What is a Ball Valve? Working Principle, Function, Types & Uses

1. What is a Ball Valve? What is the Mechanism of Ball Valves?

A ball valve is a type of quarter-turn shut-off valve. Inside the valve is a hollow, perforated, and pivoting ball that controls the flow of a fluid or gas. When you turn the valve handle 90 degrees, the ball's bore either aligns with the direction of flow (opening the valve) or becomes perpendicular to the flow (closing the valve).

 

Ball valves can be operated manually, with handles or levers, or through actuation. Manual valves require a physical operator to control the flow. Actuation, on the other hand, utilizes electric, hydraulic, or pneumatic power to open or close the valve. This method is ideal for complex control systems or remote locations where manual operation is impractical.

 

As for ball valve uses, their simple operation, reliable sealing, and durability make them a popular choice in numerous settings, such as chemical processing, oil and gas management, food and beverage production, and even irrigation systems. They even have specialized versions for high-pressure and high-temperature environments.  Wherever quick shut-off and secure sealing are essential, ball valves are often the preferred solution. 

 

 

  
1.1 Circuit Function

Ball valves come in two main configurations based on the number of ports they offer: 2-way and multi-port (3-way or 4-way). 2-way valve type is the most common choice and is typically operated manually. Three-way or multi-port valves, on the other hand, offer more complex functionality. Their L-shaped or T-shaped internal bore allows them to handle multiple media sources or divert flow in different directions. This makes them ideal for tasks like distributing or mixing fluids.

 

2. Parts of a Ball Valve

Let's break down the key components that make a ball valve function:

• Body (or Housing): The primary structure of the valve, this robust enclosure contains and protects all internal parts. It's crafted from durable materials like metal, thermoplastic, or lined metal to withstand the demands of its operating environment. Inlet and outlet ports on the body allow for piping connections.
  
  
• Ball: The central flow control element, the ball is a sphere with a central hole. Rotating the ball determines whether the bore aligns with the flow path or blocks it. Hollow balls have an internal cavity allowing for higher flow rates. So, increased turbulence and higher flow velocities are worth paying attention to. 
  
  
• Stem: The stem connecting the ball to the external control mechanism (usually a handle, but can be automated). Rotating the stem turns the ball, opening or closing the valve. The stem needs robust seals to prevent fluid leaks where it passes through the bonnet.
  
  
• Seats: Soft rings surround the ball, providing a tight seal when the valve closes. Seats prevent leakage by firmly pressing against the ball.
  
  
• Bonnet: An extension on the valve body protecting the stem and its seals. The bonnet might be bolted or welded to the body and is essential for high-pressure/temperature operations.

3. Types of Ball Valves

Ball valves come in a variety of designs to suit different requirements. We'll categorize them based on their housing assembly, ball design, end connection, and bore profile.

3.1 Housing Assembly 

One-piece

The simplest design, where the body is a single molded or machined piece. One-piece valves are often the most economical option, but they mostly cannot be repaired or replaced if internal components fail.

Two-piece

Two-piece ball valves, the most common type, consist of a body with one end connection and a separate piece that houses the trim and the other end connection. These valves offer a good balance between affordability and repairability. They can be disassembled and repaired once removed from the system.

 

Three-piece

Three-piece ball valve features two end caps and a body. These end caps are threaded or welded to the piping system while the body detaches for cleaning or repairs. The detachable body is invaluable for maintenance without shutting down the entire line.

Choosing the right ball valve housing type depends on your priorities. Typical applications include one-piece for simple water lines, two-piece for moderate industrial processes, and three-piece for demanding systems where maintenance efficiency is critical.

 

Explore our selection of ball valves in various housing assembly types.

 

3.2 Ball Design

The design influences the ball's capability for pressure and wear:

Floating

This is the most common design. The floating ball moves laterally within the valve body when closed, held in place by two seats. A shaft connects to the ball at one end, restricting lateral movement when the valve is open. Sealing relies solely on fluid pressure. During closure, inlet pressure pushes the ball against the outlet seat, preventing fluid from escaping. Since pressure creates the seal, floating ball valves are best suited for low to moderate-pressure applications in smaller diameters. 

