Dead Weight Safety Valve

Figure 4.14 Dead Weight Safety Valve

Steam pressure acting in upward direction is counter balanced by the dead weight of safety valve acting in downward direction. When steam pressure exceeds the dead weight of safety valve, valve rises from its valve seat and steam escapes into the atmosphere. The construction of dead weight safety valve is shown in Figure 4.14. There is a vertical steam pipe having a valve seat at its mouth. A valve is fitted in the valve seat. Above the valve a dead weight is applied. When steam pressure becomes higher than the dead weight, valve rises from the valve seat and steam at high pressure is released into the atmosphere. Again, when steam pressure becomes normal, i.e., less than dead weight, valve returns to valve seat.