Non Return Valve

When a valve is operated by the pressure of a fluid, it is called a non-return valve, because, due to the reduction in the pressure of the fluid, the valve automatically shuts-off, ensuring non-return of the fluid. Figure 18.31a shows a brass/gun metal valve with a bevelled edge on the valve seat. The isometric view of the inverted valve shows the details of the webs. However, in the non-return valve, a separate valve seat is not provided