US3843950A - Porous electric heating element - Google Patents

Porous electric heating element Download PDF

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Publication number
US3843950A
US3843950A US00268672A US26867272A US3843950A US 3843950 A US3843950 A US 3843950A US 00268672 A US00268672 A US 00268672A US 26867272 A US26867272 A US 26867272A US 3843950 A US3843950 A US 3843950A
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US
United States
Prior art keywords
heating element
electric heating
metal
layers
skeleton
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
US00268672A
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English (en)
Inventor
H Schladitz
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.)
Schladitz Whiskers AG
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Schladitz Whiskers AG
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
Priority claimed from DE19712133932 external-priority patent/DE2133932C/de
Application filed by Schladitz Whiskers AG filed Critical Schladitz Whiskers AG
Application granted granted Critical
Publication of US3843950A publication Critical patent/US3843950A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/10—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium
    • F24H1/101—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium using electric energy supply
    • 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
    • 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
    • H05B3/141—Conductive ceramics, e.g. metal oxides, metal carbides, barium titanate, ferrites, zirconia, vitrous compounds
    • 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

Definitions

  • a known body of this type consists of a plurality of elongated felted together electrically conductive parts which are metallically connected to one another at their point of contact. These parts may consist of hairs, needles, small rods or whiskers with a diameter of less than pm, or of leaf-shaped particles of less than 1 pm thick.
  • the porous body is manufactured from these elongated parts or particles by the latter first being formed into a loose accumulation of material which is compressed to the desired porosity. The individual particles are then connected metallically to one another at their points of contact, for example by metallisation from the gaseous phase.
  • a porous, electrically conductive body comprising a preformed skeleton of electrically nonconductive or weakly conductive material, the inside surface of which is metal-coated by metallic products of decomposition of a thermally decomposable metal compound.
  • the skeleton may be a plurality of layers of fabric, which may consist of glass, quartz and particularly carbon fibres, and which generally has a very even resistance to flow.
  • the skeleton may alternatively be an open pore foam body, preferably made from carbon or polyamide foam, which can nowadays be manufactured with a very regular pore size.
  • a substantially regular through-flow of medium to be treated can be guaranteed.
  • a skeleton can easily be manufactured in the desired dimensions of the finished body, from these starting materials, by cutting, stamping or other known methods. If a foam substance is used, the skeleton can be produced to the desired size by foaming it into an appropriate mould.
  • the resultant skeleton is then heated to a temperature required for decomposition of the metal compound and the latter, present in vapour form, can flow through it until such time as sufficient metal has been deposited on the inner surface of the skeleton to achieve the desired electrical conductivity. In this way, it is possible by simple means to produce a body of virtually any desired electrical conductivity.
  • the heating of the skeleton necessary to decompose the metal compound becomes particularly simple if the skeleton has a low initial electrical conductivity, since then the skeleton can be heated by the direct throughflow of current.
  • this initial conductivity can be achieved by a weak pre-metallising of the fabric, preferably likewise by the depositing of metal from the gaseous phase.
  • the body according to the invention can preferably be used as an electric heating element, in which case the skeleton is provided with contacts for connection to a current source. These contacts can be connected to the metallised skeleton by depositing of metal during thermal decomposition of the metal compound.
  • the body according to the invention can however also be used as a hot and cold electrode for electrochemical processes, fuel cells or collectors.
