A conduit for cooling a heating element includes an inlet mouth for entry of a fresh air flow, a plurality of cooling channels, the fresh air flow dividing between the channels into a plurality of air flows to collect heat produced by the heating element, an outlet mouth for an exit of a heated air flow, the heated air flow resulting from a merger of the plurality of air flows after the heat collection, and air deflectors in the outlet mouth facing the channel outlets situated closest to an exit opening of the outlet mouth relative to the other channel outlets to prevent at least one of the plurality of air flows from exiting the cooling channels. The air deflectors extend over lengths which reduce as distances from the opening of the outlet mouth increase to guide the air flows towards the exit opening of the outlet mouth.