- Figure 1: The steam running past the ball now puts pressure on the ENTIRE ball, rather than just the 'sealing face'. The discharging steam is contained in an annular ring that keeps the pressure ABOVE atmospheric...how much above is adjustable. This adjustment, combined with the total area of the ball exposed to the now flowing steam, keeps the ball 'up'
- Figure 3: Not all valves have these balls. I personally like valves with more of an industrial poppet type of seat (Figure 2), that is guided both top and bottom...makes me a bit more comfortable...
Articles on Safety Valves: