Gkn Aerospace Services Limited

Peter English

Stuart Martin Lewis

Nicholas John Winter

David John Armstrong

Thomas Stephen Rowe Richards

An electrothermal heater for an ice protection system includes a laminated heater mat which comprises a primary heater element layer, a secondary heater element layer, and at least one dielectric layer interposed between the primary and secondary heater element layers, and control apparatus which comprises power supply apparatus and a current detector. The control apparatus is configured to have (i) a first mode in which the power supply apparatus supplies a heater current to the primary heater element layer and does not supply a heater current to the secondary heater element layer and the current detector monitors the secondary heater element layer for detecting a leakage current of the heater current of the primary heater element layer indicative of burn-out of the primary heater element layer and (ii) a second mode in which the power supply apparatus supplies a heater current to the secondary heater element layer and does not supply a heater current to the primary heater element layer. The control apparatus is configured to switch from the first mode to the second mode in response to detection of said leakage current by the current detector.

Electrothermal heater

An ice-protection system has first and second zones of a leading edge of an aerodynamic or streamlined aerodynamic component, each zone having a de-icing apparatus and an ice-detection sensor positioned behind an elongated convex window as to be aero-conformal with the leading edge. The ice-detection sensor is in the form of a module and has a sensor head having a front face and abutments at ends of the window. The ice-detection sensors may have a central light emitter and a plurality of sensor elements peripheral to the light emitter. The ice-protection system also has a control system responsive to the ice-detection sensors to control the respective de-icing apparatus, and may activate automatically a sequence of operation.

Ice protection system

A dielectric component with electrical connection is provided for a laminated heater mat () for an ice protection system for an aircraft (). The dielectric component with electrical connection comprises at least one dielectric layer () comprising thermoplastic material, and the dielectric layer () or a stack of the dielectric layers () has first and second main surfaces and a hole () extending between the first and second main surfaces. A first sprayed metal coating () comprises a first portion () deposited on the first main surface () adjacent to the hole () and a second portion () which projects into the hole. A second sprayed metal coating () comprises a third portion deposited on the second main surface () adjacent to the hole () and a fourth portion () which projects into the hole (). The second portion () overlaps the fourth portion () to form a continuous conductive path between the first main surface and the second main surface. This provides a cheap, neat and thin connection through the dielectric layer or the stack of dielectric layers.

Dielectric component with electrical connection

Electrical apparatus such as a heater () for an ice protection system for an aircraft () comprises a laminate such as a heater mat () and a connector (-). The laminate () comprises dielectric layers (-) and an electrical element such as a heater element (), and each dielectric layer of the laminate comprises thermoplastic material. The connector (-) comprises a ribbon having first and second ends and a metal conductor (). The ribbon comprises thermoplastic material and its first end () is embedded in the laminate and is laminated to adjacent first and second ones of the dielectric layers (-) of the laminate. Because the thermoplastic material of the ribbon is the same as or is compatible with the thermoplastic material of the first and second dielectric layers, the formation of an undesirable discontinuity at the interfaces between the first end of the ribbon and the first and second dielectric layers is prevented. Thus, cracks are less likely to be initiated at the interfaces during the use of the electrical apparatus, and de-lamination is less likely to occur.

Electrical apparatus

An electrothermal heater mat () is provided for an ice protection system for an aircraft () or the like. The heater mat () is a laminated heater mat and comprises dielectric layers (-), a heater element () and a temperature sensor (). Each dielectric layer (-) comprises thermoplastic material, and the temperature sensor () comprises a sprayed metal track () deposited on a substrate () comprising thermoplastic material. The substrate may be one of the dielectric layers () or a separate carrier () which is smaller than the dielectric layers (-). The substrate () is laminated to at least a first one of the dielectric layers () and the thermoplastic material of the substrate is (i) the same as the thermoplastic material of the first dielectric layer such that the thermoplastic material of the substrate is dispersed or merged into the thermoplastic material of the first dielectric layer or (ii) compatible with the thermoplastic material of the first dielectric layer such that the thermoplastic material of the substrate is fused to the thermoplastic material of the first dielectric layer. Thus, the formation of an undesirable discontinuity at the interface between the substrate () and the first dielectric layer () is substantially prevented or minimized.

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Luton, United Kingdom

Peter English