FIELD: well construction. SUBSTANCE: collar includes body with radial holes; closing cylindrical sleeve located inside body and provided with landing seat for separating plug; arresting device for locking the sleeve from rotation; and device for locking the sleeve in upper position and locking of its landing seat from rotation. Collar has plugs closing body radial holes relieving pressure. Arresting device for locking of sleeve from rotation is made in the form of eccentric cylindrical landing socket in body below radial holes and part of sleeve made eccentric and entering body landing socket in lower position. EFFECT: simplified design, higher reliability and facilitated manufacture of collar. 2 cl, 1 dwg
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