What is a Ball Valve?
It is a shutoff valve that maintains the flow of a gas or liquid, a rotary ball having a bore. The medium flows through or is blocked by spinning the ball a quarter turn (90 degrees) on its axis. A long service life characterizes them and provides suitable sealing over the life span, even when the valve is not used for a long time.
Why We Used the Ball Valve?
A ball valve has good durability, ease of use, and outstanding sealing properties. Even after years of service, they provide exceptional shutoff. As a result, a ball valve is an excellent option for a shutoff valve. Further, they are more resistant to contaminated media than other valves. Due to their less precision flow control, ball valves are rarely used as control valves. However, they are economical and used in applications where precise flow control accuracy is not required.
What is a Plug Valve?
A plug valve is a manual quarter-turn rotary valve. It employs a cylindrical or tapered plug (plug-shaped disk) to allow or prevent straight-through passage within the body. Plug valves provide a straight passage through the ports. It allows fluid to pass through the plug opening with minimal turbulence. Flow can be either open or closed in either direction.
Ball Valve Vs. Plug Valve: Structural Difference
Ball Valves Structure
The ball valve is an altered plug valve with a spherical disc and circular bore channel. The disc contains a port, which is an opening. The valve opens when the port is aligned with the valve’s dual ends. The medium could be flowing through it. Flow stops when the port is vertical to the edges of the valve.
Ball valves have a compact design, ease of maintenance, and compatibility with water, acids, natural gas, and solvents. Therefore, it is useful for many applications. Even in the severe operating conditions of media such as hydrogen peroxide, oxygen, methane, and ethylene, ball valves are an excellent option. Traditional gas shutoff ball valves are most suitable for open and close operations. In contrast, more advanced or customized models provide flow control and throttling capabilities.
Plug Valves Structure
A plug valve with a cylindrical disc controls liquid flow through one or more pathways that move laterally. When the valve opens, the hollow conduit aligns with the flow. It allows the liquid to flow freely. After a 90-degree rotation closes the valve, the stopper is readjusted to restrict flow.
The plug valve is a small, uncomplicated valve that distributes the media flow. However, some specialized types of plug valves can operate in high-temperature. However, their primary applications are in medium or low-pressure and low-temperature conditions.
Ball Valve Vs. Plug Valve: Components
- Parts of the Ball Valve
1)Valve Body
This is the primary component of the valve and contains all of the on/off control components.
2)Rotary Ball
The ball is designed with a central bore (hole) through which the fluid moves. Turning the stem controls the path of the ball.
3)Stem
This is the connection between the ball and the external control mechanism. For instance, the stem is connected to a handle or actuator in a manual ball valve.
4)Seats
These discs are located between the body and the ball. In addition to providing a seal between the two, seats support the object.
5)Power Source
The stem of the ball valve is turned using either manual or electrically-powered mechanisms. Manual actuation consists of levers and handles under the control of an operator. Automated power sources include electric, pneumatic, and hydraulic actuation.
6)Packing
This is a seal that prevents the media from the stem.
7)Bonnet
The body component that contains the stem and packing is the bonnet.
- Plug Valve Components
The plug valve has the following major parts:
1. Valve Body
2. Stem
3. Handle
4. Plug Ports
5. Plug disc
1) Valve Body
The valve’s body is also known as its casing. It comprises all of the valve’s internal components. It prevents internal components from being damaged by falling external objects. The valve’s body is connected to the conduit via an end connection.
2) Stem
The stem is used to join the actuator to the plug disc. Connected to the handle or actuator is the stem. This component of the plug valve transfers the handle’s motion to the disc.
As the disc moves, it opens or closes the valve based on the specifications. The diaphragm assembly or packing helps in stem leakage prevention.
The leaking of the valve seat stopped by pressing the plug into the sleeve or by using an alternative sealing method.
3) Handle
This is an external component of the valve. The handle plays a substantial role in the opening or closing of the valve. An operator is necessary to operate the handle. As the handle is turned, it is moved to the stem, which moves it to the inserted disc.
4) Plug Ports
The plug disc may contain multiple connections. These are also referred to as passages. The fluid begins to circulate within the system and passes through these ports.
5) Plug disc
The insert disc features a tapered shape. This disc has at least one interface. It connects to the stem. Through the stem, it receives the motion of the valve handle.
There is a solid metal disc with tapered ends within the plug valve. The valve disc’s design differentiates it from other valves, such as the globe valve.
Ball Valve Vs. Plug Valve: Working Mechanism
Ball Valve Working
The ball valve resembles the butterfly valve in its operation. It consists of a ball with a drilled opening in the center. The position of the ball orifice determines whether the flow is open or closed. The ball is attached to the stem, which is, in turn, attached to the tool handle or actuator. To initiate fluid flow, the actuator rotates approximately 90 degrees clockwise. When it rotates, it turns the stem, which rotates the ball.
When the ball’s opening is aligned with the fluid flow, the flow begins through the valve. To stop the flow, the actuator rotates 90 degrees counterclockwise and turns the stem in the same direction. As the ball rotates 90 degrees counterclockwise, the fluid flow completely stops.
The ball can be maintained in partially open and partially closed states for flow control. If the valve were left partially open for an extended period under high-pressure drop conditions, the soft seats would tend to flow around the ball orifice edge. They could potentially lock the ball in place.
Plug Valve Working
The body of the plug valve has either a tapered or parallel seat. This seat fits a plug. The position of the plug’s opening determines the flow through the valve. Ports are the openings in the valve body that enable fluid to enter or exit. The stopper is rotated 90 degrees; the fluid flow is completely opened or closed.
