Classifications

• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01H—STREET CLEANING; CLEANING OF PERMANENT WAYS; CLEANING BEACHES; DISPERSING OR PREVENTING FOG IN GENERAL CLEANING STREET OR RAILWAY FURNITURE OR TUNNEL WALLS
  • E01H5/00—Removing snow or ice from roads or like surfaces; Grading or roughening snow or ice
• • 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
  • H05B3/342—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater flexible, e.g. heating nets or webs heaters used in textiles
  • H05B3/347—Heating elements having extended surface area substantially in a two-dimensional plane, e.g. plate-heater flexible, e.g. heating nets or webs heaters used in textiles woven fabrics
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63J—AUXILIARIES ON VESSELS
  • B63J2/00—Arrangements of ventilation, heating, cooling, or air-conditioning
• • 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
  • H05B2203/002—Heaters using a particular layout for the resistive material or resistive elements
  • H05B2203/005—Heaters using a particular layout for the resistive material or resistive elements using multiple resistive elements or resistive zones isolated from each other
• • 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
  • H05B2203/007—Heaters using a particular layout for the resistive material or resistive elements using multiple electrically connected resistive elements or resistive zones
• • 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
  • H05B2203/011—Heaters using laterally extending conductive material as connecting means
• • 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
• • 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
  • H05B2214/00—Aspects relating to resistive heating, induction heating and heating using microwaves, covered by groups H05B3/00, H05B6/00
  • H05B2214/02—Heaters specially designed for de-icing or protection against icing