  • the body When used as an electric heating element, the body may take the form of a ring which is provided with one contact on the inner periphery and another on the outer periphery. This form of embodiment is particularly apposite if the skeleton is formed by a foam substance.
  • the body On the other hand, the body may also take the frm of a column, the end faces of which are provided with contacts. This column can be formed by a foam substance or by placing a plurality of fabric discs or plates one on top of another. This column can take the form of a hollow cylinder and the medium to be heated can pass through it from the outside inwardly or from the inside outwardly.
  • the skeleton consists of a plurality of layers of a fabric discs or plates of the desired dimensions are stamped or cut from a fabric, laid one on top of another in a required quantity and are pressed together by electrodes engaging at the ends of the pile so laid, the pile is heated by direct through-flow of current to a temperature necessary to decompose the metal compound, and the metal compound is then passed through the pile in vapour form until such time as sufficient metal giving the desired electrical conductivity has been deposited on the inner surfaces of the discs or plates.
  • a foam body is cut to the desired dimensions from a block of foam material, and is then heated by direct through-flow of current to the temperature necessary to decompose the metal compound and the vaporised metal compound is then passed through the body until sufficient metal giving the desired electrical conductivity has been deposited on the inner surface of the foam body.
  • the foam body can also be produced by foaming the material in a mould corresponding to the final form of the porous body.
  • the electrical resistance of the pile or of the foam body can be constantly measured and, when the desired value is attained, the supply of metal compound and of current can be stopped.
  • a carbonyl of the metals iron, chromium, nickel, tungsten, molybdenum, or a mixture of such carbonyls is preferably used.
  • metal carbonyls have the property that above a certain temperature, they decompose into metal and carbon monoxide, the metals being deposited in finely crystalline form and in the atomic state on the inner surface of the skeleton, so forming a rigidly adhering coating. The longer the metal carbonyl vapour flows through the skeleton, the thicker the deposit of metal will naturally be, and the higher will be the electrical conductivity.
  • Other useful metal compounds are for example metal-acetyl-acetonates, such as platinumacetyl-acetonate, dicumene chromium or dibenzene chromium, platinum carbonyl chlorides et al.
  • FIG. 1 is a diagram of apparatus for forming a porous, electrically conductive body from layers of fabric
  • FIG. 2 is a diagram of apparatus for forming a .porous, electrically conductive body from a block of foamed material
  • FIG. 3 is a longitudinal section through a heating element according to the invention.
  • FIG. 4 is an enlarged fragmentary view of two adjoining discs each comprising a layer of fabric with the applied metal coating.
  • a tube 1 Located side by side in a tube 1 made from an electrically non-conductive material or coated on the inside with an electrically non-conductive material, there are a plurality of discs 2 which have been cut from a premetallised glass-fibre fabric.
  • the individual fibres are for example 5 microns thick.
  • the discs 2 are located between two longitudinallydisplaceable electrodes 3 and 4 each of which consist of a gas permeable material or are provided with through ducts 5 and by which the discs are pressed against one another in intimate contact. A pressure of less than 1 kp/sq.cm is normally sufficient for this.
  • the ends of the tube 1 are closed by covers 6 and 7, through which the connections 8 and 9 of the electrodes 3, 4 pass in fluid tight fashion.
  • electrodes can be connected to a current source 11 through a switch 10.
  • a connection 12 for the supply of metal carbonyl vapour
  • a connection 13 for the discharge of the carbon monoxide resulting from the decomposition of the carbonyl, and any non-decomposed carbonyl vapour.
  • the discs 2 are pressed together by the electrodes 3, 4.
  • the switch 10 is closed, so that the discs 2 are heated by the direct through-flow of current until they have reached the desired temperature at which decomposition of the metal carbonyl to be used occurs. In the case of nickel carbonyl, this temperature is between and l60C.
