Uniform Heat Distribution in Resistive Heaters For Anti-Icing and De-Icing

Abstract

The concept of the present invention describes configurations to provide uniform heat distribution of resistive heaters. This configuration allows successful anti-icing and deicing with relatively low applied power. One aspect involves the use of a thin film heater applied just underneath the topcoat to efficiently direct all heat to the surface, allowing anti-icing and de-icing with minimal power. This can be accomplished by employing a hybrid electrode interface, using a metal foil or metal braid that is attached to the aircraft surface with a structural adhesive that has been smoothed along the edges with metal-filled adhesive. Another aspect of the present invention uses an array of heater cells created as a single sheet and a heat spreading material, provided underneath or overtop of the heater cells.

1 - 17 . (canceled) 
     
     
         18 . A method of making an array of CNT heater cells on an aircraft surface, comprising:
 providing an aircraft surface;   attaching pairs of electrodes to the aircraft surface with an adhesive;   placing a mask over a portion of the surface between the pairs of electrodes;   spraying a layer of CNTs over the electrodes and the mask; and   removing the mask to form at least two heater cells separated by a region with little or no CNTs; where each heater cell comprises a pair of electrodes in electrical contact with a CNT layer that is disposed between a pair of electrodes.   
     
     
         19 . The method of  claim 18  further comprising depositing a heat spreading layer on the aircraft surface prior to the step of placing the mask on the surface. 
     
     
         20 . The method of  claim 19  further comprising depositing a heat spreading layer over the aircraft surface after the step of placing the mask. 
     
     
         21 . The method of  claim 20  further comprising depositing the heat spreading layer onto the mask and electrodes. 
     
     
         22 . The method of  claim 19  wherein the heat spreading layer is applied by coating the surface with a coat of solvent-based epoxy. 
     
     
         23 . The method of  claim 18  further comprising wrapping a fibrous non-woven veil over the array. 
     
     
         24 . The method of  claim 23  further comprising applying an epoxy layer over the veil. 
     
     
         25 . The method of  claim 18  wherein the aircraft surface is part of an existing aircraft. 
     
     
         26 . The method of  claim 18  further comprising depositing a protective layer having a thickness of 500 μm or less, or more preferably 100 μm or less, after the step of removing the mask. 
     
     
         27 . The method of  claim 18  wherein the surface comprises apertures for passing leads through the aircraft surface. 
     
     
         28 . The method of  claim 18  further comprising scuffing the surface prior to the step of attaching electrodes. 
     
     
         29 . The method of  claim 28  further comprising wiping the surface with a solvent prior to the step of attaching electrodes. 
     
     
         30 . The method of  claim 28  further comprising Corona treating the surface prior to the step of attaching electrodes. 
     
     
         31 . The method of  claim 18  wherein the leads, between 2 in to 3.5 in in length, were placed in parallel, spaced between 1.5 in to 2.5 in apart, and attached to the substrate with an adhesive. 
     
     
         32 . The method of  claim 18  wherein the interface between the leads and CNT heaters has a smooth transition created by applying an insulating epoxy. 
     
     
         33 . The method of  claim 18  further comprising attaching the electrodes to the surface with a structural adhesive. 
     
     
         34 . The method of  claim 33  wherein the amount of structural adhesive is metered to prevent spreading of the adhesive past the leads. 
     
     
         35 . The method of  claim 18  further comprising applying a conductive polymer onto the electrodes. 
     
     
         36 . The method of  claim 28  wherein the scuffing is performed mechanically using a rough surface and/or chemically using an ammonium hydroxide bath followed by an ultrasonic bath. 
     
     
         37 . The method of  claim 18  further comprising curing the array after removal of the mask.