US2861163A - Heating element - Google Patents

Heating element Download PDF

Info

Publication number
US2861163A
US2861163A US59728856A US2861163A US 2861163 A US2861163 A US 2861163A US 59728856 A US59728856 A US 59728856A US 2861163 A US2861163 A US 2861163A
Authority
US
Grant status
Grant
Patent type
Prior art keywords
material
particles
resistance
finely divided
conductive
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
Application number
Inventor
Asakawa George
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Antioch College
Original Assignee
Antioch College
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
Grant date

Links

Images

Classifications

    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR
    • H05B3/00Ohmic-resistance heating
    • H05B3/10Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12Heater 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
    • H05B3/14Heater 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
    • H05B3/146Conductive polymers, e.g. polyethylene, thermoplastics
    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHTING NOT OTHERWISE PROVIDED FOR
    • H05B3/00Ohmic-resistance heating
    • H05B3/40Heating elements having the shape of rods or tubes
    • H05B3/54Heating elements having the shape of rods or tubes flexible
    • H05B3/56Heating cables

Description

Nov. 18, 1958 e. ASAKAWA HEATING ELEMENT Filed July 11, 1956 INVENTOR. 650,956 Asa/mm 5mm 015m, [my/7% United States Patent O HEATING ELEMENT Application July 11, 1956, Serial No. 597,288

8 Claims. (Cl. 201-72) This invention relates to an electrical resistance heating element, useful for example as the heat source in an electric blanket.

Objects of the invention are to provide an electrical resistance element wherein:

(1) The heat output of the element is automatically regulated without using any extraneous thermostat mechanisms, and

(2) The element is capable of formation by low cost extrusion processes.

Other objects of this invention will appear in the following description and appended claims, reference being had to the accompanying drawing forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

In-the drawings: 7 V

Fig. l is a sectional view through a resistance heating element constituting one embodiment of the invention.

Fig. 2 is a sectional view through a second embodiment of the invention.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

In Fig. 1 of the drawings there is shown a resistance heating element 2 including a core or strand of partially conductive material 4 and a covering of dielectric material 5. The term partially conductive is used to indicate a material wherein a portion of the material is a conductor of electricity and another portion is a nonconductor of electricity. The conductor portion comprises finely divided conductive particles 6, and the nonconductive portion comprises a dielectric thermally expansible material 8.

Particles 6 are thoroughly mixed or dispersed in material 8 so as to define a number of electrically conductive paths through core 4. The conductive particles may be formed of different materials, as for example carbon, a metal such as copper or aluminum, silicon, silicon carbide, lead sulfide, iron sulfide or molybdenum sulfide. I have found carbon in the form of carbon black to be most suitable.

The volumetric proportions of. conductive particles 6 and expansible material 8 vary somewhat depending on the nature of the conductor and its particle size. Metals, in particle sizes larger than about 40 microns, for example, preferably comprise about 75 percent of the core volume. In the case of carbon black, in particle size of about 20-500 millimicrons, the conductor preferably occupies about 40 percent of the core volume.

Although, as indicated, I may use relatively larger particle sizes (e. g. 40 microns) in relatively higher volumetric proportion (e. g. 75 percent), I have found that r 1 2,861,163 Ce Patented Nov. 18, 1958 the most suitable compositions are those which include a more finely divided conductor (e. g. 20-500 millimicrons) in a relatively smaller proportion (e. g. 40 percent). It is probably for this reason that carbon black has been found to be the most suitable conductor. In addition to its contribution in the form of small particles, carbon black has stability at high temperatures and proper resistance at low concentration.