  • the carbonyl vapour is then supplied to the connection 12, flows through the electrode 4 and the discs 2 and is decomposed in the region of the discs 2, the metal atoms released being deposited on the individual fibres of the discs 2 and forming a cohesive metal coating.
  • the carbon monoxide and non-decomposed carbonyl flow through the electrode 3 and are carried off at the outlet connection 13.
  • the ammeter 14 indicates the current strength and thus the electrical resistance of the column formed by the discs 2. Once the desired electrical conductivity of this column is reached, the flow of carbonyl is shut off and the switch 10 is opened.
  • the metal coating may vary in thickness from 0.1 to several microns. The metal coating connects the individual discs 2 into one cohesive but still porous body which can now be removed from the tube 1.
  • the elec trodes 3,4 are connected to this body by the deposited metal, so that it constitutes a ready-to-use heating element.
  • the skeleton used is a foam body 15 in the form of a ring, consisting for example of a carbon foam produced from foamed synthetic resins by carburisation.
  • a foam is characterised by a very low specific weight, a high pore volume and a regular pore size.
  • a contact ring 17 is provided on the inside periphery 16 of the ring 15 while a contact ring 19 is provided on the outside periphery 18.
  • the contact rings 17 and 19 can be connected to a current source 11' by a switch 10. Upon closing the switch 10, the foam body 15 is heated to the desired temperature by the direct through-flow of current, whereupon a metal carbonyl vapour is passed through the foam body 15 in the direction of the arrow 20.
  • the vapour decomposes inside the body 15, so that metal atoms are deposited on its inner surface.
  • the ammeter 14' can be used to monitor the electrical resistance of the body 15. When the desired electrical conductivity is achieved, the switch 10' is opened and the supply of carbonyl vapour discontinued.
  • the contact rings 17 and 19 are, in this method, connected rigidly to the foam body 15 by the metallisation treatment and can therefore be used for connecting the completed heating element to a current source.
  • the method illustrated in FIG. 1 can also be used for manufacturing a heating element consisting of a foam body.
  • FIG. 3 shows a longitudinal section through a heating element according to the invention, which can be used for example for vaporising liquid fuel, and which can find application in internal combustion engines or oil burners.
  • This heating element consists of a column 21 manufactured by the method illustrated in FIG. 1 from layers of fabric or a foam body having the form 'of a hollow cylinder and provided on its end faces with contacts 22, 23.
  • the liquid fuel passes through this body from outside over the entire length of the hollow cylinder and is carried away in vapour form through the central hole 24. In principle, the through-flow may also take place from the inside outwardly.
  • An electric heating element comprising an electrically conductive porous body the pores of which forming passages for a fluid to be heated, said porous body consisting of a plurality of layers of a fabric made of f1- bers selected from the group consisting of glass, quartz and carbon fibers, said layers being arranged regularly one upon each other and being connected to each other in an electrically conductive manner by a metal deposition produced by decomposition of a thermally decomposable metal compound, said metal deposition forming at the same time a metal coating on the fibers of the fabric forming said layers, and electrodes in contact with spaced apart portions of the skeleton formed by said interconnected layers.
  • An element according to claim 1 in the form of a ring-like electric heating element, wherein the electrodes are provided on the inner and outer peripheries thereof.
  • An element according to claim 1 in the form of a column-like electric heating element, wherein the electrodes are provided on the end faces thereof.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Resistance Heating (AREA)
  • Instantaneous Water Boilers, Portable Hot-Water Supply Apparatuses, And Control Of Portable Hot-Water Supply Apparatuses (AREA)
  • Paper (AREA)
US00268672A 1971-07-07 1972-07-03 Porous electric heating element Expired - Lifetime US3843950A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19712133932 DE2133932C (de) 1971-07-07 Poröser, elektrisch leitender Korper, insbesondere elektrisches Heiz element

