CUT-OFF VALVE Russian patent published in 2003 - IPC

FIELD: automatic disconnection of hydraulic systems of industrial equipment. SUBSTANCE: body of cut-off valve has three adjacent chambers: first chamber is communicated with pressure pipe line through inlet and outlet holes; inlet cavity of this chamber is provided with pressure differential control unit. Mounted at area of conjugation of outlet cavity and outlet hole is seat which is engageable with plunger at the moment of operation of valve. Plunger is connected with valve body by means of return spring and back stroke limiter and is located in cavity of second chamber which is communicated with main pressure pipe line in section between pump and valve body through inlet hole and pipe line of pulse main. Third chamber is divided into two parts by means of piston provided with sealing surface and rod. Upper portion of this chamber is provided with drainage passage connecting this chamber with cavity of second chamber and hole where piston rod is located. Lower portion of this chamber is connected with controllable zone of main pressure pipe line. Located in this portion of chamber is spring imparting pressure to piston which may be changed by means of adjustable bolt. Body of adjustable bolt is provided with retainer for limiting the piston stroke. Proposed valve excludes losses of working fluid in case of damage of pipe line. EFFECT: enhanced reliability at varying flow rates of liquid. 1 dwg