SEVERN GLOCON CONTROL VALVES

Severn Glocon have been designing & manufacturing Control Valves & Actuatorsfor approximately 40 years and this has led to extensive international experienceacross the whole spectrum of the Process Industry.Applications range from the most simple to the most severe, involving noisereduction, high pressure drop, low temperature, corrosive / abrasive, toxic fluidsand many more. Although continued expansion has found it necessary to pursuestandardisation in keeping with other leading equipment manufacturers, SevernGlocon remains dedicated to provide, whenever asked, valves for applicationsthat are commercially acceptable and above all technically correct.

At Severn Glocon Specials are Standard

All products are designed with the help of CAD systems in accordance withinternational standards using a wide range of materials to suit the application andmanufactured with the latest CNC machining technology. The stringent demandsthat the Process Industry market makes on its suppliers are easily met by SevernGlocon due to the flexible approach taken to customers requirements togetherwith a refined Quality Assurance system that has been certified in accordancewith BS EN ISO 9001: 1994. As a result, thousands of Severn Glocon valves arenow operating in plants throughout the world. All valves supplied carry their ownunique serial number enabling trace ability and when repaired / overhauled areentered into a comprehensive Service Records Data base.

SEVERN GLOCON LTD.Control Valves for the Process Industry

Manual

SG 10

Sizing and SelectionManual

Severn Glocon Technical Manual Scope

Scope

Sizing and selection of control valves demands an accurate knowledge of the operatingparameters into which this equipment is to be placed. Upon the selection of this finalcontrol element relies the automatic operation of most modern processing and industrialplant.

In operation these valves control processes which operate continuously or intermittently,without attention, to regulate process parameters such as flow rate, pressure,temperature, level, etc. The advances of computer technology within the industry,together with the demand for designs capable of handling a wider range of process andfluid requirements, within a very competitive market, has necessitated a higher level ofaccuracy in sizing and selection of these critical control elements. This coupled with theuse of high technology valves, to deal with increasing temperature and pressure rangeapplications, gives rise to a demand for a greater understanding of the control valveoperating characteristics.

The Severn Glocon procedures for control valve selection recognizes theserequirements, the sizing formulae used within this manual basically follow thosepublished in the referenced national standards, combined with Valve Style Modifier datadeveloped from the companys valve testing programmes.

The Severn Glocon Control Valve Sizing and Selection Manual is divided into a numberof parts each containing information required during the specification of a control valve,and includes both selection guidelines and material considerations.

SEVERNGLOCON

Contents of Technical Manual SGT 10

SGT 10/1 Scope.Scope of Sizing and Selection.Contents of Technical Manual.Valve Identification System Top Level.Actuator Identification System Top Level.Instrumentation Identification System Top Level.

SGT 10/2 Control Valve Sizing.Introduction.Standards Reference.Sizing Nomenclature.Generalised Liquid Flow.Flashing Flow.Cavitation and Cavitation Index.Liquid Sizing.Liquid Flow Velocity.Flashing Liquid Velocity Calculation.Flow of Vapours and Gases.Gas Velocity Calculation.Mixed Phase Fluids.

SGT 10/3 Flow Characteristics.Quick- Opening Flow Lift Characteristics.Linear Flow Lift Characteristics.Equal Percentage Flow Lift Characteristics.Modified Equal Percentage or Parabolic Flow Lift Characteristics.

SGT 10/4 Pressure Recovery Factors.Valve Lift v Pressure Recovery Charts.Nomenclature.Pressure Recovery Formulae.Pressure Recovery Tables and Charts.

SGT 10/5-Pipework Connected to Valve.Reducers and Expanders.Determination of Coefficient Fp.Calculation of Coefficient Ki.Calculation of Combined Recovery CoefficientFLP.Modified Cavitation Index p.Charts of Cv/d^2 versus Fp.Charts of Cv/d^2 versus FLPCharts of Cv/d^2 versus p.

SGT 10/6 Viscous Flows.Viscous Flow Regimes.Valve Style Modifier Fd Values.Valve Reynolds Number Factor FRCalculation of Viscous Flow Effect on Valve Cv.

SGT 10/7- Recommended Pressure Drops.Limiting Pressure Drops and Trim Materials.Temperature considerations.Produced noise and power conversion.Calculation of liquid and gas energy levels.

SGT 10/8 Noise Prediction.Introduction.Standards Reference.Sizing Nomenclature.Liquid Noise.Liquid Noise Calculation Example.Aerodynamic Noise Generation.Aerodynamic Noise Prediction.Aerodynamic noise Calculation Example.

SGT 10/9 Fixed Area Attenuators.Flow Path Noise Attenuation.Valve Seat Exit Diffusers.Baffle Plates.Absorption Silencers.MLT. Vent SilencingPressure Recovery and Style modifier Fd Values.

SGT 10/10 Valve Actuator Sizing.Static Forces on Valve Trims.Seat Leakage Requirements.Allowances for Friction.Dynamic Forces on Valve Trims.Calculating Correct Actuator Thrust Requirements.Actuator and Trim Dimensional data.