Nevertheless, despite being a quarter-turn valve, plug valves are less efficient than ball valves. They can only operate in an entirely open or closed position. When the plug’s port is aligned with the inlet and outlet ports, fluid flow is maintained through the valve. The reduced area of the plug port causes a pressure decrease, which is a disadvantage compared to a ball valve.
Ball Valve Vs. Plug Valve: Size
Ball Valve Size
| Size | D | L | H |
| ¼ inch | 0.23 | 2.99 | 2.20 |
| 3/8 inch | 0.32 | 2.99 | 2.20 |
| ½ inch | 0.51 | 4.02 | 2.20 |
| ¾ inch | 0.75 | 4.25 | 2.72 |
| 1 inch | 0.99 | 4.53 | 3.50 |
| 1 ½ inch | 1.50 | 5.24 | 4.49 |
| 2 inch | 1.89 | 6.06 | 4.72 |
Plug Valve Size
| Standard Valve Size (Inches) | Minimum Opening Diameter (Inches) |
| ¼ | 0.2500 |
| 1/8 | 0.125 |
| ½ | 0.5000 |
| 3/8 | 0.3750 |
| 1 | 0.9795 |
| ¾ | 0.7300 |
| 1 ½ | 1.4625 |
| 1 ¼ | 1.2290 |
| 2 | 1.9480 |
| 2 ½ | 2.4100 |
| 3 | 2.8800 |
| 3 ½ | 3.3560 |
| 4 | 3.8260 |
Ball Valve Vs. Plug Valve: Sealing Properties
Both plug and ball valves are quarter-turn valves whose stems are closed and open with a 90-degree rotation. These valves are utilized predominantly for shutoff purposes. Nonetheless, there are a few distinctions between them.
Ball Valve Sealing
Due to their minimal torque requirements, ball valves are lighter in weight and easier to operate. Recent innovations in seal injections and chemical sealing solutions have effectively resolved this problem.
Plug Valve Sealing
The sealing surface area of a plug valve is significantly larger than a ball valve’s. This enhances sealing capabilities, requiring more power and torque during operation.
Ball Valve Vs. Plug Valve: Maintenance
- Ball Valve Maintenance
Regular maintenance is an effective way to ensure long-lasting, uninterrupted operation. Inspect the valve within the first year of operation for any potential leaks. Perform a complete maneuver cycle (moving the handle to open and shut the valve) every three months. This may inspect the valve for any leaks or corrosion and prevent the formation of scales. Scales are the solids that gather on valves and pipelines over time. It significantly decreases production rates and equipment damage. In extreme conditions, the valve should be checked more frequently.
- Plug Valves Maintenance
Plug valves have fewer moving parts and a simplified design, which makes them relatively simple to maintain. Additionally, after removing the plug, the remaining valve body is easy to clean.
Compared to ball valves, plug valves are less expensive to operate. To prevent the valve body and plug from rusting out, the plug of a plug valve slots beneath the bushing. Only the bushing and upper seal were replaced to maintain the valve’s optimal performance and service requirements over time.
Ball Valve Vs. Plug Valve: Application
Plug Valve Application
Plug valves have increased surface area and unrestricted fluid flow. However, it is appropriate for applications involving abrasive materials such as waste and slurries. They ensure a secure seal when managing corrosive substances. However, their anti-corrosion properties make them a reliable option for demanding applications.
Ball Valve Application
A ball valve is a common choice for automation. It is used in natural gas and crude oil transfer, LNG services, and field gas processing. They are also useful in various industrial settings. These are turbine platforms, oil refinery feedstock lines, and hydrocarbon processing.
Ball Valve Vs. Plug Valve: Lifespan
Ball valves have a longer lifespan than plug valves. A plug valve must withstand greater torque and have a greater contact area with the medium. This indicates that the valve has endured greater wear and tear. However, it is more prone to corrosion. Unique characteristics of ball valves prevent the medium from continuously contacting the disc even though it contains more moving parts; the low torque results in less wear and strain.
Ball Valve Vs. Plug Valve: Material and Working Conditions (Temperature)
Ensure that the material of the valve can withstand the operation’s maximum and minimum temperature requirements. The housing and seal material typically determines the temperature range of a ball valve. Common ranges are listed below, but consult the datasheet for validating your ball valve.
Brass ball valve: -20°C to 60°C (-4°F to 140°F)
PVC ball valve: -10°C to 60°C (14°F to 140°F)
Stainless steel ball valve: -40°C to 220°C (-40°F to 428°F)
Plug Valve Materials
Plug valves can be produced from various materials, both metallic and plastic. The most common plug valve materials are
Steel
Stainless Steel
Bronze
Brass
Plastic
Are Plug Valve Is Better Than Ball Valve?
In simple terms, plug valves are better than ball valves for the following principal reasons:
You cannot use ball valves instead of plug valves, but you can use plug valves instead of ball valves.
The more accessible valves to use are plug valves. Ball valves, on the other hand, have space between the body and the ball. Although the ball valve is closed, some medium stays in the hole. You have to clean the medium before you can use the machine again. This problem happens a lot in places that make chemicals and food. Ball valves are ineffective when a prolonged interruption in time makes it impossible to clean the medium properly.
Plug valves have a full port, which means they let all the flow through. The port on a ball valve, on the other hand, can be the full or limited port.
Ball Valve Vs. Plug Valve: Conclusion
Plug and ball valves regulate fluid flow using a simple on/off or multipath function. Consider the following when deciding when to use a ball valve versus a plug valve:
A plug valve is the best option for complex applications due to its flawless sealing and simple application structure. In addition, they are cheaper than ball valves. However, they are not as compact as ball valves. This may result in a decrease in pressure from the inlet to the exhaust. Choose ball valves for large-scale, high-pressure applications that need simple operation. They are easier to operate and more compact than plug valves. However, their sealing capabilities are slightly diminished.