The valves are the most commonly used mechanical devices for different household and industrial applications. The valves have multiple types designed according to the nature of the application. A ball valve is a most commonly used type of valve. It uses to control the different fluids such as liquid, gases, and vapors. This article explains the ball valve working, types, applications, and uses.
What is a Ball Valve?
A type of valve which uses a hollow, turning, and perforated ball to control the fluid flow is known as a ball valve. The ball of the valve has a hole in the middle. This ball sets in between the two seats. The position of the ball is controlled via an actuator or wrench handle.
The ball valve has the ability to control, guide, direct and modulate the flow of different fluids such as liquids, gases, and vapors.
The ball of the valve opens or closes the fluid flow by turning the wrench handle at 90 degrees clockwise or anticlockwise direction respectively. It starts the flow when the hole of the ball becomes parallel to the direction of the fluid flow. As the wrench handle is turned anticlockwise up to 90 degrees, the ball stops the fluid flow.
The ball valves have high reliability and long service life. You can operate them pneumatically, electrically, or manually.
These valves provide reliable sealing for a long time, even in case of dirty fluids. They offer high resistance against harmful fluids than other valve types. Therefore, they are preferable over globe valves and gate valves.
For some specific applications, the ball valves may also use as a check valve. Such types of valves have a solid ball that stops the unwanted backflow of the fluid. This type of ball valve is not much famous due to the inadequate precision of the fluid flow control than other types of check valves.
Working of Ball Valve
The ball valve works very similarly to the butterfly valve. It has a ball that has a bored hole in the center. The position of the ball hole decides the opening or closing of the flow. The ball is connected to the stem, which is further connected to the wrench handle or actuator.
A ball valve works in the following way:
To start the fluid flow, the actuator rotates clockwise about 90-degrees. When it turns, it rotates the stem. The stem turns the ball.
When the hole of the ball is in line with the fluid flow, the flow starts through the valve.
To stop the flow, the actuator rotates anticlockwise about 90-degrees and also turns the stem in the anticlockwise direction. As the ball turns anticlockwise about 90-degrees, it fully stops the fluid flow.
The ball is kept in partial open and partial close conditions for throttling flow. If you left the partially open valve for a long time under high-pressure drop conditions, the soft seats would lean to flow around the ball orifice edge and possibly permanently lock the ball in that position.
Read More: Working of Globe Valve
Types of Ball Valves
The ball valve has the following major types:
- Standard Port Valve
- V Port Valve
- Multi-Port Valve
- Reduced-Port Valve
- Full Port Valve
- Single Body or One-Piece Ball Valve
- Two-Piece Valve
- Three Piece Valve
- Top Entry Valve
- Side Entry Valve
- Welded Body Valve
1) Standard Port Ball Valve
These types of ball valves have smaller ball and port than the full port ball valves. This valve has a low cost. However, the fluid flow in this valve is somewhat restricted due to the size of the pipe.
Standard port valves have more pressure drop than other types of ball valves. These valves are ideal for high flow rate systems.
2) V Port Ball Valve
The “V” in a V-port valve denotes the ball design or design of the seat. This type of valve gives you more control to efficiently open and close the fluid flow. It has an almost linear flow.
These valves are designed stronger because high velocity fluids are passed through them. Such high viscosity liquids can quickly damage standard valves.
Read More: Different types of Valves
3) Multi-Port Ball Valves
It has 3 or 4 directions with an L or T-shaped hole in the middle of the valve.
- T-shaped valve has the ability to connect any pair of ports.
- The L-shaped valve can link the middle port to the side port.
The multi-port ball valve has an inlet that is usually orthogonal to the plane of the outlet. The ball of a 4-way ball valve has two L-shaped ports called X-port.
4) Reduced Port Ball Valve
The reduced port ball valves are also called RB or reduced bore valves. In this valve, the flow area is less than the pipe, and the fluid flowing by the valve is one pipe size less than the pipe size of the valve. The reduced-port valve causes a pressure loss in the pipeline.
5) Full Port Ball Valve
These valves have more cost than other types of ball valves. The oversized balls in full bore ball valves reduce friction drop because the hole in these ball valves has a similar size to the pipe. Therefore, it has more size than other valves, but it does not limit the flow rate.
Full bore ball valves are commonly used in throttling services on a variety of systems with low-pressure drops and high flow coefficients.
6) Single Body or One-Piece Ball Valve
This type of ball valve has a solid cast body to reduce the leaking issues. The body of this valve is not divided into pieces like split pieces valves.
Most commonly, these valves are made of cast iron. It has the lowest cost than other types of ball valves. One of the main disadvantages of the single body ball valve is that you can’t open it for maintenance or cleaning.
They use for small applications. Single body valves often have smaller openings and low cost than other ball vales.
7) Two-Piece Ball Valve
The body of the two-piece ball valve is divided into two pieces; one piece contains one end joint and body, the second piece is attached to the 1st piece, fixes the trim in its position, and also contains the second end joint.
The main benefit of this valve is that you can disassemble it for repair, maintenance, and cleaning. The main disadvantage of this valve is that you need to remove it completely from the pipeline to separate its two pieces. These valves usually have a reduced bore. These are repairable valves.
