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What You Need To Know About Globe Valves

In this article, we cover everything you need to know about globe valves, including their types, parts, and working principles.  Plus, we provide tips on how to select the ideal globe valve based on factors such as material, size, and pressure limits.

Globe valves are regulating or shutoff valves used to control liquid flow.  They come in various styles and configurations to meet specific needs and applications.  Selecting the ideal globe valve for your application can be daunting due to its various shapes and design variants.  Globe valves come in a range of materials, sizes, and pressure limits to meet your application.  Selecting the appropriate one is key to getting maximum performance from your valve.

Let’s take a detailed look into the globe valves and how to choose the best one for you.

What Are Globe Valves?

A globe valve is a linear motion closing-down valve that utilizes a disc to start, stop, and throttle fluid flow.  The seat opening varies in direct proportion to disc travel and thus makes it ideal for tasks requiring controlling flow rate.

Globe Valves can be employed in a number of applications, such as steam and condensate service, temperature or pressure regulation in pipelines, and even nuclear plant process control.  They come with various body and stem designs that can be tailored to meet specific requirements.

Globe valve disk designs come in three basic forms: ball, composition, and plug.  The ball disk is ideal for low-pressure or temperature applications, while the composition disk features a hard insert ring that ensures tight closure.  Finally, plug disks offer better throttling than either ball or composition disks and may be used when hard service requirements exist.

Globe valves come in several body patterns, the three most popular being standard, angle, and Y-shaped.  Of these three options, the standard pattern is by far the most prevalent and typically employed for throttling services.

What Are the Parts of a Globe Valve?

A typical globe valve consists of the following parts:

Back Seat

The back seat in a globe valve is positioned at the rear of the valve body. 

Its primary function is to provide a secondary seating surface, preventing system leakage when the valve is fully open. 

It serves as a safety feature, especially during maintenance or repairs, offering a redundant seal.

Bonnet

The bonnet is a crucial part of the globe valve, securing the internal components and acting as a cover for the valve body. 

It is attached to the valve body and houses the stem and disc assembly. The bonnet plays a key role in maintaining the integrity of the valve’s internal structure.

Disc or Plug

The disc or plug is the movable component within the globe valve that regulates the flow of fluid. 

When the valve is in operation, the disc moves against the seat to either allow or block the flow. 

The disc design varies based on the valve’s intended application and flow control requirements.

Gland Bolts and Nuts

Gland bolts and nuts are used to secure the gland, which houses the packing material. 

These bolts and nuts ensure proper compression of the packing, preventing leaks along the stem.

Gland Bushing and Flange

The gland bushing provides support to the stem and ensures a tight seal around the stem. The gland flange secures the gland assembly and provides structural stability to the valve.

Handwheel (Mechanical Actuator)

The handwheel serves as a manual actuator, allowing users to control the opening and closing of the valve. It is an essential component for operations requiring human intervention.

Packing

Packing is a sealing material placed around the stem to prevent fluid leakage along the stem. It provides a secure seal while allowing the stem to move freely during operation.

Pressure Seal Gasket

The pressure seal gasket ensures a tight seal between the valve body and the bonnet, preventing fluid leakage under high-pressure conditions.

Seat Ring

The seat ring is a stationary part of the valve where the disc or plug makes contact to create a seal. It is essential for controlling the flow and preventing leakage.

Stem

The stem connects the handwheel or actuator to the disc or plug, transmitting the force required to control the flow. It is a critical component for the overall functionality of the valve.

Valve Body (Globular Shape)

The valve body, typically with a globular shape, houses the internal components and provides the main structure for the valve. It features inlet and outlet ports for fluid flow.

Yoke

The yoke is a bracket-like structure that supports the stem and helps in the proper alignment of the moving parts. It ensures smooth operation and stability.

Yoke Sleeve

The yoke sleeve surrounds the stem and protects it from external elements. It contributes to the overall durability and longevity of the valve.