Lever safety valve works on the principle of second system of lever as shown in Figure 4.16. In this valve, there is a lever which can rotate about fulcrum but its movement is limited by a guide. When moment about fulcrum due to steam pressure exceeds the moment about fulcrum due to weight applied on the lever, valve is lifted off the seat and steam is escaped out. Again valve returns to its seat when pressure becomes normal.
Figure 4.16 Lever Safety Valve
Leave a Reply