Patent Number: 050283839
Section: claims

1. In a nuclear reactor plant, an improved steam depressurization valve positioned in a steam discharge pipe for controlling the venting of steam pressure from the reactor through the pipe, said improved depressurization valve consisting essentially of the combination of: a valve housing including a cover forming a chamber and having a partition plate dividing said chamber into a fluid pressure activation compartment and a steam flow control compartment, said valve housing being provided with an inlet connection and an outlet connection in the steam flow control compartment, and a fluid duct in communication with the fluid pressure activation compartment and connected to a source of fluid pressure for operating the valve; a valve seat mounted within the steam flow control compartment surrounding the inlet connection in the housing and a valve cylinder traversing the partition plate and reciprocally movable within an opening in said partition plate with one terminal end extending into the fluid pressure activation compartment and the other terminal end extending into the steam flow control compartment coaxially aligned with the valve seat surrounding the inlet connection thereby providing a reciprocatable valve member for making closing contact with the valve seat and withdrawing therefrom for opening to enable steam flow through the valve. 2. The steam depressurization valve of claim 1, wherein the reciprocatable valve cylinder is provided with guides to inhibit lateral movement and direct the reciprocal movement of the valve cylinder to and away from contact with the valve seat. 3. In a nuclear reactor plant, an improved steam depressurization valve positioned in a steam discharge pipe for controlling the venting of steam pressure from the reactor through the pipe, said improved depressurization valve comprising: a valve housing including a cover forming a chamber and having a partition plate dividing said chamber into a fluid pressure activation compartment and a steam flow control compartment, said valve housing being provided with an inlet connection and an outlet connection in the steam flow control compartment, and a fluid duct in communication with the fluid pressure activation compartment and connected to a source of fluid pressure for operating the valve; a valve seat mounted within the steam flow control compartment surrounding the inlet connection in the housing and a valve cylinder traversing the partition plate and reciprocally movable within an opening in said partition plate with one terminal end extending into the fluid pressure activation compartment and the other terminal end extending into the steam flow control compartment coaxially aligned with the valve seat surrounding the inlet connection thereby providing a reciprocatable valve member for making closing contact with the valve seat and withdrawing therefrom for opening to enable steam flow through the valve, said valve seat surrounding the inlet connection comprises a cylinder section welded to the valve housing at one end and having a radially projecting flange at the other end with a contoured extended valve seating surface. 4. The steam depressurization valve of claim 3, wherein the reciprocally movable valve cylinder is provided at its terminal end adjacent to the valve seat with a radially projecting flange substantially conterminous with the valve seat flange and having a contoured surface facing and complimentary to the contoured valve seating surface whereby the two contoured valve surfaces can meet in a matching relationship. 5. In a nuclear rector plant, an improved steam depressurization valve positioned in a steam discharge pipe for controlling the venting of steam pressure from the reactor through the pipe, said improved depressurization valve comprising: a housing including a cover forming a chamber and having a partition plate dividing said chamber into a fluid pressure activation compartment and a steam flow control compartment, said valve housing being provided with an inlet connection and an outlet connection in the steam flow control compartment, and a fluid duct in communication with the fluid pressure activation compartment and connected to a source of fluid pressure for operating the valve; a valve seat mounted within the steam flow control compartment comprising a cylindrical section surrounding the inlet connection with one end adjoining said connection and having a radially projecting flange at the other end with a contoured extended valve seating surface, and a valve cylinder traversing the partition plate and reciprocally movable within an opening in said partition plate, with one terminal end extending into the fluid pressure activation compartment and the other terminal end extending into the seam flow control compartment coaxially aligned with the valve seat surrounding the inlet connection, said valve cylinder end extending into the steam flow control compartment housing having a radially projecting flange substantially conterminous with the valve seat flange and having a contoured surface facing and complimentary to the contoured valve seating surface whereby the two contoured valve surfaces can meet in matching relationship, thus providing a pressure actuated reciprocatable valve member for making closing contact with the valve seat and withdrawing therefrom for opening steam flow through the valve. 6. The steam depressurization valve of claim 5, wherein the reciprocatable valve cylinder is provided with guides to inhibit lateral movement and direct the reciprocal movement of the valve cylinder to and away from matching contact with the valve seat. 7. The steam depressurization valve of claim 5, wherein the contoured surface of the radially projecting flange of the valve seat is provided with at least one valve sealing member. 8. The steam depressurization valve of claim 5, wherein the reciprocatable valve cylinder is surrounded by two bellow fluid seals. 9. The steam depressurization valve of claim 8, wherein the partition plate is provided with a leak-off duct passing laterally therethrough from adjacent the valve cylinder within the surrounding bellows outward to the exterior of the valve housing. 10. In a nuclear reactor plant, an improved steam depressurization valve positioned intermediate along a steam discharge pipe for controlling the venting of steam pressure from the reactor through the pipe, said improved depressurization valve comprising: a housing including a domed cover forming a chamber and having a partition plate dividing said chamber into a fluid pressure activation compartment and a steam flow control compartment, said valve housing being provided with an inlet connection and an outlet connection in the steam flow control compartment, and a fluid duct in communication with a source of fluid pressure for operating the valve; a valve seat mounted within the fluid flow control compartment comprising a cylindrical section surrounding the inlet connection with one end adjoining said connection and having a radially projecting flange at the other end with a contoured extended valve sealing flange provided with an annular valve sealing member, and a valve cylinder traversing the partition plate and reciprocally movable within an opening in said partition plate with one terminal end extending into the fluid pressure activation compartment and the other terminal end extending into the steam flow control compartment coaxially aligned with the valve seat surrounding the inlet connection, said valve cylinder being surrounded by two bellow fluid seals and provided with guides to inhibit lateral movement, an end of the valve cylinder extending into the fluid flow control compartment having a radially projecting flange substantially conterminous with the valve seat flange and having a contoured surface facing and complimentary to the contoured valve seating surface whereby the two contoured valve surfaces can meet in matching relationship, thus providing a pressure actuated reciprocatable valve member for making closing contact with the valve seat and withdrawing therefrom for opening fluid flow through the valve; said partition plate having a leak-off duct passing laterally therethrough from adjacent the valve cylinder within the surrounding bellow outward to the exterior of the valve housing.