
EP0140893A1 (en) 1985-05-15
FI844891L (fi) 1984-12-11
US4629869A (en) 1986-12-16
FI844891A0 (fi) 1984-12-11
JPS59502161A (ja) 1984-12-27
SE8206442D0 (sv) 1982-11-12
SE8206442L (sv) 1984-05-13
FI80820C (sv) 1990-07-10

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