Intoduction to valve technology

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    Introduction to

    Valve Technology

    Presented by

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    What is an Ideal Valve?

    Shuts off or controls the rate of flow into, inside of, or out of piping

    or other closed conduits.

    When open, offers the least resistance possible to the flowingproduct

    When closed, seals tightly permitting no fluid to pass. Resistant to bending loads and vibration on the associated piping.

    Impervious to corrosion.

    Uneffected by erosive particulate matter.

    Withstands damage from large objects in the fluid stream.

    Tolerates temperature extremes or cycling.

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    Actual valves rarely approach the ideal performance of the perfect

    valve.The engineer and user must compromise, weighing the value of eachperformance quality against the cost to provide it.

    What is Reality?

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    Types of Valves

    Valve types range from simple shut off devices to complex servo-systems.

    Sizes vary from tiny metering valves used in aerospace applicationsto pipeline and industrial valves weighing tons.

    Operating pressures may be as high as 100,000 psi or as low as avacuum.

    Temperatures may be as low as the cryogenic region or as high asthose of molten metals.

    Leakage requirements may be very strict where even the tiniest leakmay be disastrous, or they may have lenient where loss is of minorimportance.

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    Valves may be classified in different ways such as :

    1. the function

    2. the closure member

    Valves Classifications

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    Shut-off Valves

    Non-return Valves

    Control Valves

    Safety Valves

    Valve classification

    1- By Function

    scope of this presentation are Shut-offand Non-return valves only

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    Valves Classification 2 .By Closure Member

    2.1- Gate Valves

    Gate valves are characterizedby a sliding gate which ismoved perpendicular to thedirection of flow.

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    1/2 800 GATE VALVE

    BOLTED BONNET - OS&Y

    Gate Valve Examples

    Valves Classification 2 .By Closure Member

    2.1- Gate Valves

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    48 150 GATE VALVE

    BOLTED BONNET - OS&Y

    Gate Valve Examples

    Valves Classification 2 .By Closure Member

    2.1- Gate Valves

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    GATE VALVEINSIDE SCREW

    WATER SERVICE

    Valves Classification 2 .By Closure Member

    Gate Valve Examples2.1- Gate Valves

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    GATE VALVESPARALLEL SLIDE GATE

    FOR POWER PLANT

    Valves Classification 2 .By Closure Member

    Gate Valve Examples2.1- Gate Valves

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    GATE VALVESBellows Sealed

    and 16

    Valves Classification 2 .By Closure Member

    Gate Valve Examples2.1- Gate Valves

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    GATE VALVE FOR WELLHEAD

    PARALLEL SLIDE SLAB GATE

    Valves Classification 2 .By Closure Member

    Gate Valve Examples2.1- Gate Valves

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    KNIFE GATE VALVE

    Valves Classification 2 .By Closure Member

    Gate Valve Examples2.1- Gate Valves

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    Valves Classification 2 .By Closure Member

    Globe valves have a closure

    member, usually in the form ofdisc or plug, which is moved bya stem perpendicular to a ringshaped seat.

    Globe valves are used primarilyfor throttling purpose.

    2.2- Globe Valves

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    Straight (std) Pattern

    GLOBE VALVE

    Valves Classification 2 .By Closure Member

    Straight pattern globe valve have

    a limited flow coefficient due tothe 90 angle of the flow passage

    The seat can be renewable

    (screwed-in) or integral ( a welddeposit of Stellite Gr 6)

    Globe Valve Examples2.2- Globe Valves

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    Y Pattern

    GLOBE VALVE

    Valves Classification 2 .By Closure Member

    The stem and closure member is

    assembled at an angle tomaximize the flow coefficient (CV)of the valves (limiting the loss ofspeed)

    Usually welded bonnet, and inhigh pressure for Steam service

    Globe Valve Examples2.2- Globe Valves

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    BELLOWS SEAL

    GLOBE VALVE

    Valves Classification 2 .By Closure Member

    Globe Valve Examples

    The entire stem, stem packing

    and back seating arrangement isisolated from the flow bore by aflexible metallic bellows.

