COMMON VALVE TYPES
A Ball Valve is a valve with a spherical disc, the part of the valve which controls the flow through it. The sphere has a hole, or port, through the middle so that when the port is in line with both ends of the valve, flow will occur. When the valve is closed, the hole is perpendicular to the ends of the valve, and flow is blocked. The handle or lever will be inline with the port position letting you “see” the valve's position. The ball valve, along with the butterfly valve and plug valve, are part of the family of quarter turn valves.
Ball valves are durable and usually work to achieve perfect shutoff even after years of disuse. They are therefore an excellent choice for shutoff applications (and are often preferred to globe valves and gate valves for this purpose). Ball valves are used extensively in industrial applications because they are very versatile, supporting pressures up to 1000 bar and temperatures up to 752°F (500°C) depending on the ball valve design and material. Sizes typically range from 0.2 to 48 inches (0.5 cm to 121 cm). They are easy to repair and operate.
Ball valves are durable and usually work to achieve perfect shutoff even after years of disuse. They are therefore an excellent choice for shutoff applications (and are often preferred to globe valves and gate valves for this purpose). Ball valves are used extensively in industrial applications because they are very versatile, supporting pressures up to 1000 bar and temperatures up to 752°F (500°C) depending on the ball valve design and material. Sizes typically range from 0.2 to 48 inches (0.5 cm to 121 cm). They are easy to repair and operate.
AQSA supplies full bore, reduced bore, L-Port and T-Port in 2 piece and 3-piece valves in Carbon steel, Alloy Steel, Stainless Steel, Duplex and Super Duplex.
Gate Valves are also known as a sluice valve, is a valve that opens by lifting a round or rectangular gate/wedge out of the path of the fluid. The distinct feature of a gate valve is the sealing surfaces between the gate and seats are planar, so gate valves are often used when a straight-line flow of fluid and minimum restriction is desired. The gate faces can form a wedge shape, or they can be parallel. Gate valves are primarily used to permit or prevent the flow of liquids, but typical gate valves should not be used for regulating flow, unless they are specifically designed for that purpose. Because of their ability to cut through liquids, gate valves are often used in the petroleum industry. For extremely thick fluids, a specialty valve often known as a knife valve is used to cut through the liquid.
Butterfly Valves are valves which can be used for isolating or regulating flow. The closing mechanism takes the form of a disk. Operation is similar to that of a ball valve, which allows for quick shut off. Butterfly valves are generally favored because they are lower in cost to other valve designs as well as being lighter in weight, meaning less support is required. The disc is positioned in the center of the pipe, passing through the disc is a rod connected to an actuator on the outside of the valve. Rotating the actuator turns the disc either parallel or perpendicular to the flow. Unlike a ball valve, the disc is always present within the flow, therefore a pressure drop is always induced in the flow, regardless of valve position.
A Check Valve, Clack Valve, Non-Return Valve or One-Way Valve is a valve that normally allows fluid (liquid or gas) to flow through it in only one direction.
An important concept in check valves is the cracking pressure which is the minimum upstream pressure at which the valve will operate. Typically, the check valve is designed for and can therefore be specified for a specific cracking pressure.
A Globe Valve, different from ball valve, is a type of valve used for regulating flow in a pipeline, consisting of a movable disk-type element and a stationary ring seat in a generally spherical body.