, The purpose of thermally expansible material 8 is to 1) spread conductive particles 6 apart as the temperature of core 4 is increased, and (2) thereby increase the resistance of core 4 to current flow. The increased resistance is effective to choke ofi the current through core 4 so as to regulate the heat output at a desired maximum value. The thermally expansible, non-conductive material may be formed of different materials, as for example waxes, paraflin, polyethylene or polysiloxane. The term thermally expansible material will be understood to refer to a material which undergoes a substantial increase in its volumetric displacement when I its temperature is increased. The term non-conductive will be understood as being used in a relative sense to indicate a material having substantially greater resistance to current fiow than the dispersed conductive particles, it being appreciated that the non-conductive material conducts small quantities of electricity but offers a. higher resistance to its passage than the conductive particles.

Covering 5 may include one or more dielectric materials, as for example a coating of nylon immediately adjacent core 4 and an outer coating of polyethylene or rubberQfor moisture resistance. Core 4 may be formed bya low cost extrusion operation and cut to desired length after application of covering 5.

Operation of the Fig. 1 element is such that when element 2 is first connected into an electrical circuit particles 8 are quite close together so as to form a great number of conductive paths through material 4. Continued current flow through material 4 heats up expansion material 8. Material 8 is thereby expanded so as to spread particles 6 apart. Spreading of particles 6 apart increases the effective resistance of material 4 to current flow and thereby regulates the current and wattage through the element. As a result the heat developed by the current flow is regulated at a desired maximum value in accordance with the transition temperature range of the particular material chosen for material 8. It will be understood that different ones of the expansion materials undergo the major portions of their expansions at difierent temperatures or different temperature ranges. The higher the expansion temperature of a given expansion material the greater will be the regulated heat output of the resistance element. Of course the length and cross sectional area of the element will also be factors in determining the total heat output.

It is contemplated that a plurality of resistance elements, each containing a different expansion material, could be incorporated into a heating blanket or other heating device. By connecting the various elements to dilferent ones of the terminals on a conventional multistep switch difierent heat levels may be obtained in accordance with the switch setting.

The Fig. 2 construction is in many respects similar to the Fig. 1 construction, and similar reference numerals are employed wherever applicable. The essential difference between the Fig. 1 construction and the Fig. 2 construction is that the Fig. 2 construction includes a continuous length of conductive high resistance wire 10, preferably formed of Nichrome. The purpose of wire 10 is to provide for continued current flow in the event that broken spots or gaps should be formed in mate rial 4. Preferably the diameter of the wire is so chosen that the resistance of the wire is more than the cold temperature resistance of material 4'. By using a relatively thin high resistance wire the heat output of the Wire can be held at a minimum and the action of material 4 whereby its resistance increases with temperature increase can be retained. Wire 10 can be economically incorporated into the element by utilizing Wire 10 as the core around which material 4 is extruded during formation ofthe element.

I claim:

1. An electrical resistance element comprising a wirelike strand of partially conductive material; said strand of material being formed of solid, finely divided electrically conductive particles dispersed in a softenable thermally expansible dielectric material; and a covering of solid sealing material surrounding said strand, said covering material being a non-conductor of electricity;

whereby the finely divided particles are caused to develop heat during the passage of an electric current, with said thermally expansible' dielectric material undergoing a volumetric expansion so as to increase the spacing between adjacent ones of the finely divided particles in such manner as to control current flow through the strand and thereby limit its heat output.

2. The combination of claim 1 wherein the conductive particles are carbon. v

3. The combination of claim 1 wherein the expansible material is polyethylene.

4. The combination of claim 1 wherein the finely divided particles are of a particle size in the range of about 20 millimicrons to about 40 microns, and the finely divided particles occupy between 40% and 75% of the partially conductive material volume. v

5. The combination of claim 1 wherein the finely divided particles have a particle size of about 40 microns, and the finely divided particles occupy about 75% ofthe partially conductive material volume,

6. The combination of claim 1 wherein the finely divided particles have a particle size in the range of about 20500 millimicrons, and the finely divided particles occupy about 40% of the partially conductive material volume.

7. The combination of claim 1 wherein the finely divided particles are carbon black having a particle size in the range of about 20500 millimicrons; the finely divided particles occupy about of the partially conductive material volume; and the thermally expansible material is polyethylene.