8) Three Piece Ball Valve
The body of this valve is divided into three parts (i.e., a body and two end caps)—all of these parts are connected to each other via bolt connection. The design of the three-piece valve ensures easy removal of the central valve part (the part contains seat, stem, and ball) from the pipe.
This design permits easy removal of the debris, exchange of the seats and seals, and minor polish scratches on the ball without complete removal of the valve from the pipeline.
The main benefit of this valve is that you can repair or clean it without removing it from the pipe. The three-piece valves have more costs than other types of ball valves.
9) Top Entry Valve
It is a type of ball valve that assembles the ball from its top side part. This design allows the seats and ball to be maintained without valve removal from the pipeline. It is best suitable for large systems. You can also clean it without removing it from the pipeline.
Most commonly, casting metal is used for the construction of the top entry valve. Since it is made by casting, some additional NDE testing is required to remove the defects of the casting process.
The advantage of these types of ball valves is that their design allows for minimal threaded connections that minimize leakage possibilities.
10) Side Entry Ball Valves
It is a type of valve that assembles the ball from its side part. Mostly, the body of the side entry valve is divided into two or three parts.
A stud or bolt is used to assemble each piece of the valve body. The forged metal is used for the construction of the side entry valve. This design minimizes defects caused by the casting valve.
These valves have an easy assembly. The trim parts also have a comfortable alignment. These types of ball valves have quick delivery times while casting products require additional testing.
11) Welded Body Ball Valves
It is a fully welded valve. It does not have leakage issues through bolt connections. You can’t maintain or repair the welded body valves on-site.
To clean or maintain the welded body valves, you need to remove them completely from the pipeline. These ball valve types are employed for buried or underground systems where maintenance is not desirable.
All body welding processes are suitable for construction materials and are identified and carried out according to the relevant criteria. The non-destructive testing (NDTS) must also be accomplished on the perimeter welded joints of the body.
Parts and Function of Ball Valve
The ball valve has the following major parts:
- Valve body
- Valve seats
- Seat ring
1) Valve Housing
The body or housing of the ball valve is a most important part. It covers all the internal parts of the valve. It ensures the safety of the internal parts. Thermoplastic-lined or thermoplastic metal is used for the construction of the housing. The stem of the valve passes through the valve housing.
The actuators are used for automatic ball valves. The pneumatic, hydraulic or electrical actuation systems don’t require an operator to operate the valve. An automatic system is used to control this actuation system. The actuators are best suitable for complicated control systems.
3) Rotary Ball
The rotary ball plays a big role in starting or closing the fluid flow. It has a hole in the center through which fluid flows. This ball is linked to the stem. The movement of the stem decides the ball’s position.
4) Stem or Shaft
The stem makes a connection between the ball and the control mechanism. It links the control mechanism (i.e., handle or actuator) to the ball. One end of the shaft connects to the ball while the other end connects to the handle or actuator.
It takes clockwise or anticlockwise motion by the control mechanism and transfers this motion to the ball.
It contains packing rings and O-rings to stop fluid leakage through the bonnet and stem.
The seat acts as a disc installed between the ball and the body. The ball valves have two seats. These seats provide a seal between the body and the ball. The ball sits in between the seats to stop the flow.
The downstream seat is installed near the valve discharge side. The upstream seat is located near the valve suction side. The upstream and downstream seats are located on the opposite sides of each other.
The handles are used in the manually operated ball valves. The rotation of the handle guides the ball to open or close the flow.
The packing acts as a seal around the valve stem. It stops the fluid from leaking through the stem.
The valve bonnet covers the packing and stem. It ensures the safety of the stem and its packing. The bonnet is bolted or welded to the valve housing. A hard metal uses for the construction of the bonnet.
Ball Valve Hole Designs
The hole of the ball valves has the following designs:
- Full Bore: This design is also referred to as full-bore design. It has the same hole diameter as the pipe diameter. It has the lowest friction losses and makes easy cleaning of the valve.
- Reduce Bore: This is the most commonly used design. The maximum valves contain reduce bores. It has less diameter than the full bore, but it may have more friction losses than the full bore.
- V-shaped: This design controls the flow rate more precisely as the ball spins.
- Vented: The vented vale contains a small hole on the upstream side. This bore removes useless pressure from the valve into the atmosphere.
Ball Valve Actuation Methods
The ball valves may be operated or actuated through the below-given actuation methods:
- Manual Ball Valves: The manually operated ball valves have a lever or handle to control the valve. A person operates the handle. This type of valve is best for small applications.
- Electric Actuation: In this method, electricity uses to operate the valve. Such valves are also known as motorized ball valves. These actuators are ideal for slow operating cycle applications.
- Pneumatic Actuation: In this method, compressed air is used to operate the valve. There is no need of labor to operate the valve. These are ideal valves for high durability and quick operating cycle applications.
- Hydraulic Actuation: The hydraulic actuation method is very similar to pneumatic actuation, but it uses a pressurized fluid in place of compressed air. This actuation process delivers more torque output than other types.
