Ball valve is part of the quarter turn valve family. The distinct feature of a ball valve is its hollow ball-shaped disc that acts to stop or start media flow. The ball disc is one of the quickest valves because it only needs a quarter turn to open or close.
Advantages
- Great shut on/off capability.
- Minimal leakage through wear & tear if properly used.
- Low maintenance cost.
- Minimal pressure drop.
- Time & labor effective to operate.
Disadvantages
- Not suitable as control or throttling valve.
- Not suitable for thicker media as sedimentation could occur and damage the valve disc & seat.
- Surge pressure could occur due to rapid closing and opening.
Applications
Ball valves are suitable for fluid, gaseous and vapor applications that need bubble-tight shutting down. While primarily for low pressure uses, high pressure and high temperature applications apply to ball valves with metal seats.
Ball Valve Parts
Body
This refers to the framework of the valve that keeps all parts intact. This part is attached to the pipes in the pipe system. The body may have one, two, or three pieces. We will discuss this difference in a later section.
Stem
The stem refers to the shaft that connects the inner ball to a handle or actuator. This part transfers the movement of the actual quarter turn force from the actuator to the inner ball part.
Packing
The packing prevents leaks from the valve from escaping to the external environment.
Bonnet
The bonnet is the housing that covers both the packing and the stem. This provides a tertiary leakage protection.
Ball
The ball is the hollow sphere placed in the middle of the valve. When turned, it will either allow the media to pass through the valve or not.
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Seat
As its name connotes, this part seats the ball device inside the valve. The seat provides the secondary protection from leakage as the valve closes.
Actuator
Found external to the body, the actuator opens or closes the valve from the outside. Opening can be done manually or automatically.
All You Need to Know About Ball Valves
These valves belong to the quarter-turn on/off valve family. This means that a 90-degree turn can either permit or stop the flow of media using a ball-like mechanism inside the valve. Ease of operation is the main advantage of ball valves. In industrial applications, this is a very reliable device for a complete and tight shutoff.
However, this type should not regulate flow media as in a partially open or closed manner. The pressure might affect some valve parts.
This article provides information about ball valves, including understanding its components, knowing what to consider when buying them, comparing the pros and cons, as well as identifying various classifications of ball valves. You can also check out what is a ball valve exactly in our blog post.
What Are Ball Valves Used For?
Almost all industrial applications need protection from leaks. This is particularly important to those that require tight shut mechanisms. Such examples are the purely liquid or gaseous applications, including natural gas industries, chemical storage and those that work with corrosive fluids. Slurries don’t work well for these valves.
Why Choose Ball Valves?
Drop
This means that there is no need for a higher and powerful pump to move the fluid and gas. It also means the change of pressure from high to low is minimal, ensuring the smooth running of the pipe components.
No Stem
The valve does not include a stem part that pops up or down depending on the movement. Hence, no gas or liquid gets out of the pipe when the valve is shut off or turned on.
Cost-effective
This type of valve does not cost much yet lasts for a long time. There are more choices because of varied designs.
Versatile
This valve supports high pressures and temperatures. It can withstand up to 700 bars and 200°C.
Easy To Operate
It only takes a 90°-turn for the valve to shut down or turn on.
Easy To Fix
Because of its simple design, especially the top entry, fixing and assembling them is easier compared to other valve types. Check out all top ball valve manufacturers in China in this article according to the factors mentioned above and choose suitable one for your applications.
Ball Valve Types By Valve Openings
Ball valve body types have two classifications according to the size of the valve in relation to the pipe size.
Full Port Type
This type has the same internal diameter type as the internal diameter of the attached pipe. The advantage of this design is reduced friction. Used in refining and petrochemical industries, this design does not restrict fluid flow, albeit more expensive to install.
Reduced Port Type
Also known as standard port valves or reduced bore. Additionally, the valve is one size smaller than the piper to which it is attached to. This type is often used in gas and oil applications.
V-Port Type
This is a more specialized ball valve as it acts as a control valve too. The ball or seat can have a V shape since it has either a V-shaped ball or seat. This design allows for a more uniform media flow so there is a lesser pressure drop compared with the other two port types.
Types By Number of Pieces
One Piece Type
One piece housing is the cheapest kind because either welded or forged together. The downside of this kind is, assembly for cleaning or replacement is impossible.
Two Piece Type
As its name connotes, it is made of two pieces connected by a thread. For an internal replacement or cleaning, removal of the valve from the pipeline is necessary.
Three Piece Type
Bolt connections keep the three-piece housing molded together. Cleaning, check up or disassembly without removing everything is possible. But this is the priciest among the three options.
Considerations When Buying Ball Valves
#1 Size
The size or the diameter of a ball valve matters. There are ball valves that supply only the full port valve. This means they have the same diameter as the pipe. Sizing matters because it affects the flow of the gas or liquid. Diameters can vary from a ¼ valve to as large as a 2” valve.
#2 WOG
Another term for water, oil or gas, WOG refers to the material passing through the valve and pipes. Each of these has different pressure ratings, which, in turn, can carry or affect various pressure ratings.
Understanding these two, as well as how valve sizes and materials interact, are determining factors in vaulting in valve efficiency.
#3 Body Material
The common one is the steel ball type, but industries also use brass or bronze with nickel plating. Most of the time, 316-grade steel is the preferred material. But, take note, this depends on the type of media flow and other conditions. Non-corrosive media should use electroless nickel plated carbon steel balls. Avoid chrome-plated ball valves because these are much more prone to corrosion.
#4 Ports
Ports are the entry and exit points of valves, which can either be full or standard. They can restrict fluid or gas flow.
#5 The Type of Flow Media
Flow media refers to the component that passes through the valve. Similarly, the type of fluid or gas plays a role in choosing the right kind of valve. In relation to this, it can produce reactions when in contact with the valve.
#6 The Entire Piping System
These valves are just part of the equation. Considerations should include the requirements of the entire system. For instance, the purpose of the piping system is relative to the suitability of the valve.
#7 Industry Standards
Valves should meet the criteria provided by the industry. Studies back up the standards followed by industries. By knowing what the industry requires and following this ensures minimal errors, accidents, and the likes.
#8 Seat Material
Valves using soft seats often have limited pressure threshold. However, softer materials are great sealers.
These valve seats often use a type of polytetrafluoroethylene (PTFE) as a rule of thumb. One example is Teflon. One catch here, though, low-pressure applications should only use virgin PTFE.
Another soft material often used in ball valves is neoprene or fluorocarbon elastomer. Generally ideal for pulp and paper applications, this material is highly resistant to oil and moderate chemicals. However, this material is not great for highly corrosive acids such as hydraulic fluids.
Mid-range pressure applications use filled PTFE. On the contrary, high-pressure applications utilize polyether ether ketone (PEEK). Pure liquid or gas media applications use soft seats while abrasive medium uses metal seat ball valves. Meanwhile, low-pressure systems employ tungsten carbide as the coating.
Soft seat materials do not react well in high temperatures. Therefore, use a seat made from graphite. What determines the type of seating to use are the ball valve pressure rating and the materials.