VALVES

VALVESVALVES

VALVE DEFINITION

VALVES ARE MECHANICAL DEVICES SPECIFICALLY DESIGNED TO:

•DIRECT

•START

•STOP

•MIX

•REGULATE

FLOW, PRESSURE OR TEMPERATURE OF A PROCESS FLUID

• Valves can be designed to handle either LIQUID or GAS applications.

• Industrial Valves : Size 0.5” Nominal Dia (DN15) to 48” (DN1200).

• 90% of Valves are 4” (DN100) or smaller in size.

SERVICEVacuum to over 13,000 psi (897 bar)

MATERIALS OF CONSTRUCTIONIron, Steel, Plastic, Brass, Bronze (or) a

number of special Alloys

HISTORY

• In 1712, Englishman Thomas Newcomen invented a simple Iron Plug Valve, to regulate the flow of steam to the piston – The first known application of a Throttling valve.

• Corliss Steam Engine unveiled in 1876 was designed with Self-acting Control Valves.

• Invention of Crude oil as an inexpensive and plentiful form of power in early 19th century spawned the creation of Petroleum Refinery, Petrochemicals, Process Industries, Paper, Food, Beverage Industries creating need for various types of valves.

VALVE CLASSIFICATION

a) Function classifications:• ON-OFF (Block valves) – Block or allow

flow• Non-return (Check valves) – Allow flow to

travel in one direction• Throttling (Full open to full close) –

Regulation of flow (Can be used as ON-OFF also)

b) Application Classification:• General Service valves (Manual or

Automated) – -46oC to 343oC, Class 150 to 600, Non-corrosive applications.

• Special service – Custom engineered – High pressure, high temperature, corrosive/erosive medium.

• Severe service – Valves with special features to handle volatile applications, very high pressure drops, severe cavitation, flashing, choking, beyond 593oC, liquid Sodium applications.

c) According to motion:• Linear motion – sliding stem design.• Rotary motion – through quarter turn or 45o

range to open or block the flow.

d) According to Port size:• Full port valves• Reduced port valves

Other types of Valves

• Block & Bleed valves – To prevent intermixing of fluids (Fin Fan cooler, wash water systems)

• Butterfly valves – Water applications (AWWA standards)

• Blow-off valves – Steam systems

TERMS AND DEFINITIONS

• ANSI rating class – Numerical pressure design class defined in ASME B 16.5 and used for reference purposes.

• ANSI rating class is designated by the word ‘CLASS’ followed by a number. Ex: Class 150.

• Bi-directional valve – Valve designed for blocking the fluid in both downstream and upstream direction.

• Bleed – drain or vent.• Block valve – Gate, Plug or Ball valve that blocks

flow to downstream when in closed position

• Locking device – Part or an arrangement of parts for securing a valve in the open and (or) closed position.

• NPS – Nominal pipe size.• PN – Numerical pressure design class as defined

in ISO-7005-1. (PN followed by a number). Ex: PN16.

• Pressure containing parts – Parts such as body, bonnet, gland, stem, gasket, bolting designed to contain pipeline fluid.

• Process wetted parts – Parts exposed directly to pipeline fluid.

ABBREVIATIONS

BM Base Metal

CE

Carbon Equivalent =

{%C+(%Mn/6)+(%Cr+%Mo+%V)/5+(%Ni+%Cu)/15}

Limit: 0.43 – Heat analysis, 0.45 – Product.

DBB Double Block and Bleed

DN Nominal Size

HAZ Heat Affected Zone

HR Rockwell Hardness

HV Vickers Hardness

MPD Maximum Pressure Differential

MT Magnetic Particle Testing

NDE Non-Destructive Examination

NPS Nominal Pipe Size

NP Nominal Pressure

WPS Welding Procedure Specification

PQR Procedure Qualification Record

WQR Welder Qualification Record

WM Weld Metal

PT Penetrant Testing

PWHT Post Weld Heat Treatment

ANSI PRESSURE CLASSPOUNDS OF FORCE PER SQUARE INCH OF SURFACE AREA

NOMINAL PRESSURE – ALLOWABLE

PRESSURE IN BAR

150 16

300 40

600 100

900 160

1500 250

2500 400

4500 700

VALVE SELECTION

• Valve co-efficient or Flow co-efficient

Cv = Flow X m sqrt Sp. Gravity at flowing temperature / pressure drop

Cv = One US gallon (3.78 litres) of 60oF (16oC) water that flows through an opening (valve) during 1 minute with a 1 psi (0.1 bar) pressure drop

END CONNECTIONS

• Threaded (1.5” and smaller sizes) (NPT)

• Flanged End (2” and larger) – Integral, separable

• Welded End (Class 900 and higher) – Socket welded (2” and smaller), Butt welded (3” and higher)

PRESSURE CLASSES

• Six standard classes – 150, 300, 600, 900, 1500 or 2500 – As per B 16.34 standard

• Special classes – 15, 4500 Etc.