SEVERN GLOCON NUMBERING SYSTEMValve Identification System Top Level

DescriptionProduct Family

First Digit(ValveSeries)

Second Digit(Product

Construction)

Third Digit(Product Shape)

Fourth Digit(Pressure Grouping)

2000 Series GlobeSplit Body 2

1 = Plastic2 = Reserved3 = Bar Stock4 = Casting5 = Forged6 = FabricationX = Special / Other

1 = Globe2 = 3 Way3 = Angle5 = Z Pattern7 = 3 Way AngleX = Special / Other

0 = ANSI 125 (PN 10)1 = ANSI 150 (PN 20)2 = ANSI 300(PN50)3 = ANSI 600(PN110)4 = ANSI 900 (PN150)5 = ANSI 1500(PN250)6 = ANSI 2500(PN240)7 = ANSI 4500(API 10000)D = Design RatedX = Special / Other

3000 Series GlobeCold Box

Extended Body3 As above

1 = Globe2 = 3 Way5 = Z Pattern8 = Long Z PatternX = Special / Other

As above

4000 Series GlobeCold Box Welded

Body Extension4 As above

1 = Globe2 = 3 Way3 = Angle5 = Z PatternX = Special /Other

As above

5000 Series GlobeMulti Purpose &Field Cryogenic

5 As above

1 = Globe2 = 3 Way3 = Angle5 = Z Pattern6 = High CapacityX = Special /Other

As above

6000 Series GlobeCorrosive Duty Lined 6 As above

1 = Globe (Pfeiffer)4 = Y PatternX= Special /Other As above

7000 Series GlobeUltra High Purity 7 As above

1 = Globe2 = 3 Way3 = Angle5 = Z PatternX = Special /Other

As above

8000 Series Butterfly 8

1 = Standard(Class II)2 = Rubber Lined3 = High Performance4 = TSO Cryogenic5 = Plastic Lined6 = Ultra High PurityX = Special / Other

1 = Wafer2 = Lugged Wafer3 = Double Flanged4 = U Pattern

X= Special /Other

As above

9000 Series BallValve 9

1 = Full Bore2 = Reduced Bore3 = Vee BallX= Special / Other

1 = Flangeless2 = Flanged As above

SEVERN GLOCON NUMBERING SYSTEM

Actuator Identification System Top Level

First Digit(Actuator Series)

Second Digit(Duty / Action)

Third Digit(Actuator SizeSeries)

Fourth Digit(Ancillaries)

A = Rotary NumotorB = Pneu Cylinder +Rotary LinkageE = Electric MotorF = Electro HydraulicG = Gearbox &H/WheelL = LeverM = Manual H/Wheel.OS&YN = NomotorP = PneumaticCylinderR = Rack & Pinion(1/4 Turn)W = Spring &diaphragmY = Self Acting PilotX = Special / Other

0 = Manual Operation1 = Modulating (AFO)2 = Modulating (AFC)3 = Modulating (AFS)4 = Reserved5 = On/Off (AFO)6 = On/Off (AFC)7 = On/Off (AFS)X = Special / Other

A = 25 in2B = 50 in2C = 100 in2D = 200 in2E = 400 in2F = 600 in2G = 38 in2H = 75 in2J = 150 in2K = 300 in2X = Special / Other

H = side MountedHandwheelT = Top MountedHandwheelJ = Top MountingJacking ScrewM = Maximum LimitShopL = Minimum LimitShopN = NoneX = Special / Other

Key

AFO = Air Fail OpenAFC = Air Fail CloseAFS = Air Fail Stayput

Notes: Actuators size also applies to manual handwheels, for example MOCN is C series size handwheel.

Instrumentation Identification System Top Level

First Letter(Product Family)

Second Letter(Operating Range)

First Digit(Construction

Material)

Third Letter(Connection

Size)B = Volume BoostersC = Check ValvesF = FiltersG = Filter RegulatorsJ = Junction BoxesL = Lock-up ValvesP = Positioners (Pneumatic)R = Positioner (Electrical)X = Special / Other

E = Electrical 4-20 maG = Pneumatic 3-15 psig (0.2-1.0 bar)H = Split RangeN = Natural Gas 0-100 psig (0-7 bar)P = Air 0-100 psig (0-7 bar)

1 = Aluminium2 = Brass3 = Stainless Steel

A = NPTB = NPTC = NPTD = 1 NPT

Example I-BPIA is a Volume Booster working on air (0-100 psig). Aluminium construction with NPT connections.

Severn GloconTechnical ManualControl Valve Sizing

Contents.

Introduction.Standards Reference.Sizing Nomenclature.Generalised Liquid Flow.Flashing Flow.Cavitation and Cavitation Index.Liquid Sizing.Liquid Flow Velocity.Flashing Liquid Velocity Calculation.Flow of Vapours and Gases.Gas Velocity Calculation.Mixed Phase Fluids.

Introduction.Selection of a control valves demands anaccurate knowledge of the operatingparameters into which the control valve is tobe placed. The control valve flow capacityCv determined by the formulae given isbased upon the industry standardsreferenced below.The Cv calculations include consideration ofthe various flow regimes, together with theeffects of flow conditions which incurflashing or cavitation. The techniques forevaluating the effects on Cv, of highlyviscous fluids and pipework reducers andexpanders is given in other parts of thismanual, as are the valve produced noiselevels with recommended pressure dropsand energy conversion levels.To ensure correct selection of valve size inorder to maximize operational working life,fluid velocity calculations are includedtogether with recommended limits for thedifferent flow conditions.

Standards used in Sizing.

BS5793 : Part 2 Section 22.IEC 534-2 : Section 2.ANSI/ISA : S75.01 : S75.02.

Standards Reference.

ISA RP75.23-1995.IEC 534-8-4.

Figure 1. Severn Glocon MLT Low NoiseValve.

SEVERNGLOCON

General nomenclature used within this publication.Note : For clarity specific nomenclature is listed locally when dealing with specializedtopics.

