Valve

Valve

A valve is a device that regulates, directs, or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fittings, but are usually discussed as a separate category. In an open valve, fluid flows in a direction from higher pressure to lower pressure.

Types of Valves

Valves vary widely in form and application. Some of the most common types include:

Ball Valve

A ball valve is a quarter-turn valve that uses a hollow, perforated, and pivoting ball to control flow through it. It is open when the ball's hole is in line with the flow and closed when it is pivoted 90-degrees by the valve handle.

Gate Valve

A gate valve opens by lifting a barrier (gate) out of the path of the fluid. Gate valves are used when a straight-line flow of fluid and minimum restriction is desired.

Globe Valve

A globe 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.

Check Valve

A check valve, also known as a non-return valve, allows fluid to flow through it in only one direction. Check valves are two-port valves, meaning they have two openings in the body, one for fluid to enter and the other for fluid to leave.

Butterfly Valve

A butterfly valve is a valve that isolates or regulates the flow of a fluid. The closing mechanism is a disk that rotates.

Applications

Valves are used in a variety of applications, including:

• Water supply systems
• Wastewater treatment
• Oil and gas industry
• Chemical and pharmaceutical manufacturing
• Power generation

Operation

Valves can be operated manually, either by a handle, lever, pedal, or wheel. They can also be automated, driven by changes in pressure, temperature, or flow. More complex control systems using actuators are used for automatic control.

Materials

Valves are made from a variety of materials, including:

• Brass
• Bronze
• Steel
• Stainless steel
• Plastic

Related Pages

• Pipe (fluid conveyance)
• Pump
• Hydraulics
• Pneumatics

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