• Intermediate classes – Ex. 3300 (CS valve for 150oC, 450 bar)

Casting Quality Factors

• ASME Codes / B 16.34

Especially for corrosive, high pressure, high temperature applications

• Level – 1

• Level – 2

• Level – 3

• Level indicates severity levels of imperfections

Casting imperfections include

• A – Gas porosity

• B – Sand, slag inclusions

• C – Shrinkage

• D – Cracks

• E – Hot tears

• F – Inserts

• G – Mottling

Examination of Steel castings are done as per

• ASME Sec:VIII Div:1 Mandatory Appendix:7

• ANSI B 16.5

• ANSI B 16.34

Radiographic examination standardsThickness Standard

Up to 2” (51 mm)ASTM E 446

(Std Reference Radiographs)

2” – 4.5” (51-114 mm)ASTM E 186


4.5” – 12” (114mm-305mm)

ASTM E 280


Above 12”ASTM E 280 / UT exam is

done

RT spotsAs per sketch in B 16.34

standards

VALVE MANUFACTURING

• Valve design• Pattern development• Establish methoding process with Statistical

Quality Control• Pilot casting• Tests / Acceptance standards• Fix quality factors• Machining of castings

• Bought out items (other items like stem, gasket, packing, fasteners, hand wheel, disc, yoke, seat ring)

• Assembly

• Testing

• Marking / Punching

• Despatch

• VTR / Release note of TPI

• Spares, valve key Etc.

MATERIAL

• Carbon Steel – up to 425oC

• Chrome-Moly Steel – Corrosive, H2S environment

• SS - >535oC, high temperature, corrosive applications

• A216 WCB (CS), A217 C5 (AS), A351 CF8M, CF3M (SS)

TRIM MATERIAL

API 600 Trim No.

Service StemBody seat

ringWedge

Back seat bush

8MP / LP Steam

SS 410 RC22 max

Body MOC +

HF

Body MOC + 13% Cr

RC22 max

SS 410 RC22 max

12Corrosive

serviceSS 316

Body MOC +

HF

Body MOC + SS 316 RC22

max

SS 316 RC22 max

5 HP Steam Both body seat / wedge is Stellited.

MATERIAL TESTING

• Chemical composition – basic, alloying elements

• Mechanical properties – UTS, YS, % elongation, hardness Etc.

• Special properties – Impact, high corrosion resistant properties Etc.

Various Heat Treatment processes conducted in valve manufacturing

• Normalizing

• Hardening

• Annealing

• Tempering

• Solution Annealing

EXAMINATIONS

• Visual

• Liquid Penetrant

• Magnetic particle examination

• Radiography

• Ultrasonic examination

TEST PROCEDURE – API 600• Gate valve : Shell

BackseatAir seatHydro seat

• Globe valve : ShellBackseatAir seatHydro seat

• Check valve : ShellHigh pressure closure testLow pressure closure testLow pressure air seat test

(optional)

REPAIR

• Weld repairs should be approved by TPI / Client

• WPS / PQR / Welder qualifications – check

• NDT

• Post weld heat treatment

• Tests as above

Gasket Selection

• Purpose : Prevent leakage from joint

Prevent leakage to atmosphere

Allow function of internal mechanism• Material / : CAF, Spiral Wound, Ring Joint type

types

PACKING

Any soft material encased in a bonnet or in a body used to seal a valve closure elements stem or shaft is called packing. It is held by a packing follower or guides.

Ex: Graffoil, Impregnated Graffoil Etc.

CLOSING ELEMENTS

• GATE

• GLOBE

• BALL

• PLUG

• BUTTERFLY Etc.

TYPES OF OPERATION• MANUAL

• GEAR OPERATED

• ACTUATOR OPERATED

COMMON VALVE PROBLEMS

• High pressure drop – Result in cavitation, flashing, choked flow, high noise levels, vibrations.