Unit Definition Imperial Metric

a Sonic Velocity ft /sec m / secCv Valve Flow Coefficient US Units ----------Kv Valve Flow Coefficient ----------- Metric Unitsd Valve Nominal Diameter inches mmD Internal Diameter of Pipe inches mmFd Valve Style Modifier ----------- ----------Ff Critical Pressure Ratio ----------- ----------Fk Ratio of Specific Heat Factor = K / 1.4 ----------- ----------FL Pressure Recovery Factor ( see Table 1 ) ----------- ----------Fp Piping Geometry Factor ----------- ----------Kie Incipient Cavitation Coefficient ----------- ----------Gf Upstream Liquid Specific Gravity ----------- ----------Gg Gas Specific Gravity ( Relative to air 1 ) ----------- ----------K Gas Specific Heat Ratio ----------- ----------Mn Mach Number ----------- ----------M Molecular Weight ----------- ----------P1 Upstream Pressure lbf/in2 A bar AP2 Downstream Pressure lbf/in2 A bar APv Vapour Pressure at inlet conditions lbf/in2 A bar APc Thermodynamic Critical Pressure lbf/in2 A bar Ap Pressure Drop Across Valve lbf/in2 barPvc Apparent Pressure at vena contracta lbf/in2 A bar AQ Volumetric Flow Rate ( liquid ) US gpm m3/hrq Volumetric Flow Rate ( gas ) scf / hr m3/hrT1 Inlet Temperature ( absolute units ) o R o Ku Specific Volume ( 1 / Specific Weight ) ft3 / lb m3 / kgV Velocity ft / sec m / secw Weight or Mass Flowrate lb/hr kg/hrx Fraction of Liquid Flashed to Vapour ---------- ----------X Pressure Drop ratio p / P1 --------- ----------XT Pressure Drop Ratio Factor --------- ----------Y Expansion Factor ( Gas / Liquid Ratio ) --------- ----------Z Compressibility Factor --------- ----------Y1 Specific Weight (Upstream Conditions) lb/ft3 kg/m3

General Cavitation Index --------- ----------mr Cavitation Index System Application --------- ---------- mr Manufacturers Recommended Valve style --------- ----------

cavitation index.

Flow Coefficient Cv.Each valve which is supplied by Severn Glocon has a specified design Cv which has beendetermined in flow tests carried out in accordance with ISA Standard S75. 02.The definition of Cv is the flow of water at 60o F in US gallons per minute, that produces apressure drop of 1 lb/in3 across the fully open valve.

Flow Coefficient Kv.An alternative flow coefficient Kv is now often used within the S.I. system of units. This is definedas the flow of water Gf = 1 between 6o C and 34oC in m3/hr with a pressure drop across the fullyopen valve of 1 bar (or 1Kgf/cm2).

Bar units :- Kv = Cv / 1.167 Kgf/cm2 Units :- Kv = Cv / 1.178.

Generalised Liquid Flow within a ControlValve.This passage of a liquid through a controlvalve is very complex and includes regionsof high turbulence, impingement, boundarylayer separation and low static pressures.Within these regions can also be seen thegrowth and rapid collapse of cavities withinthe liquid, which result whenever theprevailing fluid pressure falls below thevapour pressure of the liquid. Thesubsequent rise in pressure, above thevapour pressure value results in cavitation.See Figure 2.The lowest pressures can normally bemeasured immediately after a restriction,which causes a reduction in flow area and aconsequent loss of pressure, resulting in alocalized increase in fluid velocity. SeeFigure 3.As the flow passes from the control valveinlet towards the trim entry, the staticpressure reduces due to frictional andturning losses. Fluid approaching the trimhas to accelerate in order to pass throughthe area contraction presented by the trimentry geometry. This acceleration continuesuntil a point just downstream from the trimoutlet where the maximum stream velocity isreached, this is recognized as the venacontracta.The typical flow path through a control valveis shown in figure 4.Down stream of the vena contracta the flowarea expands, resulting in a reduction in flowstream velocity and consequent rise in staticpressure. The amount of pressure recoveryis a function of the control valve trim designand is quantified as the valve pressurerecovery factor FL.

FL2 = P1 P2 / P1 PvcWhere :- Pvc = Pv FFand FF = Fluid critical pressure ratio factorwhich is = [ 0.96 0.28 [ Pv/Pc]0.5 ]

This factor is used within the control valvesizing formulae, and the relationship of theactual p to the pvc is an important factorin determining the point at which cavitationor flashing would start.As the main noise and vibration producerswithin a control valve, on liquid service, areflow velocity and cavitation it is essential toselect the correct trim for the application. Inaddition the velocity of a fluid through avalve has a major influence on the erosiveeffects both within the valve body and trim.While cavitation can quickly render a valveunserviceable.The values of the pressure recoverycoefficient FL at different valve lifts are givenin SGT 10/4.

Figure 2. Pressure Variations within aControl Valve

Figure 3. Static Pressure and VelocityRelationship.

Figure 4: Typical Flow Path through aControl Valve

Flashing Flows.When a control valve reduces the inletpressure to below the fluid vapour pressure,and on exiting the trim the local statepressure remains below this level, thenflashing of the fluid results. See Fig 2. Oneof the main problems which arise fromflashing service is erosion of the valve andtrim if correct selection of the constructionmaterials is not undertaken. This is due toincrease in velocities cause by the change influid state, which results in fluid particlesbeing carried at high speed in the ensuinggaseous / fluid stream.Practice has shown that the single stagetrim, constructed from materials with gooderosion resistance, often provides the bestsolution for flashing service. Contouredtrims, with their high recovery values, offeradvantages when large amounts of flashingproduct are required. However, the singlecage guided valve provides a highly stableand vibration resistant trim for the higherduty flashing applications, when the flow isdirected over the head to dissipate theenergy and take advantage of the hardenedtrim construction materials.Selection of a valve, with an angle bodyconfiguration, where the inlet is at rightangles to the outlet can provide a goodsolution for flashing service, particularly ifthe outlet expands to a greater area than theinlet. If a Globe Valve is selected thenprotection of the body by fitting internal flowsdiffusers may well be required, particularly ifthe fluid is contaminated eg. Sand in oil/gasseparation flashing service. Figure 5 showsa trim with typical flashing damage.