    The bellows is attached to thebottom end of the stem and to thebonnet by welding.

    2.2- Globe Valves

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    Compact BellowsSealed Globe Valve for

    Steam and DowTherm

    Valves Classification 2 .By Closure Member

    ECO-L-VALVE

    The entire stem, stem packing and back

    seating arrangement is isolated from theflow bore by a flexible metallic bellows.

    The bellows is replaceable (screwed on

    the stem).

    Globe Valve Examples2.2- Globe Valves

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    In this small globe valve, theclosure member is a taperedneedle point plug which actsagainst a small orifice.

    Valves Classification 2 .By Closure Member

    Globe Valve Examples2.2- Globe Valves

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    Valves Classification 2 .By Closure Member

    Similar in appearance to a ball

    valve, it employs a mechanicalwedge closure in which the seal issqueezed tight by the downwardmotion of the stem.

    2.4- Rising Stem Ball Valves

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    Valves Classification 2 .By Closure Member

    2.3- Pinch Valves

    Uses a rigid bar to press against

    a flexible element such as adiaphragm or rubber tube topinch off the flow.

    Is used in systems carryingslurries, as they are low in cost,and insensitive tocontamination.

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    Valves Classification 2 .By Closure Member

    2.5- Ball Valves

    The ball valve is basically a

    ported sphere in a housing.

    Rotation of the sphere by 90changes the position from open

    to closed and from closed toopen.

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    Ball Valves ExampleSide Entry

    Ball assembledfrom the side of

    the body

    Valves Classification 2 .By Closure Member

    2.5- Ball Valves

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    Ball assembledfrom the top ofthe body

    Valves Classification 2 .By Closure Member

    2.5- Ball Valves

    Ball Valves ExampleTop Entry

    l Cl ifi i 2 Cl b

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    Ball Valves ExampleSide Entry, Trunnion Mounted Ball

    Side Entry Ball Valvesmay be:

    - three piece

    - two piece

    Generally, three-piecevalve is forged body,while two-piece valve iscast body.

    2 1500 ClassTwo-piece Cast Body

    Duplex Stainless Steel

    Valves Classification 2 .By Closure Member

    2.5- Ball Valves

    V l Cl ifi ti 2 B Cl M b

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    2.5- Ball ValvesBall Valve Example

    TOP ENTRY30,900 Class

    Cast Body

    Valves Classification 2 .By Closure Member

    V l Cl ifi ti 2 B Cl M b

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    2.5- Ball ValvesBall Valve Example

    Top Entry30 900 ClassForged Body

    Valves Classification 2 .By Closure Member

    Valves Classification 2 By Closure Member

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    Three-Way Ball Valves

    Valves Classification 2 .By Closure Member

    2.5- Ball Valves

    Valves Classification 2 By Closure Member

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    Valves Classification 2 .By Closure Member

    2.6- Butterfly Valves

    Consists of a disc which rotates about

    a shaft in a housing.

    Disc closes against a ring seal to stopflow.

    Used mainly in low pressure systemswhere some leakage may betolerated.

    Valves Classification 2 By Closure Member

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    Valves Classification 2 .By Closure Member

    2.7- Plug Valves

    Plug valves have the closure

    member as a tapered plughaving a rectangular port.

    The plug is rotated through 90

    to open and close the valve.

    Valves Classification 2 By Closure Member

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    Check valves (also known as

    non-return valves) areautomatic valves thatprevent a return or reverseflow of the fluid.

    They require no externalforce to operate.

    Valves Classification 2 .By Closure Member

    2.8- Check Valves

    Valves Classification 2 .By Closure Member

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    Dual Plate Wafer TypeCheck Valve

    Main advantages :

    - low weight

    - small dimensions

    - horizontal and vertical

    installation

    Valves Classification 2 .By Closure Member

    Check Valve Examples2.8- Check Valves

    Valves Classification 2 .By Closure Member

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    Check Valves

    42 600 Check Valve, featuring

    buttweld ends and weldedpupjoints complete withdamping device (Shell OmanPipeline)

    Valves Classification 2 .By Closure Member

    Check Valve Examples2.8- Check Valves