A ball valve is a type of cutoff valve that regulates the flow of a liquid or gas using a rotatable ball with a bore. The medium can flow through or be restricted by turning the ball a quarter revolution (90 degrees) around its axis. They have a long service life and ensure reliable sealing during the life of the valve, even when it is not in use for an extended period of time. As a result, they are more often used as a shutdown valve than, say, the gate valve. Read our gate valve versus ball valve page for a more in-depth comparison. Most other types of ball valves are less resistant to polluted media than ball valves. Ball valves can also be utilized as control valves in specific variants. Because of the comparatively poor efficiency in controlling the flow rate compared to other types of control valves, this application is less popular. However, the valve has certain advantages in this situation. For example, even with unclean media, it still maintains dependable sealing.
Common ball valve types
Standard (threaded)
Hydraulic
Because of its high working pressure rating and resistance to hydraulic and heating oil, hydraulic ball valves are specifically developed for hydraulic and heating systems. These valves are available in steel or stainless steel. Aside from these materials, the seats also provide hydraulic valves with high working pressure. These valves have polyoxymethylene (POM) seats that are ideal for high-pressure and low-temperature applications. Hydraulic ball valves have a maximum operating pressure of 500 bar and a maximum temperature of 80°C.
Flanged
The connecting type of flanged ball valves distinguishes them. The ports are joined to the pipe system by flanges, which are normally constructed to a certain standard. Because of their full-bore design, these valves have a high flow rate. When selecting a flanged ball valve, look for the flange compression class, which specifies the maximum pressure that this connection type can tolerate. These ball valves have two, three, or four ports that can be authorized for specific media, have an ISO top, and everything else a conventional quarter-turn valve has. They are commonly constructed of stainless steel, steel, or cast iron.
Vented
When it comes to appearance, vented ball valves resemble ordinary 2-way ball valves. The key distinction is that when the outlet port is closed, it vents to the environment. This is accomplished by drilling a tiny hole in both the ball and the valve body. When the valve is closed, the holes align with the output port, and the pressure is released. This is especially advantageous in compressed air systems, where depressurization creates a more secure working environment. These valves appear to be two-way ball valves but are actually three-way due to the little holes for venting.
Forged ball valves
Forged ball valves are produced by shaping alloys and metals while they are still solid. Heating or industrial-sized equipment that produces compressive stresses to bend the metals and alloys is used to bend the materials. Forged ball valves are better suited for industrial applications involving high temperatures, pressures, and other harsh environments. Forged ball valves can be made from materials such as brass and stainless steel. Using a die forging machine, the metal (or alloy) is heated, squeezed, bent, and shaped according to the ball valve design throughout the production process.
The die aids in shaping the metal into a precise shape, while the machine delivers adequate pressure to push the metal into the desired shape. Welding several components together is required for larger-sized ball valves. Depending on the use, the valves might also be covered with specialist coatings.
Forged ball valve benefits
Forged ball valves are sturdy and long-lasting, and they may be utilized in extremely demanding settings involving high temperatures and pressures.
The forging technique makes the ball valve less prone to problems like porosity, cracking, and shrinking.
Forged ball valves can swiftly adjust to temperature fluctuations, making them suited for use in a variety of situations.
Low maintenance requirements
Circuit function
The valve may have two, three, or four ports. The great majority of ball valves are two-way and actuated by a lever. When the valve is opened, the lever is in contact with a pipe. The handle is perpendicular to the pipe when closed. For a two-way valve, the flow direction is simply from the input to the output. Because manually controlled ball valves close quickly, there is a risk of water hammering with fast-flowing media. Some ball valves include a gearbox. The bore of 3-way valves is L-shaped or T-shaped, which influences circuit performance. As a result, numerous circuit functions such as distributing or mixing flows are possible.
Housing assembly
The valve housing assembly may be classified into three types: one-piece, two-piece, and three-piece housings. The difference is in how the valve is built, which influences the options for maintenance or repair. The valves operate in the same way in each form.
One-piece: This is the most affordable option. The two sections that round the ball are pressed or welded together. The valves are not accessible for cleaning or maintenance. This kind is commonly utilized in low-demand applications.
Two-piece valves are easily dismantled for cleaning, service, and inspection. A threaded connector is frequently used to connect the pieces. To separate the two sections, the valve must be entirely removed from the pipe.
Three-piece: More costly valves frequently have three components. Bolt connections are commonly used to hold the pieces together. This implementation has the benefit of allowing the valve to be serviced without having to remove the complete valve from the pipeline.
Ball design
The "floating ball design" is the most frequent. Two sealing rings hold the ball in place as it is hung in the medium. A trunnion ball design can be seen on several high-quality valves. To alleviate the stress on the valve seats, the ball is supported at the top and bottom.
Floating balls are used in the majority of ball valves. The valve seats provide support for the ball.
Trunnion: Trunnion valves have large diameters and high operating pressures (for example, DN >100mm and 30 bar). To alleviate the stress on the seat rings, the ball is supported on the bottom and top. Trunnion valves often have a lower working torque.
The profile of the hole in the ball might be a full bore, reduced bore, or V-shaped.
The majority of ball valves have a decreased bore. As a result, friction losses are introduced into the system via the valve. These losses are nevertheless minimal in comparison to other types of valves. Reduced bore one-piece ball valves are nearly often used.
Full bore: The bore diameter of a full bore valve is the same as the bore diameter of the pipe. The benefit is that there are no additional friction losses, and the system is mechanically easier to clean (pigging). The disadvantage is that the ball and housing are larger than those found in normally reduced bore quarter-turn valves. As a result, the cost is slightly greater, and for many applications, this is not necessary. Full port ball valves are another name for them.
V-shaped: The ball or valve seat hole has a "V" shaped contour. As a result, by spinning the ball, the appropriate flow rate may be regulated more accurately. A linear flow characteristic can be approached by adjusting the profile.
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