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Ball Valve vs. Globe Valve: Understanding Their Structure and Main Components

Globe Valve Components and Structure

They are popular because of their large bodies and distinctive shapes, such as “Y” or “Z,” which we will discuss further later. Its body houses all of the other important internal components to allow the valve to do its work. The other components are the following:

Disc: The component that moves up and down, allowing or preventing material flow through the valve. The sealing component might be a plug or a ball, although the disc design is commonly used. 

Stem: It connects the disc and the actuator. Therefore, it allows you to pull the sealing component up or down through turning the actuator. 

Seats: Usually made from materials like teflon and stainless steel. It is a ring that the disc is pressed against when the valve is closed. 

Bonnet: Attached into the valve’s body with the stem packing to further leakage.

Packing: A vital component as it serves as a second seal to prevent leakage at the stem.

Actuators or handles: This is used to raise or lower the stem to manually open and close the valve. It can be a lever for smaller sizes or handwheels for bigger ones. 

Ball Valve Components and Structure

They are also known for their round-shaped bodies. However, they are more easily available in smaller sizes. It had components identical to a globe valve, such as a stem and a sealing component attached to the actuator. 

But there’s a difference between them and the globe valve in terms of components’ structure. Here are some important distinctions to take note of: 

Ball: This is the sealing element for this valve. It includes a hole in the centre that can be aligned with the pipe, allowing materials to flow. When rotated, this may serve as a seal, blocking the path. Unlike the other valve, the sealing component cannot be a plug or disc.

Seats: Their seats are located on the ball’s sides, top and bottom, to create a tight seal when the valve is closed. They’re often made from softer materials like PTFE (Teflon). 

Ball Valve and Globe Valve Difference: Working Principle

Ball Valve 

The ball’s hole is aligned with the pipe to allow materials to flow through when the actuator is turned. But turning the actuator in the opposite direction rotates the ball 90 degrees, and the solid part faces the pipe’s passage.

So, this closes the valve because the ball blocks the path. Furthermore, the seats located in the ball prevent leaking while it is closed. 

Globe Valve

The actuator moves the stem and disc to open or close the valve. You can do this by turning it to raise the stem and disc from the seat.

The higher the stem raises the disc from the stationary seat, the wider the passage becomes, allowing more materials to pass through. Lowering the disc, on the other hand, prevents or reduces the amount of material that flows across the valves. 

The size of the opening, therefore, determines the flow rate. 

Ball Valve vs. Globe Valve: Manufacturing Process

Ball valves are easier to manufacture since they contain fewer components and a simpler assembly than the other.

Globe valve manufacturers also had to ensure proper alignment of the various components, like the seat to the stem, in order to guarantee its quality. This contributes to the challenging manufacturing process of these valves.

Furthermore, both are made from durable materials such as:

Plastic

Ceramic

Metals like stainless steel

However, ball valves are tested mostly for their easy shut-off capabilities and simple daily operation. Globe valves, on the other hand, are usually tested for effective sealing and throttling.