Classifications

• • 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
  • H05B3/20—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater
  • H05B3/22—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible
  • H05B3/28—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible heating conductor embedded in insulating material
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
  • D06F75/00—Hand irons
  • D06F75/08—Hand irons internally heated by electricity
  • D06F75/24—Arrangements of the heating means within the iron; Arrangements for distributing, conducting or storing the heat
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06F—LAUNDERING, DRYING, IRONING, PRESSING OR FOLDING TEXTILE ARTICLES
  • D06F75/00—Hand irons
  • D06F75/08—Hand irons internally heated by electricity
  • D06F75/26—Temperature control or indicating arrangements
• • 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
  • H05B3/20—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater
  • H05B3/22—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible
  • H05B3/28—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible heating conductor embedded in insulating material
  • H05B3/283—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible heating conductor embedded in insulating material the insulating material being an inorganic material, e.g. ceramic
• • 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
  • H05B3/20—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater
  • H05B3/22—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible
  • H05B3/28—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible heating conductor embedded in insulating material
  • H05B3/286—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater non-flexible heating conductor embedded in insulating material the insulating material being an organic material, e.g. plastic
• • 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
  • H05B2203/00—Aspects relating to Ohmic resistive heating covered by group H05B3/00
  • H05B2203/002—Heaters using a particular layout for the resistive material or resistive elements
  • H05B2203/003—Heaters using a particular layout for the resistive material or resistive elements using serpentine layout

Definitions

• the present invention relates to a new electric heating element in the form of a film or thin sheet with a laminated structure comprising at least one electrically conductive layer and at least one substrate.
• Electric heating elements used in household applications such as irons, grills, etc. are formed of resistance wires embedded in an insulating ceramic material, itself placed in a metallic envelope.
• One drawback of this type of electric heating element is its thermal inertia.
• Another disadvantage is that it does not lend itself to complex contours.
• Electric heating elements in the form of sheets with several layers are also known: an electrically conductive layer formed of a thin metallic film, bonded to a substrate by means of a hot-melt adhesive layer which must resist the heat.
• Suitable hot-melt layers are extruded films with a thickness generally greater than 20 ⁇ m.
• This heating element is the low conductivity of the hot-melt film. This low conductivity can also not be improved appreciably by the incorporation of heat conducting charges in the extruded layer.
• the invention overcomes the disadvantages mentioned. It offers a heating element in the form of a thin film, with low thermal inertia and the manufacture of which is simplified.
• the heating element according to the invention comprises at least one substrate and at least one layer of electrical resistance adhering to the substrate by a binder formed from a dispersion or solution or powder deposited directly on the substrate.
• the binder according to the invention can be chosen from dispersions or solutions or powders of at least one polymer (or copolymer), the melting point of which is higher than the operating temperature of the heating element and which can be deposited on a substrate, if necessary under a thin thickness.
• the polymer is chosen from perfluorinated polymers, in particular perfluoro-alkoxy-alkane (PFA), MFA, polytetrafluoroethylene (PTFE).
• a dispersion or solution is chosen of at least one of the polymers mentioned above and which can be heavily charged if necessary by heat conducting charges and electrically insulating, for example oxide aluminum AI 2 O 3 , silicon carbide SiC, mica, glass powder.
• the substrate according to the invention which has in particular a mechanical support function for the heating element, as well as an electric insulator function, can be any sheet selected according to the application envisaged for the heating element.
• This sheet may be based on a thermoplastic or thermosetting material or on a cellulosic material, or a fabric or veil of glass impregnated or not, based on ceramic fibers, or an extruded or unwound sheet.
• thermoplastic or thermosetting material is chosen in particular from polytetrafluoroethylene (PTFE), perfluoro-alkoxy-alkane (PFA), MFA, perfluoro (ethylene-propylene) (FEP), ethylene-tetrafluoroethylene (ETFE), fluoride poly (vinylidene) (PVDF), polyethylene terephthalate (PET), polyimide (KAPTON).
• PTFE polytetrafluoroethylene
• PFA perfluoro-alkoxy-alkane
• MFA perfluoro (ethylene-propylene)
• FEP ethylene-tetrafluoroethylene
• ETFE ethylene-tetrafluoroethylene
• PVDF fluoride poly (vinylidene)
• PET polyethylene terephthalate
• KAPTON polyimide
• the substrate generally has a thickness of between 20 ⁇ m and 500 ⁇ m or more if necessary, depending on the application.
• the electrical resistance layer is a film or a thin sheet of an electrically conductive material, in particular based on a metal such as copper, nickel, aluminum or an alloy of metals such as bronze, brass, Constantan R.
• a metal such as copper, nickel, aluminum or an alloy of metals such as bronze, brass, Constantan R.
• this can have on at least one of its two faces a structured surface obtained for example by rolling in a calendering machine provided with rollers with structured surface or a rough surface obtained for example by sandblasting or abrasive treatment.
• the conductive metal sheet can alternatively be replaced by an electrically conductive fabric or by a layer formed by a carpet of electrically conductive fibers.
• the thickness of the conductive thin film can be calculated according to the conductor and the application envisaged for the heating element, that is to say according to the desired electrical power.
• the conductive film can have the form of a serpentine circuit.
• a serpentine circuit Such a form is obtained for example from a continuous film which is treated in places by chemical etching, using in particular a mixture of hydrochloric acid and hydrogen peroxide.
• the electrical resistance is obtained directly with the desired shape by depositing on the substrate an electrically conductive composition, for example by screen printing, by electrostatic spraying with the use of a stencil, etc.
• the electrical resistance layer merges with the binder layer which for this purpose is heavily loaded with particles in the form of powder or fibers of electrically conductive material, for example metallic particles or coated particles of metal, or even graphite.
• the heating element according to the invention generally also comprises an electrical insulating coating covering the electrical resistance layer.
• This coating is for example a second substrate of the type of the first substrate described above, which can adhere to the electrical resistance layer via another adhesive layer.
• composition of the heating element from thin layers gives it a low thickness, which results in a very reduced thermal inertia.
• the invention also relates to a method for manufacturing the heating element.
• the substrate, the binder and the electrically conductive layer used are chosen from the products described above.
• the method uses the following steps: - the substrate to be used as a support, at least intermediate, is prepared for the production of the heating element,
• the binder is deposited on the substrate from a dispersion or solution or a powder of this binder
• the conductive layer which is in particular in the form of a metallic film, is assembled by pressing, for example by pressing between the plates of a press or by calendering between rollers, with the substrate coated with the binder,
• the conductive layer is chemically treated, in particular by chemical etching, in order to give this layer the desired shape for the electrical resistance,
• a second substrate coated with a binder layer is assembled by pressing with the prelaminated element by placing the binder layer of the second substrate in contact with the conductive layer, - finally the heating element with a laminated structure, of low thickness and low thermal inertia.
• binder solution or dispersion makes it possible to obtain thin layers and, nevertheless, very good adhesion between the elements of the laminate, and which is preserved over time and under the most extreme conditions of use.
