Self-contained cut-off device

A self-contained cut-off device comprising a body, a stop valve, a restrainer, a potential energy accumulator, and a hold-release arrangement,

• the accumulator being installed in the body on a base ring;
• the hold-release arrangement being immovably fixed in the body and provided with clamping elements;
• the stop valve comprising a valve head and a seat;
• the valve head comprising:
• a drum, whose edges are provided with gaskets, and whose outer surface has a conical groove adapted to interact with the clamping elements, and whose inside surface defines a through passage for a flow, the passage having a conical portion, which expands from an inlet to an outlet thereof, and a cylindrical portion at the outlet, into which cylindrical portion the conical portion merges, and
• a replaceable valve nipple mounted at the inlet of the through passage for a flow;
• the valve head being coupled with the potential energy accumulator;
• the seat comprising an annular portion, which is provided with circulation passages therein, and a boss comprising a cylindrical portion merging into a spherical portion with a spherical end, the cylindrical portion being adapted to mate the cylindrical portion of the passage of the drum, the spherical portion being adapted to mate the conical portion of the passage of the drum;
• the hold-release arrangement being located in a hermetically sealed cavity formed between the body and the outer surface of the drum.