US 12,351,320 B2
Electrothermal heater
Peter English, Redditch (GB)
Assigned to GKN Aerospace Services Limited, Redditch (GB)
Appl. No. 16/603,641
Filed by GKN Aerospace Services Limited, Redditch (GB)
PCT Filed Apr. 12, 2018, PCT No. PCT/EP2018/059469
§ 371(c)(1), (2) Date Oct. 8, 2019,
PCT Pub. No. WO2018/189341, PCT Pub. Date Oct. 18, 2018.
Claims priority of application No. 1705997.3 (GB), filed on Apr. 13, 2017.
Prior Publication US 2021/0009274 A1, Jan. 14, 2021
Int. Cl. B64D 15/12 (2006.01); H05B 1/02 (2006.01)
CPC B64D 15/12 (2013.01) [H05B 1/0236 (2013.01); H05B 2214/02 (2013.01)] 14 Claims
OG exemplary drawing
 
1. An electrothermal heater for an ice protection system, the heater comprising:
a laminated heater mat comprising 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
a control apparatus comprising a power supply apparatus and a current detector;
wherein 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;
wherein 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; and
wherein the secondary heater element layer functions as a temporary ground plane in the first mode and as a heater in the second mode.