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Ball valves have a spherical closure unit that provides on/off control of flow. The sphere has a port (bore) through the center. When the valve is positioned such that the bore is aligned in the same direction as the pipeline, it is in the open position, and fluid can flow through it. When rotated 90°, the bore becomes perpendicular to the flow path, meaning the valve is closed, and fluid cannot pass through. Ball, butterfly, and plug valves make up the quarter-turn valve family.
The most common ball valve design is two way, which enables flow to linearly travel from the inlet to the exit. Three- and four-way ball valves enable flow to travel in multiple directions, including 90° angles.
Differences in ball movement
Trunnion-mounted ball valves feature additional mechanical anchoring at the top and bottom on the ball. This design makes them suitable for larger-bore and higher-pressure operations as well as reduces valve torque because the ball is supported in two places. The trunnion-mounted stem absorbs the thrust from the line pressure, preventing excess friction between the ball and seats; therefore, at full-rated working pressure, operating torque remains low.
CAMERON T30 Series fully welded ball valves are trunnion mounted. These ball valves deliver maximum strength and resistance to pipeline pressure and stress. Plus, their compact, spherical design also eliminates body flanges, thus reducing overall size and leak paths.
Floating ball valves are attached only to the stem, not held in place by a trunnion. This sometimes causes the ball to float slightly downstream, which then causes the ball to press against the seat, creating a positive seal.
Rising stem ball valves incorporate tilt-and-turn operation, eliminating seal rubbing—one of the primary causes of valve failure. When the valve is closed, the core is wedged against the seat, ensuring positive shutoff. When the valve is open, the core tilts away from the seal, and flow passes uniformly around the core face.
ORBIT rising stem ball valves leverage this operating principle, delivering fast, low-torque operation and long-term, reliable performance. They also eliminate localized high-velocity flow, which can create uneven seat wear in conventional ball, gate, and plug valves.
Differences in bores
Full-port (fullbore) ball valves have a bore internal diameter (ID) approximately equal to the pipeline ID, which reduces friction and pressure loss across the valve and eliminates flow restrictions. This type of bore is ideal when pigging may be necessary.
Reduced-port (reduced-bore) ball valves have bores that are one or two nominal sizes smaller, providing more restricted flow path that generally result in higher energy losses. Available in full and reduced ports, TK trunnion-mounted ball valves feature robust design, superior sealing, and stainless steel overlays. They are widely used in the oil and gas industry’s most severe service applications.
V-port ball valves have a “V”-shaped ball or seat. Also known as control valves, they control flow velocities when the application requires.
How It Works: Gate Valves
Very low friction loss, saving energy and reducing cost of ownership
All valves are designed to stop, allow, or throttle the flow of a process fluid. Gate valves—one of the original valve designs—are ideally suited for on-off, primarily liquid, service. A gate valve functions by lifting a rectangular or circular gate out of the path of the fluid. When the valve is fully open, gate valves are full bore, meaning there is nothing to obstruct the flow because the gate and pipeline diameter have the same opening. This bore diameter also determines the valve size. An advantage of this fullbore design is very low friction loss, which saves energy and reduces total cost of ownership.