GATE VALVE Russian patent published in 2003 - IPC

FIELD: manufacture of fittings; shutting-off high-pressure pipe lines. SUBSTANCE: proposed gate valve has body, cover, gate and rod with sealing units mounted in such position that circular cavity is formed between them. This cavity is communicated with atmosphere through normally closed valve. This cavity is also connected with cavity of gate valve through shut-off unit. Shut-off unit is made in form of cylinder divided into adjacent cavities by piston. One adjacent cavity is communicated with circular cavity and other adjacent cavity is communicated with cavity of body. Cylinder is provided with rod engageable with piston. Hollow rod of cylinder is provided with valve. EFFECT: extended functional capabilities; improved operating properties; enhanced operational reliability. 3 dwg