EP0771285A1 - Element chauffant - Google Patents

Element chauffant

Info

Publication number
EP0771285A1
EP0771285A1 EP95925928A EP95925928A EP0771285A1 EP 0771285 A1 EP0771285 A1 EP 0771285A1 EP 95925928 A EP95925928 A EP 95925928A EP 95925928 A EP95925928 A EP 95925928A EP 0771285 A1 EP0771285 A1 EP 0771285A1
Authority
EP
European Patent Office
Prior art keywords
mat
heating element
propeller blade
blade according
propeller
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.)
Withdrawn
Application number
EP95925928A
Other languages
German (de)
English (en)
Inventor
Roy Frederick John Withyholt Cottage McCARTHY
Paul Desmond Barnfield
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.)
Smiths Aerospace Gloucester Ltd
Original Assignee
Smiths Aerospace Gloucester Ltd
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
Application filed by Smiths Aerospace Gloucester Ltd filed Critical Smiths Aerospace Gloucester Ltd
Publication of EP0771285A1 publication Critical patent/EP0771285A1/fr
Withdrawn legal-status Critical Current

Links

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
    • H05B3/34—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater flexible, e.g. heating nets or webs
    • H05B3/36—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater flexible, e.g. heating nets or webs heating conductor embedded in insulating material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64D—EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENTS OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT
    • B64D15/00—De-icing or preventing icing on exterior surfaces of aircraft
    • B64D15/12—De-icing or preventing icing on exterior surfaces of aircraft by electric heating
    • 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
    • H05B2203/013—Heaters using resistive films or coatings
    • 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
    • H05B2203/017—Manufacturing methods or apparatus for heaters