8. An electrical resistance element comprising a wirelike strand of partially conductive material; said strand of material being formed of solid finely divided electrically conductive particles dispersed in a softenable thermally expansible non-conductive material; a continuous strand of conductive-resistive material extending along the partially conductive material; said conductive-resistive material having a higher electrical resistance than the partially conductive material; and a covering of solid sealing material surrounding said partially conductive material; said covering material being a non-conductor of electricity; whereby the finely divided particles are caused to develop heat during the passage therethrough of an electric current, with said thermally expansible material undergoing a volumetric expansion so as to increase the' spacing between adjacent ones of the finely divided particles in such manner as to control current flow through the strand and thereby limit its heat output.

References Cited in the file of this patent UNITED STATES PATENTS

US2861163A 1956-07-11 1956-07-11 Heating element Expired - Lifetime US2861163A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US2861163A US2861163A (en) 1956-07-11 1956-07-11 Heating element

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US2861163A US2861163A (en) 1956-07-11 1956-07-11 Heating element

Publications (1)

Publication Number Publication Date
US2861163A true US2861163A (en) 1958-11-18

Family

ID=24390880

Family Applications (1)

Application Number Title Priority Date Filing Date
US2861163A Expired - Lifetime US2861163A (en) 1956-07-11 1956-07-11 Heating element

Country Status (1)

Country Link
US (1) US2861163A (en)