Calculation of Valve Cv in FlashingService.In order to calculate the % flash that willoccur within a valve the full thermodynamicproperties of the flowing fluid are required.This involves taking a heat balance in orderto calculate the amount of liquid and vapourphases, however, with the exception ofwater these thermodynamic details are notnormally available.Investigation on standard control valves hasshown that only up to 50% of flashing takesplace in the region of the valve seat, theremained occurring in the valve outlet orpipework. In the absence of accurateprocess data, using this value, the individualCv values for the liquid and vapour phasescan be calculated, which may be consideredas a maximum in order to size the valve.Arguably this could lead to oversizing thevalve but this has to be balanced against thepotential erosion and choking effects whichcould occur with too small a valve beingselected.

In selecting the body size the maximumoutlet vapour phase velocity should notexceed some 250m/s or 0.3 Mn. A line sizevalve is often specified in high pressure dropcases, with flashing flows.

Figure 5. Trim with Flashing Damage.

Figure 6. Trim with Cavitation Damage.

Cavitation.Simply viewed, cavitation consists of theformation, growth and rapid collapse ofcavities in a liquid. These vapour bubblesare generated if the local static pressurefalls below the vapour pressure. Subsequentcollapse occurs if the static pressure againrises above the vapour pressure.Different levels of cavitation can beproduced, depending upon the valveselected and the application conditions.These are generally classified by thefollowing benchmarks :-

a) Incipient Cavitationb) Constant Cavitationc) Incipient Damaged) Choking Cavitatione) Maximum Vibration Cavitation

For more information on these levels (a) to(e) see ISA Recommended Practice 75.23 1995.Figure 6 shows typical damage to a controlvalve trim, caused by constant cavitation.

Cavitation Index.Severn Glocon use a single parameter mr toindicate the operating limit, or cavitationindex, of each particular product, see Table1. This manufacturers recommended singlevalue is applicable at the full open positionfor sizing purposes. In common with FL thepressure recovery, the value of mr changeswith the valve opening. This is shown indetail within Section 4 (SGT 10/4) of thisManual for the different valve and trim stylecombinations. If the value calculated for theapplication falls below the cavitation indexgiven for the valve selected, then thecavitation in one of its forms will result. Ahigh value of mr indicates a high recoveryvalve/trim style, and one that is prone tocavitation when high pressure drops areapplied.The Cavitation Index values mr, whichSevern Glocon recommend and use, are aproduct of the valve pressure recovery factorFL2 and an incipient cavitation coefficient Kjedetermined from the testing programmescarried out on the different valve/trim styles.

mr = ( P1 - Pv ) = 1

( P1 - P2 ) = FL2 Kje

This single index allows the engineerselecting the valve / trim to quickly assessthe suitability of a product. If the value of mrcalculated for the application is below that ofthe product selected then cavitationproblems may well occur. Values of

Cavitation Index mr for different valve liftsare given in SGT 10/4. Section SGT 10/7details multiplier values for mr to account fordifferent trim materials.Low values of mr indicate the higher dutylow recovery valves. One method ofachieving this higher performance is to fit amulti-stage pressure letdown trim. Figure 7shows the pressure let down which isobtained using a 3 cage Series 5000 NovaTrim, where the overall pressure recovery issignificantly lower than if a single cage valvehad been selected.The Multi-Labyrinth Trim (MLT) pressureletdown curve shown in figure 8 takes thisadvantage further by providing much greaterfluid velocity control within the trim, byincorporating the pressure reducing effectsof multi-turns, commingling of flow streamstogether with impingement and fluiddirectional changes.

Figure 7. Pressure Curve 3 C.C. Series5000

Figure 8. Multi-Labyrinth Trim. MLT.

Table 1. Generalised Values of Pressure Recovery Factor FL and Cavitation Index mr

Valve Series Valve Type Trim Style Flow Direction RecoveryFL

Cavitation Index mrTrickle Under

Over0.930.93

1.261.26

Contoured UnderOver

0.850.80

1.731.93

Globe &Corner Series

2410

Cage Plug UnderOver

0.890.89

1.581.58

3 Way Series2430

Contoured Mixing &Diverting

0.80 1.93

Trickle UnderOver

0.930.93

1.261.26

Contoured UnderOver

0.890.71

1.582.36

Series 2000 SplitBody

Angle Series2430

Cage Plug UnderOver

0.910.91

1.341.34

Contoured UnderOver

0.850.80

1.731.93

Series 3000 & 4000Cryogenic

Globe

Cage Under or Over 0.89 1.58

Trickle UnderOver

0.930.93

1.261.26

Contoured UnderOver

0.900.85

1.541.71

Ported Under or Over 0.88 1.43

Single Cage Under or Over 0.94 1.19

Double Cage Under or Over 0.95 1.17

Triple Cage Under or Over 0.96 1.14

Quad Cage Under or Over 0.97 1.12

Globe Series5410

Multi-labyrinth Under or Over 0.99* 1.05*

3 Way Series5420

Contoured Mixing &Diverting

0.85 1.71

Trickle UnderOver

0.930.93

1.261.26

Contoured UnderOver

0.900.72

1.542.30

Ported Under or Over 0.87 1.47

Cage Under or Over 0.94 1.19

Double Cage Under or Over 0.95 1.17

Triple Cage Under or Over 0.96 1.14

Quad Cage Under or Over 0.97 1.12

Series 5000 Multi-Purpose

AngleSeries 5430

Multi-labyrinth Under or Over 0.99* 1.05*

GlobePTFE Lined

Contoured UnderOver

0.900.85

1.651.85

Series 6000Corrosive

Y Pattern Contoured UnderOver

0.900.83

1.541.81

Series 7000Ultra High Purity

GlobeUHP

Contoured UnderOver

0.900.83

1.541.79

Series 80001/4 Turn Rotary

Butterfly Vane Through 0.66 [60o]0.53 [90o]

