Globe Valves:

A globe valve is a linear motion valve used to start, stop, and regulate fluid flow. The Z-body globe valve is described in below figure. As display in the figure, the globe valve disk could be fully erased from the flowpath or it can totally close the flowpath. The necessary principle of globe valve operation is the perpendicular movement of the disk away from the seat.

This causes the annular space among the disk and seat ring to gradually close as the valve is closed. This feature provides the globe valve good throttling ability that permits its use in regulating flow.

Thus, the globe valve might be used for both starting and stopping fluid flow and for regulating flow. 

While compared to a gate valve, a globe valve commonly yields much less seat leakage. This is since the disk-to-seat ring contact is more at right angles that allow the force of closing to shortly seat the disk.

Figure: Z-Body Globe Valve

Globe valves could be arranged then which the disk closes against or in the similar direction of fluid flow. While the disk closes against the way of flow, the kinetic energy of the fluid impedes closing but aids opening of the valve. While the disk closes in the similar direction of stream, a kinetic energy of the fluid aids closing but impedes opening. This feature is preferable to other designs although quick-acting stop valves are essential.

Globe valves also have drawbacks. A most evident shortcoming of the easy globe valve is the high head loss from two or more right angle turns of flowing fluid. Discontinuities and Obstructions in the flowpath lead to head loss. Within a large high pressure line, a fluid dynamic effect from pulsations, impacts, and pressure drops could damage trim, stem packing, and actuators. Further, large valve sizes needs considerable power to operate and are especially noisy within high pressure applications.

Other disadvantages of globe valves are the huge openings essential for disk assembly, heavier weight than other valves of the similar flow rating and the cantilevered mounting of the disk to the stem.