Cited By (45)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3138686A (en) * 1961-02-01 1964-06-23 Gen Electric Thermal switch device
US3167255A (en) * 1961-05-08 1965-01-26 Sames Mach Electrostat Electrostatic sprayer system having a separate high resistivity conductor
US3204066A (en) * 1961-10-24 1965-08-31 Gen Electric Thermal-electrical control device having thermally expansive material as a switch actuator
US3238355A (en) * 1962-12-10 1966-03-01 Douglas Aircraft Co Inc Particle filled conductor
US3309643A (en) * 1964-01-02 1967-03-14 Massachusetts Inst Technology Electric heating element
US3410984A (en) * 1966-05-03 1968-11-12 Gen Electric Flexible electrically heated personal warming device
US3412358A (en) * 1966-09-09 1968-11-19 Gulton Ind Inc Self-regulating heating element
US3435401A (en) * 1966-10-05 1969-03-25 Texas Instruments Inc Insulated electrical conductors
US3489884A (en) * 1966-12-28 1970-01-13 Texas Instruments Inc Heated windshield wiper and blade therefor
US3501619A (en) * 1965-07-15 1970-03-17 Texas Instruments Inc Self-regulating thermal apparatus
US3513297A (en) * 1967-05-31 1970-05-19 Gulton Ind Inc Heat radiating articles
US3564199A (en) * 1968-12-30 1971-02-16 Texas Instruments Inc Self-regulating electric fluid-sump heater
US3584190A (en) * 1970-02-27 1971-06-08 Texas Instruments Inc Self-regulating heat applicator
US3617694A (en) * 1970-01-27 1971-11-02 Texas Instruments Inc Electrical contact means for hair curler having elongated annular heater
US3617695A (en) * 1970-01-27 1971-11-02 Texas Instruments Inc Electrical contact means for hair curler having elongated annular heater
US3619560A (en) * 1969-12-05 1971-11-09 Texas Instruments Inc Self-regulating thermal apparatus and method
US3632971A (en) * 1970-01-27 1972-01-04 Texas Instruments Inc Self-limiting electric hair curler heater
US3646315A (en) * 1967-12-20 1972-02-29 Texas Instruments Inc Self-regulated heating device
US3662149A (en) * 1969-09-16 1972-05-09 Braun Pebra Gmbh Heated lock for motorcars
US3689736A (en) * 1971-01-25 1972-09-05 Texas Instruments Inc Electrically heated device employing conductive-crystalline polymers
US3973100A (en) * 1972-12-27 1976-08-03 Texas Instruments Incorporated Self-limiting electric hair curler heater
US4000647A (en) * 1971-07-31 1977-01-04 Dornier Gmbh Heating device for flow sondes
US4088269A (en) * 1975-11-06 1978-05-09 Vdo Adolf Schindling Ag Electrically heated windshield washer spray nozzle assembly
US4162395A (en) * 1975-11-07 1979-07-24 Murata Manufacturing Co., Ltd. Heating unit for heating fluid
US4212425A (en) * 1978-02-27 1980-07-15 Vdo Adolf Schindling Ag. Electrically heated windshield washer spray nozzle assembly
US4213031A (en) * 1976-10-21 1980-07-15 Bosch-Siemens Hausgerate Gmbh Heat sealing roller having a temperature self-controlled PTC heating resistor for welding thermoplastic foils
US4250631A (en) * 1979-01-24 1981-02-17 Leonard Moses Tobacco-pipe holder and dryer
US4313101A (en) * 1978-05-18 1982-01-26 Hotfoil Limited Electrically impedant articles
US4315237A (en) * 1978-12-01 1982-02-09 Raychem Corporation PTC Devices comprising oxygen barrier layers
US4352008A (en) * 1979-01-26 1982-09-28 Firma Fritz Eichenauer Electric heating device for heating the interior of a switch cabinet
US4354092A (en) * 1978-10-05 1982-10-12 Matsushita Electric Industrial Co., Ltd. Electric hair curling iron with rechargeable battery power supply
US4470898A (en) * 1973-03-20 1984-09-11 Raychem Limited Polymer compositions for electrical use
US4574187A (en) * 1980-08-29 1986-03-04 Sprague Electric Company Self regulating PTCR heater
US4576827A (en) * 1984-04-23 1986-03-18 Nordson Corporation Electrostatic spray coating system
EP0180274A1 (en) * 1984-11-01 1986-05-07 Danny Zimmerman Electrical heating element
US4650972A (en) * 1985-10-04 1987-03-17 Emerson Electric Co. Heating cable and method of making same
US4739935A (en) * 1986-03-12 1988-04-26 Nordson Corporation Flexible voltage cable for electrostatic spray gun
US5228460A (en) * 1991-12-12 1993-07-20 Philip Morris Incorporated Low mass radial array heater for electrical smoking article
US5802709A (en) * 1995-08-15 1998-09-08 Bourns, Multifuse (Hong Kong), Ltd. Method for manufacturing surface mount conductive polymer devices
US5849129A (en) * 1995-08-15 1998-12-15 Bourns Multifuse (Hong Kong) Ltd. Continuous process and apparatus for manufacturing conductive polymer components
US6020808A (en) * 1997-09-03 2000-02-01 Bourns Multifuse (Hong Kong) Ltd. Multilayer conductive polymer positive temperature coefficent device
US6172591B1 (en) 1998-03-05 2001-01-09 Bourns, Inc. Multilayer conductive polymer device and method of manufacturing same
US6228287B1 (en) 1998-09-25 2001-05-08 Bourns, Inc. Two-step process for preparing positive temperature coefficient polymer materials
US6236302B1 (en) 1998-03-05 2001-05-22 Bourns, Inc. Multilayer conductive polymer device and method of manufacturing same
US6429533B1 (en) 1999-11-23 2002-08-06 Bourns Inc. Conductive polymer device and method of manufacturing same

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2322773A (en) * 1941-07-28 1943-06-29 Melville F Peters Electrical conductor
US2412701A (en) * 1941-02-27 1946-12-17 Nat Carbon Co Inc Brush for electrical machinery

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2412701A (en) * 1941-02-27 1946-12-17 Nat Carbon Co Inc Brush for electrical machinery
US2322773A (en) * 1941-07-28 1943-06-29 Melville F Peters Electrical conductor