3.537.27

Series 9000 Turn Rotary

Standard BallV Ball

Reduced BoreV - Flow

Through 0.500.75

9.092.50

Note: * Indicates two stages of multi-labyrinth trim.

Flow of Non Vapourising Liquids.The flow rate of a liquid through a controlvalve can be treated as incompressible andtherefore a function of the differentialpressure p ie ( P1 P2 ) providing theliquid does not vapourise between the inletand outlet of the valve.If a vapour is formed either transitionallythrough the onset of cavitation or constantwith the introduction of flashing, then thisrelationship to differential pressure willprobably change. Different flow regimesdepend on the level of vapourisation and areused to describe the fluid behaviour.

Normal Flow.Normal flow describes the case when thefluid is assumed to be incompressible (novapour formation). Under this condition thevolume flow rate is proportional to thesquare root of the pressure drop across thevalve, shown in Figure 9.

Transitional Flow Regime. (Semi-criticalFlow)When the static pressure at the venacontracta just falls below the fluid vapourpressure pressure bubbles form and the flowcannot be assumed incompressible. Thistransitional zone between non vapourisingand vapourising liquid (choked) flow,coincides with the onset of incipientcavitation.Cavitation which occurs in this transitionalzone can produce damage within the valve,and is to be avoided. Figure 9 illustrates thedifferent flow regimes referenced topressure drop versus flowrate through thevalve.

Flow of Vapourising Liquids (ChokedFlow).Choked flow is the limiting or maximum, flowrate reached when no further increase inupstream pressure changes the throughput,with constant downstream conditionsapplied. At this stage the pressure at thevena contracta has reached its minimum iesupercooled vapour pressure Pvc. Furtherpressure drop only increases cavitation orflashing levels. Figure 10 shows therelationship between the flow regimes.

Severn Glocon Sizing of Liquids.In common with most valve sizingtechniques Severn Glocon follow the ISAguidelines and omit the semi-critical flowregime. This assumes that the normal flowfollows the straight line shown on figure 9until it intersects with the critical flow line. Anerror of some 2% results from thisassumption, but the calculation procedure ismuch simplified. Figure 11 shows thevarious stages of flow with reference also

made to the onset of cavitation, and theconditions which result in mechanicaldamage of the trim.

Figure 9. Different Flow Regimes.

Figure 10. Relationship between FlowRegimes.

Figure 11. Different Stages of Flow andCavitation.

Liquid Flow Valve Sizing ProcedureThe following flow chart gives the sequence of steps used during the selection of a control valve.

Yes

No

Re-entry

No

No

No

No

No

No

No

Equations12 to 15

Calculate% flash

Select trimCv & valve size

Equations16 & 17

Calculate flowvelocities

Calculate soundpressure level

Is velocityacceptable?

Calculate powerconversion

Is power levelacceptable?

Is SPL OK?

End

Equation18

250m/s or0.3 Mn

SeeSGT 10/7

SeeSGT 10/7

SeeSGT 10/8

Re-enter atpoint 1

Start

Select TrimStyle

Sequence Re-entryPoint 1

Equation 2CalculateAp limit

Is P1-P2> P1-Pv

Flow isflashing

DetermineValve Cv

Calculatecavitationindex osa

See Table1

Confirm suitabilityof trim style

Equation 3

Equations4,5,6,7

Determine valveCv

Re ProductBulletins

Select Trim designCv & Valve size

SeeSGT 10/4

& equation 2

Using new FL atValve opening

recalculate Dp limit

See Table 1Check cavitation

index and confirmtrim selection

SeeSGT 10/5SGT 10/6

Recalculate Cvusing corrections

for pipework & fluidviscosity

Equations8,9,10,11

End

Is trim design Cvacceptable?

Is velocity acceptable?See Table 2

SeeSGT 10/7

SeeSGT 10/7

SeeSGT 10/8

Is energy levelacceptable?

Is SPL OK?

Calculate soundpressure level

Calculate powerconversion

Calculate flowvelocities

2

2

2

Re-enter at point 1

Re-enter at point 1

Valve Flow Coefficient Cv Liquids.The valve flow coefficient Cv is used todetermine the valve and trim size required tosatisfy a particular flow rate at a specifiedpressure drop. Once this Cv value is knownthen a suitable valve trim combination canbe selected with a design Cv that meetsthese capacity requirements. The selectedvalve design Cv will fix the minimumrequirements for valve size, however,pipeline size and inlet/outlet flow velocitiesmust also be considered.Valve rangeability must not be exceeded,therefore sizing should be carried out atmaximum, normal and minimum flowratesand pressures.

Sizing Procedure Turbulent Flow

(a) Calculate the value of Pvc

where :- Pvc = Pv FFand FF = Fluid critical pressure ratio factor

which is = [ 0.96 0.28 [ Pv/Pc ] 0.5 ] ------ (1)

(b) Determine the limiting pressure drop,

corresponding to commencement of criticalflow.

p limit=FL2 (P1-Pvc) = FL2 (P1-Pv FF) ----- (2)Generalised values of FL2 can bedetermined from Table 1 or if the valveopening is known then refer to SGT 10/4.

