Cooling air bleed device in a turbine engine

A turbine engine cooling air bleed device for cooling components in a turbine engine, comprising:

• an annular conduit formed in a housing that has a radially internal portion swept by an airflow, the annular conduit including at least one air inlet orifice;
• and
• a flap valve that controls air entering through the orifice,
• wherein the orifice is formed in an upstream radial wall of the conduit, and
• wherein the flap valve includes a plate applied against said upstream radial wall, the plate being slidably movable on said upstream radial wall via a maneuvering member that is mobile in translation parallel to the upstream radial wall between a first position in which the plate covers and closes off the orifice and a second position in which the plate is moved away from the orifice such that said orifice is open.