Definitions

• the invention relates to methods, systems and structures for modifying ice adhesion strength between ice and selected objects. More particularly, the invention relates to methods, systems and structures that apply electrical energy to the interface between ice and objects so as to either increase or decrease the ice adhesion strength to facilitate desired results. 2. Statement of the Problem
• Ice adhesion to certain surfaces causes many problems. For example, excessive ice accumulation on aircraft wings endangers the plane and its passengers. Ice on ship hulls creates navigational difficulties, the expenditure of additional power to navigate through water and ice, and certain unsafe conditions. The need to scrape ice that forms on automobile windshields is regarded by most adults as a bothersome and recurring chore; and any residual ice risks driver visibility and safety.
• Icing and ice adhesion also causes problems with helicopter blades, and with public roads. Billions of dollars are spent on ice and snow removal and control. Ice also adheres to metals, plastics, glasses and ceramics, creating other day-to-day difficulties. Icing on power lines is also problematic. Icing adds weight to the power lines which causes power outages, costing billions of dollars in direct and indirect costs.
• the ice adhesion strength is decreased, making it possible to remove ice from the object by wind pressure, buffeting or light manual brushing.
• the ice adhesion strength between ice and surfaces of objects in contact with the ice are increased. For example, when the ice adhesion strength is increased between automobile tires and icy roadways, there is less slippage and fewer accidents.
• a charge is generated at the interface of ice in contact with a object, it is possible to selectively modify the adhesion between the ice and the object.
• U.S. Patent No. 6,027,075 discloses a power source connected to apply a DC voltage across the interface between ice and the surface upon which the ice forms.
• the object having the conductive surface can be an aircraft wing or a ship's hull (or even the paint applied to the structure).
• U.S. Patent No.6,027,075 discloses a first electrode connected with the surface; a nonconductive or electrically insulating material is applied as a grid over the surface; and a second electrode is formed by applying a conductive material, for example conductive paint, over the insulating material, but without contacting the surface.
• a conductive material for example conductive paint
• 6,027,075 is formation of the grid electrodes and associated insulating layers.
• the individual components of the grid system, including electrodes, wiring and insulators, are fabricated on a small scale.
• Photolithographic techniques are capable of fabricating such grid systems. oto t ograp y s use very ef ectively in integrated circuit fabrication.
• the use of photolithography to form a grid system for modifying ice adhesion, however, is less suitable. It involves a large number of patterning and etching steps. Applied to ice control technology, photolithography is expensive, complicated and unreliable.
• An embodiment of the present invention replaces the grid described in U.S. Patent No.6,027,075.
• An embodiment of the present invention provides a composite coating comprising separate, closely spaced wire electrodes separated by insulator fibers.
• the wire electrodes and insulator fibers are typically woven together using known and reliable industrial technologies.
• the wire electrodes are connected alternately to a DC power source in such a manner to function as cathodes and anodes.
• the composite coating is durable and flexible, and is typically applied to the surface to be protected using conventional adhesives.
• the metal wires may be gold, platinum-plated titanium or niobium, or other material with high resistance to electro-corrosion.
• dielectric insulator fibers nylon, glass or other dielectric material may be used.
• the dielectric fibers keep the metal electrodes apart, while providing coating integrity.
• the dielectric insulator fibers electrically insulate the wire electrodes from the surface on which the composite coating is applied.
• Typical wire diameters are in the range of from 10 to 100 ⁇ m, with the same range of open space between the electrode wires and insulator fibers. If ice forms in and over the composite coating, a dc bias is applied to the electrodes. As a result, the ice adhesion strength at the interface of the ice and the surface of the object being protected is modified.
• the wire electrodes of a composite coating are connected to a DC bias source so that they have the same DC bias.
• the surface on which the composite coating is applied is electrically conductive and has an opposite DC bias. Ice formed in the spaces of the composite coating close the electrical circuit.
• a wire mesh comprising electrically conductive wires is formed.
• the wire mesh is disposed on an electrically conductive surface, with an insulating layer interposed between the wire mesh and the surface.
• a DC bias is applied to the wire mesh and an opposite DC bias is applied to the surface. Ice that is formed in the spaces of the wire mesh closes the electrical circuit.
• the invention takes the form of a composite cloth, it contains both the functional anodes and cathodes necessary for the system to work. Therefore, it is not important whether the surface of the object to be protected is electrically conductive or nonconductive.
• FIG. 1 shows a deicing system incorporating an electrical coating to deice surfaces in accord with the invention
• FIG.2 shows an alternate deicing system incorporating an electrical coating to deice surfaces in accord with the invention
• FIG. 3 depicts a composite coating having cathode wires and anode wires in accordance with the invention that operates to modify the adhesion of ice formed on a surface;
• FIG. 4 depicts a composite coating in accordance with the invention in which the electrode wires have the same bias
• FIG. 5 depicts a wire mesh in accordance with the invention.
• FIG. 1 shows one system 10 incorporating an electrical deicing coating 12 to affect ice 14 that might adhere to surface 16.
• Surface 16 may for example be an airplane wing, helicopter blade, jet inlet, heat exchanger for kitchen and industrial equipment, refridgerator, road signs, ship overstructures, or other object subjected to cold, wet and ice conditions. More specifically, coating 12 is applied over surface 16 to protect surface 16 from ice 14. Coating 12 is preferably flexible so as to physically conform to the shape of surface 16.
• a voltage is applied to coating 12 by power supply 18.
• this voltage is over two volts and generally between two and one hundred volts, with higher voltages being applied for lower temperatures.
• approximately 20V is applied to coating 12 to provide 10mA/cm ⁇ 2 current density through very pure atomospheric ice such as found on airplane wings.
• ice 14 decomposes into gaseous oxygen and hydrogen through electrolysis. Further, gases form within ice 14 generating high- pressure bubbles that exfoliate ice 14 from coating 12 (and hence from surface 16).
• Typical current density applied to coating 12 is between about 1-10mA/cm ⁇ 2.
• voltage regulator subsystem 20 is connected in feedback with power supply 18, and hence with the circuit formed by coating 12 and ice 14, so as to increase or decrease DC voltage applied to coating 12 according to optimum conditions.
• FIG. 2 shows one system 40 incorporating an electrical deicing coating 42 to affect ice 44 that might adhere to conductive surface 46.
