What is a Ball Valve?
A ball valve is a flow control device that uses a hollow, perforating, and pivoting ball to control the flow of liquid or gas flowing through it. The ball is rotated using a handle or lever to open or close the valve, and the flow is controlled by the position of the ball about the valve seat. It opens when the ball hole is in line with the flow inlet and closes when it is pivoted 90 degrees by the valve handle or lever, thus blocking the outflow. The handle lies flat and aligned to the flow when open and is perpendicular to the flow when closed, to enable easy visual confirmation about the status of the valve.
Ball valves have a long service life and provide reliable sealing over their long life span as they are very durable. They are designed with special measures that permit only a 90-degree rotation to open or close the valves. Ball valves are commonly used in plumbing or industrial applications due to their durability, ease of operation, and ability to withstand high pressure and temperature conditions. Moreover, they are available in a wide range of sizes, and a variety of materials like steel, brass, and plastic. They can be used for both full-on and full-off applications as well as modulating flow controls.
Ball Valves are a popular industrial choice because of their reliable and air-tight sealing. Another advantage of using ball valves is that they perform well after many cycles and even after long periods of disuse. This makes ball valves an excellent choice for shut-off and control applications and is preferred over gates and globe valves. But they lack the fine controls of those alternatives in throttling applications. Moreover, ball valves are more resistant to contaminated media, than most other types of valves.
Types of ball valves
The following are the most common types of ball valves:
• Standard (Threaded)
• Flanged
• Vented
• Hydraulic
Ball valves are also classified according to the metals and materials used to manufacture them, as well as their dimensions and sizes. Ball valves are available in different sizes and dimensions to cater to the different industries and the purposes they are used for.
Ball valves based on materials are classified into the following types:
• Mild Steel Ball Valve
• Brass Ball valve
• Forged Carbon steel Ball valve
• Iron Ball Valve
• Stainless Steel Ball Valve
• PP Ball Valve
Different Uses of Ball Valves
Ball valves are used in many different industries and hydrocarbon process applications:
• Oil and Natural Gas Industry
• Manufacturing Sectors
• Chemical Storage
• Residential Uses
Ball Valve Specifications
While installing or ordering the ball valves, one must go through the ball valve specifications. To get the desired results and control of the fluid or gas, the ball valve must be selected based on the required ball valve specifications in consideration for your particular usage.
All industrial setups and facilities have different productions, raw materials, and processes that require different materials and temperature setups. You need to install the appropriate ball valve material to mechanize and control such materials with different temperatures. One must consider the ball valve specifications to select the appropriate ball valve with the proper dimension to suit the factory machines and setup, to get the desired result and longevity.
Advantages of Ball Valve
• Compact and low-maintenance design
• Requires no lubrication
• Cost-effective among all of the valves
• Leak-proof service
• Open and close quickly and easily
• Ball valves have multi-way design flexibility
Different Components of a Ball Valve?
Ball valves are usually made of metal, plastic, or metal fused with ceramic. For better durability, the ball in the valve is chrome plated. Ball valves feature certain moving parts just like any other industrial valve.
The components of a ball valve are:
• Body or Shell
The shell of a ball valve houses all other components of the valve. It is also the first pressure boundary of the valve, as it imparts to the ball valve the first line of resistance against the flow of materials through pipes connected to the valve. The body of a ball valve is the main framework of the valve. It enables holding together and protecting the other components or parts of the ball valve.
• Bonnet
The opening of the ball valve’s body is covered by the bonnet. To ensure that it stays intact and in place, it is usually bolted or screwed to the body. Bonnet becomes the second pressure boundary of the valve as it reinforces the strength of the body to counter the pressure of materials flowing through the pipes connected to the valve. The bonnet is usually made of the same material as the body of the valve to enhance its strength and durability.
