EP0098253A1 - Câble de chauffage et procédé pour sa fabrication - Google Patents

Câble de chauffage et procédé pour sa fabrication Download PDF

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Publication number
EP0098253A1
EP0098253A1 EP19830850178 EP83850178A EP0098253A1 EP 0098253 A1 EP0098253 A1 EP 0098253A1 EP 19830850178 EP19830850178 EP 19830850178 EP 83850178 A EP83850178 A EP 83850178A EP 0098253 A1 EP0098253 A1 EP 0098253A1
Authority
EP
European Patent Office
Prior art keywords
conductors
heating cable
plastic
plastic layer
apertures
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Withdrawn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
EP19830850178
Other languages
German (de)
English (en)
Inventor
Gösta Rudolf Nilsson
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.)
KIMA ELPRODUKTER AB
Original Assignee
KIMA ELPRODUKTER AB
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 KIMA ELPRODUKTER AB filed Critical KIMA ELPRODUKTER AB
Publication of EP0098253A1 publication Critical patent/EP0098253A1/fr
Withdrawn legal-status Critical Current

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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
    • H05B3/40—Heating elements having the shape of rods or tubes
    • H05B3/54—Heating elements having the shape of rods or tubes flexible
    • H05B3/56—Heating cables

Definitions

  • This invention relates to heating cables and methods of making such cables.
  • Heating cables have already been suggested, which include two electric conductors extending longitudinally of each other in spaced relation, each of said conductors having an insulating coating. These insulated conductors are further enclosed in a first insulating covering which forms a support for a resistance wire which is helically wound along the entire length of the cable and which in turn is surrounded by a main insulating sheath.
  • the cable can also be reinforced with a shielding or reinforcing layer surrounding the main insulating sheath or layer, and said shielding or reinforcing layer may be provided with an outer corrosion proofing layer.
  • the points of contact between the conductors and the resistance wire are arranged alternately along the length of the cable.
  • Heating cables consisting of two parallel bare-wire conductors which are enclosed in an electrically semi-conductive composition of the PTC type, have also been suggested already, cf. for example European application 8235.
  • PTC type here means a markedly positive temperature coefficient for the resistivity of the composition, i.e. the resistivity increases relatively slowly up to a certain critical temperature above which it increases very rapidly.
  • the current flow between the bare-wire conductors is directed at right angles to the longitudinal direction of the conductors, for which reason the composition must have so high a resistivity as is reached only above said critical temperature.
  • an automatic temperature control in a heating cable and the cable can be cut at an optional point, but in practice such a heating cable is unreliable owing to non-homogeneities along the length of the conductors.
  • the object of the present invention therefore is to provide a heating cable which has been considerably improved compared to the above-described known heating cables, and a method for making said improved heating cable.
  • a heating cable including at least two electric conductors extending longitudinally of each other in spaced relation, each of said electric conductors having an insulating coating
  • the characteristic features that the coating completely covers the respective conductors except for apertures in said conductors, which are spaced longitudinally of and arranged alternately in the conductors, that the conductors are surrounded by a continuous plastic layer of relatively low and substantially temperature-independent resistivity, said plastic layer being in contact with the conductors in the apertures so that the current flow through the plastic layer is substantially longitudinally directed, and that an electrically insulated outer layer completely covers said plastic layer.
  • the method of making a heating cable which includes at least two electric conductors extending longitudinally of each other in spaced relation, each of said conductors having an insulating coating, is characterised according to the invention in that apertures in the insulating coatings are provided alternately on the conductors at intervals corresponding to the intended supply voltage and the desired effect at said voltage, that the conductors are provided with a surrounding continuous layer by extrusion of a plastic of relatively low and substantially temperature-independent resistivity, and that an electrically insulating outer layer is applied by extrusion to cover said plastic layer.
  • Applying the heating cable construction according to the invention permits using electrically conductive plastic of relatively low and substantially temperature-independent resistivity. Still, the construction is such that an adaptation to any extra-low and low voltages in say the range of 12-440 V is possible. For example, a plastic having a temperature coefficient lower than 5% can be used.
  • the heating cable according to the present invention besides eliminates substantially all disadvantages inherent in the conventional wire wound heating cable.
  • Fig. 1 to which a first reference is made, illustrates a conventional heating cable 1 having two electric conductors 2 which are insulated by means of a high-insulating coating 3.
  • the coatings and their insulations are embedded in a covering 4 which consists of say silicone rubber and forms a support for a resistance wire 5 which is helically wound along the entire length of the cable.
  • the resistance wire 5 is surrounded by the main insulation 6 of the cable, which in turn is preferably surrounded by a shield or reinforcement 7 of say galvanized iron wire.
  • the cable On the outside, the cable has a corrosion proofing layer 8 of some suitable plastic.
  • Fig. 2 shows some embodiments of the heating cable according to the invention in cross-section.
  • the electric conductor may be a single conductor 9 or a conductor 10 composed of several strands.
  • the conductors 9, 10 have a high-insulating coating 11 which may consist of lacquer, enamel, yarn, a chemical insulation or a plastic insulation.
  • the coating 11 covers the respective conductors completely except for apertures 12 which are spaced apart along the conductors in an alternating manner thereon, as is apparent from Fig. 4.
  • Fig. 4 shows that covers the respective conductors completely except for apertures 12 which are spaced apart along the conductors in an alternating manner thereon, as is apparent from Fig. 4.
  • the apertures can be realized by abrasion of the high-insulating coating 11, by annular peeling thereof or by unilateral scraping off of the coating 11.
  • the electrically conductive plastic layer 13 thus is contact with the conductors 9 and 10 in said apertures, for which reason the current-flow through the plastic layer 13 will be substantially longitudinally directed.
  • An electrically insulating outer layer 14 covers the plastic layer 13 completely.
  • the plastic layer 13 may consist of a polyethylene plastic, in which case temperatures of up to about 90 0 C can be achieved in the cable, or silicone plastic, in which case higher temperatures of up to about 270 0 C can be achieved in the cable.
  • a usable plastic is a semi-conductive quality of an elastomeric thermoplastic with the designation XT6002:70. This plastic is available from ASEA KABEL AB and more particularly is a butyl-doped polyethylene plastic which is extrudable and has a volume resistivity of less than 10 3 ohm.cm. A typical temperature coefficient is.2.5-3.0% in the temperature range 25-75°C.
  • the intervals between the apertures may be reduced to about 1 dm, and compared with a conventional wire wound heating cable a reduction of the manufacturing cost by about 50% can be attained.
  • apertures may alternately.be made in the insulating coatings of the conductors utilized, at intervals corresponding to the intended supply voltage and the desired effect at this voltage.
  • the apertures can be realized while the conductors are advanced through an extruding nozzle in which the plastic of relatively low resistivity is applied in a continuous layer surrounding the conductors.
  • the conductive plastic will thus make direct electric contact with the conductors through said apertures.
  • an electrically insulating outer layer for example of polyvinyl chloride, can be applied in order to cover the electrically conductive plastic layer.