Materials Used for Ball Valves Construction
Following are the most commonly materials used for the construction of the ball valves:
It is an alloy of zinc and copper. It is famous because of its shiny surface. This is the most commonly used material for the construction of ball valves because it has high durability and toughness. It has the ability to bear extreme temperature and pressure.
2) Stainless Steel
Stainless steel has a high content of chromium and some content of nickel. It is an alloy of steel. It is famous because of its high durability, toughness, and strength. The high amount of chromium increases the ability of the valve to resist weather and corrosion.
The stainless has the ability to retain its strength under high temperature and pressure conditions.
3) Polyvinyl Chloride (PVC)
Polyvinyl Chloride is a rigid, durable, and tough material. These materials have less strength than stainless steel and brass. They are less expensive than brass and stainless steel. PVC butterfly valves are highly bases and corrosion-resistant.
4) Polypropylene Ball Valve (PP)
Propylene monomer is used for the construction of PP. It is a flexible, lightweight, durable, and tough thermoplastic. It excellently resists bases and acids. The chemical resistance ability of the PP material reduces by increasing temperature.
Polypropylene Ball Valves are used in paper, sugar, chemicals, and fertilizers industries.
5) Chlorinated PVC (CPVC)
CPVC contains almost the same features as PVC. This material has the ability to resist higher temperatures due to that it is ideal for hot water applications.
Iron is the most common material employed in gas, water, oil, and steam lines. Iron is a valuable material in the manufacture of ball valves because it can withstand extreme pressure and temperatures. It provides excellent performance.
Applications of Ball Valves
The ball valves are used all over the world for different household and industrial applications.
The ball valves are used for the following industries:
- Manufacturing Facilities
- Irrigation & Water Treatment Devices
- Vehicle Wash Systems
- Chemical Admixtures & Treatment
- Oil & Gas
- Food & Beverage Equipment
- Power Processing
- Outdoor Hoses
- Washing Machines
Advantages and Disadvantages of Ball Valves
Advantages of Ball Valves
- The ball valve has a simple design.
- It has a relatively small volume and is more lightweight than the gate valve.
- Easy to repair and disassemble.
- The stem packing seal of this valve can’t be damaged easily.
- In these valves, the fluid has low resistance. A pneumatic valve is one of the lowest fluid resistances in any valve category.
- It has a quick working cycle and easy operation.
- These have a high flow rate and low-pressure drop.
- It provides a perfect seal.
- Quickly open and close.
Disadvantages of Ball Valves
- It has high wear and tear than the gate valve and globe valve when it is used for wrong fluids like slurries.
- The cavities around the ball and seat make it unsuitable for slurry applications. The slurry tends to block or solidify in the cavity, significantly increasing the operating torque of the valve and causing the valve failure.
- It opens and closes too quickly, which generates overpressure and hammering issues.
- Abrasive solids suspended in the liquid or gas flow can destroy the valve’s seat and the ball’s surface if the ball moves over the seat during cleaning.
- These valves are difficult to clean (except top entry design valves).
- The ball valves have high wear and tear issues.
- These valves with drive procedure must be installed vertically.
- These are not ideal for throttling flow.
Ball Valve Vs Gate Valve
|Ball Valve||Gate Valve|
|It has a ball for closing and opening the fluid flow.||It has a gate-type disk for opening and closing the fluid flow.|
|These valves can be used for flow regulation.||These valves can’t be used for fluid flow regulation purposes.|
|It has a small size than the gate valve.||The gate valve has large size.|
|Its design is simple.||Its design is more complicated than a ball valve.|
|These valves have high wear and tear as compared to gate valves.||These have low wear and tear force.|
|These are lighter than gate valves.||Gate valves have high weight than ball valves.|
|It provides a perfect seal than gate valves.||It cant provide an efficient seal like ball and butterfly valves.|
What are the ball valves used for?
The ball valves are used to control the fluid flow through a hollow perforated ball. They are used to regulate, guide, direct and modulate the fluid flow.
How many types of ball valves have?
The ball valves have the following types:
- Side Entry Ball Valves
- Top Entry Valve
- Welded Body Ball Valves
- Standard Port Ball Valve
- V Port Ball Valve
- Full Port Ball Valve
- Reduced-Port Ball Valve
- Multi-Port Ball Valve
- One-Piece Ball Valve
- Two-Piece Ball Valve
- Three Piece Ball Valve
Which industries use ball valves?
The ball valves are very important for the piping systems. Ball valves are most commonly used in the oil and gas industries.
For upstream systems, these valves handle the oil flow. For the midstream, the valves protect the system by controlling the flow of gas and oil.
What are the components of the Ball Valve?
The ball valve has the following components:
- Actuator or Handle
- Joint Gasket
- Gland Nut
- Seat Ring
- Stem Nut
Which is better ball valve or gate valve?
Ball valves provide a tight seal and are more reliable, and durable than gate valves. However, they have more cost than the gate valves. Ball valves are typically used to close and control applications. The ball valve close and open instantly, making it more susceptible to water hammer than the gate valve.