US3364335A - Device for electrically heating surface structures such as roads, bridges, airport runways, walls, and the like - Google Patents

Device for electrically heating surface structures such as roads, bridges, airport runways, walls, and the like Download PDF

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Publication number
US3364335A
US3364335A US400814A US40081464A US3364335A US 3364335 A US3364335 A US 3364335A US 400814 A US400814 A US 400814A US 40081464 A US40081464 A US 40081464A US 3364335 A US3364335 A US 3364335A
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United States
Prior art keywords
heating
current
conductor
heating conductor
conductor means
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Expired - Lifetime
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US400814A
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English (en)
Inventor
Palatini Benno
Pferschy Herbert
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Individual
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Individual
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D13/00—Electric heating systems
    • F24D13/02—Electric heating systems solely using resistance heating, e.g. underfloor heating
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
    • E01C11/00—Details of pavings
    • E01C11/24—Methods or arrangements for preventing slipperiness or protecting against influences of the weather
    • E01C11/26—Permanently installed heating or blowing devices ; Mounting thereof
    • E01C11/265—Embedded electrical heating elements ; Mounting thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/32—Insulated conductors or cables characterised by their form with arrangements for indicating defects, e.g. breaks or leaks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B9/00—Power cables
    • H01B9/04—Concentric cables
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/26—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents
    • H02H3/32—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors
    • H02H3/34—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors of a three-phase system
    • H02H3/347—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors of a three-phase system using summation current transformers
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/22—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices
    • H02H7/226—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for distribution gear, e.g. bus-bar systems; for switching devices for wires or cables, e.g. heating wires
    • 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
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/26—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents
    • H02H3/32—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors
    • H02H3/33—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors using summation current transformers
    • H02H3/334—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors using summation current transformers with means to produce an artificial imbalance for other protection or monitoring reasons or remote control
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]

