|Número de publicación||US2978665 A|
|Tipo de publicación||Concesión|
|Fecha de publicación||4 Abr 1961|
|Fecha de presentación||11 Jul 1956|
|Fecha de prioridad||11 Jul 1956|
|Número de publicación||US 2978665 A, US 2978665A, US-A-2978665, US2978665 A, US2978665A|
|Inventores||George Asakawa, Sergius Vernet|
|Cesionario original||Antioch College|
|Exportar cita||BiBTeX, EndNote, RefMan|
|Citas de patentes (5), Citada por (67), Clasificaciones (14)|
|Enlaces externos: USPTO, Cesión de USPTO, Espacenet|
April 4, 1961 s. VERNET ETAL 2,978,665
REGULATOR DEVICE FOR ELECTRIC CURRENT Filed July 11, 1956 INVENTOR Sees/us Vsmver 5y GEORGE AsAK/Ju/A 5mm, 0mm [my/W4;
partially conductive material 12.
mid-States tent REGULATOR DEVICE FOR ELECTRIC CURRENT Sergius ,Vernet and George Asakawa, Yellow Springs, Ohio, assignors, by direct and mesne assignments, to Antioch College, Yellow Springs, Ohio, a corporation of Ohio Filed ul 11, 1956, Ser. No. 597,292 6 Claims. (Cl. 338-223 load, thereby preventing any overload condition from existing for any substantial period of time,
(4) The device is responsive to ambient temperature and/or'current input for the performance of its current- The device automatically increases its resistance to current'fiow with increasing temperature before a maximum temperature is reached; thereby choking off the current before it becomes excessive and giving a very sensitivecurrent control action with a minimum fluctuation in current flow. I
Otherobjects of thisinvention will appear in the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in i the several views.
In the drawings: I
Fig. '1 is anelevational view of one embodiment of the invention.
' Fig. 2 is a plan view of'the Fig. l embodiment.
. Fig. 3 is an enlarged sectional view on line 3--3 in to be understood that the invention is not limited in its application to the details of construction and arrange .ment 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 thepurpose of description and not of limitation;
In the drawings' there'is shown a current regulating device 2 including two spaced electrodes 4 and 6. Each of electrodes 4 and 6 includesa circular disk 8 and a rod 10, both being formed of brass or other metal having the ability to conduct electric current.
Between disks 8 there is secured a disk or wafer of The term partially conductive is used to indicate a material wherein a portion of the material is conductive and another portionis non-conductive. Material 12 preferably comprises finely divided conductive particles dispersed in a mixture of (l) thermally expansible, non-conductive materialand 2) material preventing flow of the expansible material from' b'etweenthe electrodes in the transition temperature range of'said expansible material.
The purpose of the finely divided conductive particles is to impart a degree of electrical conductivity to material 12 by forming a number of conductive paths through said material. 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.
The purpose of the thermally expansible, non-conductive material is to (1) spread the conductive particles apart as the temperature of material 12 is increased, and (2) thereby increase the resistance of material 12 to current flow. The thermally expansible, non-conductive material may be formed of different materials, as for example waxes, parafiin, 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 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 flow 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.
The purpose of the flow-preventing material is to contain the 'expansible material when it is in a liquid or semi-liquidistate, as when it has undergone a transition from a lowtemperature contracted condition (in the solid state) to a higher temperature expanded condition (in the liquid or semi-liquid gel state). The flow-preventing material may, be formed of different materials, as for example rubber; a high melting plastic such as polytetrafluoroethylene, polymonochlorotrifiuoroethylene, polyadipamide, polyvinyl chloride or acrylonitrile resin; or a high melting wax. The term high melting as used herein refers to a material which is solid in the transition temperature range of the thermally expansiblemateri-al, i.e. a material which'changes from a solid to a liquid at a temperature above the transition temperature range of the expansible material.
Preferably the volumetric proportions of the component materials making up material 12 are about 40% conductive particles, 40% thermally expansible material and 20% flow-preventing material.
Mixing of the component materials together can be effected on a two-roll rubber mill. The product emerges from the rubber mill as a sheet of material. When relatively rigid materials such as polytetrafluoroethylene and polyethylene are used ascomponent materials the sheet of material is pulverized in a hammer mill and subsequently compressed into the desired wafer shape by suitable molding mechanisms. When relatively soft materials are used as components for material 12 the hammer mill operation can be omitted. Wafer 12 is secured against the inner faces of disks 8 by conventional bonding agents.
