Ball valves are used to regulate the flow of liquids and gases. You can read about their applications, how they work, the different types of ball valves, and much more here.
Table of Contents
What Is a Ball Valve?
Ball valves are fittings with a perforated ball as the shut-off element. They are mostly used as shut-off valves. A characteristic feature of a shut-off valve is its complete closure by rotating the axis by only 90° (in contrast, for example, to globe valves and gate valves). Ball valves can be equipped with actuators to automate the opening and closing process.
What are Ball Valves Used For?
The most important applications include:
- Water and Gas Supply: They are frequently used in drinking water installations, heating systems, and gas pipelines to control the flow of media.
- Industry: Ball valves are indispensable in the chemical industry, oil and gas production, food processing, and the pharmaceutical industry.
- Heating and Sanitary Technology: They are used in mobile and stationary heating systems, solar systems, and sanitary systems, often for draining and filling circuits.
- Critical Applications: Special ball valves are designed for high-pressure, high-temperature, and abrasive environments, such as those found in the energy sector or in cryogenic applications.
Wherever a fast and reliable shut-off mechanism for liquids or gases is required, they are a preferred choice.
How Does a Ball Valve Work?
A perforated ball serves as the shut-off element. By rotating the ball by 90 degrees, the flow of the medium is either fully enabled or stopped. The seat rings are positioned so that the pressure of the medium on the ball or seat ring leads to an increase in the contact pressure between the ball and the seat ring. In the case of a floating ball design, the ball is pressed into the opposite sealing surface; in the case of a trunnion-mounted ball, the fluid presses the seal against the housing and the ball.
What Different Types and Sizes of Ball Valves Are There?
Ball valves are distinguished by the size of the bore, the type of seal, and the mounting of the ball:
1. By Bore Size
- Full Bore: The bore in the ball has the same inner diameter as the connected pipeline, resulting in low flow losses.
- Reduced Bore: The bore in the ball has a smaller inner diameter than the connected pipeline.
2. By Seal Type
- Soft-Seated Ball Valves: Usually with a plastic seat ring (often PTFE) for temperature ranges up to 220 °C.
- Metal Seated Ball Valves: Used for higher operating temperatures and/or media containing solids.
3. By Ball Mounting
- Floating Ball: The ball is held in position by the seat in sealing rings arranged on both sides.
- Trunnion-Mounted Ball: The ball is provided with a trunnion on two opposite sides, which is mounted in the housing, meaning only one seat ring is required.
Additionally, there are:
- Three-Way Ball Valves: The ball has an L- or T-bore to distribute the flow of the medium to one or two outlets.
- Four- or Five-Way Valves: Further variants with more complex flow distributions
Ball valves are available in a variety of sizes to meet different requirements and applications. Sizes are usually specified in inches (for threaded connections) or as nominal diameter (DN, for flanged connections).
Common Ball Valve Sizes
- Inch Specifications (for threaded connections): 1/4″, 3/8″, 1/2″, 3/4″, 1″, 1 1/4″, 1 1/2″, 2″, 2 1/2″ and larger
- Nominal Diameters (DN, for flanged connections): DN15, DN20, DN25, DN32, DN40, DN50, up to very large nominal diameters such as DN1000 for industrial applications like pipelines
The selection of the correct size depends on the pipe diameter and the required flow rate.
How Are Ball Valves Used in Connection with Mobile Heating Systems?
They are used to drain or fill the heating system. Their quick shut-off function is particularly advantageous here. They allow for easy and controlled filling of liquids (e.g., heat transfer fluid) and quick draining when necessary. Ball valves are ideal for systems that need to be regularly filled and drained, such as mobile heating systems or tanks.
Which Is Better, Ball Valve or Gate Valve?
Both ball valves and gate valves are used to regulate the flow of liquids and gases in pipelines, but they differ in design, function, and their advantages and disadvantages:
| Feature | Ball Valve | Gate Valve |
|---|---|---|
| Function | Opens or closes the flow with a 90-degree rotation of a perforated ball, allowing for immediate opening and closing | Regulates flow by raising or lowering a wedge or plate perpendicular to the flow direction, requiring multiple turns of the handwheel |
| Advantages | – Quick opening and closing (quarter turn) – Low flow resistance with full bore – Good sealing in the closed state – Compact design – Low maintenance | – Low pressure drop when fully open – Suitable for large nominal diameters and high pressure – No dead space |
| Disadvantages | – Limited flow regulation capability (not proportional to the angle of rotation) – Can cause water hammer when closed quickly – Dead space where media can accumulate (hygienic concerns in certain applications) – Higher operating forces for large nominal diameters and high pressure | – Slow opening and closing – Not suitable for throttling (wear when partially open) – Requires more vertical space for the gate – Can lead to wear on the sealing surfaces with frequent use |
Conclusion: The choice between a ball valve and a gate valve heavily depends on the specific application. For quick shut-off and full-flow applications, ball valves are often the better choice. For applications requiring low pressure drop and handling large volumes, gate valves are more advantageous.
Can a Ball Valve Become Leaky?
Yes, it can become leaky over time. This can have various causes:
- Wear of the Seals: The seal rings (often made of PTFE) are wear parts. Frequent opening and closing, high temperatures, aggressive media, or solids in the medium can damage them or cause them to lose their elasticity, leading to leaks.
- Deposits: Particles or deposits in the medium can settle between the ball and the seal, impairing the seal’s integrity.
- Corrosion: In the case of aggressive media, corrosion can occur on the housing or the ball, which can lead to leaks.
- Water Hammer: Pressure surges can stress the seal rings and eventually lead to damage and leaks.
- Improper Installation or Maintenance: Faulty installations or a lack of maintenance can also negatively affect the lifespan.
Regular maintenance and the selection of the correct type are crucial to prevent leaks.
References:
Tameson.de. (seen on 08/22/2025). Kugelhahn-Anwendungen.
Domdor.com (seen on 08/22/2025). Absperrschieber vs. Kugelhahn.
Deki-valve.com (seen on 08/22/2025). What are the disadvantages of the ball valves?