Figure 1. 316 stainless steel flanged ball valve with red lever handle.
What Is a Ball Valve?
A ball valve is a quarter-turn isolation valve that uses a hollow, perforated and pivoting ball to control flow through it. When the ball's bore is aligned with the pipeline, the valve is open and the media flows straight through with minimal pressure drop; when the ball is rotated 90 degrees, the bore is perpendicular to the flow and the valve is closed.Ball valves are known for their reliable sealing, long service life and quick operation, and they perform well for on/off (shut-off) service across a very wide range of 2 pressures and temperatures. A quarter turn from fully open to fully closed makes
them ideal for automated actuation as well as manual operation.
How Does a Ball Valve Work?
The working principle of a ball valve is simple and reliable: a ball with a cylindrical or spherical bore is mounted between two seats inside the valve body. Turning the stem rotates the ball. In the open position the bore is parallel to the pipe axis, allowing full flow; in the closed position the solid face of the ball presses against the seats,
blocking the flow completely.
Because the flow path is straight, a ball valve has one of the lowest flow coefficients (Cv) losses of any valve type — there is almost no turbulence or pressure drop in the fully open position. This makes it a preferred choice for high-flow pipelines and for
media that are sensitive to pressure loss.
Figure 2. Ball valve structure: the ball rotates on the stem between the seats to open or close the
flow path.
Ball Valve Parts and Components
Table 1. Main parts of a ball valve and their functions.
Types of Ball Valves
Ball valves are classified by ball mounting, body construction and flow characteristics. Choosing the right type depends on pressure class, pipe size, service and
maintenance requirements.
Figure 3. Floating ball valve (left) vs trunnion mounted ball valve (right).
By ball mounting
Floating Ball Valve. The ball is held between two seats and “floats” slightly. Media
pressure pushes the ball against the downstream seat to form the seal. Cost-effective,
widely used for low and medium pressure (typically up to ~PN40 / Class 300).Trunnion Mounted Ball Valve. The ball is fixed by upper and lower trunnions; the
seats move to seal. Lower operating torque and stable sealing under high pressure,
1-Piece Ball Valve. One-piece body, usually reduced bore; compact and low cost.
Typically used for small sizes and light service where the valve is replaced rather
than repaired.2-Piece Ball Valve. Two-part body held by a threaded or bolted joint; easy to service.
The most common construction for stainless steel threaded and flanged ball valves.3-Piece Ball Valve. Three-part body allows the centre section to be removed from
the line for maintenance without disturbing the pipe ends — the best choice where in-
Full Bore (Full Port). The ball bore equals the pipe inner diameter. Zero flow
restriction, minimal pressure drop; used where pigging, cleaning or maximum flow is
required.Reduced Bore (Reduced Port). The ball bore is smaller than the pipe bore, typically
one size down. Lower cost and torque; acceptable where pressure drop is not critical.V-Port / Regulating Ball Valve. A V-shaped notch in the ball gives a predictable flow
characteristic, enabling throttling and flow regulation in addition to shut-off.Ball Valve Materials
Material selection determines corrosion resistance, pressure-temperature limits and
cost. For most industrial and export applications, stainless steel ball valves are the
pressure pushes the ball against the downstream seat to form the seal. Cost-effective,
widely used for low and medium pressure (typically up to ~PN40 / Class 300).Trunnion Mounted Ball Valve. The ball is fixed by upper and lower trunnions; the
seats move to seal. Lower operating torque and stable sealing under high pressure,
suitable for high-pressure and large-diameter lines (Class 600 and above, DN50+).
By body construction
1-Piece Ball Valve. One-piece body, usually reduced bore; compact and low cost.
Typically used for small sizes and light service where the valve is replaced rather
than repaired.
2-Piece Ball Valve. Two-part body held by a threaded or bolted joint; easy to service.
The most common construction for stainless steel threaded and flanged ball valves.3-Piece Ball Valve. Three-part body allows the centre section to be removed from
the line for maintenance without disturbing the pipe ends — the best choice where in-
line repair and seat replacement matter.
By bore and flow characteristics
Full Bore (Full Port). The ball bore equals the pipe inner diameter. Zero flow
restriction, minimal pressure drop; used where pigging, cleaning or maximum flow is
required.
Reduced Bore (Reduced Port). The ball bore is smaller than the pipe bore, typically
one size down. Lower cost and torque; acceptable where pressure drop is not critical.
V-Port / Regulating Ball Valve. A V-shaped notch in the ball gives a predictable flowsuitable for high-pressure and large-diameter lines (Class 600 and above, DN50+).
By body construction
line repair and seat replacement matter.
By bore and flow characteristics
characteristic, enabling throttling and flow regulation in addition to shut-off.
standard choice.
ratings; metal seats handle high temperature and abrasive media.
Ball Valve Connection Types
Compression / push-fit — quick-connect ends for tubing and instrument lines.
607 / ISO 10497 also available).
different situations:
Table 3. Ball valve vs gate valve comparison.
Ball Valve Applications
Food, beverage & pharmaceutical — hygienic stainless steel ball valves.
Figure 4. Stainless steel ball valves installed in an industrial piping system.
How to Choose the Right Ball Valve
test reports and quality documentation.
Ball Valve FAQ
and are widely used in oil & gas, chemical, water and HVAC systems.
Q. What is the difference between a floating and a trunnion mounted ball valve?
to seal, giving stable performance at high pressure and large sizes.
Q. What is the difference between a 2-piece and a 3-piece ball valve?
without disconnecting the pipe ends — ideal where maintenance access is limited.
Q. Which material should I choose, SS304 or SS316?
recommended choice for most industrial and export applications.
Q. How do I know the pressure rating of a ball valve?
specifications, delivery time and a factory-direct quotation.
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