Another variation on the globe valve design is the port-guided globe valve, where the plug has an unusual shape, projecting into the seat.
Thus, the seat ring acts as a guide for the plug to keep the center-lines of the plug and seat always aligned, minimizing guiding stresses that would otherwise be placed on the stem. This means that the stem may be made smaller in diameter than if the valve trim were stem-guided, minimizing sliding friction and improving control behavior.
Port-guided Globe Valve
Valve :
Essentially a flow control device. Can be used either just for on/off or throttling.
Globe valve :
The word ‘globe’ indicates the type of obturator/disk. Obturator is an object used to obstruct a hole. Basically its the valve closure member. Globe obturator indicates a globular/conical closure member. This kind of closure member enables the valve to be used for throttling purposes.
Port-guided :
The flow path of the fluid in this valve is guided by the geometry of the valve port/bore. So the flow of the fluid is guided by the port and not the plug/disk.
A photograph showing a small port-guided globe valve plug appears in the following photograph:
Some globe valves use a pair of plugs (on the same stem) and a matching pair of seats to throttle fluid flow. These are called double-ported globe valves.