• the manufacturing process uses the following operations:
• the electrically conductive composition is deposited on the prepared substrate using a screen printing screen or a stencil, - the deposited layer is dried,
• a second substrate coated with a layer of binder is assembled by pressing with the substrate coated with the heating resistor.
• the electrical resistance is finally embedded in the binder layer of the second substrate.
• the manufacturing process can then use the following operations:
• a dispersion of the binder and electrically conductive particles is deposited on the prepared substrate, - after optional drying of the deposited layer, this layer containing the metallic particles is chemically treated so as to give it the desired shape for the electrical resistance ,
• a second substrate coated with a layer of binder is assembled by pressing with the substrate coated with the electrical resistance previously prepared.
• FIG. 1 represents the different stages of the manufacture of an example of a heating element according to the invention using a metal film as an electric heating resistance.
• FIG. 2 represents the various stages of the manufacture of an example of a heating element according to the invention using a layer based on metallic particles as an electric heating resistance.
• FIG. 3 and 4 show a heating element according to the invention provided with a thermostat.
• FIG. 5 represents an application for heating elements according to the invention.
• the substrate 1 serving as a support is a sheet formed from a glass fabric impregnated with PTFE 80 ⁇ m thick.
• a coating 2 of PFA dispersed in water is deposited by the coating technique using a doctor blade or a pencil. After drying at a temperature of 350 ° C., a layer of
• a metal sheet 4 50 ⁇ m thick is deposited in Constantan and these elements are assembled by pressing between the plates of a press, under a pressure of 40 bars at 350 ° C. for a few minutes.
• the assembly After having protected with a varnish deposited by screen printing the parts of the metal sheet intended to form the electrical resistance, the assembly is treated with a mixture of hydrochloric acid and hydrogen peroxide in order to obtain the desired shape for the heating resistance by chemical etching.
• a prelaminated element 5 is obtained.
• a thin heating element 8 is finally obtained which can be cut to the desired dimensions and which can be used in various applications.
• the cutting can be carried out at the level of the prefabricated element, the coating with the second substrate taking place on the precast elements cut out.
• the substrate 9 serving as a support can be the same as that described in relation to FIG. 1.
• a dispersion 10 containing PFA and electrically conductive metal particles is deposited on this PTFE-based substrate.
• the content of metal particles is determined so as to have a continuous electrical contact in the coating layer 11 formed on the substrate after drying. This content depends in particular on the dimensions and the shape of the metallic particles. Then the chemical etching of the conductive coating layer 1 1 is carried out and a prelaminated element 1 2 is obtained.
• This prelaminated element 1 2 is then assembled with a second substrate 1 3 coated in this example with the layer 14 of binder based on PFA.
• a thin heating element 15 is obtained which can be cut to the desired dimensions. Alternatively, the cutting takes place at the prefabricated elements (prelaminated).
• the heating element according to the invention can be used both in household applications and in industrial applications which require the use of heating elements of small thickness and low thermal inertia. Several heating elements can be used in combination.
• the heating element can also be used with advantage in aggressive environments such as treatment baths.
• the heating element can be more or less flexible depending on the conductive layers and the applications envisaged.
• the heating element can be used in a flat or thermoformed form, especially when it comes to stiffening it. It can still be used thanks to its thin thickness in the form of a ribbon wound for example around tubes. It can also optionally be provided with an adhesive layer so as to ensure the connection with the object to be heated.
• the heating element according to the invention can also be provided with a thermostat in the form of a flat thermocouple placed in an adhesive layer adjacent to a substrate.
• a thermostat in the form of a flat thermocouple placed in an adhesive layer adjacent to a substrate.
• An embodiment of such a heating element is shown schematically in Figures 3 and 4.
• This heating element 1 6 comprises a first substrate 1 7, an adhesive layer 1 8 containing the heating resistor 1 9, a second substrate 20, a second layer adhesive 21 containing a thermocouple 22 and a third substrate 23.
• the proximity of the thermocouple 22 of the heating resistor allows very rapid temperature regulation.
• FIG. 5 is shown an application which uses several heating elements according to the invention.
• three heating elements 24, 25, 26 are arranged in the sole 27 of an iron.
• These three heating elements can have the same electrical resistivity or, alternatively, different constant or variable resistivities depending on the temperature.
• Each heating element corresponds to a heating zone which can if necessary be controlled separately by a thermostat or alternatively by the resistive layer itself. This arrangement in combination allows very good control of the temperature of the sole regardless of the ironing method used.

Applications Claiming Priority (3)

Publications (2)

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ID=9478691

Family Applications (1)

Country Status (9)

Families Citing this family (45)

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• 1995
  • 1995-05-04 FR FR9505329A patent/FR2733871B1/fr not_active Expired - Fee Related
• 1996
  • 1996-04-30 WO PCT/IB1996/000390 patent/WO1996035317A1/fr active IP Right Grant
  • 1996-04-30 CA CA002220001A patent/CA2220001A1/fr not_active Abandoned
  • 1996-04-30 AU AU53445/96A patent/AU5344596A/en not_active Abandoned
  • 1996-04-30 AT AT96910147T patent/ATE337693T1/de not_active IP Right Cessation
  • 1996-04-30 JP JP8533154A patent/JPH11505060A/ja not_active Withdrawn
  • 1996-04-30 US US08/945,556 patent/US6054690A/en not_active Expired - Fee Related
  • 1996-04-30 DE DE69636473T patent/DE69636473T2/de not_active Expired - Fee Related
  • 1996-04-30 EP EP96910147A patent/EP0824847B1/de not_active Expired - Lifetime
• 2006
  • 2006-11-27 JP JP2006318838A patent/JP2007115702A/ja active Pending

Non-Patent Citations (1)

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