Abstract: A membrane for most commonly known nozzles has an elastically flexible, compressible resilient material placed between said inside surface of said plate and the opposite surface of the insert face; an annular outer portion that is initially flat; a projection at its center portion in bell-shaped dome form at its active surface which abuts against the inside surface of the central plate, said membrane forming a supplementary recess in its opposite surface and said insert front surface; an annular hermetic seal enclosing a small air chamber, said air chamber being deformable under pressure by the deformation of said membrane; said projecting dome at the center portion of the membrane being seated against the inside walls of the outlet orifice in the plate, describing an annular seal against said walls of said outlet channel.