• Water hammer effects – Due to sudden stoppage of flow, shock waves are generated, avoid sudden pressure surges.

• Erosion, Corrosion• Defects, leaks (Gland leaks)• Operational issues – closing, opening Etc.

ACCREDITATIONS

• API – Monogram

API – 6D for Gate, Plug, Ball, Check valves

• ISO – 9001

• ISO – 14000

• IBR / EIL, TDC, TPI approvals

Purchasing Issues

• Valve data sheet• Drawing• Specifications• QAP• Stage / Final inspections• Storage, Installation• Spares• Warranty, Guarantee issues• Vendor surveys for enlistment

INSTALLATION

• For best performance, it is recommended that Gate, Globe valves are installed in vertical position with the stem operating end at the top, horizontal or at an angle in between.

• Swing check valves can be installed in vertical or horizontal pipelines. However, in vertical pipelines the flow should always be in the upward direction.

• Swing check valves should never be installed at the outlet of a Reciprocating pump – as the pulsating flow will damage internals of the valve.

• Gate valves have bi-directional capabilities and can be installed in any direction.

• Globe valves to be installed in the direction of arrow.

• Check valves are unidirectional. Flow direction and arrow direction should coincide.

OPERATION• GATE VALVES : Should be fully open or fully

closed. Throttling will cause wire drawing at seating area leading to damage, leak. Clockwise: close, anticlockwise: open.

• GLOBE VALVES : Used for throttling. It is advisable not to use Globe valves for flow control below 10% of full opening. Clockwise: close, anticlockwise: open.

• CHECK VALVES : All are swing type which automatically open by the velocity pressure of flow and close by the gravitational force when flow reverses or stops.

Maintenance Issues

• Periodical cleaning, flushing, greasing

• Check gear box, actuator mechanisms

• Installation issues

• Online leak arresting (clamps, cold repairs Etc.)

PARTS

• Disc and Seat that directly affect the flow

• Stem that moves the Disc

• Body and Bonnet that house the Stem / internal parts

• Operator that moves the Stem

DESIGN / TESTING CODES

VALVE DESIGN TESTING

GATEAPI 600, BS 1414,

DIN 3202 API 598, ANSI B 16.34,

BS 6755,

DIN 3230

GLOBE BS 5352

CHECKBS 5352 (Forged) /

BS 1868 (Cast)

Other relevant Standards include:

• API 6D – Petroleum & Natural Gas Industries – Pipeline Transportation Systems – Pipeline Valves

• ASME B 16.5 – Pipe flanges and flanged fittings (1/2” to 24”)

• ASME B 16.10 – Face to face and end to end dimensions of valves

• ASME B 16.25 – Butt welded ends

• ASME B 16.34 – Flanged, threaded and welding ends.

• ASME B 16.47 – Large Dia steel flanges (26” to 60”)

• NACE TM 0284 – HIC testing

• NACE MR0175 – Sulfide Stress Cracking resistant metallic materials for oil field equipment

• API 6 FD / API 607 – Fire safe testing of valves

PRESERVATION

• End caps

• Water ingress

• Check prior to installation

Special Applications

• NACE – MR0175

• IBR – FORM - III C

• AWWA Stds. – Water applications

• Custom designed – PAREX rotary valves

• Cryogenic applications – very low temperatures : N2, LPG (-180oC)

TRACEABILITY

• Manufacturer Name Plate

• Heat No. / Lot No. / Sl. No.

• Size / Rating

• W.O. No.

• VTR / Release Note of TPI

Famous / Approved Manufacturers

• AUDCO

• KSB

• FOURESS

• SANMAR

COST ASPECTS

• Size, Rating

• Additional Features (Gear, Actuator)

• Special Requirements (NACE, RT Quality)

• Location of Supplier vs. User

• Mandatory Requirements

QUESTIONS / VALIDATION:

• What is a Valve?• What is the purpose of a Valve?• What are types of Valves?• What are the Design/Testing standards?• What NDT are done in manufacturing stage?• What is AWWA Std? Where is it applicable?• What is Cv?• What are Appurtenances for valves? Name any 03.• What are different types of ends of valves?• What are NACE application Standards?• What is an IBR valve? What is the Form No.?

THANK YOUTHANK YOU

VALVES

Documents

Transcript of VALVES