Globe Valve Detail 2

This illustration shows a valve plug (B.) We have already learned that the bottom part of the plug is matched to the valve seat at the bottom to provide a good seal. In this illustration we see that the top of the plug is also designed to match a seat ring located above the plug. When the valve is opened, the plug is moved all the way up until it seats itself against the backseat (A.) The advantage of using the back seat is that it seals off the stuffing box from the fluid.

This photo also shows the gasket placed between the valve body and the bonnet flanges.

Graphic Courtesy: Beric-Davis Valves