'a pressure relieving device for high capacity,high temperature and high pressure steam in super critical boiler'

摘要

The invention relates to a pressure relieving device for high capacity, high temperature and high pressure steam in super critical boiler, comprising a base (02) integrated with an inlet neck (01) and a seat bushing (03), a closing element disc (06), connected to a first end of a spindle (15) and, a disc holder (08) in a tandem guide (10), the assembly being connected to the base (02) including a cover plate (11), a second end of the spindle (15) connected to a spring (13); one each first and second chamber (A, B) for entry and exhaust of steam, the first chamber (A) receiving steam from the disc holder (08), the second chamber (B) receiving steam from the first chamber (A) through a secondary area formed by a floating washer (12) and a spindle overlap collar (14) formed on the spindle (15); one each upper and lower adjusting rings (07, 05) allows attaining a 100 percent lift of the spindle (15), the spindle lift being restricted upon attaining said lift by a lift stop (09) resting against the cover plate (11); the spindle overlap collar (14) during discharge by the valve is enabled to rise to a fixed position above the floating washer (12), the spindle overlap collar (14) further being enabled during closing of the valve spindle to move down to the floating washer (12), wherein the overlap collar (14) is constructed to have two differential diameters to allow an increase an area between the floating washer (12) and the spindle (15), wherein the movement of the overlap collar (14) above and below the floating washer (12) resulting a downward thrust in a direction of the spring loading leading to a positive and precise closing of the valve device, wherein the base (02), the inlet neck (01), and the seat bushing (03) are respectively formed with A351-CF8M, A182-F91, and A182-F347H materials, and wherein the base, inlet neck, and seat bushing are formed as a single integrated component through a welding process of dissimilar materials.