Connection device for tubular elements

A connection device comprising:

• a first tubular element, a second tubular element, and a coupling sleeve in order to connect the first tubular element and the second tubular element, the coupling sleeve having a first female portion and a second female portion having respectively a first inner thread and a second inner thread, the first tubular element and the second tubular element having respectively a first male portion and a second male portion, the first male portion and the second male portion having respectively a first outer thread which is configured to cooperate with the first inner thread of the coupling sleeve, and a second outer thread which is configured to cooperate with the second inner thread of the coupling sleeve, such as to permit coupling by screwing of the first male portion to the interior of the first female portion and of the second male portion to the interior of the second female portion, the first male portion comprising a free end having a first axial stop surface, the second male portion having a free end comprising a second axial stop surface and an outer sealing surface extending between the second axial stop surface and the second outer thread, the second axial stop surface being configured to come into contact against the first axial stop surface when the first male portion and the second male portion are coupled respectively in a coupling position in the interior of the first female portion and the second female portion, the free end of the first male portion also comprising an annular sealing lip, projecting axially relative to the first axial stop surface, the sealing lip being configured to cover the outer sealing surface and to come into sealed radial contact against said outer sealing surface when the first axial stop surface and the second axial stop surface are in contact against one another, the sealing lip having an outer periphery on which part of the first outer thread is provided, wherein the first outer thread has a conical portion and a cylindrical portion which is positioned axially between the conical portion of the first outer thread and the free end of the first male portion, such that the cylindrical portion is at least partly arranged on the sealing lip.