 

Trunnion

Unlike floating ball valves, trunnion ball valves boast an additional shaft, which is called the trunnion. This cradles the ball and restricts its movement to rotation along the shaft's axis. They are typically with spring-loaded seats, which are activated by inlet pressure pushing the ball against the seals for a tight closure. Trunnion valves excel in high-pressure applications and automation with smaller actuators.

 

3.3 Hole Designs

The shape and size of the hole through the ball significantly impact flow characteristics and the valve's suitability.

Reduced Bore

Reduced boreholes are in most ball valves. The bore is smaller than the pipe diameter, which introduces friction losses. But these losses are relatively small compared to other types of balls. Due to their economic price, reduced bore design is still a popular selection.

Full Bore

The diameter of full-bore ball valves is equal to the pipe’s diameter. This design minimizes friction losses, resulting in maximum flow capacity. But they may have a slightly higher cost.

V-Shaped

A V-shaped notch is cut into this kind of ball or the valve seat. By rotating the ball, the size of the V-notch exposed to the flow path changes, providing more precise flow control than standard designs. V-shaped ball valves are well-suited for applications requiring fine flow adjustments.

 

3.4 End Connections

End connections are the points where the ball valve interfaces with your piping system.  Choosing the right type is crucial for proper installation and leak-free operation:

Threaded

The valve body has internal threads (female) or occasionally external threads (male) that mate directly with the pipe. Threaded connections are simple, common for smaller valves, and work well at moderate pressures.

Flanged

The valve body has flat faces with bolt holes that align with matching flanges on the pipe.  Gaskets between the flanges ensure a leak-tight seal. Flanged connections are reliable, robust, and well-suited for larger valves and higher-pressure systems.

3.5 Other Types

Cavity-filled
The cavity around the ball within the valve body is filled with a sealant or lubricant. This serves two purposes: it prevents the buildup of debris that could interfere with valve operation, and it provides a secondary layer of sealing for sensitive or hazardous fluids.

4. Materials for the Construction of Ball Valves

4.1 Brass

Brass is the most common material for ball valves due to its combination of affordability, durability, and versatility. This tough, yellowish-reddish metal alloy (copper and zinc) boasts high resistance to temperature, pressure, corrosion, and even microbial growth thanks to copper's antimicrobial properties. While generally safe for various chemicals, brass will dezincify in high-chlorine environments, which shrinks its strength. Despite this limitation, its ease of fabrication, lightweight, and cost-effectiveness make it a popular choice across food processing, chemical plants, oil and gas applications, and even potable water delivery systems.

 

4.2 Stainless Steel

Stainless steel shines as the go-to material for ball valves when dealing with harsh environments and corrosive media. Type 304 and 316 are the most popular choices. Type 316 provides superior performance in harsh environments. Type 304 is referred to as "18/8" due to its composition of 18% chromium and 8% nickel. However, compared to brass or PVC valves, stainless steel does require a higher torque to operate. This is an important factor to consider when choosing an actuator (electric or pneumatic) to ensure it can handle the increased turning force.

 

4.3 PVC

These offer lightweight construction, excellent corrosion resistance against many chemicals, and affordability. PVC (polyvinyl chloride) and CPVC (chlorinated polyvinyl chloride) are common, with CPVC handling higher temperatures. Plastics are typically used in water systems and chemical applications where pressures and temperatures are moderate.

 

4.4 Comparison of Ball Valve Materials

 

Material	Pros	Cons	Typical Applications
Brass	Cost-effective, Good corrosion resistance	Sensitive to dezincification	Water lines, low pressure
Stainless Steel	Durable, Corrosion-resistant, High-strength	More expensive	Wide range of industrial & commercial uses
PVC/plastics	Lightweight, Chemical resistant, Inexpensive	Limited temperature/pressure range, less durable	Water systems, some chemical processes

 

 

5. Pros and Cons of Ball Valves

Ball valves offer a number of benefits for flow control.

 

5.1 Quick Operation

The quarter-turn design means you can go from fully open to fully closed (and vice versa) with just a quick turn of the handle. This is invaluable in emergencies where rapid shut-off is needed or in processes where swift changes in flow are required.