(c) Valve sizing pressure drop.If the pressure drop across the valve is lessthan or equal to the limiting pressure dropp limit then the flow is normal and the actualsizing pressure drop p sizing is taken as theactual value given.

If the value p sizing > p limit then p must betaken as the value determine for p limit. Thisaccounts for cavitating and flashing flows.

(d) Determination of Cavitation Index.Determine the cavitation index for thesystem application from the followingequation.

SA = ( P1 - Pv ) ---------------------------- (3)

( P1 P2 )Select a trim and valve style with a mr valuefrom table 1 smaller than or equal to the SAvalue calculated.

(e) Calculation of the flow coefficient Cv

Based on the information available selectone of the four equations (1) to (4). Usingthe p value determined above, and Fp=1 asthe piping geometry factor.Imperial Units

Cv = Q ( Gr / p) 0.5 ------------------------- (4) Fp

Cv = W ----------------- (5) 63.3 Fp ( 1 p) 0.5

Metric Units

Cv = Q ( Gr / p) 0.5 -------------------------- (6) 0.865 Fp

Cv = W ----------------- (7) 27.3 Fp ( 1 p) 0.5

(f) Select the trim design Cv andappropriate valve size.It is normal to operate at 50% - 70% valveopenings.Calculate the actual valve opening anddetermine the correct value for FL and mrfrom SGT 10/4.

(g) Re-calculate the new limiting pressuredrop.Using the new FL value determine the psizingvalue. Using this value, repeat the steps toconfirm the trim and valve selection.

(h) Re-calculate the final Cv.Taking into account any corrections for thepipework configuration Fp and fluid viscosity,by referring to sections SGT 10/5 & SGT10/6 of this manual. The value of Cv isdetermined.

(i) Calculate valve exit velocity.Based upon the information available selectone of the equations (5), (6), (7) or (8) anddetermine the valve inlet and outletvelocities, as detailed in liquid flow velocitysection. Should these levels be excessivewhen compared with the recommendedlimits given in Table 2, resulting in a changein valve size, then repeat step (g).

(j) Check on energy conversion at valveWith valves and trims which are to convertlarge amounts of energy, a check should becarried out to determine the suitability of thevalve and trim selected. Refer to sectionSGT 10/7 of this manual which details theformulae to be used in calculating theseenergy levels. The recommended pressuredrops, materials of construction and energyconversion levels for valves and trims is alsogiven.

Factors Influencing Velocity Limits.

In the selection of a valve to work on eitherliquids or gases, one of the majorconsiderations is the effect of flow velocitywithin the both the trim and the valve body.

The main factors which have to beconsidered for limiting the velocities withinthe valve are :-

1) reduction in pressure loss.

2) minimize erosion damage.

3) reduce vibration potential.

4) energy conversion.

5) secondary noise potential.

6) phase difference between trim andinlet turbulence.

Selection of the trim design can enablehigher body velocities to beaccommodated. A well guided cagetrim, is far less likely to suffer vibrationand instability problems due to flowimpingement, than a trim fitted with asmall stem guide.

Liquid Flow Velocity.

With liquids high fluid velocities can lead toerosion and vibration problems. Table 2gives mean velocity limits which should beapplied during valve selection. However, itshould be noted that local velocity levelswithin the valve, due to turbulence, will bemuch higher.

Procedure.

a) Calculate the mean flow velocity throughthe valve body, using the appropriateequation below.

Imperial

Velocity = 0.408 Q/d2 volume flow ------ (8)

Velocity = 8.2 x 10-4 w/Gr d2 weight flow -- (9)

Metric

Velocity = 354 Q/d2 volume flow ------ (10)

Velocity = 0.354 w/Gr d2 weight flow ----- (11)

b) Compare the calculated flow velocityvalue with the recommended limits of thevalve selected from the Table 2.

c) If outside the velocity limits given uselarger valve size as appropriate.

Table 2. Maximum Recommended Valve Body Velocities for Liquid Flows.

Valve Type Valve Size Trim Style Valve Body MaterialCarbon Steel Alloy Steel Br/Cu/Ni Alloy Plastic & Lined

ins mm ft/s m/s ft/s m/s ft/s m/s ft/s m/sSeries to 2 12 to 50 Contoured 41 12.5 46 14 25 7.6

2000 & 3000 3 to 6 80 to 150 34 10.4 36 10.9 21 6.41 to 12 25 to 300 Seat / Cage 35 10.6 38 11.5 22 6.7

Series 1 to 12 25 to 300 Seat / Cage 43 13.1 52 15.8 25 7.65000 & 9000 14 to 24 350 to 600 Guided 35 10.7 43 13.1 21 6.4

Series 1 to 6 25 to 150 All 28 8.5 30 9.1 20 6.1 10 3.16000 & 7000 8 to 16 200 to 400 Types 23 6.9 25 7.6 15 4.6 8 2.4

Series 4 to 12 100 to 300 All 28 8.5 30 9.1 20 6.1 10 3.18000 14 to 24 350 to 600 Types 23 6.9 25 7.6 15 4.6 8 2.4

>24 >600 23 6.9 25 7.6 15 4.6 8 2.4

For other sizes consult factory.

