US3826895A - Electrical fluid heating device - Google Patents

Electrical fluid heating device Download PDF

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Publication number
US3826895A
US3826895A US00358344A US35834473A US3826895A US 3826895 A US3826895 A US 3826895A US 00358344 A US00358344 A US 00358344A US 35834473 A US35834473 A US 35834473A US 3826895 A US3826895 A US 3826895A
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US
United States
Prior art keywords
heating
homogenizing
heating elements
zones
electrical
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Expired - Lifetime
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US00358344A
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English (en)
Inventor
H Schladitz
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Schladitz Whiskers AG
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Schladitz Whiskers AG
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Publication date
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Publication of US3826895A publication Critical patent/US3826895A/en
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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
    • 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
    • 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
    • H05B3/42—Heating elements having the shape of rods or tubes non-flexible
    • H05B3/48—Heating elements having the shape of rods or tubes non-flexible heating conductor embedded in insulating material

Definitions

  • An electric heating device for heating flowing fluid includes a tubular body of electrical insulation material adapted for through flow of the media.
  • a plurality of porous electric heating elements of disc-like form electrically connected in series span the tube at intervals and are arranged in series in the direction of flow.
  • Each heating element is pervious to fluid flow and is comprised of electrically conductive fibers or whiskers felted together.
  • the heating elements are interspersed with non-heating homogenizing zones located between adjacent heating zones.
  • each homogenizing zone merely comprises an empty space.
  • the homogenizing zones comprises a porous mass of electrically conductive fiber skeletons. The pore volume and electrical conductivity of the homogenizing mass are very much greater than those of the porous heating elements and the homogenizing masses form the electrical connections whereby the heating elements are connected electrically in series.
  • This invention relates to electrical heating devices. It is particularly concerned with the rapid heating of fluid media such as gases, liquids, vapors or aerosols.
  • a well known heating device described in German Pat. No. 1,288,705 has a heating element consisting of a plurality of electrically conducting filaments felted and in metallic contact with one another. These filaments are preferably so-called whiskers, and through the felt flows the medium to be heated.
  • a heating element offers to the fluid medium to be heated a very large heating surface, and at the same time it displays a very low resistance to flow, so that the medium can be heated to a determined temperature in an extremely short time.
  • the medium among other things must be in contact with the heating element for a certain length of time which is related to the length of the heating element in the direction of flow and to the rate of flow.
  • High rates of flow require a longer heating element to attain a determined final temperature than is necessary than with low rates of flow.
  • a long heating element consisting of an electrically conducting fiber skeleton cannot, however, in practice be made with the necessary homogeneity, so that it is unavoidable that certain points of the fiber skeleton are more densely felted than others. During the heating of a fluid, these dense points are heated more strongly than the others owing to the greater resistance to fluid flow and the greater electrical current flow.
  • the fluid is a liquid this can cause local evaporation while the temperature of the liquid elsewhere remains well below the evaporation point.
  • the vapor bubbles interfere with the flow of liquid through the heating element to a considerable extent. This can be related to the fact that the volume passed through a capillary suddenly drops when the liquid has reached its boiling point.
  • an electrical heating device for heating fluid media comprising a body adapted for through flow of said media and electrical heating elements housed in said body and arranged in series in the direction of flow of said media, each element consisting of a plurality of electrically conducting fibers or whiskers felted together and in metallic contact with one another, and the heating elements being interspersed with homogenizing zones in which no appreciable heating of the media takes place.
  • the heating device is divided into individual, consecutive heating stages.
  • Each element can be made substantially homogeneous with uniform porosity of the fiber skeleton. This is because they can be relatively short, for example with lengths of l to 5 mm. Even if there is a lack of homogeneity in the fiber skeleton, leading to excessive heating of the fluid medium, there takes place in the intermediate stages, or homogenizing zones, a mixing of the hotter and cooler constituents so that, on entering the next heating element, the fluid again displays a homogeneous temperature.
  • the intermediate stages therefore prevent the paths of vapor bubbles derived from the dense points of the heating elements extending throughout the heating device.
  • the intermediate stages or homogenizing zones can be formed by empty spaces, in which any vapor bubbles formed can dissolve in the liquid.
  • they may be formed by electrically conducting fiber skeletons whose pore volume and electrical conductivity are considerably greater than those of the heating stages. In each such fiber skeleton, which owing to its greater conductivity participates only slightly in the heating of the fluid medium, intensive mixing of the vapor and liquid components can be achieved.
  • the neighboring heating elements are for preference separated from one another by distance pieces which also establish the electrical connection between the heating stages.
