De-icing system for a wind turbine blade

A wind turbine blade (10) having a blade de-icing system, the wind turbine blade comprising a root end (16) and a tip end (14), a leading edge (18) and a trailing edge (20), the blade having an outboard portion provided towards said tip (14) end and an inboard portion provided towards said root end (16), the wind turbine blade (10) further comprising a blade shell structure forming an outer surface of the wind turbine blade (10), the blade de-icing system arranged to convey a heated fluid to provide heat to portions of the wind turbine blade, wherein the blade de-icing system comprises:

• an insulated outflow channel (70) flowing from said root (16) end to a location adjacent said tip (14) end;
• a heating channel (72) in the outboard portion of the blade, the heating channel flowing from said location adjacent said tip end (14) along the leading edge (18) of the blade in the outboard portion of blade, wherein said heating channel (72) comprises:
• an insulated wall arranged to define a leading edge cavity between said insulated wall and an internal surface of said blade shell structure at the leading edge of the wind turbine blade in said outboard portion;
• and
• flexible seal members arranged between respective upper and lower sides of said insulated wall and respective adjacent portions of the internal surface of said blade shell structure,
• wherein said insulated wall is supported by an internal shear web of said wind turbine blade, and
• wherein said flexible seal members are non-load carrying members and act to isolate forces associated with said insulated wall from the internal surface of said blade shell structure at said heating channel;
• and
• an insulated return channel (78) in the inboard portion of the blade, the insulated return channel (78) extending from the root end side of the heating channel to the root end of the blade,
• wherein said de-icing system is arranged to convey heated fluid from said root end (16) through said outflow channel (70) to said tip end (14), from said tip end (14) through said heating channel (72) to said insulated return channel (78), and from said insulated return channel (78) to said root end (16), said de-icing system configured to heat the leading edge (18) of the blade in said outboard portion of the blade.