A rotary coating sprayer including a spray bowl rotating about an axis of rotation and an air turbine for driving the bowl. The turbine includes a rotor and a body forming a support for the rotor and defining at least one air feedline for a rotation chamber wherein the rotor blades are arranged. The feedline includes an intermediate chamber defined, radially to the rotation axis, between the body and a ring mounted around the body. In this way, lowering of temperature of an element of the sprayer housing due to flow of exhaust air from the turbine, is limited.