  • These distance pieces can be formed from tubular bodies, each of which surrounds an empty space representing an intermediate stage.
  • the distance pieces can be formed by the aforementioned electrically conducting fiber skeletons whose fibers or whiskers have a cross-section which may be a multiple of the cross-section of the whiskers forming the heating elements.
  • the electrical heating device body is tubular and of electrically insulating material, the heating elements being of disc-like form spanning the tube at intervals. If directly heated by an electric current, the supply is conveniently to contacts on the first and last heating elements. It is also possible, however, for these to be arranged within an induction coil.
  • the fibers forming the heating elements are for preference polycrystalline metal whiskers with a diameter of, for instance, 0.5 to 20 pm, as such whiskers are distinguished for extremely high strength and thus can withstand high fluid pressures without breaking and being carried along by the liquid.
  • other filaments can successfully be used, for instance metallized carbon filaments.
  • the metallic connection of the fibers at their points of contact can be effected by any of a number of well known methods for instance by metallizing in the gas phase, welding by brief local melting with the aid of coherently bunched light rays, electron beam welding, ultrasonic welding, the galvanic separation of metals or by currentless metal coating.
  • polycrystalline metal whiskers is meant extremely fine metal filaments or hairs which have grown from the gas phase, such as are described in German Pat. No. 1,224,934.
  • the ratio between the diameter and length of these whiskers, or of the other previously mentioned fibers, can amount to more than 111000.
  • FIG. I is a longitudinal section through a first form of electrical heating device according to the invention.
  • FIG. 2 is a longitudinal section through a second form.
  • the heating device of FIG. 1 has a tubular jacket 1 of electrically insulating material in which are fitted several disc-like heating elements 2 arranged and connected in series with respect to the direction of flow S of the fluid medium to be heated.
  • Each heating element 2 consists of a plurality of electrically conducting filaments, preferably so-called whiskers, which are felted together and connected metallically with one another at their contact points.
  • Neighboring heating elements 2 are separated from one another by distance pieces 3, which also serve to establish the electrical connection between the heating elements.
  • These distance pieces 3 are each formed by a tubular body fitting closely within the tubular jacket 1 and each bounding an empty space 4 representing an intermediate stage.
  • wire lattices or filters are arranged between the distance pieces 3 and the neighboring heating elements 2 and cover the circular faces of the elements 2.
  • the first and the last heating elements 2 are provided with respective contact plates 6 in the form of sieves or filters, which are connected to the positive and negative poles of a source of current.
  • the temperature homogenizing of the medium heated in the previous heating elements so that on entering the following heating element, the medium has a substantially uniform temperature, and any vapor bubbles formed in the heating of liquids are dissolved.
  • the disc-like heating elements 2 can be made by machine with largely uniform pore size, without great difficulty and expense.
  • the number of heating elements connected in series is optional and depends on the final temperature desired, on the rate 4 of flow and on the electrical power available.
  • the heating device of FIG. 2 differs from that of FIG. 1 mainly in that the intermediate stages between neighboring heating elements 2 are not formed by empty spaces, but by filament skeletons 7, which have in principle the same structure as those of the heating elements 2, but possess a larger pore volume and very much greater electrical conductivity. These skeletons 7 further the mixing of the components of the medium that are already in the form of vapor with those that are still liquid.
  • the heating elements 2 consist of polycrystalline iron whiskers with an average diameter of about 1 pm and the skeleton has a pore volume of about 65 percent and an electrical resistance of about 1 ohm.
  • the filament skeletonof each intermediate stage 7 may consist of whiskers with a diameter of about 40 pm and a a pore volume of about percent and an electrical resistance of about 0.01 ohm.
  • media comprising a body having a first end and a second end and adapted for through flow of said media and a column of electrical heating elements having a first and second end and housed in said body between the body ends, the heating elements being arranged normal to the direction of fluid flow and in series in the direction of flow of said media to form adjacent heating zones, each element being pervious to fluid flow and comprised of a plurality of electrically conducting fibers felted together, the heating elements being interspersed with homogenizing zones in which no appreciable heating of the media takes place, each homogenizing zone being between adjacent heating zones, each of said homogenizing zones comprising a porous mass of electrically conducting fiber skeletons pervious to fluid flow whose pore volume and electrical conductivity are very much greater than those of the heating elements, the homogenizing skeletons forming electrical connection between adjacent heating zones, whereby all heating zones are connected in series, and coupling means for coupling the column ends to an electric power source.
  • each said fiber skeleton consists of metal fibers whose cross-section is a multiple of the cross-section of the fibers forming the heating elements.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Resistance Heating (AREA)
  • Instantaneous Water Boilers, Portable Hot-Water Supply Apparatuses, And Control Of Portable Hot-Water Supply Apparatuses (AREA)
  • Surface Heating Bodies (AREA)
US00358344A 1972-05-10 1973-05-08 Electrical fluid heating device Expired - Lifetime US3826895A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2222849A DE2222849C3 (de) 1972-05-10 1972-05-10 Elektrische Heizvorrichtung zum raschen Erhitzen von strömenden Medien

