Patent ID: 6923301

Claim:
A hydrodynamic brake comprising: a stator having an axis, a coaxial rotor for cooperating with the stator and rotatable around the axis, the stator being shaped to define an annular recess opening toward the rotor and a plurality of stator vanes extending toward the rotor, the annular recess of the stator has a bottom surface defining the annular recess thereof, the rotor being shaped to define an annular recess opening toward the recess of the stator and the rotor having a plurality of rotor vanes extending toward the stator, both the stator recess and the rotor recess together define a toroid-shaped space; a supply of a first medium to the toroid-shaped space for providing a brake action during rotation of the rotor by the first medium cooperating with the vanes of the stator and the rotor during rotation of the rotor; at least one inlet for supplying a second medium to the toroid-shaped space such that the second medium reduces circulation of air in the toroid-shaped space during rotation of the rotor with respect to the stator, wherein the second medium inlet is arranged to supply the second medium at at least one location in the toroid-shaped space and with a pressure and in a supply direction into the space which is at least partly directed toward the principal flow direction of air circulating in the toroid-shaped space during rotation of the rotor; the at least one inlet for supplying the second medium includes at least one inlet jet for supplying a jet of the medium into the toroid-shaped space, the inlet jet includes an injection portion shaped and positioned to inject the second medium into the toroid-shaped space, the injection portion for the second medium comprises an orifice arranged in the bottom surface of the recess of the stator so as to supply the second medium at an injection angle between 15° and 45° to a radius that extends from the orifice to a center of the toroid-shaped space.