Plug Valve vs. Ball Valve (1)

We all know very well that valves are used for controlling the flow of liquids and gases in different types of situations. For example, in our homes, valves that are used in gas applications are the plug valves. They are also used in toilet tanks, on the other side. The water spigots also have valves that are used outside the home.

Valves are used in different industries as well as in homes. Different valves offer different functionality, porting, longevity, control, and type capabilities. In this post, we will discuss the comparison between plug valve and ball valves in detail.

However, keep in mind that both the plug valves and ball valves show the same function. Both are used in controlling the flow of gas or liquid either in a simple function or as a multipath function.

What are plug valves?

In a plug valve, fluid is stopped or started through rotational movement. The disk has a plug-like shape, which is where its name comes from. Inserted in the valve body is a removable plug of a cylindrical or tapered shape. An angled passage is formed at a right angle to the longitudinal axis of the plug.

Opening the plug valve allows the inlet and outlet ports of the valve to line up with the passage in the plug. When it is turned to 90 degrees from the open position, fluid cannot flow through the aperture because of the solid part of the plug.

Availability of plug valves

Plug valves are usually available either in the lubricated form or in the non-lubricated design. Most surprisingly, it is also available in various port openings to the plug and different plug designs. One-piece top-entry plug valves share a lot of characteristics with one-piece top-entry ball valves. Due to their similarities, ball valves and plug valves are very similar types of valves.

The structure of plug valves is simple.

Plug valves are very simple types of valves that are simple in structure and smaller in size. By turning the plug valve at a 90-degree angle, you can easily open the valve. Keep in mind that plug valves are usually used in low-temperature conditions as well as low-pressure conditions.

They usually have smaller diameters to use in any situation. Unfortunately, the sealing surface of the plug valve is easy to wear where you can increase its longevity by treating the plug valve wisely. This is the main reason it is easily stuck in high-pressure and high-temperature conditions, which are not suitable for flow regulating.

What are ball valves?

With good shutoff capabilities, it is possible to shut off a ball valve. Opening or closing the valve is accomplished by turning the valve 90°. The valve can operate more quickly by utilizing this feature, and leakage will be reduced due to gland seal wear.

Ball valves can be categorized into two main types:

Full bore

In full bore valves, the size of the valve opening is the same as the diameter of the piping.

Reduced bore

The diameter of the pipe and valve opening is smaller in reduced bore valves.

Remember that different manufacturers and companies usually prefer the full bore ball valves because they usually minimize the pressure drop across the valve.

Closed or fully open position

In general, ball valves are used in either a fully open or fully closed position.

Keeping them partially open does not allow them to regulate flow. This is because the ball valves rely on soft valve seats shaped like a ring.

The reason is that when we use ball valves in a partially open position, the pressure is only applied to the portion of the valve seat, which can cause deformation. Unfortunately, the sealing properties are impaired if the valve seat deforms. In the end, the ball valve will leak as a result.

Less expensive and low maintenance cost

However, ball valves are good in the sense of being less expensive than any valve configuration and have low maintenance costs. A quick turn on/off and no lubrication required to make these ball valves the most compact valves available. Moreover, the ball valves offer tight sealing with low torque.

The throttling characteristics of conventional ball valves are poor. As a consequence of high-velocity flow impinging on the seat, the exposed portion rapidly erodes.

Evolve from the plug valve

Ball valves usually evolve from the plug valve with a ball as its closing parts. Mainly we can use ball valves to cut off or change the flow direction of the medium. There is very little resistance in the flow path through the medium because the valve cavity is completely horizontal.

Mainly the ball valves are compact in structure, easy to operate, and easy to maintain. Ball valves are therefore used in different types of medium such as solvent, water, acid, natural gas, and other media.

Most surprisingly, ball valves are also used in harsh media such as hydrogen peroxide, methane, ethylene, or oxygen. The ball valve is generally specified for direct opening and closing, but recent developments have led to the design of ball valves with the ability to throttle and control flow.

Why are plug valves better than ball valves?

There are many reasons why plug valves are better than ball valves.

First of all, the plug valve cannot replace the ball valve, while the ball valve can replace the plug valve.

It is easier to use the plug valves than the ball valves. On the other side, there is a space between the body and the ball. However, the ball valve has some drawbacks.

A certain amount of medium remains within the space after the ball valve has been installed and the plant has been closed for maintenance or a weekend shut-down. Once the plant restarts, the medium will need to be cleaned.

Chemical and food factories commonly encounter this type of problem. The medium is unable to be completely cleaned, making ball valves useless. A plug valve is a full port device, allowing the full flow of fluid. On the other hand, a ball valve can either be a full port or a reduced port.

Many companies and manufacturers specialize in producing high-quality plug valves to suit the specific needs of our customers. Plug valves are available in many styles at the store.

How do ball valves work?

A ball-shaped disc is present, which makes the Ball valve. It is a circular disc with a hole in the middle and allows the medium to flow through it. The medium will flow when the hole is in line with the ends of the valves. Ultimately, the flow of the medium stops when the port is closed, and the hole is turned to oppose the ends of the valves.

How do plug valves work?

