Vale of a hydraulic circuit with constant pressure drop

A pressure valve comprising a body including at least one discharge opening and at least one intake opening provided with a seat, a fluid being able to pass from upstream to downstream from the intake opening to at least one discharge opening, a slide valve sliding in a housing of said body opposite the seat, said slide valve including a cylindrical skirt closed by a head to delimit with said housing a chamber, a biasing element tending to bring a flank of the slide valve head closer to a face of the seat, a sealing lip by which the flank of the head and the face of the seat are maintained at a distance when the head is bearing on the seat under the action of the biasing element, the head including at least one hole passing through its flank to communicate the chamber with at least the discharge opening, each hole opening into an annular space communicating with each discharge opening, being located opposite the face of the seat and downstream of the lip relative to the intake opening, said annular space delimiting with the lip a widening forming a diverging portion for the fluid passing through the valve in order to reduce the pressure in the chamber by the Venturi effect when the slide valve is open.