ABSTRACT
A poppet valve uses a metal disk to open or close the valve by inserting the disk into the flow stream, as shown in Fig. 2. The disk and shaft assembly is usually called a poppet. Typically, the pressure force on the poppet is designed to be statically balanced. The relationship between the position of the valve and the flow area is not as linear as it is with the butterfly valve. This can be a problem for valves which need to close slowly to prevent water hammer. The advantage of the poppet valve over the butterfly valve is that it can be made leak-tight because the valve seals directly against the valve seat. Most of the poppet valves have a bellows to provide sealing and spring rate. Thus, the failure of the bellows during the vibration could occur if the bellows' surge frequency matches the frequency of the input vibration.