Publications (1)

Publication Number Publication Date
US3826895A true US3826895A (en) 1974-07-30

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ID=5844574

Family Applications (1)

Application Number Title Priority Date Filing Date
US00358344A Expired - Lifetime US3826895A (en) 1972-05-10 1973-05-08 Electrical fluid heating device

Country Status (13)

Country Link
US (1) US3826895A (is)
JP (1) JPS4949237A (is)
AT (1) AT323294B (is)
BE (1) BE799326A (is)
CA (1) CA981735A (is)
CH (1) CH554518A (is)
DE (1) DE2222849C3 (is)
DK (1) DK140119C (is)
FR (1) FR2184039B1 (is)
GB (1) GB1414431A (is)
IT (1) IT987170B (is)
NL (1) NL7306457A (is)
SE (1) SE388931B (is)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3934117A (en) * 1973-03-27 1976-01-20 Schladitz Hermann J Electric fluid heating device
US3943221A (en) * 1972-11-17 1976-03-09 Schladitz Hermann J Apparatus for atomizing and/or vaporizing liquid in a stream of gas
US4334350A (en) * 1978-07-26 1982-06-15 Chemotronics International, Inc. Shareholders Method utilizing a porous vitreous carbon body particularly for fluid heating
WO1991010867A1 (en) * 1990-01-16 1991-07-25 Automated Dynamics Corporation Porous ceramic body electrical resistance fluid heater
US5231267A (en) * 1991-04-26 1993-07-27 Metcal, Inc. Method for producing heat-recoverable articles and apparatus for expanding/shrinking articles
US5324904A (en) * 1988-10-03 1994-06-28 Imperial Chemical Industries Plc Reactors for effecting chemical processes
US5431886A (en) * 1994-04-08 1995-07-11 W. R. Grace & Co.-Conn. Combined electrically heatable converter
US6327426B1 (en) * 2000-10-26 2001-12-04 Ceramatec, Inc. Apparatus and method for delivering a beneficial agent
EP1139694A3 (en) * 2000-03-30 2004-11-24 Toshiba Ceramics Co., Ltd. Fluid heating apparatus
US20070210075A1 (en) * 2006-03-02 2007-09-13 John Self Induction heater
US20090114734A1 (en) * 2007-11-01 2009-05-07 Oshkosh Truck Corporation Heating control system using a fluid level sensor and a heating control element
US20130284169A1 (en) * 2011-01-24 2013-10-31 Resmed Limited Humidifier
US20160084495A1 (en) * 2014-09-22 2016-03-24 University Research Glassware Corporation Continuous ultrapure steam generator

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5216926A (en) * 1975-07-30 1977-02-08 Sony Corp Color cathode ray apparatus
GB9008984D0 (en) * 1990-04-21 1990-06-20 Atomic Energy Authority Uk Gas heater
EP0454346A1 (en) * 1990-04-21 1991-10-30 United Kingdom Atomic Energy Authority Exhaust particulate filter
GB9727046D0 (en) * 1997-12-22 1998-02-18 Morris Nigel H Electrical heater element

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR487436A (fr) * 1916-03-09 1918-07-03 Ferdinand Leon Alfred Rouget Porte-outils pour l'usinage des obus ou pièces similaires
US1277657A (en) * 1916-12-12 1918-09-03 Filbar Electric Heater Ltd Electrical apparatus for heating liquids.
FR512845A (fr) * 1920-03-31 1921-02-01 Jean Bally Appareil pour le chauffage électrique des fluides
US2837623A (en) * 1956-05-26 1958-06-03 Birmingham Small Arms Co Ltd Treatment of fluids
GB1096375A (en) * 1964-07-28 1967-12-29 Schladitz Whiskers Ag Method and apparatus for heating fluids
US3688083A (en) * 1970-07-31 1972-08-29 Atomic Energy Authority Uk Electric fluid heater