Definitions

  • surfacings which consist of a plastic grid the stays of which are hollow. These hollow stays carry heating conductors closely below the surface.
  • the grid is fastened to the support and fixed to it by pouring a filler into the meshes.
  • the heating conductors consist, for instance, of an insulated standard copperaluminumdron strand. They are arranged in the grid in meander shape with small spacings so that the entire heated area is covered. They are directly connected to the service net. In mechanical respects, particularly due to their excellent adherence to the support and their thermal properties, these heated surfacings are eminently suitable for taxiways and runways.
  • the heating conductors are arranged immediately below the surface, the heat-up times are extraordinarily short so that their use is not only economical, but moreover a preset control is made possible which enables eflicient operation under all conditions occurring in practice.
  • This plurality of advantages is compared to the only substantial shortcoming that low voltages can be connected to the heating conductors, since these are not sufficiently protected to avoid risk to man and animal in the case of defects occurring in the device.
  • the risk factor is incompatible with the safety rules existing in most countries so that at present an eflicient heated surfacing is indeed known, but can or may not be used.
  • An object of the present invention is to provide a heating conductor and to choose its connection in such a way that absolute safety is guaranteed, although a high operating voltage is applied.
  • this is obtained by accomplishing the following characteristics in combination: (a) a heating conductor arranged below the surface of the structure, preferably enclosed in a grounded metallicconductor sheathing, which is connected to a voltage exceeding the permissible tolerance for man and animal; (b) at least one electrical safety connection which,
  • the immediate disconnection is mainly ensured by the fact that the grounded sheathing enclosing the insulated heating conductor is constituted as a closed sheath or as a coil and that this sheathing is surrounded by an insulating layer so that for the conductor stretching over a considerable length a locally defined grounding is provided and in the case of a short circuit between heating conductor and sheathing a current passes through this defined grounding, which serves to trigger switching operations.
  • the safety connection can be conceived as a voltageoperated leakage protective grounding or as a fault current protective grounding.
  • Heating conductors Mechanical protection of the heating conductors is provided by laying them closely below the surface of the structure in tubes or in unilaterally open sections of preferably trapezoidal cross section made, for instance, of glass-reinforced plastic.
  • the meshes between the tubes or sect-ions should be preferably filled up with an insulating filling cement, e.g., a synthetic-resin mineral aggregate.
  • an insulating filling cement e.g., a synthetic-resin mineral aggregate.
  • the heating conductors are preferably connected to a three phase power current.
  • the technical particularities pertaining to the surfacing itself are not important. They are determined by the intended use and the service requirements.
  • the use of the surfacing for airport runways, roads or floors, walls and ceilings evidently determines the selection of the material for the embedding of the heating conductors, the shape of the embedding, and the filler.
  • requirements as to adherence of temperature changes, wear resistance, permissible moisture absorption, etc play a decisive part.
  • the heating capacity and consequently the selection of the conductor cross section and possibly the operating voltage which exceeds, however, in any case the values of low voltage, are determined by the special duties of the heated surfacing. Particularly high requirements must be met by the heated surfacings of bridges, if freezing or formation of fog is to be prevented.
  • the operating system of the safety switch can be chosen arbitrarily. Tests have shown that with a threephase power current connection the above-mentioned requirements are fully met by an inductive fault current protective switch means. With this fault current protective switch the leak cur-rent is determined by means of a totalizing current transformer. The current feeds are found as a primary winding round an iron core carrying a secondary winding. As long as the heating cable is not defective, the vector sum of the current in the current transformer equals zero. 1f the heating cable becomes defective, the vector sum of the current in the primary winding no longer is zero and thus a current is induced in the secondary winding which triggers a switch via a highly sensitive relay. The sensitivity and the time of response can be adjusted in a relatively simple way.
  • FIG. 1 is a perspective view of a cross-section through a heating cable
  • FIG. 2 shows diagrammatically a fault current protective ground arrangement.
  • This sheath 3 is grounded.
  • a sheathing 4 is provided, made of polyamide with low water absorption; this sheating 4 not only electrically insulates the sheath 3 along the cable from the surrounding structure, but additionally protects the cable against penetration of moisture and humidity as well as mechanical damage.
  • a three-phase heating cable 5 is directly corn nected through a switch 6 to a network 7.
  • the metal sheathing 3 of the heating cable has a ground connection 8.
  • the switch 6 is associated with a totalizing current transformer 9.
  • a fault current trip 10 is inductively coupled with the totalizing current transformer.
  • the switch 6 If, owing to some cable defect, the vector sum of the current of the three phases does not equal zero, the current so induced and passing through the fault current trip 10 triggers the switch 6.
  • the sensitivity of the switch ranges within the order of magnitude of 10 to 10 ma. (milliamperes) and its reaction time is to about 200 msec. (milliseconds).
  • a voltage-operated leakage protective system can be provided.
  • the protective conductor 11 is grounded via a voltage-operated trip coil and this voltage-operated trip coil is connected in parallel with an o-vervoltage arrester.
  • a device for electrically heating objects of large surface area comprising heating conductor means arranged under the surface to be heated and electrically grounded, means for supplying the heating conductor means with a voltage exceeding the tolerance of human beings and animals, the latter means including a voltage supply means and current feeds from the supply means to the conductor means and an electrical safety device for selectively interrupting the connection between the heating conductor means and the voltage supply means in the event of ground leakage or short circuit of the heating conductor means, said safety device comprising switch means between the voltage supply means and the heating conductor means, a current transformer having a primary winding constituted by said current feeds and a secondary winding inductively coupled to the primary winding, said current transformer having zero output when the vector sum of the current in the current feeds is balanced and equal to zero, and a trip coil operatively coupled to said switch means and to the secondary winding of the transformer for opening the switch means when the vector sum of the current supplied to the conductor means is not equal to zero, said conductor means including a plurality of heating conductors each

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Civil Engineering (AREA)
  • Thermal Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Architecture (AREA)
  • Chemical & Material Sciences (AREA)
  • Structural Engineering (AREA)
  • Power Engineering (AREA)
  • Resistance Heating (AREA)
  • Surface Heating Bodies (AREA)
  • Road Paving Structures (AREA)
  • Control Of Resistance Heating (AREA)
US400814A 1963-05-31 1964-10-01 Device for electrically heating surface structures such as roads, bridges, airport runways, walls, and the like Expired - Lifetime US3364335A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT444863A AT258340B (de) 1963-05-31 1963-05-31 Einrichtung zum elektrischen Beheizen flächenhafter Beläge

Publications (1)

Publication Number Publication Date
US3364335A true US3364335A (en) 1968-01-16

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ID=3564138

Family Applications (1)

Application Number Title Priority Date Filing Date
US400814A Expired - Lifetime US3364335A (en) 1963-05-31 1964-10-01 Device for electrically heating surface structures such as roads, bridges, airport runways, walls, and the like

Country Status (8)