• Conductive surface 46 may for example be an airplane wing, helicopter blade, jet inlet, heat exchanger for kitchen and industrial equipment, refridgerator, road signs ship overstructures, or other object subjected to cold, wet and ice conditions.
• coating 42 is applied over surface 46 to protect surface 46 from ice 44.
• Coating 42 is preferably flexible so as to physically conform to the shape of surface 46.
• a voltage is applied between coating 42 and surface 46 by power supply 48.
• the bias voltage applied to coating 42 may be equal and opposite to the bias voltage applied to surface 46.
• an insulator 45 may be disposed between coating 42 and surface 46; insulator 45 preferably comprises a dielectric mesh configuration described below.
• the voltage between coating 42 and surface 46 is over two volts and generally between two and one hundred volts, with higher voltages being applied for lower temperatures.
• ice 44 When voltage is applied, ice 44 decomposes into gaseous oxygen and hydrogen through electrolysis. Further, gases form within ice 44 generating high- pressure bubbles that exfoliate ice 44 from coating 42 (and hence from surface 46).
• Typical current density applied to coating 42 is between about 1-10mA/cm ⁇ 2.
• voltage regulator subsystem 50 is connected in feedback with power supply 48, and hence with the circuit formed by coating 42, surface 46, and ice 44, so as to increase or decrease DC voltage applied to coating 42 according to optimum conditions.
• the composite coating comprises metal electrode wires separated by dielectric insulator fibers in a flexible format so as to be applied to surface 16 needing protection from ice.
• a dc bias By applying a dc bias, the ice adhesion strength between ice and the electrodes of coating, as well as between ice and surface, is modified.
• Ice has certain physical properties which allow the present invention to selectively modify the adhesion of ice to conductive (and semi-conductive) surfaces. If a charge is generated on the surface coming on contact with ice, it is possible to selectively modify the adhesion between the two surfaces.
• ice is a protonic semiconductor, a small class of semiconductors whose charge carriers are protons rather than electrons. This phenomenon results from hydrogen bonding within the ice. Similar to typical electron-based semiconductors, ice is electrically conductive, although this electrical conductivity is generally weak.
• LLL liquid-like layer
• the LLL is also a major factor of ice adhesion strength.
• the combination of the semiconductive properties of ice and the LLL allows one to selectively manipulate ice adhesion strength between ice and other objects.
• water molecules within a piece of ice are randomly oriented. On the surface, however, the molecules are substantially oriented in the same direction, either outward or inward. As a result, all their protons, and hence the positive charges, eitherface outward or inward. While the exact mechanism is unknown, it is likely that the randomness of water molecules trans tions to an or ere or entat on w t n the LLL.
• the practical result of the ordering is that a high density of electrical charges, either positive or negative, occurs at the surface.
• Ice includes polar water molecules that strongly interact with any solid substrate which has dielectric permittivity different from that of ice.
• any solid substrate which has dielectric permittivity different from that of ice.
• Electrolysis is an important factor. When a dc current flows through ice, gaseous hydrogen (H 2 ) and oxygen (O 2 ) accumulate at the ice interfaces in the form of small bubbles, due to ice electrolysis. These bubbles play a role in the development of interfacial cracks, reducing the ice adhesion strength.
• FIG. 3 depicts a composite coating 100 having cathode wires 102 and anode wires 104, in accordance with the invention.
• Dielectric wires 106 form an insulating weave about wires 102, 104 to prevent shorting.
• Wires 102, 104 for example connect to power supply 18 (or supply 48) such that appropriate current density affects ice adhering to coating 100.
• the current density is made to decrease adhesion strength between ice and coating 100, such that coating 100 operates to protect surfaces, such as surface 16, from ice.
• Typical spacings between wires 102 are 10- 50 ⁇ m; typical spacings between wires 104 are also 10-50 ⁇ m.
• Wires 102, 104 are for example made from gold, platinum plated titanium or niobium, or from metal with high resistance to electro-corrosion.
• FIG. 4 depicts a composite coating 120 in accordance with the invention.
• Coating 120 has alternating electrode wires 122, each with equal bias from the connected power supply. Coating 120 may for example be applied to surface 46 of FIG.2, where surface 46 is conductive; a voltage potential exists between surface 46 and wires 122.
• An insulating mesh 124 prevents wires 122 from shorting, and further prevents shorting between wires 122 and surface 46. Ice 44 completes the circuit between wires 122 and surface 46 to invoke the ice adhesion modifications of the invention.
• FIG. 5 depicts a wire mesh coating 150 constructed in accordance with the invention. Mesh coating 150 is generally conductive, with both wires 152 and weave components 154 being conductive.
• Mesh coating 150 is thus applied to conductive surface 46 with an insulator 45 disposed therebetween.
• Insulator 45 is constructed so as to protect surface 46 when ice 44 completes the circuit between mesh coating 150 and surface 46.
• a voltage potential between mesh coating 150 and surface 46 modifies the adhesion strength of ice 44 as desired.
• a typical current density applied to coatings of the invention are from 1 to 10 mA/cm 2 .
• Operating voltages are typically in the range of from 2 to about 100 volts, depending on ice temperature and spacing between wires. The lower the temperature, the higher the voltage required. The larger the interwire spacing, the higher the voltage required. For a typical temperature of -10 °C and a spacing of 50 ⁇ m, a bias of approximately 20 volts provides a current density of about 10 mA/cm 2 through very pure ice.
• anode wires 104, FIG. 3) have a very high resistance to anodic corrosion. For that, they may be coated with thin layers of platinum or gold or amorphous carbon. Other alloys may also be applied.
• Cathode wires 102 should also be impenetrable to hydrogen. Examples of good cathode material include gold, copper, brass, bronze, and silver.
• a composite coating or wire mesh in accordance with the invention is flexible.
• wire meshes and composite coatings described herein can be fabricated using conventional methods used in industry.
• An inventive mesh or composite coating can be applied to a surface by simply stretching it over the surface of with a thin layer of adhesive placed between the composite coating or mesh and the surface.

Applications Claiming Priority (3)

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• 2000
  • 2000-12-28 EP EP00986766A patent/EP1242280A4/de not_active Withdrawn
  • 2000-12-28 KR KR10-2002-7008545A patent/KR100465032B1/ko not_active IP Right Cessation
  • 2000-12-28 CN CN00817886A patent/CN1414919A/zh active Pending
  • 2000-12-28 JP JP2001550108A patent/JP2004501015A/ja active Pending
  • 2000-12-28 WO PCT/US2000/035529 patent/WO2001049564A1/en not_active Application Discontinuation
  • 2000-12-28 AU AU22946/01A patent/AU2294601A/en not_active Abandoned
  • 2000-12-28 RU RU2002120184/11A patent/RU2218291C1/ru not_active IP Right Cessation
  • 2000-12-28 CA CA002395673A patent/CA2395673C/en not_active Expired - Fee Related

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