Globe valves are devices that are used to control the flow of liquid in a pipeline. They can be used to either stop fluid flow completely, slow it down or allow the fluid to flow freely. Globe valves have a globe-shaped body (hence the name), a flat piece and a ring that the flat piece fit into to stop the fluid flow. Understanding how they work can be really interesting.
How They Work
Globe valves contain an important device called a baffle. This is the device that is responsible for regulating fluid flow. The baffle consists of two parts, a flat plug and a ring-shaped seat. When the plug is completely fit into the seat, fluid flow is totally restricted. You can control the baffle by either opening it a little or closing it, depending on the amount of fluid flow you want.
Furthermore, there are automatic and manual globe valves. Automatic globe valves lack the threaded stems of the manual ones and they slide smoothly from a closed position to open to regulate the flow of fluid in the pipeline. The mechanical device that is used to operate automatic globe valves is called an actuator.
Globe valves are usually used in applications where constant flow of fluid is not required. Even when the valve is fully open, the baffle can sometimes restrict fluid flow. The valves are usually used as sample valves i.e. opened only when a sample of a fluid is needed.