Cited By (48)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3138686A (en) * 1961-02-01 1964-06-23 Gen Electric Thermal switch device
US3167255A (en) * 1961-05-08 1965-01-26 Sames Mach Electrostat Electrostatic sprayer system having a separate high resistivity conductor
US3204066A (en) * 1961-10-24 1965-08-31 Gen Electric Thermal-electrical control device having thermally expansive material as a switch actuator
US3238355A (en) * 1962-12-10 1966-03-01 Douglas Aircraft Co Inc Particle filled conductor
US3309643A (en) * 1964-01-02 1967-03-14 Massachusetts Inst Technology Electric heating element
US3501619A (en) * 1965-07-15 1970-03-17 Texas Instruments Inc Self-regulating thermal apparatus
US3410984A (en) * 1966-05-03 1968-11-12 Gen Electric Flexible electrically heated personal warming device
US3412358A (en) * 1966-09-09 1968-11-19 Gulton Ind Inc Self-regulating heating element
US3435401A (en) * 1966-10-05 1969-03-25 Texas Instruments Inc Insulated electrical conductors
US3489884A (en) * 1966-12-28 1970-01-13 Texas Instruments Inc Heated windshield wiper and blade therefor
US3513297A (en) * 1967-05-31 1970-05-19 Gulton Ind Inc Heat radiating articles
US3646315A (en) * 1967-12-20 1972-02-29 Texas Instruments Inc Self-regulated heating device
US3564199A (en) * 1968-12-30 1971-02-16 Texas Instruments Inc Self-regulating electric fluid-sump heater
US3662149A (en) * 1969-09-16 1972-05-09 Braun Pebra Gmbh Heated lock for motorcars
US3619560A (en) * 1969-12-05 1971-11-09 Texas Instruments Inc Self-regulating thermal apparatus and method
US3617694A (en) * 1970-01-27 1971-11-02 Texas Instruments Inc Electrical contact means for hair curler having elongated annular heater
US3617695A (en) * 1970-01-27 1971-11-02 Texas Instruments Inc Electrical contact means for hair curler having elongated annular heater
US3632971A (en) * 1970-01-27 1972-01-04 Texas Instruments Inc Self-limiting electric hair curler heater
US3584190A (en) * 1970-02-27 1971-06-08 Texas Instruments Inc Self-regulating heat applicator
US3689736A (en) * 1971-01-25 1972-09-05 Texas Instruments Inc Electrically heated device employing conductive-crystalline polymers
US4000647A (en) * 1971-07-31 1977-01-04 Dornier Gmbh Heating device for flow sondes
US3973100A (en) * 1972-12-27 1976-08-03 Texas Instruments Incorporated Self-limiting electric hair curler heater
US4470898A (en) * 1973-03-20 1984-09-11 Raychem Limited Polymer compositions for electrical use
US4088269A (en) * 1975-11-06 1978-05-09 Vdo Adolf Schindling Ag Electrically heated windshield washer spray nozzle assembly
US4162395A (en) * 1975-11-07 1979-07-24 Murata Manufacturing Co., Ltd. Heating unit for heating fluid
US4213031A (en) * 1976-10-21 1980-07-15 Bosch-Siemens Hausgerate Gmbh Heat sealing roller having a temperature self-controlled PTC heating resistor for welding thermoplastic foils
US4212425A (en) * 1978-02-27 1980-07-15 Vdo Adolf Schindling Ag. Electrically heated windshield washer spray nozzle assembly
US4313101A (en) * 1978-05-18 1982-01-26 Hotfoil Limited Electrically impedant articles
US4354092A (en) * 1978-10-05 1982-10-12 Matsushita Electric Industrial Co., Ltd. Electric hair curling iron with rechargeable battery power supply
US4315237A (en) * 1978-12-01 1982-02-09 Raychem Corporation PTC Devices comprising oxygen barrier layers
US4250631A (en) * 1979-01-24 1981-02-17 Leonard Moses Tobacco-pipe holder and dryer
US4352008A (en) * 1979-01-26 1982-09-28 Firma Fritz Eichenauer Electric heating device for heating the interior of a switch cabinet
US4574187A (en) * 1980-08-29 1986-03-04 Sprague Electric Company Self regulating PTCR heater
US4576827A (en) * 1984-04-23 1986-03-18 Nordson Corporation Electrostatic spray coating system
EP0180274A1 (en) * 1984-11-01 1986-05-07 Danny Zimmerman Electrical heating element
US4687903A (en) * 1984-11-01 1987-08-18 Danny Zimmerman Thermostatically controlled electrically heated soldering bit
US4650972A (en) * 1985-10-04 1987-03-17 Emerson Electric Co. Heating cable and method of making same
US4739935A (en) * 1986-03-12 1988-04-26 Nordson Corporation Flexible voltage cable for electrostatic spray gun
US5228460A (en) * 1991-12-12 1993-07-20 Philip Morris Incorporated Low mass radial array heater for electrical smoking article
US5802709A (en) * 1995-08-15 1998-09-08 Bourns, Multifuse (Hong Kong), Ltd. Method for manufacturing surface mount conductive polymer devices
US5849129A (en) * 1995-08-15 1998-12-15 Bourns Multifuse (Hong Kong) Ltd. Continuous process and apparatus for manufacturing conductive polymer components
US5849137A (en) * 1995-08-15 1998-12-15 Bourns Multifuse (Hong Kong) Ltd. Continuous process and apparatus for manufacturing conductive polymer components
US6020808A (en) * 1997-09-03 2000-02-01 Bourns Multifuse (Hong Kong) Ltd. Multilayer conductive polymer positive temperature coefficent device
US6223423B1 (en) 1997-09-03 2001-05-01 Bourns Multifuse (Hong Kong) Ltd. Multilayer conductive polymer positive temperature coefficient device
US6172591B1 (en) 1998-03-05 2001-01-09 Bourns, Inc. Multilayer conductive polymer device and method of manufacturing same
US6236302B1 (en) 1998-03-05 2001-05-22 Bourns, Inc. Multilayer conductive polymer device and method of manufacturing same
US6228287B1 (en) 1998-09-25 2001-05-08 Bourns, Inc. Two-step process for preparing positive temperature coefficient polymer materials
US6429533B1 (en) 1999-11-23 2002-08-06 Bourns Inc. Conductive polymer device and method of manufacturing same

