Shut-off device

A shut-off device for progressive regulation of the flow rate of fluid flowing along a longitudinal axis of a pipe, comprising:

• a spindle having a longitudinal axis passing through the pipe, the longitudinal axis of the spindle being substantially perpendicular to the longitudinal axis of the pipe;
• a substantially flat main shut-off member pivotably carried by the spindle so that the pipe can be closed or opened by the main shut-off member pivoting around the spindle, the spindle separating the main shut-off member so as to define a first part of the main shut-off member located on one side of the spindle, and a second part of the main shut-off member on the other side of the spindle;
• said main shut-off member having at least one orifice located entirely in one part of the main shut-off member;
• and
• at least one flap fixedly attached to the spindle and acting mechanically on said main shut-off member in such a way as to turn said member about said spindle, said at least one flap being able to regulate the rate of flow of the fluid through said at least one orifice and to close the at least one orifice where the main shut-off member only begins to pivot about said spindle, from an initial closed position, when said at least one flap reaches a predetermined non-zero angular distance φ from said member thereby allowing the fluid to flow only through the at least one orifice until the main shut-off member begins to open.