SAFETY VALVE Russian patent published in 1994 - IPC

FIELD: mining art. SUBSTANCE: arranged inside the housing provided with inlet passage and outlet passage made in form of transverse holes is hut-off member loaded with spring through the washer and provided with blind axial hole and radial holes which are in communication with axial hole. Radial holes pass through round sealing ring received by the groove made in housing when valve operates. Shutoff member is made in form of tubular sleeve and control piston made in form of shoulder of lesser diameter and engageable with spring. Housing is provided with circular bore connected with outlet passage. Circular bore is brought is communication with radial holes of shut-off member when operates. Mounted in circular bore is additional sealing ring. Fitted in tubular sleeve on side of shoulder is cover which divides the space into above-piston and under-piston chambers which are brought in communication by means of passages. EFFECT: enhanced reliability. 9 cl, 4 dwg