What is Valve? How Does it Works? Types of Valves? in PDF
A valve is a mechanical or natural object that 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 they are usually discussed separately. Fluid flows from higher pressure to lower pressure through an open valve. The word comes from the Latin valva, which means "moving part of a door," and volvere, which means "to turn, roll."
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| What is Valve? How Does it Works? Types of Valves? in PDF |
The most basic and ancient type of valve is a freely hinged flap that swings down to obstruct fluid (gas or liquid) flow in one direction but is pushed up by the flow itself when the flow is moving in the opposite direction. This is known as a check valve because it prevents or "checks" flow in one direction. Modern control valves can regulate downstream pressure or flow and are controlled by sophisticated automation systems.
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Valves have many applications, including controlling irrigation water, industrial process control, and residential applications such as on/off and pressure control to dish and clothes washers and taps in the home. Even aerosol spray cans contain a tiny valve. Valves are also used in the military and the transportation industries. Dampers are used to describe valves in HVAC ductwork and other near-atmospheric air flows. However, valves are used in compressed air systems, with ball valves being the most common type.
Applications of Valves
Valves are used in almost every industrial process, including water and sewage treatment, mining, power generation, oil, gas, and petroleum processing, food manufacturing, chemical and plastic manufacturing, and many others.
Plumbing valves such as taps for tap water, gas control valves on cookers, small valves fitted to washing machines and dishwashers, safety devices fitted to hot water systems, and poppet valves in car engines are all used in developed countries.
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There are valves in nature, such as one-way valves in veins that control blood circulation and heart valves that control blood flow in the chambers of the heart and maintain proper pumping action.
Valves can be controlled manually using a handle, lever, pedal, or wheel. Valves can also be controlled automatically by changes in pressure, temperature, or flow. These changes may act on a diaphragm or a piston, activating the valve; common examples of this type of valve include safety valves installed in hot water systems or boilers.
An actuator is required in more complex control systems that use valves and require automatic control based on an external input (for example, regulating flow through a pipe to a changing set point). An actuator will stroke the valve based on its input and set-up, allowing the valve to be precisely positioned and controlling a variety of requirements.
Contents in What is Valve? How Does it Works? Types of Valves? in PDF
Introduction
Terminologies
Types of Control Valves
Valves Components
Valves selection
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What is Valve? How Does it Works? Types of Valves? in PDF
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