Sealed coupling device adapted to be connected to a component to be checked and to seal a substantially cylindrical surface of said component, the sealed coupling device including - a hollow body with a central axial opening defining a longitudinal geometric axis and an inlet hole connecting the outside to said central axial opening; - an elongate element at least partly housed in said opening and adapted to perform axial movements with respect to said hollow body, the elongate element defining an axial through hole in communication with said central axial opening; - conduits for the passage of a fluid into the component to be checked including said inlet hole and said axial through hole; - a sealing element adapted to cooperate with said substantially cylindrical surface of the component to be checked; - a thrust element adapted to apply an axial resisting thrust between said hollow body and said elongate element; - an actuating mechanism that can be operated from the outside of the hollow body for transmitting an axial actuating thrust between said elongate element and said hollow body, said axial actuating thrust featuring an opposite sense with respect to the axial resisting thrust; characterized in that said sealing element is arranged between two stop surfaces (7, 19) which are axially movable with respect to each other with said elongate element and hollow body, respectively, said elongate element is adapted to perform rotation movements about the longitudinal axis with respect to the hollow body and to take different angular positions with respect to the hollow body, said actuating mechanism and said elongate element comprising, respectively, first and second abutment surfaces (8d, 9b) adapted to mutually cooperate, the first and/or second abutment surfaces (8d,9b) being shaped in such a way that said axial actuating thrust applies a momentum between said elongate element and said hollow body adapted to cause said rotational movements, in addition to said axial movements, of the elongate element and to change its angular position with respect to the hollow body, the sealed coupling device also includes one or more stationary reference surfaces integral with the hollow body and one or more movable reference surfaces integral with the elongate element, wherein said one or more stationary reference surfaces and said one or more movable reference surfaces - are adapted to mutually cooperate under the action of said axial resisting thrust, in order to define at least one axial reference position of the elongate element with respect to the hollow body, - are arranged in defined radial positions around said longitudinal geometric axis, and - are adapted to cooperate with each other at at least one of said angular positions of the elongate element with respect to the hollow body. - a hollow body with a central axial opening defining a longitudinal geometric axis and an inlet hole connecting the outside to said central axial opening; - an elongate element at least partly housed in said opening and adapted to perform axial movements with respect to said hollow body, the elongate element defining an axial through hole in communication with said central axial opening; - conduits for the passage of a fluid into the component to be checked including said inlet hole and said axial through hole; - a sealing element adapted to cooperate with said substantially cylindrical surface of the component to be checked; - a thrust element adapted to apply an axial resisting thrust between said hollow body and said elongate element; - an actuating mechanism that can be operated from the outside of the hollow body for transmitting an axial actuating thrust between said elongate element and said hollow body, said axial actuating thrust featuring an opposite sense with respect to the axial resisting thrust; characterized in that - are adapted to mutually cooperate under the action of said axial resisting thrust, in order to define at least one axial reference position of the elongate element with respect to the hollow body, - are arranged in defined radial positions around said longitudinal geometric axis, and - are adapted to cooperate with each other at at least one of said angular positions of the elongate element with respect to the hollow body.