Operation of the illustrated device is such that when rods 10 are connected into an electrical circuit and the temperature of material 12 is relatively low the conductive particles are quite close together so as to form a great number of conductive paths through material 12. As the temperature of material 12 is increased (due to the passage of electric current and/or an increase in ambient temperature) the thermally expansible material expands. As the temperature nears and reaches the transition range of the expansible material there is a proportionately large increase in the volume of material 12, which spreads the conductive particles apart and causes a large increase in scrapes disks 8 occupying substantially the Fig. 3 dotted line position at full expansion. The precise positions of disks 8 are of course determined by the expansion characteristics of the expansible material and the relative amount of expansible material employed.
When the device is positioned in an atmosphere having changing temperature characteristics an increase in the ambient temperature will heat material 12 so as to expand the expansible material and thereby increase the resistance to current flow. In this way the current or wattage through the device can be controlled in accordance with the ambient atmosphere temperature. By proper choice of the expansible material it is possible to regulate the current in many temperature ranges. Also, the choice of expansible material may be used to determine the width of the range, from a few degrees to a wide range.
"When the device .is operated by electric current (as distinguished from ambient temperature) an increase in the input wattage willheat material 12, and the resultant increase in resistance will tend to choke off the current before a maximum temperature is reached. As a result the heating" capacity of the current is reduced and the temperature of material 12 is decreased so as to contract the expansible material and thereby establish an equilibrium current through the device. The character of the expansible material, particle size of the conductive particles, and the proportions of component materials will determine the current carried.
The above described choke ofilaction is in contrast to that of a conventional fuse wherein no increase in resistance is experienced until the fuse material melts. .By reason of the choke off action there is less wattage fluctuation because the resistance of the device is constantly changing to meet changingcurrent conditions/1t will also be understood that there is usually no off position of the device in the sense that current flow through the device is completely stopped. A certain amount of current is always free to flow through the device. a f i It will be noted that the diameter of wafer 12 is relatively large compared to its thickness. As a result the expansible material is very quickly enabled to expand and contract in response to changes in the temperature of material 12. When the device is operated by electric current the current is enabled to spread over the entire extent of disks 8 so as to subsequently travel through all portions of material 12. The small thickness of wafer 12 (preferably about .050 inch) gives relatively short current paths and thereby allows changes in current flow to be reflected almost immediately in volumetric changes of material 12. a
When the device is operated by ambient temperature changes disks 8 act to transfer heat between material '12 and the ambient atmosphere. The surface area of the disks is relatively large for the volume of material 12, and the heat transfer action is very rapid. Thisrapid heat transfer action contributes to the prevention of any undesired wattage variation by enabling quick volumetric change of material 12.
During the expansion andcontraction of material 12 the flow-preventing material must have a slight movement in accordance with the movement ofthe expansible material. However this movement is so slight that conventional plastics, waxes and rubbers can be employed .asfiow-preventing materials without difiiculty. The use of a mixed-in flow-preventing material is advantageous by reason 'of its extremely low cost. However it is contemplated that the flow-preventing materials could be distributed around the periphery of wafer 12 in order to perform the flow-preventing or sealing function. Also a rubber sleeve or rubber coated fabric sleeve or other non-conductive sheathing can be connected between the peripheral edges of disks 8 to perform the (sealing" function.
1. A current regulator comprising spaced electrodes; and partially conductive material therebetween; said material comprising finely divided carbon particles dispersed in a mixture of polyethylene and polytetrafluoroethylene; said polytetrafluoroethylene preventing flow of the polyethylene from between the electrodes in the transition temperature range of said polyethylene; whereby, during the passage of an electric current between the electrodes the carbon particles are caused to heat and expand the polyethylene so as to increase the spacing between adjacent ones of the carbon particles in such manner as to control the current flow through the partially conductive material.
2. A current regulator comprising spaced electrodes; and partially conductive material therebetween; said material comprising 40 volumetric parts finely divided carbon particles dispersed in a mixture of about 40 volumetric parts polyethylene and 20 volumetric parts polytetrafluoroethylene, said polytetrafluoroethylene preventing flow of the polyethylene from between the electrodes in the transition temperature range of said polyethylene; whereby, during the passage of an electric current between the electrodes the carbon particles are caused toheat and expand the polyethylene so as to increase the spacing between adjacent ones of the carbon particles in such manner as to control the current flow through the partial ly conductive material.
