ballvalve

A ball valve is a type of quarter-turn valve that uses a spherical ball with a hole through the center to regulate fluid flow. When the ball aligns the hole with the pipe, fluid passes freely; when the ball is rotated 90 degrees, the hole blocks the flow, providing a rapid on/off action. Ball valves are commonly used in piping systems for water, gas, and various process fluids.

The valve consists of a bore with a threaded end, an elastomeric or metal sealing ring, and a ball that fits snugly within the seat. The ball is typically bored so that its axis is perpendicular to the flow direction. Rotating the ball with a lever or actuator moves the passage from open to closed, creating a tight seal with minimal fluid resistance in the open position. The valve’s construction allows for reliable operation with a low pressure drop when fully opened.

There are several ball valve variants. Full‑port valves have a bore the same size as the pipe, minimizing pressure drop, while reduced‑port valves have a smaller bore, resulting in higher flow resistance but lower manufacturing cost. Some designs also feature radial seats or bimetallic bellows for enhanced pressure and temperature rating.

Materials for ball valves range from plastic (PVC or CPVC) to brass, stainless steel, alloy steel, and titanium, selected based on service pressure, temperature, and chemical compatibility. The ball, seat, and stem may be made of identical or matched materials to improve longevity and corrosion resistance.

These valves are found in water distribution networks, HVAC systems, petrochemical plants, food and beverage pipelines, and medical gas supply lines. Their quick opening and closing make them suitable for emergency shut‑off applications.

Advantages of ball valves include a tight seal, durability, low operational pressure drop, and ease of cleaning. Disadvantages include potential leakage under high pressure, higher initial cost relative to gate or globe valves, and vulnerability to damage when steam or high‑temperature fluids are involved.

Ball valves evolved in the early 20th century as a response to the need for faster shut‑off valves in industrial piping. The design has been refined over decades, with modern versions incorporating ergonomic handles, electric or pneumatic actuators, and advanced sealing technologies.