Publications (1)

Publication Number Publication Date
US3843950A true US3843950A (en) 1974-10-22

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Family Applications (1)

Application Number Title Priority Date Filing Date
US00268672A Expired - Lifetime US3843950A (en) 1971-07-07 1972-07-03 Porous electric heating element

Country Status (13)

Country Link
US (1) US3843950A (enrdf_load_stackoverflow)
AT (1) AT317377B (enrdf_load_stackoverflow)
BE (1) BE785731A (enrdf_load_stackoverflow)
CA (1) CA958743A (enrdf_load_stackoverflow)
CH (1) CH548143A (enrdf_load_stackoverflow)
CS (1) CS162634B2 (enrdf_load_stackoverflow)
DD (1) DD99905A5 (enrdf_load_stackoverflow)
FR (1) FR2144707B1 (enrdf_load_stackoverflow)
GB (1) GB1402013A (enrdf_load_stackoverflow)
IT (1) IT962424B (enrdf_load_stackoverflow)
NL (1) NL7209021A (enrdf_load_stackoverflow)
SE (1) SE383938B (enrdf_load_stackoverflow)
SU (2) SU587894A3 (enrdf_load_stackoverflow)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3973234A (en) * 1974-10-08 1976-08-03 Universal Oil Products Company Precision type resistor
US4220846A (en) * 1978-07-26 1980-09-02 The Fluorocarbon Company Method and apparatus utilizing a porous vitreous carbon body particularly for fluid heating
US4310747A (en) * 1978-07-26 1982-01-12 The Fluorocarbon Company Method and apparatus utilizing a porous vitreous carbon body particularly for fluid heating
US4334350A (en) * 1978-07-26 1982-06-15 Chemotronics International, Inc. Shareholders Method utilizing a porous vitreous carbon body particularly for fluid heating
EP0402738A3 (en) * 1989-06-16 1993-03-17 Inco Limited Nickel foam
US6166619A (en) * 1995-11-11 2000-12-26 Daimlerchrysler Ag Overcurrent limiter having inductive compensation
WO2002041425A3 (de) * 2000-11-15 2002-12-12 Mtu Friedrichshafen Gmbh Brennstoffzellenanordnung
US20110110652A1 (en) * 2009-11-09 2011-05-12 Technical Analysis & Services International, Inc. (TASI) Active air heater
US20120103795A1 (en) * 2010-10-29 2012-05-03 Ta-Jen Huang Electrochemical-catalytic converter for exhaust emission control
US20150153069A1 (en) * 2012-05-23 2015-06-04 Fruit Tech Natural S.A. Apparatus and method for the ohmic heating of a particulate liquid
US20150167959A1 (en) * 2013-12-12 2015-06-18 Massachusetts Institute Of Technology Tunable Nucleate Boiling using Electric Fields and Ionic Surfactants
CN110419779A (zh) * 2019-07-15 2019-11-08 深圳市合元科技有限公司 电子烟雾化器、电子烟及雾化组件的制备方法

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE8004352L (sv) * 1979-06-14 1980-12-15 Atomic Energy Authority Uk Vermeoverforingselement och -system
US4321031A (en) * 1979-07-09 1982-03-23 Woodgate Ralph W Method and apparatus for condensation heating
DE4329558A1 (de) * 1993-09-02 1995-03-09 Friedrich Dr Ing Sperling Rußfilter für Dieselbrennkraftmaschinen
RU2477311C2 (ru) * 2010-11-17 2013-03-10 Российская Федерация, от имени которой выступает Министерство образования и науки Российской Федерации (Минобрнауки России) Способ стерилизации жидких питательных сред для культивирования биомассы

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2473183A (en) * 1947-07-16 1949-06-14 Bates Mfg Co Electrically conductive fabric
US3178377A (en) * 1961-11-06 1965-04-13 Koppers Co Inc Expandable thermoplastic polymeric material
US3198167A (en) * 1961-03-10 1965-08-03 Alloyd Corp Vapor deposition device
US3221145A (en) * 1963-09-06 1965-11-30 Armstrong Cork Co Laminated heating sheet
GB1096375A (en) * 1964-07-28 1967-12-29 Schladitz Whiskers Ag Method and apparatus for heating fluids
US3390452A (en) * 1963-03-29 1968-07-02 Irc Inc Method of making an electrical resistor
US3459924A (en) * 1968-09-25 1969-08-05 Dow Chemical Co Electrical open cell heating element
US3629774A (en) * 1968-10-21 1971-12-21 Scient Advances Inc Progressively collapsible variable resistance element