The plug valve has the shape of the cylinder and is usually made with plugs. When these plug valves align with the channel, then it opens to control the flow. Plug valves are very effective and give you quick operation. Plug valves also shut off in emergencies. As compared to the ball valves, plug valve seals are tighter.

Both these plug valves and ball valves will work efficiently if there is regular maintenance. It is important to remember that plug valves are much easier to maintain than ball valves. In plug valves, some moving parts are also available that would also need attention. However, on the other side, it is easy to remove the plug for cleaning and repairs.

Unfortunately, the ball present in the Ball valve is located in a difficult position to access. As a result, there is a chance to accumulate dirt and debris on the ball, making it difficult to move.

The lifespan of the Ball valve and plug valve

If we talk about the life span of the ball valve and plug valve, then ball valves have more life span than the plug valves. Most surprisingly, there is more chance of the plug valves getting erosion.

This is because, in the plug valves, more fluids come into contact with the cylinder and have high torque. On the other side, there are more moving parts in ball valves, so it has less contact with the medium and requires less torque.

Flexibility and customization

Ball valves have more potential for customization. On the other side, the ball valves are available in a variety of designs to choose from. Ball valves are also available in a one-piece design, two-piece body, or three-piece body.

Ball valves also give you the option to service multiple ports. Most amazingly, the ball valve comes up with top entryways and side and split body entryways.

However, if we talked about the customization of the plug valves, they are not customizable as ball valves. Plug valves have a very simple design; they are not available in many options that are present in the market.

The ports of the plug valves usually range from two ports to 5 ports. They do not exist in more than five ports because, ultimately, they will give you a loser shutoff.

Highly different applications

One of the most important differences between plug valves and ball valves is developing highly different applications. You can use plug valves in different fluids and airy materials. On the other side, ball valves are very versatile in terms of application. They are different from plug valves as they are used with thicker substances and oil and gas.

Main differences between ball valves and plug valves

Both the ball valves and plug valves are the control valves that give you a tight shutoff in different kinds of piping units. Keep in mind that both the valves are similar in terms of basic functions and applications.

Plug valves and the Ball valve work on a similar basic principle where the flow of the medium starts or stops with the help of perforated disks. However, both have some differences in different aspects. Let’s discuss the difference between the valves in detail.

  • Construction

Bored discs are present in the center of the valve in both the plug valves and ball valves. In the Ball valve, a hollow center is present where it has a spherical disc.

However, the disk in the plug valve is conical or cylindrical, with bored passages going through it. It is interesting to know that both the discs present in the ball valve are smaller than the plugging valve.

This is the main reason why plug valves give you a tighter shutoff than a ball valve.  The plug valve is also much smaller than the ball valve. Plug valves have a small footprint, so they can be fitted into smaller units.

  • Function

Control valves, such as ball and plug valves, are used to start and stop the flow of the medium. Compared with a ball valve, the plug valve’s sealing surface has a much larger area. A conical plug or cylindrical plug in a valve provides a better seal because of its larger surface area. The greater area also equates to more torque. The result is a valve that has a hard time opening and closing.

On the other hand, ball valves operate without torque. This can lead to low sealing performance because the surface area is smaller. Ball valves can easily overcome this problem with today’s chemical sealants and seal injections.

Plug valves can be relatively heavy compared to lighter-weight ball valves. Plug valves have a large solid disc or plug centered in the top of the valve, making it heavier. Because of this, plug valves are used for small applications. It is pretty expensive and really heavy to manufacture large plug valves.

  • Maintenance

Both the plug valves and ball valves need regular maintenance to work efficiently. Unfortunately, it is difficult to maintain the ball valves as the ball or disc is present deep inside the body, difficult to approach. This is one of the main things why ball valves are difficult to maintain.

According to some manufacturers, the body cavity of the valve has some particles from the medium, which is difficult to remove. On the other side, plug valves are very easy to maintain because you can easily remove and clean the plug valve.

Moreover, the plug valve gives an easy approach to the valve body. So it is very easy to maintain the plug valve without much inconvenience. Plug valves come up with simple construction and do not contain a lot of moving parts.

If we talk about the plug valves’ size, they are usually smaller than the regular valves. Its small size makes it easy to repair and maintain.

Types of ball valves

Ball valves are considered to be the most versatile control valves.  There are many types of ball valves depending on the structure and function. Due to a different structure and function, they come in the category of today’s most popular valves used in the piping industry.

You can find two types of ball valves that are very popular, such as full bore ball valves and reduced bore ball valves. In a full bore ball valve, there is an unobstructed flow of medium through the valve. Reduced bore valves restrict the flowing medium. The reason is that the size of these reduced bore valves is less than the pipeline’s diameter.

You can also find other types of ball valves, such as floating ball valves or trunnion mounted ball valves. Floating ball valves are usually required in those applications where a bidirectional shutoff is required. On the other side, trunnion mounted ball valves are specially made for high temperature and high-pressure operations.

If we talk about the types of plug valves, they do not have as many types as the ball valves. A rectangular port valve is the most common plug valve, especially for rectangular ports. However, single-port and multiport valves can also have reduced bores, but they are only suitable for low-pressure applications.

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