5.2 Excellent Shut-off Capabilities

When closed, the well-designed seats within a ball valve create a tight seal against the ball, minimizing the chance of leakage. This makes them ideal for applications where preventing leaks is critical, like in gas lines or hazardous chemical handling.

5.3 Minimal Pressure Drop

Ball valves in the open position offer minimal resistance to flow, ensuring fluids pass with minimal pressure loss. This is crucial in applications where maintaining system pressure is important.

5.4 Durability

Ball valves are generally built to last. Their simple design minimizes wear points, and they can withstand frequent operation and moderate pressures, making them a reliable choice for many industrial settings.

5.5 Low Maintenance

Due to their simple construction, ball valves often don't require frequent or complex maintenance procedures. Occasional seal or lubrication checks might be needed depending on usage, but overall they are known for low maintenance needs.

5.6 Versatility

Ball valves come in a vast range of sizes, materials (various metals, plastics), and pressure ratings. This means there's likely a ball valve configuration suited to almost any application, from household water lines to heavy industrial processes.

5.7 Bi-Directional Flow

Most ball valves allow flow in either direction, offering flexibility in system design.

 

To ensure your ball valve operates smoothly for years to come, keep these key limitations in mind:

 

5.8 Potential for Trapped Fluids

Standard ball valves have a cavity within the ball. When closed, this cavity can trap small amounts of the fluid being passed through. This can be a sanitation concern, or an issue if those fluids could solidify or freeze, potentially damaging the valve.

 

5.9 Safeguarding from Pressure Spikes

Sudden, extreme changes in pressure (known as water hammer) can shock the system and damage ball valves, especially those made of less robust materials. In systems where pressure surges are a concern, additional protection measures or reinforced valve designs might be necessary.

 

5.10 Torque Considerations

Larger ball valves, or those under high pressure, require significantly more force (torque) to turn the ball. This may make manual operation impractical, requiring gearing mechanisms for large ball valves or actuators (pneumatic or electric) for automated operation.

 

STREAMING: Your Best Ball Valves Supplier

Ball valves are a cornerstone of modern fluid control systems, valued for their reliability, ease of use, and wide-ranging adaptability. Whether you're working in industrial settings with harsh chemicals, handling high-pressure systems, or managing everyday plumbing and gas lines, STREAMING ball valves are designed to meet your needs.

 

When it comes to reliable and high-quality ball valves, look no further than STREAMING. Our ball valves are designed with precision engineering and manufactured from the finest materials to ensure exceptional performance in even the most demanding applications.

 

We invite you to explore our selection of ball valves on our product page. If you have any questions or require assistance in selecting the perfect ball valve solution for your needs, please don't hesitate to reach out to our knowledgeable team. 

 

For all your ball valve requirements, contact us today! Or visit our company overview page to learn more about us.

 

FAQs

When would you use a ball valve?

Ball valves are used in a wide array of applications requiring on/off flow control of liquids or gasses. Typical scenarios include industrial pipelines, residential water and gas lines, high-pressure systems, and any situation needing a quick shut-off and tight sealing.

 

What are the advantages of ball valves?

Ball valves offer several benefits:

 

• Quick and easy operation (quarter-turn)
• Excellent shut-off capabilities for minimal leakage
• Durable and long-lasting
• Low maintenance requirements
• Available in a wide variety of materials, sizes, and configurations for versatility

 

What is the use of a V-shaped Ball Valve?

V-shaped ball valves with their notched design provide finer flow control capabilities. They are often used for throttling applications where you need to regulate the flow rate partially, rather than just fully open or closed.

 

Why oil and grease are important?

Oil and grease in industrial systems can be dangerous due to their potential to ignite in the presence of oxygen, especially in shut-off valves where lubrication is common. This risk arises because organic materials and many metals and alloys can spontaneously combust in oxygen-rich environments.

 

What is polishing wear?

Polishing wear refers to the process where two surfaces interact, resulting in material removal and a polished finish. This smoother surface reduces friction, enhancing equipment efficiency by lowering amp draw, fuel usage, and operating temperatures.