Country Link
US (1) US3364335A (de)
AT (1) AT258340B (de)
CH (1) CH439517A (de)
DE (1) DE1459745A1 (de)
FR (1) FR1397700A (de)
GB (1) GB1064261A (de)
NL (1) NL6406067A (de)
SE (1) SE316227B (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3521030A (en) * 1966-02-25 1970-07-21 Jerry D Maahs Mobile oven unit
US3725638A (en) * 1971-06-01 1973-04-03 Arctic Roof Deicing Corp Heat radiating assembly and apparatus for permitting ice blocked water to drain off of house roofs
US3800121A (en) * 1971-04-08 1974-03-26 B Saunders Electrical heating apparatus for reducing or preventing the formation of ice on aircraft parts
US4044224A (en) * 1976-03-01 1977-08-23 General Electric Company Protective circuit for dishwasher heating element
US5558794A (en) * 1991-08-02 1996-09-24 Jansens; Peter J. Coaxial heating cable with ground shield
US5811767A (en) * 1996-12-13 1998-09-22 Sperika Enterprises Ltd. Three wire, three-phase heating cable and system
US5814792A (en) * 1996-06-21 1998-09-29 Sperika Enterprises Ltd. Extra-low voltage heating system
US5854472A (en) * 1996-05-29 1998-12-29 Sperika Enterprises Ltd. Low-voltage and low flux density heating system

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1759524B1 (de) * 1968-05-10 1970-11-12 Chisso Corp Heizeinrichtung zum elektrischen Beheizen von flaechigen Belaegen
JP2632470B2 (ja) * 1992-02-28 1997-07-23 東日本旅客鉄道株式会社 面状発熱体による踏切の融雪構造
DE4302695A1 (de) * 1993-02-01 1994-08-04 Eilentropp Kg Elektrische Heizung
CN104835587A (zh) * 2015-05-28 2015-08-12 顺德职业技术学院 一种电线间漏电保护电缆

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1788107A (en) * 1922-03-11 1931-01-06 Cons Car Heating Co Inc Electric heating system
US2649532A (en) * 1952-02-08 1953-08-18 Westinghouse Electric Corp Water heater apparatus
US3086999A (en) * 1960-04-26 1963-04-23 Aluminum Co Of America Ground circuit supervisory system
US3124738A (en) * 1964-03-10 Overvoltage protection apparatus
US3209128A (en) * 1962-11-20 1965-09-28 Smith Gates Corp Heating mat
US3214638A (en) * 1959-10-02 1965-10-26 Moser Robert Ground responsive protective system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3124738A (en) * 1964-03-10 Overvoltage protection apparatus
US1788107A (en) * 1922-03-11 1931-01-06 Cons Car Heating Co Inc Electric heating system
US2649532A (en) * 1952-02-08 1953-08-18 Westinghouse Electric Corp Water heater apparatus
US3214638A (en) * 1959-10-02 1965-10-26 Moser Robert Ground responsive protective system
US3086999A (en) * 1960-04-26 1963-04-23 Aluminum Co Of America Ground circuit supervisory system
US3209128A (en) * 1962-11-20 1965-09-28 Smith Gates Corp Heating mat

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3521030A (en) * 1966-02-25 1970-07-21 Jerry D Maahs Mobile oven unit
US3800121A (en) * 1971-04-08 1974-03-26 B Saunders Electrical heating apparatus for reducing or preventing the formation of ice on aircraft parts
US3725638A (en) * 1971-06-01 1973-04-03 Arctic Roof Deicing Corp Heat radiating assembly and apparatus for permitting ice blocked water to drain off of house roofs
US4044224A (en) * 1976-03-01 1977-08-23 General Electric Company Protective circuit for dishwasher heating element
US5558794A (en) * 1991-08-02 1996-09-24 Jansens; Peter J. Coaxial heating cable with ground shield
US5854472A (en) * 1996-05-29 1998-12-29 Sperika Enterprises Ltd. Low-voltage and low flux density heating system
US5814792A (en) * 1996-06-21 1998-09-29 Sperika Enterprises Ltd. Extra-low voltage heating system
US5811767A (en) * 1996-12-13 1998-09-22 Sperika Enterprises Ltd. Three wire, three-phase heating cable and system

Also Published As

Publication number Publication date
CH439517A (de) 1967-07-15
SE316227B (de) 1969-10-20
NL6406067A (de) 1964-12-01
AT258340B (de) 1967-11-27
DE1459745A1 (de) 1968-12-12
GB1064261A (en) 1967-04-05
FR1397700A (fr) 1965-04-30

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