Abstract: A self-contained cut-off device for the use in oil and gas extraction comprises a body, a stop valve, a potential energy accumulator, and a hold-release arrangement. The arrangement, fixed in the body, is equipped with clamping elements. The valve comprises a drum-shaped valve head and a seat. The head outer surface has a conical groove for the clamping elements. On the inside, the head has a through passage for a flow with a conical portion expanding from the inlet to the outlet, and with a cylindrical portion at the outlet. The head comprises a replaceable nipple in the inlet of the passage. The seat comprises circulation passages in its annular part and has a boss made with a cylindrical surface and a spherical surface adapted to mate the cylindrical and conical portions of the passage, respectively. A sealed cavity for a lubricant is formed between the body and outer surface.

Abstract: A self-contained cut-off device for the use in oil and gas extraction comprises a body, a stop valve, a potential energy accumulator, and a hold-release arrangement. The arrangement, fixed in the body, is equipped with clamping elements. The valve comprises a drum-shaped valve head and a seat. The head outer surface has a conical groove for the clamping elements, On the inside, the head has a through passage for a flow with a conical portion expanding from the inlet to the outlet, and with a cylindrical portion at the outlet. The head comprises a replaceable nipple in the inlet of the passage. The seat comprises circulation passages in its annular part and has a boss made with a cylindrical surface and a spherical surface adapted to mate the cylindrical and conical portions of the passage, respectively. A sealed cavity for a lubricant is formed between the body and outer surface.