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR487436A (fr) * 1916-03-09 1918-07-03 Ferdinand Leon Alfred Rouget Porte-outils pour l'usinage des obus ou pièces similaires
US1277657A (en) * 1916-12-12 1918-09-03 Filbar Electric Heater Ltd Electrical apparatus for heating liquids.
FR512845A (fr) * 1920-03-31 1921-02-01 Jean Bally Appareil pour le chauffage électrique des fluides
US2837623A (en) * 1956-05-26 1958-06-03 Birmingham Small Arms Co Ltd Treatment of fluids
GB1096375A (en) * 1964-07-28 1967-12-29 Schladitz Whiskers Ag Method and apparatus for heating fluids
US3688083A (en) * 1970-07-31 1972-08-29 Atomic Energy Authority Uk Electric fluid heater

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3943221A (en) * 1972-11-17 1976-03-09 Schladitz Hermann J Apparatus for atomizing and/or vaporizing liquid in a stream of gas
US3934117A (en) * 1973-03-27 1976-01-20 Schladitz Hermann J Electric fluid heating device
US4334350A (en) * 1978-07-26 1982-06-15 Chemotronics International, Inc. Shareholders Method utilizing a porous vitreous carbon body particularly for fluid heating
US5324904A (en) * 1988-10-03 1994-06-28 Imperial Chemical Industries Plc Reactors for effecting chemical processes
WO1991010867A1 (en) * 1990-01-16 1991-07-25 Automated Dynamics Corporation Porous ceramic body electrical resistance fluid heater
US5117482A (en) * 1990-01-16 1992-05-26 Automated Dynamics Corporation Porous ceramic body electrical resistance fluid heater
US5231267A (en) * 1991-04-26 1993-07-27 Metcal, Inc. Method for producing heat-recoverable articles and apparatus for expanding/shrinking articles
US5431886A (en) * 1994-04-08 1995-07-11 W. R. Grace & Co.-Conn. Combined electrically heatable converter
EP1139694A3 (en) * 2000-03-30 2004-11-24 Toshiba Ceramics Co., Ltd. Fluid heating apparatus
WO2002034031A1 (en) * 2000-10-26 2002-05-02 Microlin, L.C. Apparatus and method for delivering a beneficial agent
US6327426B1 (en) * 2000-10-26 2001-12-04 Ceramatec, Inc. Apparatus and method for delivering a beneficial agent
US20070210075A1 (en) * 2006-03-02 2007-09-13 John Self Induction heater
US20090114734A1 (en) * 2007-11-01 2009-05-07 Oshkosh Truck Corporation Heating control system using a fluid level sensor and a heating control element
US8119953B2 (en) 2007-11-01 2012-02-21 Oshkosh Truck Corporation Heating control system using a fluid level sensor and a heating control element
US8791393B2 (en) 2007-11-01 2014-07-29 Oshkosh Corporation Heating control system using a fluid level sensor and a heating control element
US20130284169A1 (en) * 2011-01-24 2013-10-31 Resmed Limited Humidifier
US10307559B2 (en) * 2011-01-24 2019-06-04 Resmed Limited Humidifier
US11744979B2 (en) 2011-01-24 2023-09-05 ResMed Pty Ltd Humidifier
US20160084495A1 (en) * 2014-09-22 2016-03-24 University Research Glassware Corporation Continuous ultrapure steam generator
US9631807B2 (en) * 2014-09-22 2017-04-25 University Research Glassware Corporation Continuous ultrapure steam generator

Also Published As

Publication number Publication date
NL7306457A (is) 1973-11-13
DK140119C (da) 1979-11-19
AT323294B (de) 1975-07-10
CA981735A (en) 1976-01-13
CH554518A (de) 1974-09-30
IT987170B (it) 1975-02-20
BE799326A (fr) 1973-08-31
SE388931B (sv) 1976-10-18
DK140119B (da) 1979-06-18
FR2184039A1 (is) 1973-12-21
GB1414431A (en) 1975-11-19
JPS4949237A (is) 1974-05-13
DE2222849A1 (de) 1973-11-22
DE2222849C3 (de) 1978-07-06
FR2184039B1 (is) 1979-01-12
DE2222849B2 (de) 1977-11-17

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