3. A current regulator comprising two parallel'electrically conductive disks spaced apart about .050 inch to'form spaced electrodes; and partially conductive material in the space therebetween; said material comprising solid finely divided electrically conductive particles dispersed ina mixture of (l) softenable thermally expansible non-conductive material and (2) solid non-com ductive flexible material preventing flow of the expansible material from between the disks in the transition temperature range of said expansible material; whereby, during the passage of an electric current between the disks the conductive particles are caused to heat the expansible material so as to increase the spacing between adjacent ones of the conductive particles in such manner as to control the current flow through the partially conductive material.
4.'A current regulator comprising spaced electrodes; and partially conductive material therebetween; said material comprising solid finely divided electrically conductive particles dispersed in a mixture of (l) softentable thermally expansible non-conductive polyethylene and (2) solid non-conductiye flexible material preventingflow of the expansible material from'between the electrodes in the transition temperature range of said expansible material; whereby, during the passage of an electric current between the electrodes the conductive particles are caused to heat the expansible material so as to increase the spacingbetween adjacent ones of the conductive particles in such manner as to control the current flow through the partially conductive materiaL' -,5. A current regulator comprising spaced electrodes; and partially conductive material therebetween; said material comprising solid finely divided electrically conductive particles dispersed in a mixture of (1) softenable -thermally expansible non-conductive 'materialand (2) solid non-conductive polytetrafluoroethylene preventing flow of the expansible material fi'om' between the electrodes in the transition temperature range of said expansible material; whereby, during the passage of an electric tive particles dispersed in a mixture of (1) softenable thermally expansible non-conductive material and (2) solid non-conductive flexible material preventing flow of the expansible material from between the electrodes in the transition temperature range of said expansible ma terial; whereby, during the passage of an electric current between the electrodes the conductive particles are caused to heat the expansible material so as to increase the spacing between adjacent ones of the conductive particles in such manner as to control the current flow through the partially conductive material; said flow-preventing material being selected from the group consisting of rubber and polytetrafluoroethylene.
6 References Cited in the file of this patent UNITED STATES PATENTS Benkelman Oct. 3, 1933 Ruben May 1, 1945 Edgar et al. Oct. 2, 1945 Brubaker et al. May 14, 1946 DAlelio Sept. 10, 1946 OTHER REFERENCES pages 103107.
|Patente citada||Fecha de presentación||Fecha de publicación||Solicitante||Título|
|US1929396 *||21 Abr 1930||3 Oct 1933||Continental Carbon Inc||Resistance element|
|US2375178 *||1 Oct 1941||1 May 1945||Samuel Ruben||Variable electrical resistor|
|US2386095 *||18 Feb 1944||2 Oct 1945||Du Pont||Heating device|
|US2400099 *||25 Oct 1943||14 May 1946||Du Pont||Process for obtaining shaped articles|
|US2407479 *||31 Oct 1939||10 Sep 1946||Gen Electric||Interpolymerization products|
|Patente citante||Fecha de presentación||Fecha de publicación||Solicitante||Título|
|US3138686 *||1 Feb 1961||23 Jun 1964||Gen Electric||Thermal switch device|
|US3164796 *||11 Sep 1961||5 Ene 1965||Phillips Petroleum Co||Compositions of graphite and polyethylene|
|US3204066 *||24 Oct 1961||31 Ago 1965||Gen Electric||Thermal-electrical control device having thermally expansive material as a switch actuator|
