Globe Valves

What is Globe Valves?

A globe valve generally has a spherical body that contains a movable plug element and a stationary ring seat. The two halves of the body are separated by an internal baffle. The plug element is connected to an operating hand wheel through a stem. As the wheel is turned, the screw action moves the plug towards or away from the ring seat. Globe valves can be used for stop/start function as well as to regulate fluid flow. They are useful in applications where good flow control is desired and leak tightness is important such as cooling water systems, feedwater and chemical feed systems, and fuel/lubricating oil systems.

Globe valves cost more than gate valves but provide better shut off and throttling control. The design of these valves forces the fluid to change direction as it flows through; this creates high pressure loss and turbulence. Globe valves are generally heavier than other valves. They are not suitable for fluids containing particles, high viscosity fluids and other mediums that are prone to choking.

How do globe valves work?

A circular shaped disc attached to the main valve stem is lowered and raised in order to open and close the valve. When the valve is closed, the disc sits upon the valve seat with both parts being machined in order to obtain a tight seal; the sealing surface can be flat or mitred. When the valve is opened, the flowing medium flows between the disc and seat.

What are the advantages of globe valves?

Due to the circular shape of the disc and seat, uneven wear across machined area is unusual.
Globe valves can be used for throttling (flow control), but the valve does not give a great degree of control due to the large circular shape of the disc. If fine flow adjustments are needed, the globe valve design is probably not the best option.
An angled globe valve has one less right angle turn than a straight globe valve, this leads to a lower pressure drop.

Common Applications

• Globe valves are available in a variety of sizes (NPS 1/2 thru 36) and provide users with high performance and reliability. They can help solve an array of application needs from big to small, hot to cold, general to severe.
• Bonnets are available in different styles to accommodate different application temperatures. This primarily includes standard bonnets and optional extension bonnets, which may be used to protect packing materials when the valve is used in extremely hot or cold applications.
• There are also special packing configurations for applications that require the packing system to maintain fugitive emission concentrations below environmental standards.
• Some of the most typical applications of globe valves include cooling water systems, fuel oil systems, feedwater or chemical feed systems, boiler and main steam vents and drains, and turbine lube oil systems.