Flashing Flows.When the valve outlet pressure is lower thanor equal to the saturation pressure for thefluid temperature, part of the fluid flashesinto vapour. The valve Cv is determined asfor normal flow except that the sizingpressure drop used is that determined asthe limiting pressure drop p limit where FL isreplaced by FLP ( see SGT 10/5 )This modifies equations (1,2,3) and (4) toread :-

Cv = Q ( Gr / P1-FF PV ) 0.5 ----------------- (12)

FLP

Cv = W -------- (13) 63.3 FLP ( 1 ( P1 - FF PV )) 0.5

Metric Units

Cv = Q ( Gr / P1-FF PV ) 0.5 ----------------- (14)

0.865 FLP

Cv = W -------- (15) 27.3 FLP ( 1 ( P1 - FF PV )) 0.5

The following expression may be used tocalculate the velocity under flashingconditions, the relative velocity of eachphase is largely dependent upon the vapourcontent in the downstream flow. Thisrequires knowledge of the pressure dropsand fluid thermodynamic properties which isnot often available except in the case ofwater/stream. The amount of vapourformation is usually quantified by the % flashwhich is % vapour by weight to the totalmass flow rate, and is denoted by x.

i.e. x = W v ------------------------------- (16)

W tot

x may also be calculated by considering thechanges in enthalpy across the valve asfollows :-

x = ( hf1 hf2 ) ------------------------------ (17)

hfg2

Where:-x = fraction of liquid mass flashed to vapourh11 = Enthalpy of saturated fluid at inlet temp.h12 = Enthalpy of saturated fluid at outlet pressurehfg2 = Enthalpy of evaporation at outlet pressure

Flashing Liquid Velocity.

The velocity for flashing flow may becalculated from the following equation(15) :-

V = 0.040 w { { 1-x )Vf2 + x Vg2 } -----(18)

Awhere:-x =fraction of liquid mass flashed to vapourV =Velocity in Ft/secw =Liquid flow rate lb/hrA =Valve outlet flow area ins2V12 =Saturated liquid specific volume at outlet pressure in ft3 / lb.Vg2 =Saturated vapour specific volume at outlet pressure in ft3 / lb.

Flashing Flow ExampleA valve working on water at an inletpressure and temperature of 250psia and350o F is required to reduce the outletpressure to 90psia.Reference to the steam tables shows that at90psia the saturation temperature of water is320.28oF therefore flashing is taking place.From the steam tables the following valuescan be determined.

hf1 = 321.8 Bthu/lb at 350oFhf2 = 290.7 Bthu/lb at 90psiahfg2 = 894.6 Bthu/lb at 90psia

From equation (17) x = 321.8 290.7 = 0.034

894.6Therefore %flash = 0.034 x 100 = 3.4%

If the valve has a 3ins diameter outlet and aflowrate of 4 x 105 lbs /hr then the exitvelocity may be determined by usingequation (18).

Vf2 = 0.0177 ft3/lb at 90 psia.Vg2 = 4.895 ft3/lb at 90 psia.

V = 0.04x4x105 {(1-0.034)0.0177+0.034x4.89}

7.07

Valve Exit Velocity V = 415 ft/sec

Velocity limits for flashing service.Flashing velocities should not exceed250m/s or 0.3Mn. therefore this calculatedvelocity would be acceptable for typicalSeries 2000 and 5000 bodies. Hardenedtrims should be considered for this duty andoverlayed bodies are often requireddependent upon the line fluid.Where fluid data is not available it is oftenmore appropriate to check the inlet velocity,as a single phase fluid, and a line size valveis often specified by reference to thedownstream pipework dimensions.

Gas / Vapour Flow Valve Sizing ProcedureThe following flow chart gives the sequence of steps used during the selection of a control valve.

Yes

No

Re-entry

No

No

No

No

Start

Select TrimStyle

Sequence Re-entryPoint 1

Calculate Aplimit

IsX>=Fk Xt

Flow isflashing

Ap sizingis Ap limit

Calculateexpansionfactor Y

Equation20,21

Calculate specificweight optional

Equation19

Figure 12 Determinecompressibility Z

Equations22 to 29

Determinevalve Cv

Re ProductBulletins

Select trim designCv & valve size

SeeSGT 10/4

Using new Xt factorat valve opening

recalculate Ap limit

SeeSGT 10/5SGT 10/6

Recalculate Cvusing corrections

for pipework & fluidviscosity

SeeTable 4

End

Is trim design Cvacceptable?

Is velocity acceptable?See Table 5

SeeSGT 10/7

SeeSGT 10/7

SeeSGT 10/8

Is energy levelacceptable?

Is SPL OK?

Calculate soundpressure level

Calculate powerconversion

Calculate flowvelocities

2

2

2

Re-enter at point 1

Re-enter at point 1

Flow of Vapours and Gases.Two principal regimes apply to gas andvapour flows.These are normal and critical or (choked)flow.

Normal Flow.Throughout the normal flow regime anincrease in pressure drop across the valveproduces an increase in flow. At lowpressure ratios, upto a Mach No.0.3 the flowis almost proportional to the square root ofthe pressure drop, similar to the normalliquid flow regime.At higher pressure ratios the compressibilityeffects of the flowing fluid begin to take agreater effect.The relationship between increasing flowand pressure drop gradually diminishes,until further increase in pressure ratio P1/P2produce no further increase in flow. Normalflow has now ceased.

Critical or Choked Flow.Choking is considered to have occurredwhen with constant upstream conditions, atthe valve, reducing the downstreampressure further produces no change in flowrate.

Gas / Vapour Flow Sizing.The flow of liquid through a control valvemay be considered incompressible providedit does not produce vapours, due tocavitation or flashing.This type of flow does not produce anysignificant change in density at any point inthe flow path. Because of compressibility,gases and vapours expand as the pressuredrops, thereby increasing the specificvolume. To account for the change inspecific weight, an expansion factor, Y, isnow introduced into the valve sizing formula.