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2473183A (en) * 1947-07-16 1949-06-14 Bates Mfg Co Electrically conductive fabric
US3198167A (en) * 1961-03-10 1965-08-03 Alloyd Corp Vapor deposition device
US3178377A (en) * 1961-11-06 1965-04-13 Koppers Co Inc Expandable thermoplastic polymeric material
US3390452A (en) * 1963-03-29 1968-07-02 Irc Inc Method of making an electrical resistor
US3221145A (en) * 1963-09-06 1965-11-30 Armstrong Cork Co Laminated heating sheet
GB1096375A (en) * 1964-07-28 1967-12-29 Schladitz Whiskers Ag Method and apparatus for heating fluids
US3459924A (en) * 1968-09-25 1969-08-05 Dow Chemical Co Electrical open cell heating element
US3629774A (en) * 1968-10-21 1971-12-21 Scient Advances Inc Progressively collapsible variable resistance element

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
The Condensed Chemical Dictionary, Reinhold, N.Y. 1963, p. 219. *

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3973234A (en) * 1974-10-08 1976-08-03 Universal Oil Products Company Precision type resistor
US4220846A (en) * 1978-07-26 1980-09-02 The Fluorocarbon Company Method and apparatus utilizing a porous vitreous carbon body particularly for fluid heating
US4310747A (en) * 1978-07-26 1982-01-12 The Fluorocarbon Company Method and apparatus utilizing a porous vitreous carbon body particularly for fluid heating
US4334350A (en) * 1978-07-26 1982-06-15 Chemotronics International, Inc. Shareholders Method utilizing a porous vitreous carbon body particularly for fluid heating
EP0402738A3 (en) * 1989-06-16 1993-03-17 Inco Limited Nickel foam
US6166619A (en) * 1995-11-11 2000-12-26 Daimlerchrysler Ag Overcurrent limiter having inductive compensation
WO2002041425A3 (de) * 2000-11-15 2002-12-12 Mtu Friedrichshafen Gmbh Brennstoffzellenanordnung
US20040067400A1 (en) * 2000-11-15 2004-04-08 Marc Steinfort Fuel cell assembly
US20110110652A1 (en) * 2009-11-09 2011-05-12 Technical Analysis & Services International, Inc. (TASI) Active air heater
US20120103795A1 (en) * 2010-10-29 2012-05-03 Ta-Jen Huang Electrochemical-catalytic converter for exhaust emission control
US8647482B2 (en) * 2010-10-29 2014-02-11 National Tsing Hua University Electrochemical-catalytic converter for exhaust emission control
US20150153069A1 (en) * 2012-05-23 2015-06-04 Fruit Tech Natural S.A. Apparatus and method for the ohmic heating of a particulate liquid
US9736889B2 (en) * 2012-05-23 2017-08-15 Fruit Tech Natural S.A. Apparatus and method for the ohmic heating of a particulate liquid
US20150167959A1 (en) * 2013-12-12 2015-06-18 Massachusetts Institute Of Technology Tunable Nucleate Boiling using Electric Fields and Ionic Surfactants
US9841186B2 (en) * 2013-12-12 2017-12-12 Massachusetts Institute Of Technology Tunable nucleate boiling using electric fields and ionic surfactants
CN110419779A (zh) * 2019-07-15 2019-11-08 深圳市合元科技有限公司 电子烟雾化器、电子烟及雾化组件的制备方法

Also Published As

Publication number Publication date
SU510181A3 (ru) 1976-04-05
BE785731A (fr) 1972-10-16
CA958743A (en) 1974-12-03
IT962424B (it) 1973-12-20
SE383938B (sv) 1976-04-05
DD99905A5 (enrdf_load_stackoverflow) 1973-08-20
GB1402013A (en) 1975-08-06
SU587894A3 (ru) 1978-01-05
CH548143A (de) 1974-04-11
NL7209021A (enrdf_load_stackoverflow) 1973-01-09
AT317377B (de) 1974-08-26
FR2144707A1 (enrdf_load_stackoverflow) 1973-02-16
CS162634B2 (enrdf_load_stackoverflow) 1975-07-15
DE2133932A1 (enrdf_load_stackoverflow) 1972-11-30
DE2133932B2 (de) 1972-11-30
FR2144707B1 (enrdf_load_stackoverflow) 1976-01-16

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