• Trim
The trim of a ball valve consists of all the moving parts of the valve. This includes the ball (disk), seat, stem, and sleeves. The hollow sphere in the ball acts as its disk. It is placed in the center of the valve and it turns to allow materials to pass through. The ball performs the function of being the third
pressure-resistant boundary of the valve as it comes in direct contact with the materials flowing inside the pipes connected to the valve. The stem of the ball valve connects the ball to the actuator. As the actuator is turned, the stem moves as well, in turn, rotates the ball. Welded joints connect the stem, ball, and actuator. The ball is placed in the seat of the ball. The seat is also known as the ‘seal ring’ as it holds the ball inside and provides a secure fit when the valve is closed.
• Actuator
What we use to open and close the valve is the actuator of the ball valve. Handwheels, levers, motors, solenoids, pneumatic operators, and hydraulic arms are all various ball valve actuators. In most ball valves the actuator is mounted over the bonnet of the ball valve through a yoke.
• Packing
Packing shuts out any leaks through the stem. Ball valve packing is found in the space between the stem and the bonnet. Usually made of fibrous materials like flax or Teflon packing protects the internal parts of the valve by forming a seal over them to prevent any leakages.
How Does a Ball Valve Work?
Shut-off valves that use a ball to start or stop the flow of materials through the valve are known as ball valves. The ball in the valve is similar to the disc in other valves and performs a similar function. The ball is hollow and has a hole that is also called the bore. When you move the actuator, the ball
rotates to a point where part or the entire bore comes in line with the inlet and outlet of the valve’s body. This permits the materials to flow through the valve.
• To close the valve the actuator is moved again. When this is done the ball rotates to a point where the bore becomes perpendicular to the flow path. This stops the materials from flowing. Most ball valves require a 90-degree turn of the actuator to fully open or close. The valve can be kept open
partially but that can damage the ball valve. This is the reason why ball valves are not used for throttling applications. They are most appropriate for applications where tight shutoff is required for example to control the flow of gas.
• Depending upon the number of valve seats and ports, ball valves can be uni-directional, bi-directional, or multi-directional. For example, a single-seat two-way ball valve will be unidirectional with the flow direction indicated on the valve. The same valve with two seats will be bidirectional. In this valve, one seat will be on the upstream side while the other will be on the downstream side of the ball. Three-way, four-way, and five-way multiport ball valves can be unidirectional if the flow is entering through a designated port. Multiple port ball valves allow flow in more than one direction
eradicating the need for various valves. Downstream equipment can be damaged because of surge pressure due to rapid opening and closing.
Applications of Ball Valves
Because ball valves provide reliable leak protection they are ideal for innumerable industrial applications. Moreover, its low-pressure drop can open and close ball valves quickly which makes them great for liquid and gas applications. Because ball valves are also extremely multifaceted they can be utilized for subsea, underground, and cryogenic services. Air, gas and liquid applications require bubble-tight service hence ball valves are used. They are also useful in low-point drains and high-point vents for liquid, gas, and other fluid applications. Ball valves can also regulate cooling water and feed water systems. They can also be used for steam services. as feed lines, turbine and compressor skids, crude oil plants, generator skids, polymer plants, LNG plants, field gas plants, industrial gas processing plants, oil refineries, hydrocarbon processing, and automated process applications, all use ball valves. While in petroleum refining, desalination, and brewing stainless steel ball valves are used.
The Advantages and Disadvantages of Using Industrial Ball Valves
Ball valves are preferred to be used in many different industrial applications despite some limitations:
Advantages
• Ball valves give bubble-tight service
• They can be quickly opened and closed
• They are comparatively smaller in size and lighter in weight than gate valves
• Multiple ports eliminate the need for more valves
• They offer a lot of variety in terms of construction and design
• They can be equally adept at managing the flow of clean and slurry materials
• They provide extremely dependable service even in high-pressure and high-temperature
applications
• Ball valves can be easily Actuated as compared to gate or globe valves
Disadvantages
• Ball valves are useful only for full shut-off operations. They are not appropriate for sustained
throttling applications
• Ball valves can be damaged by slurry or corrosive materials as particles can settle in the body
cavities of the valve causing wear, leakage, and valve failure