Similar Documents

Publication Publication Date Title
US3376403A (en) Bottom-hole electric heater
US3316345A (en) Prevention of icing of electrical conductors
US3582968A (en) Heaters and methods of making same
US3191151A (en) Programmable circuit
US3344385A (en) Flexible resistance element with flexible and stretchable terminal electrodes
US3414705A (en) Component oven
US5106540A (en) Conductive polymer composition
US4401885A (en) Planar heat generating device
US4358667A (en) Cartridge-type electric immersion heating element having an integrally contained thermostat
US5140297A (en) PTC conductive polymer compositions
US4845838A (en) Method of making a PTC conductive polymer electrical device
US4117312A (en) Self-limiting temperature electrical heating cable
US2581212A (en) Electrically heated fabric
US5057674A (en) Self limiting electric heating element and method for making such an element
US4845343A (en) Electrical devices comprising fabrics
US5195013A (en) PTC conductive polymer compositions
US2679569A (en) Electrically conductive film
US4821010A (en) Thermal cutoff heater
US3793716A (en) Method of making self limiting heat elements
US3947656A (en) Temperature controlled cartridge heater
US2790053A (en) Shielded ignition cable and resistors
US4574188A (en) Elongate electrical assemblies
US3584190A (en) Self-regulating heat applicator
US2274839A (en) Electrically heated hose
US3084242A (en) Electric heater wire