Definitions

  • the present invention relates to heating elements for propeller blades, a method of forming heating elements, and a method of fastening a heating element to apparatus such as a propeller blade.
  • the present invention in its first aspect provides a propeller blade having an electrically powered heating element, the heating element comprising a mat of fibres having surfaces which are electrically conductive.
  • the fibres can be electrically conductive throughout, and are preferably carbon fibres.
  • the fibres can be metal coated. The metal coating of the fibres is preferably of nickel.
  • the fibre mat has the advantage of being more damage tolerant compared with conventional zig-zagged wire heaters. Whereas a small hole in the region where wire is laid out leads to a break of the connection and total heating failure, a hole in a heating element according to the present invention merely results in a changed current path. This is a significant practical advantage in view of the relative likelihood of the front edges of propeller blades being damaged. Furthermore, holes can be intentionally cut in a fibre mat so as to adapt the distribution of heat which the mat provides.
  • Preferred heating elements according to the present invention also have the advantage that they can be made significantly thinner than the wire and rubber layers known in the prior art.
  • the preferred heating element can be fitted directly on a blade without such indentations and still have low air resistance.
  • the mat of the heating element can be made up of more than one mat portion.
  • the portions can be shaped to fit respective sides of a propeller blade adjacent the leading edge of the blade, or the mat or mat portions can be wrapped over the blade leading edge.
  • the mat or mat portions can cover substantially all of the blade surfaces, this being especially suitable for anti-icing rather than de-icing operation.
  • the mat portions can be connected in series or parallel, or could be continuous so as to constitute a single mat. Multiple mats or mat portions can be provided one over another, so as to form a composite. Furthermore, if a mat or mat portion becomes damaged, a repair can be made by simply fixing another mat or mat portion over the top of the first, so as to be electrically connected to the first.
  • the heating element can be adapted to produce an optimum heat distribution pattern.
  • the mat or mat portions of the heating element can be shaped so as to have variable resistivity along their length.
  • dimensions such as length, width, and thickness can be varied, and gaps or holes provided in mats or mat portions.
  • the heating element can include a resilient cover such as a polyurethane layer.
  • the present invention in its second aspect relates to a heating element comprising a fibre mat in which at least the surfaces of the fibres are electrically conductive, the mat being backed by a perforated backing, the mat being fixed to the backing by film adhesive.
  • the backing acts either to control the flow of adhesive to the mat and/or to absorb excess adhesive so as to provide a heating element with bonded layers in which the fibres of the mat have not become substantially separated by the adhesive.
  • the backing is preferably glass fibre filter paper.
  • Film adhesive is preferably a resin.
  • the heating element can be mounted on a propeller blade such that the perforated backing is towards the blade surface.
  • the perforated backing can then electrically insulate the fibre mat from the blade.
  • the perforated backing preferably provides strength and stability whilst allowing the heating element to be flexible for fitting to the surface of apparatus to be heated. In particular, it is suitable for fitting to an aircraft propeller blade.
  • the present invention in a third aspect is a method of producing a heating element by providing a fibre mat with a perforated backing, applying film adhesive to the surface of the fibre mat or backing, and curing to fuse the adhesive so as to bond the paper and mat.
  • the curing step preferably results in a heating element which is still flexible.
  • the resulting bonded element can then be applied to apparatus to be heated such as a propeller blade, and fixed thereto.
  • the present invention in its fourth aspect is a method of providing a heating element on an apparatus to be heated by applying a fibre mat with a perforated backing to the apparatus, at least a surface of the mat or a surface of backing being provided with a film adhesive, and curing to fuse the adhesive so as to bond the filter paper and fibre mat to each other and to the blade.
  • This can be done as a single curing step.
  • the curing can be done in two stages, first to bond the mat and paper, and secondly, to fix the resulting composite to the blade.
  • Figure 1 is a diagrammatic oblique view of a heating element applied to a propeller blade
  • Figure 2 is a diagrammatic oblique view of an alternative heating element
  • Figure 3 is a diagrammatic view illustrating the layered structure of the heating elements.
  • the heating element comprises two mats 1,2.
  • the mats 1,2 are made of nickel coated carbon fibre.
  • the mats 1,2 are fixed to the propeller blade 12 adjacent a leading edge 14. In alternative embodiments, multiple mats could be provided one over the other.
  • the blade root of the propeller 4 includes two studs 5,6.
  • the studs 5,6 can be connected directly to mats 1,2 as shown in Figure 1, or via connecting wires 7,8 as shown in Figure 2.
  • One stud 5 is positive, whilst the other stud 6 is negative.
  • power is supplied to the mats 1,2 via the studs 5,6 by way of bus bars 9,10 fastened to the mats 1,2.
  • the two mats 1,2 are connected together near the tip of the propeller blade 12 via a further bus bar 16.
  • Multiple mats 1,2 can be laid one over the other so as to provide additional heating. Alternatively, they could be replaced by a single continuous layer or composite of multiple continuous layers.
  • the geometry of the mats 1,2 can be optimised so as to provide a preferred heating pattern. In particular, holes can be made in the mat for this purpose.
  • the heating element consists of nickel coated carbon fibre mats 1,2 backed by glass fibre filter paper 18.
  • a fibre mat and filter paper backing are fastened together using a resin 20 such as a polyurethane resin.
  • the resin 20 is preferably applied to the outwardly directed surface of the filter paper, then the mat and filter paper are keyed together by curing the resin 20.
  • the perforations through the weave of the filter paper acts to soak up excess resin, avoiding excessive resin between the fibres of the fibre mat. Some resin soaks into the mat providing some protection and giving rise to a small reduction in resistivity as fibres move apart. The resulting composite is still flexible.
  • the composite is fitted onto a propeller blade 12 preferably with the filter paper 18 toward the blade 12.
  • the composite is further cured under applied pressure so as to fasten the heating element to the blade.
  • the pressure can be supplied by covering the composite with a flexible membrane so as to define an enclosed space then causing a vacuum in that space, so that the membrane presses the composite.
  • the present invention provides a simple yet robust heating element which can be produced and/or applied to apparatus to be heated in a simple and effective way.

