Valves are essential components of piping systems, which regulate the flow of fluids, such as water, gas, and oil. They are used to start, stop, and control the flow of fluids in a piping system. Valves come in different types, including ball valves, gate valves, globe valves, butterfly valves, and check valves, each designed for specific applications
A valve is a mechanical device that controls the flow of fluids (liquids, gases, or slurries) by opening, closing, or partially obstructing various passageways through a piping system.
A valve is a generic name for device with a movable feature that opens and closes the passageway in order to allow, prevent or control the flow of fluids.
3. Introduction
Valves are essential components of piping systems, which regulate the flow of fluids, such as water, gas, and
oil. They are used to start, stop, and control the flow of fluids in a piping system. Valves come in different
types, including ball valves, gate valves, globe valves, butterfly valves, and check valves, each designed for
specific applications
A valve is a mechanical device that controls the flow of fluids (liquids, gases, or slurries) by opening,
closing, or partially obstructing various passageways through a piping system.
A valve is a generic name for device with a movable feature that opens and closes the passageway in
order to allow, prevent or control the flow of fluids.
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4. Valve
Body: Usually metallic or plastic
Stem: Transmit motion from handle or
controlling device, may be linear, rotatory
combination of those.
Bonnet: Optional part, used to simplify
cleaning
Plug: Device to control flow rate
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5. Reason for using valves:
To restrict, control, and stop the flow of liquid.
They are found virtually in all industrial process including water and sewage processing, mining, power
generation, processing of oil gas and petroleum.
In nature there are valves, for example one-way valves in veins controlling the blood circulation, and heart
valves controlling the flow of blood in the chambers of the heart and maintaining the
correct pumping action.
Valves may be operated manually, either by a handle , lever, pedal or wheel. Valves may also be automatic,
driven by changes in pressure, temperature, or flow. These changes may act upon a diaphragm or
a piston which in turn activates the valve, examples of this type of valve found commonly are safety
valves fitted to hot water systems or boilers.
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6. Types of valve
Based on their working mechanism, valves are divided into different types:
• Ball Valve
• Butterfly Valve
• Globe Valve
• Gate Valve
• Diaphragm Valve
• Plug Valve
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7. Ball Valve
It uses hollow, perforated and pivoting ball
to control fluid. It opens when balls hole is
in line to flow and closed when the
opening is perpendicular.
Advantage: Ease of repair, operation, and
versatility
Disadvantage: Lack fine control
Uses: They are commonly used in
applications that require low friction,
minimal pressure drop, and a tight shut-
off..
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9. Butterfly Valve
Contains disc unlike ball in ball valve.
Working principle: Same as ball valve.
Advantage: Can control flow better
Disadvantage: It can’t pigged for
cleaning.
Uses: in applications that require high
flow rates, low-pressure drop, and quick
operation.
[In pipeline transportation, pigging is the
practice of using pipeline inspection gauges or
gadgets, devices generally referred to
as pigs or scrapers, to perform various
maintenance operations. This is done without
stopping the flow of the product in the
pipeline]
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11. Globe Valve
It consist of movable plug and stationary
seat in generally spherical body. Other
parts are stem, bonnet, and cage.
Working mechanism: It has opening that
forms seat and the movable plug can be
screwed open or close. By controlling the
screwing, flow rate can be altered.
Advantage: Easy to operate and clean
Offer more resistance to fluid flow and
high pressure drop when even open.
Disadvantage: High pressure drop.
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13. Gate Valve
In this valve, the closure element is a gate or
barrier as proposed by name. It is also
known as sluice valve.
Mechanism: It acts by shutting the pathway
similar to guillotine action.
Advantage: Less complex
Disadvantage: Friction and erosion is a
problem.
Uses: Used to completely shut off fluid flow or
provide full flow in pipeline. Used in high
temperature and high pressure environment.
Often seen in power plants, water treatments,
mining, and offshore applications.
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15. Diaphragm Valve
Valve with elastomeric diaphragm that
rest on seat when closed. Used to handle
slurries, corrosive materials, sludge etc.
Working Mechanism: Pinched to close
and loosen to open.
Advantage: Bidirectional, can be repaired
without flow obstruction.
Reduce leakage
Disadvantage: Body must be immune to
corrosion
Uses: Ideal for handling liquids with solid
particulate matter
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17. Plug Valve
Valve containing plug as the stopgap
measure.
Working Mechanism: Valve contains
hollow passageway to fit the valve which at
quarter turn either block or allow the fluid
flow.
Advantage: Low pressure drop Manual
force used for operation.
Disadvantage: Can’t be used for
throttling.
[Throttling: Act of chocking or constricting
pathway]
Uses: Used in handling low pressure low
temperature fluids.
In multiport construction
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19. Functions of Valves
Starting and Stopping Fluid Flow: Valves are used to start and stop fluid flow in a piping system.
Flow Control: Valves are used to control the flow of fluid through a piping system.
Pressure Regulation: Valves are used to regulate the pressure of fluid in a piping system.
Direction Control: Valves are used to control the direction of fluid flow in a piping system.
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20. Applications of Valves
Oil and Gas: Valves are used in oil and gas exploration, production, and transportation to control the flow
of fluids.
Water and Wastewater: Valves are used in water and wastewater treatment plants to control the flow of
water and other fluids.
Chemical Processing: Valves are used in chemical processing plants to control the flow of fluids in
different stages of the production process.
Power Generation: Valves are used in power generation plants to control the flow of fluids in steam
turbines and other equipment.
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