|US3238355 *||10 Dic 1962||1 Mar 1966||Douglas Aircraft Co Inc||Particle filled conductor|
|US3243753 *||13 Nov 1962||29 Mar 1966||Kohler Fred||Resistance element|
|US3327272 *||22 Jun 1964||20 Jun 1967||Stern Barry J||Negative resistance device|
|US3359521 *||26 Oct 1965||19 Dic 1967||Cognitronics Corp||Bistable resistance memory device|
|US3410984 *||3 May 1966||12 Nov 1968||Gen Electric||Flexible electrically heated personal warming device|
|US4177376 *||4 Ago 1975||4 Dic 1979||Raychem Corporation||Layered self-regulating heating article|
|US4237441 *||1 Dic 1978||2 Dic 1980||Raychem Corporation||Low resistivity PTC compositions|
|US4238812 *||1 Dic 1978||9 Dic 1980||Raychem Corporation||Circuit protection devices comprising PTC elements|
|US4318220 *||14 Feb 1980||9 Mar 1982||Raychem Corporation||Process for recovering heat recoverable sheet material|
|US4329726 *||30 Nov 1979||11 May 1982||Raychem Corporation||Circuit protection devices comprising PTC elements|
|US4330703 *||24 Sep 1979||18 May 1982||Raychem Corporation||Layered self-regulating heating article|
|US4352083 *||21 Abr 1980||28 Sep 1982||Raychem Corporation||Circuit protection devices|
|US4450496 *||26 Ene 1981||22 May 1984||Raychem Corporation||Protection of certain electrical systems by use of PTC device|
|US4517449 *||11 May 1983||14 May 1985||Raychem Corporation||Laminar electrical heaters|
|US4543474 *||6 Ene 1982||24 Sep 1985||Raychem Corporation||Layered self-regulating heating article|
|US4548662 *||23 Ene 1985||22 Oct 1985||Raychem Corporation||Method of providing a protective covering over a substrate|
|US4650972 *||4 Oct 1985||17 Mar 1987||Emerson Electric Co.||Heating cable and method of making same|
|US4764664 *||20 Nov 1985||16 Ago 1988||Raychem Corporation||Electrical devices comprising conductive polymer compositions|
|US4866253 *||15 Ago 1988||12 Sep 1989||Raychem Corporation||Electrical devices comprising conductive polymer compositions|
|US4876440 *||7 Feb 1989||24 Oct 1989||Raychem Corporation||Electrical devices comprising conductive polymer compositions|
|US4935156 *||27 Sep 1982||19 Jun 1990||Raychem Corporation||Conductive polymer compositions|
|US5174924 *||4 Jun 1990||29 Dic 1992||Fujikura Ltd.||Ptc conductive polymer composition containing carbon black having large particle size and high dbp absorption|
|US5294374 *||20 Mar 1992||15 Mar 1994||Leviton Manufacturing Co., Inc.||Electrical overstress materials and method of manufacture|
|US5382938 *||25 Oct 1991||17 Ene 1995||Asea Brown Boveri Ab||PTC element|
|US5537286 *||26 Jun 1992||16 Jul 1996||Raychem S.A.||Method of preparing planar PTC circuit protection devices|
|US5802709 *||16 Abr 1997||8 Sep 1998||Bourns, Multifuse (Hong Kong), Ltd.||Method for manufacturing surface mount conductive polymer devices|
|US5849129 *||16 Oct 1997||15 Dic 1998||Bourns Multifuse (Hong Kong) Ltd.||Continuous process and apparatus for manufacturing conductive polymer components|
|US5849137 *||28 Mar 1997||15 Dic 1998||Bourns Multifuse (Hong Kong) Ltd.||Continuous process and apparatus for manufacturing conductive polymer components|
|US5864280 *||28 Ago 1996||26 Ene 1999||Littlefuse, Inc.||Electrical circuits with improved overcurrent protection|
|US5880668 *||28 Ago 1996||9 Mar 1999||Littelfuse, Inc.||Electrical devices having improved PTC polymeric compositions|
|US6020808 *||3 Sep 1997||1 Feb 2000||Bourns Multifuse (Hong Kong) Ltd.||Multilayer conductive polymer positive temperature coefficent device|
|US6023403 *||26 Nov 1997||8 Feb 2000||Littlefuse, Inc.||Surface mountable electrical device comprising a PTC and fusible element|
|US6059997 *||12 Mar 1996||9 May 2000||Littlelfuse, Inc.||Polymeric PTC compositions|
|US6128168 *||14 Ene 1998||3 Oct 2000||General Electric Company||Circuit breaker with improved arc interruption function|