Abstract

Elément chauffant (1, 2) alimenté par l'énergie électrique, destiné à une pale d'hélice, et composé d'une enveloppe de fibres possédant au moins des surfaces électroconductrices. Cette enveloppe peut posséder un support perforé auquel elle est fixée à l'aide d'un adhésif. Des procédés de production de l'élément chauffant et de fixation de celui-ci sur une pale d'hélice impliquent une étape de durcissement afin de lier l'enveloppe et le support à l'aide de l'adhésif.
EP95925928A 1994-07-21 1995-07-19 Element chauffant Withdrawn EP0771285A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB9414744A GB2291575A (en) 1994-07-21 1994-07-21 Heating element for aircraft surface.
GB9414744 1994-07-21
PCT/GB1995/001713 WO1996003316A1 (fr) 1994-07-21 1995-07-19 Element chauffant

Publications (1)

Publication Number Publication Date
EP0771285A1 true EP0771285A1 (fr) 1997-05-07

Family

ID=10758688

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95925928A Withdrawn EP0771285A1 (fr) 1994-07-21 1995-07-19 Element chauffant

Country Status (3)

Country Link
EP (1) EP0771285A1 (fr)
GB (1) GB2291575A (fr)
WO (1) WO1996003316A1 (fr)

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2756253B1 (fr) * 1996-11-27 1999-01-29 Eurocopter France Elements resistifs pour le chauffage d'un profil aerodynamique, et dispositif de chauffage d'un profil aerodynamique incorporant de tels elements
FR2756254B1 (fr) * 1996-11-27 1999-01-29 Eurocopter France Dispositif de chauffage d'un profil aerodynamique
DE10151298A1 (de) * 2001-10-17 2003-04-30 Joerg Runge-Rannow Heizfolie aus mehreren Schichten und Verfahren zu deren Herstellung
US6753513B2 (en) * 2002-03-19 2004-06-22 Hamilton Sundstrand Propeller de-icing system
RU2007149271A (ru) 2005-05-27 2009-07-10 Белл Хеликоптер Текстрон Инк. (Us) Выдерживающий нагрузки проводящий/резистивный композитный гибридный нагреватель для теплового противообледенительного устройства
GB2433185B (en) * 2005-12-06 2011-08-10 Hotfoot Heated Membranes Ltd Heating element
WO2012125919A1 (fr) * 2011-03-16 2012-09-20 GKN Aerospace Services Structures, Corp. Stratifié composite à pont de circuit souple et son procédé de fabrication
FR3068195B1 (fr) * 2017-06-27 2019-07-19 Airbus Helicopters Procede de fabrication d'un equipement tournant de voilure tournante muni d'un degivreur, ledit equipement tournant et un drone muni dudit equipement tournant
EP3708496B1 (fr) * 2019-03-15 2023-11-29 Ratier-Figeac SAS Dégivrage de lames
US11427336B2 (en) 2020-03-25 2022-08-30 Goodrich Corporation High strain tolerant chord-wise ice protection layout
GB2607884B (en) * 2021-06-11 2023-11-15 Ubiq Aerospace As System and method for deicing of a carbon composite propeller

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2356336A1 (fr) * 1976-06-25 1978-01-20 Licentia Gmbh Element chauffant a resistance electrique destine a etre utilise notamment sur des profiles d'avions ou sur des pales de rotors d'helicopteres
DE2707317A1 (de) * 1977-02-19 1978-08-24 Licentia Gmbh Elektrisches widerstands-heizelement
DE2628731C3 (de) * 1976-06-25 1981-03-26 Licentia Patent-Verwaltungs-Gmbh, 60596 Frankfurt Elektrisches Widerstands-Heizelement
GB2121745A (en) * 1982-06-17 1984-01-04 Westland Plc Aircraft de-icing apparatus
US4764665A (en) * 1985-07-02 1988-08-16 Material Concepts, Inc. Electrically heated gloves
WO1991011891A1 (fr) * 1990-01-24 1991-08-08 Hastings Otis Stratifie electroconducteur de regulation de temperature de surfaces

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9603316A1 *

Also Published As

Publication number Publication date
GB9414744D0 (en) 1994-09-07
GB2291575A (en) 1996-01-24
WO1996003316A1 (fr) 1996-02-08

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Legal Events

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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Effective date: 19970131

AK Designated contracting states

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Designated state(s): FR

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Effective date: 19970923

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18D Application deemed to be withdrawn

Effective date: 19980204