Valves Types by A Aziz Arfaj.ppt

8/15/2019 Valves Types by A Aziz Arfaj.ppt

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Prepared and Presented By:

Abdulaziz M. Al ArfajSr. Mechanical Inspector


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Introduction

In the petroleum industry, the primaryresponsibility of the inspector is to insure plantsafety, quality of materials, and achievemaximum plant reliability and efficiency. Thepiping system makes up a major part of the anypetroleum processing operation,a veryimportant part of the piping system is the

valve.


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Definition & basic functionGeneral :

The most common mechanical device used inSaudi Aramco plants is the valve.Definition:The Valve is a mechanical device that is used to

control the flow of liquids & gases through thepiping system.

Basic Functions of valves:1. Shut off or open a system to fluid flow.2. Regulate or throttle any fluid flow.3. Prevent backflow.4. Relive pressure.


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Maine categories of valves

Valves have four main categories in Saudi AramcoPlant & Piping Services :

• Block Valve (Gate, Ball, Plug, Butterfly, Diaphragm, Globe) • Throttle Valve ( Globe,Butterfly, Diaphragm,) • Automatic Control Valves• Check Valves


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GATE VALVE

About 75% of all valve in process plant are gate valves.The gate valve is an optimum

engineering and economicChoice for on or off service. Thistype of valve is not suitable tothrottle flow because the valveseating surfaces can erode rapidlyfrom fluid flow when the valve isnot in the fully open or fully closed

position.

Gate Valve


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Valve symbols

Gate Valve


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Plug Valve

When quick on/off

or tight shutoff isrequired a plug valveis good choice asblock valve, since itoperated by a handleinstead of a wheel,only a quarter (1/4)turn of the handlewill change the plugfrom fully closed tofully open.


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PLUG VALVE


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Ball Valve

Ball valve like plug valverequires only ¼ turn.Soft seated ball valve arenot normally used forthrottling servicebecause the valve softseats will be subjected toerosion or distortion/displacement caused byfluid flow.


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- Close the line more quickly than gate valve- Plug valve and ball valves are considered to betight

shut-off (TSO) valves.

However, plug valve and ball valve are moreexpensive than gate valve. For this reason, they are

not as common as gate valves.

Advantage of Plug and Ball valves over Gate Valves


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Angle Valve

An Angle Valve is aglobe valve which iscombined with thefunction of a 90 deg.

Elbow, which neededwhere the piping makesa 90 deg. Turn. AngleValve come in class

rating from 150 to 600and in sizes from ½ inchto 12 inches.


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Butterfly Valve

The butterfly valve uses a flatcircular disk control line flowin the piping system. Butterflyvalve can be used as blockvalve or a throttle valve.Although a Butterfly Valveconstitute a small percentageof all valves used in process

plant application, their lowcost and simple operationwarrant their considerationwhenever possible.


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Globe Valve

Globe Valve are multi-turn throttling valve. AllGlove Valve pattersinvolve a change in flow

direction, they are notsuitable for piping systemthat requires scraping.Rarely used for strictlyon/off block valveoperation (gate valvelower cost and much lowerpressure drop).


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Automatic Control Valves is similar to aglove valve because it is used to controlthe rate flow. Notice that the automaticcontrol valve has no wheels, handles or

levers to operate. The top of the valve hasa diaphragm that moves the valve stem.An instrument control system change thepressure on the diaphragm to open, close

or adjust the valve. Automatic controlvalves are found throughout any largeplant and are used to control such thingssuch as temperature, flow, liquid, level,and pressure.

Automatic Control Valves


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Needle Valve

Needle Valve are

throttling valvethat are used forvery accuratecontrol of flowwith a rangingsize from 1/8 to1 inch, theycome in allclasses and theyare often used athigh pressure .


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Diaphragm Valve

Diaphragm Valve aremulti-turn, corrosionproof valves. They maybe operated open,

throttled or closed. Adiaphragm corrosiveand dangerous systemproducts. A diaphragmvalve is a pack less valvewhere the flexiblefunction as both aclosure and a seal.


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Check Valves are designed to

prevent flow reversal forsystem that requiredprotection against backflow.

Swing-Type Check ValveWhen the system products isflowing, a disc inside the valveis forced open allowing theproduct to flow. If flowdirection changes (back flow)the disc swing down onto a

seat and the valve is closed.

Swing Type Check Valve


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Other Types of Check Valve

Piston check valve (A )

Lift check valve (B)

Ball check valve ( C )


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BI- 3150 VALVES QUANTITES

Around13737valveswill be

installed inBerriEthanRecoveryProject @BGP


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Conclusion

For an inspector to do a better job he must havea good basic understanding of the equipmentthat he will be inspecting . In this case inspectormust be able to identify the type of the valve,

and its function within the piping system,moreover identifying the internal part of thevalve and their functions & to be able to identify

the material used in the valve parts.

Valves Types by A Aziz Arfaj.ppt

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