|US6144540 *||9 Mar 1999||7 Nov 2000||General Electric Company||Current suppressing circuit breaker unit for inductive motor protection|
|US6157286 *||5 Abr 1999||5 Dic 2000||General Electric Company||High voltage current limiting device|
|US6172591||5 Mar 1998||9 Ene 2001||Bourns, Inc.||Multilayer conductive polymer device and method of manufacturing same|
|US6215636 *||12 Mar 1998||10 Abr 2001||Siemens Automotive, S.A.||Device for supplying electric power to several parallel-fed circuits, and method for making same|
|US6223423||9 Sep 1999||1 May 2001||Bourns Multifuse (Hong Kong) Ltd.||Multilayer conductive polymer positive temperature coefficient device|
|US6228287||17 Sep 1999||8 May 2001||Bourns, Inc.||Two-step process for preparing positive temperature coefficient polymer materials|
|US6236302||13 Nov 1998||22 May 2001||Bourns, Inc.||Multilayer conductive polymer device and method of manufacturing same|
|US6242997||18 Dic 1998||5 Jun 2001||Bourns, Inc.||Conductive polymer device and method of manufacturing same|
|US6282072||23 Feb 1999||28 Ago 2001||Littelfuse, Inc.||Electrical devices having a polymer PTC array|
|US6429533||23 Nov 1999||6 Ago 2002||Bourns Inc.||Conductive polymer device and method of manufacturing same|
|US6582647||30 Sep 1999||24 Jun 2003||Littelfuse, Inc.||Method for heat treating PTC devices|
|US6597551||12 Dic 2001||22 Jul 2003||Huladyne Corporation||Polymer current limiting device and method of manufacture|
|US6628498||31 Jul 2001||30 Sep 2003||Steven J. Whitney||Integrated electrostatic discharge and overcurrent device|
|US7132922||23 Dic 2003||7 Nov 2006||Littelfuse, Inc.||Direct application voltage variable material, components thereof and devices employing same|
|US7183891||5 Oct 2004||27 Feb 2007||Littelfuse, Inc.||Direct application voltage variable material, devices employing same and methods of manufacturing such devices|
|US7202770||8 Abr 2003||10 Abr 2007||Littelfuse, Inc.||Voltage variable material for direct application and devices employing same|
|US7609141||26 Feb 2007||27 Oct 2009||Littelfuse, Inc.||Flexible circuit having overvoltage protection|
|US7843308||26 Feb 2007||30 Nov 2010||Littlefuse, Inc.||Direct application voltage variable material|
|US20030218851 *||8 Abr 2003||27 Nov 2003||Harris Edwin James||Voltage variable material for direct application and devices employing same|
|US20040201941 *||23 Dic 2003||14 Oct 2004||Harris Edwin James||Direct application voltage variable material, components thereof and devices employing same|
|US20070139848 *||26 Feb 2007||21 Jun 2007||Littelfuse, Inc.||Direct application voltage variable material|
|US20070146941 *||26 Feb 2007||28 Jun 2007||Littelfuse, Inc.||Flexible circuit having overvoltage protection|
|US20090027821 *||26 Jul 2007||29 Ene 2009||Littelfuse, Inc.||Integrated thermistor and metallic element device and method|
|DE1218589B *||16 Jul 1963||8 Jun 1966||Lehigh Valley Ind Inc||Thermoelektrischer Schalter, insbesondere Blinkgeber|
|DE2948281A1 *||30 Nov 1979||19 Jun 1980||Raychem Corp||Elektrische schaltung und schaltungsschutzeinrichtung|
|EP0038715A1||21 Abr 1981||28 Oct 1981||RAYCHEM CORPORATION (a Delaware corporation)||Circuit protection devices|
|EP0128664A1 *||10 May 1984||19 Dic 1984||RAYCHEM CORPORATION (a Delaware corporation)||Laminar electrical heaters|
|EP0250776A1||29 Jun 1984||7 Ene 1988||RAYCHEM CORPORATION (a Delaware corporation)||Method for detecting and obtaining information about changes in variables|
|EP0388990A2||20 Feb 1987||26 Sep 1990||RAYCHEM CORPORATION (a Delaware corporation)||Method and articles employing ion exchange material|
|EP0487920A1 *||30 Oct 1991||3 Jun 1992||Asea Brown Boveri Ab||PTC element|
|Clasificación de EE.UU.||338/223, 252/511, 252/512, 252/516, 252/510|
|Clasificación internacional||H02H9/02, H01C7/02, H01B1/24|
|Clasificación cooperativa||H02H9/026, H01C7/027, H01B1/24|
|Clasificación europea||H01B1/24, H02H9/02E, H01C7/02D|