Throttle globe valves use a linear motion to move a closure into and out of the valve seat, with the valve body being a spherical chamber. They are designed to control process flow, pressure, or temperature when combined with an actuator assembly. A cage or retainer-style design is used in many single-seat bodies to hold the seat seal, provide plug guiding, and give a method for determining the flow characteristics of a specific valve. Single-seat globe valve bodies with cage or retainer structure may also easily adjust flow characteristics by changing the trim, enabling decreased capacity flow, noise reduction, or decreasing or eliminating cavitation.
Globe valves provide users exceptional performance and reliability and come in a range of sizes from DN15 to DN900. They can assist in meeting a variety of application demands, from general to severe, small size to big size, hot temperature to cold temperature.
Different kinds of bonnets are offered to handle various application temperatures. To protect packing materials when the valve is used in highly hot or cold situations, this principally includes basic bonnets and optional extension bonnets.
For situations where the packing system must keep fugitive emission concentrations below environmental requirements, there are additional specific packing arrangements.
Boiler and main steam vents and drains, fuel oil systems, feedwater or chemical feed systems, turbine lubrication oil systems, and cooling water systems are just a few of the many places where globe valves are used.
Globe valves can be equipped with either balanced or unbalanced valve plugs. Balanced plugs permit equal process pressure above and below the valve plug, with the normal flow down through the seat ring. Unbalanced valve plugs are solid with no through the hole, and flow is typically upward via the seat ring.
There are various ways to guide the plug in globe valves, the most popular of which are cage guided and post-guided. Cage-guided assemblies come in both balanced and unbalanced plug configurations. This method of guiding employs the outside diameter of the plug to touch the inside diameter of the cage, which provides excellent plug stability and alignment but necessitates extremely tight tolerances between the plug and cage. The seat retainer is used in place of the retainer in the post-guided assembly. The seat retainer has a guide cage that guides the post on the plug. Because this method provides for an unobstructed flow route around the plug, the back-guided trim is better appropriate for viscous and unclean fluids.
Globe valves can be linear, equal percentage, or quick opening and can satisfy capacity demands from 0.001 Cv up to 12,000 Cv through a variety of trims with various flow characteristics.
Additionally, there are specialty trims that may be used in clean or unclean applications to stop noise and cavitation problems.
A globe valve can be opened, closed, or adjusted to the desired flow rate. Valves can be manipulated either manually or mechanically.
As an example, the petroleum sector uses globe valves because they have several benefits.
Globe valves are often used in control and isolation systems. This motion is straightforwardly linear. Since this is the case, it can quickly allow or restrict fluid flow. It makes for a secure seal. This is why globe valves are commonly utilized in the petroleum industry.
Internal Components Differ Between Gate Valves And Globe Valves
A gate valve’s closing element is a plate or disk like a “gate” that is parallel to the plane of the valve seat.
The globe valve’s closing part, known as the “plug,” travels perpendicular to the plane of the valve seat.
Globe valves have a high capacity for throttling, but gate valves are not employed for throttling. Gate valves are ideal for isolation, whereas globe valves are ideal for regulating or throttling.
Globe Valve Vs. Gate Valve
Globe and gate valves are the most common types of valves in the industry, each having its own unique functions and design features. Below, we highlight the key distinctions between globe valves and gate valves: