Valves are mechanical devices installed into fluid systems that allow you to control, stop, and start fluid flow through an application. Ball valves and globe valves are two popular types of fluid control valves that close in different ways. Learning which valve type is the most suitable for your application can help you install the right one to ensure the seamless operation of your system.
John Valves has manufactured and distributed a range of valves to help businesses control their fluid system applications for 125 years. In this article, we compare a ball valve vs globe valve and explain the pros and cons of each.
Ball valve vs globe valve
The primary distinction between the ball and globe valves is how they close and restrict the flow of fluids. Ball valves use a hollow ball with a stem attached that rotates the ball horizontally and are often referred to as rotational valves. Globe valves have a plug or disc attached to a stem that moves up and down vertically, which is why they’re also referred to as stroke valves. Therefore, ball valves are ideal for systems that require an on and off isolation function without reducing the pressure in the application. In comparison, globe valves are excellent at regulating the flow by being able to be operated in a partially open position to restrict flow.
The difference in their operation
Both valves work to control fluid flow, though their design and operational differences make them suitable for different applications. The operational differences of a ball valve vs globe valves are discussed below:
A ball valve is a type of quarter-turn valve that controls the flow through it using a hollow ball attached to a stem and handle for an operator to turn. Ball valves are open when the hole in the ball is in line with the flow so that the fluid can flow through the hole. When rotated 90-degrees by turning the valve handle, the ball closes and the flow of fluid through the valve flow stops. It’s easy to determine the status of the valve by inspecting the position of the handle. When the handle aligns with the flow through the pipe, it’s open, and when perpendicular to the flow, it’s closed.
Globe valves are known for their spherical body shape, with an internal partition separating the body into two halves. A circular opening in the dividing partition creates a seat on which a moveable plug or disc can be screwed down to close the valve and stop the fluid flow.
Globe valve stems are connected to an external handwheel which operators turn to move the plug into a closed or open position. The position of the plug or disc in the globe valve can be varied between fully open and fully closed to suit the required flow rate for a particular application, making them an excellent valve for precise regulation control. The closer the plug is located to the seat in the body, the greater is the flow restriction through the valve. A globe valve’s seating is parallel to the line of flow, and they feature a short travel stroke that requires fewer turns to move the plug or disc to stop or start the flow.
Pros and cons of ball valves and globe valves
Below we take a look at a ball valve vs globe valve in terms of their advantages and disadvantages:
Advantages of ball valves
Ball valves have the following advantages:
- One of the easiest valves to operate with their simple quarter turn (90 degree) operation.
- Easy to visually confirm the status of the valve by the position of the handle. When the handle is parallel to the flow, it’s open and when it’s perpendicular, it’s closed.
- Have a low pressure drop and relatively high flow capacity.
- Can work well in high pressure and high-temperature applications.
- Robust construction with a long service life.
- Cost-efficient with low on-going maintenance costs.
- Easy to disassemble and the replacement of any worn parts is straight forward.
Disadvantages of ball valves
Ball valves have the following disadvantages:
- Poor throttling capabilities, they’re primarily used in either the fully open or fully closed position.
- Not suitable for use on slurries or other thick liquids that can lead to the cavities around the ball and seats becoming ‘clogged’ making operation of the valve difficult.
Advantages of globe valves
Globe valves have the following advantages:
- Can be used for high-pressure and high-temperature systems, when design and materials permit..
- Good shutoff capability.
- Suitable for throttling and regulating flow due to their ability to be used in partially open positions.
- Their short travel stroke means fewer turns are required to fully open and close, saving time and wear on valve parts.
- Easy to maintain and resurface the seats.
Disadvantages of globe valves
Globe valves have the following disadvantages:
- Requires greater force or a larger actuator to seat the valve.
- Low coefficient of flow resulting in a higher pressure loss across the valve in comparison to other ‘straight through’ valve types.
A ball valve vs globe valve serve similar functions to control fluid flow, but their unique designs suit different applications. Ball valves are easy to operate and are cost-effective, and they provide a straightforward way to determine the valve’s opening status. While they’re great for stopping and starting fluid flow, they’re not suitable for regulating flow. Globe valves have excellent flow regulation capabilities and can be precisely positioned to control the flow, but they’re not as convenient to operate.