Landscapes

  • Insulated Conductors (AREA)
  • Resistance Heating (AREA)
EP19830850178 1982-06-24 1983-06-23 Câble de chauffage et procédé pour sa fabrication Withdrawn EP0098253A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8203931 1982-06-24
SE8203931A SE8203931L (sv) 1982-06-24 1982-06-24 Vermekabel och sett att framstella densamma

Publications (1)

Publication Number Publication Date
EP0098253A1 true EP0098253A1 (fr) 1984-01-11

Family

ID=20347175

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19830850178 Withdrawn EP0098253A1 (fr) 1982-06-24 1983-06-23 Câble de chauffage et procédé pour sa fabrication

Country Status (2)

Country Link
EP (1) EP0098253A1 (fr)
SE (1) SE8203931L (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4859812A (en) * 1987-01-28 1989-08-22 Homac Mfg. Company Flat cable and sealing element
EP0344734A1 (fr) * 1988-06-01 1989-12-06 Matsushita Electric Industrial Co., Ltd. Composition chauffante pour l'autorégulation de la température
US4924038A (en) * 1987-01-28 1990-05-08 Homac Mfg. Company Flat cable sealing element
FR2667755A1 (fr) * 1990-10-03 1992-04-10 Deleage Pierre Cable chauffant, destine au chauffage direct par rayonnement.

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3757086A (en) * 1972-10-05 1973-09-04 W Indoe Electrical heating cable
DE3017826A1 (de) * 1979-05-10 1980-11-20 Sunbeam Corp Flexible heizelemente und verfahren zu deren herstellung
US4286376A (en) * 1975-01-20 1981-09-01 Raychem Corporation Method of making heater cable of self-limiting conductive extrudates
EP0040537A2 (fr) * 1980-05-19 1981-11-25 RAYCHEM CORPORATION (a California corporation) Compositions de polymères conducteurs à coefficient positif de température et dispositifs les contenant ainsi que méthode pour leur fabrication
DE3115242A1 (de) * 1980-06-24 1982-05-13 Sunbeam Corp., 60650 Chicago, Ill. Heizkabel, insbesondere fuer elektrische heizdecken
US4330703A (en) * 1975-08-04 1982-05-18 Raychem Corporation Layered self-regulating heating article

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3757086A (en) * 1972-10-05 1973-09-04 W Indoe Electrical heating cable
US4286376A (en) * 1975-01-20 1981-09-01 Raychem Corporation Method of making heater cable of self-limiting conductive extrudates
US4330703A (en) * 1975-08-04 1982-05-18 Raychem Corporation Layered self-regulating heating article
DE3017826A1 (de) * 1979-05-10 1980-11-20 Sunbeam Corp Flexible heizelemente und verfahren zu deren herstellung
EP0040537A2 (fr) * 1980-05-19 1981-11-25 RAYCHEM CORPORATION (a California corporation) Compositions de polymères conducteurs à coefficient positif de température et dispositifs les contenant ainsi que méthode pour leur fabrication
DE3115242A1 (de) * 1980-06-24 1982-05-13 Sunbeam Corp., 60650 Chicago, Ill. Heizkabel, insbesondere fuer elektrische heizdecken

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4859812A (en) * 1987-01-28 1989-08-22 Homac Mfg. Company Flat cable and sealing element
US4924038A (en) * 1987-01-28 1990-05-08 Homac Mfg. Company Flat cable sealing element
EP0344734A1 (fr) * 1988-06-01 1989-12-06 Matsushita Electric Industrial Co., Ltd. Composition chauffante pour l'autorégulation de la température
US5196145A (en) * 1988-06-01 1993-03-23 Matsushita Electric Industrial Co., Ltd. Temperature self-controlling heating composition
FR2667755A1 (fr) * 1990-10-03 1992-04-10 Deleage Pierre Cable chauffant, destine au chauffage direct par rayonnement.

Also Published As

Publication number Publication date
SE8203931L (sv) 1983-12-25
SE8203931D0 (sv) 1982-06-24

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Legal Events

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

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

17P Request for examination filed

Effective date: 19840331

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19860108

RIN1 Information on inventor provided before grant (corrected)

Inventor name: NILSSON, GOESTA RUDOLF