Calculation of Flow Coefficient CvGases

a) Determine the Limiting Pressure DropCalculate the specific heat factor Fk relativeto air from the following equation.

Fk =k/1.4 where k is gas specific heat ratio.

Calculate the ratio of actual pressure drop toabsolute inlet pressure x from

X = p / P1

Therefore plimit occurs when X = Fk XTWhere XT is the pressure drop ratio fromTable 3.

b) Valve sizing pressure drop.If the pressure drop across the valve is lessthan or equal to the limiting pressure dropplimit then the flow is normal and the actualsizing pressure drop psizing is taken as theactual value given.

If the value of psizing > plimit then p mustbe taken as the value determine for plimit.c) Calculation of Expansion Factor Y.The expansion factor Y can be calculatedfromY = 1 X ----------------------------------- (19)

3 Fk XT( Limits 1.0 >= Y >=0.67 )

d) Calculation of the Inlet Specific Weight 1.If the inlet specific weight is required for the usein the valve sizing equations then this may becalculated from the following expressions.

Imperial1 = MP -------------------------------- (20) 10.72 Z T1

Metric1 = ( M P1 x 105 ) -------------------------- (21) 8314 Z T1

e) Determine the Compressibility Factor ZTo obtain the compressibility factor Z, it isfirst necessary to calculate the reducedpressure Pr and the reduced temperature Trusing the following equations.

Pr = P1 / Pc and Tr = T1 / Tc

Where :- suffix r is the reduced value suffix 1 is the absolute upstream value suffix c is the absolute critical value

Using the values of Pr and Tr calculated findZ in Figure 12.

f) Calculate the Flow Coefficient CvDepending upon the process conditionsgiven, select one of the equations listedbelow, assuming Fp = 1.

Imperial units

Cv = w -------- (22) 63.3 Fp Y ( X P1 1 ) 0.5

Cv = q (Gg T1 Z / X)0.5 --------(23) 1360 Fp P1 Y

Cv = w (T1 Z / X M)0.5 ---------(24) 19.3 Fp P1 Y

Cv = q (M T1 Z / X)0.5 ---------(25) 7320 Fp P1 Y

Metric Units

Cv = w -------- (26) 27.3 Fp Y ( X P1 1 ) 0.5

Cv = q (Gg T1 Z / X)0.5 --------(27) 417 Fp P1 Y

Cv = w (T1 Z / X M)0.5 ---------(28) 94.8 Fp P1 Y

Cv = q (M T1 Z / X)0.5 ---------(29) 2250 Fp P1 Y(g) Select the trim design Cv andappropriate valve size.It is normal to operate at 50% - 70% valveopenings.Calculate the actual valve opening anddetermine the correct value for XT from SGT10/4.

(h) Re-calculate the new limiting pressuredrop.Determine the plimit value ( arising from anyrevision of XT ). Using this value, repeat thecalculation steps to confirm the trim andvalve sizing.

(i) Re-calculate the final Cv.Taking into account any corrections for thepipework configuration Fp and fluid viscosity,by referring to sections SGT 10/5 & SGT10/6 of this manual. The value of Cv isdetermined.

(j) Calculate valve exit velocity.Based upon the information available selectone of the equations from Table 4 anddetermine the valve inlet and outletvelocities, as detailed in Gas flow velocitysection. Should these levels be excessivewhen compared with the recommendedlimits given in Table 5, resulting in a changein valve size, then repeat step (i).

(k) Check on energy conversion at valve.With valves and trims which are to convertlarge amounts of energy, a check should becarried out to determine the suitability of thevalve and trim selected. Refer to sectionSGT 10/7 of this manual which details theformulae to be used in calculating theseenergy levels. The recommended pressuredrops, materials of construction and energyconversion levels for valves and trims is alsogiven.

Figure 12. Compressibility Factors for Gases.

Table 3. Compressible Flow Pressure Drop Ratios, XT

Valve Series Valve Type Trim Style Flow Direction Ration XTSeries 2000 Split

BodyGlobe & Corner

Series 2410Trickle Under

Over0.850.78

Contoured UnderOver

0.730.66

Cage Plug UnderOver

0.910.91

3 WaySeries 2420

Contoured Mixing &Diverting

0.66

AngleSeries 2430

Trickle UnderOver

0.850.78

Contoured UnderOver

0.710.66

Cage Plug UnderOver

0.910.91

Series 3000 &4000 Cryogenic

GlobeSeries 3410

Contoured UnderOver

0.730.66

Cage Under or Over 0.91Series 5000

Multi-PurposeGlobe Series

5410Trickle Under

Over0.850.78

Contoured UnderOver

0.750.7

Ported Under or Over 0.79Single Cage Under or Over 0.88Double Cage Under or Over 0.90Triple Cage Under or Over 0.92Quad Cage Under or Over 0.94

Multi-labyrinth Under or Over 0.98*3 Way Series

5420Contoured Mixing &

Diverting0.7

Angle Series5430

Trickle UnderOver

0.850.78

Contoured UnderOver

0.750.67

Ported Under or Over 0.79Single Cage Under or Over 0.86Double Cage Under or Over 0.89Triple Cage Under or Over 0.91Quad Cage Under or Over 0.93

Multi-labyrinth Under or Over 0.98*Series 6000Corrosive

Globe PTFELined

Contoured UnderOver

0.750.7

Y Pattern Contoured UnderOver

0.680.66

Series 7000 UltraHigh Purity

Globe UHP Contoured UnderOver

0.750.7

Series 8000 Turn Rotary

Butterfly Through Vane 60o90o

0.360.26

Series 9000 Turn Rotary

Standard BallV - Ball

Reduced BoreV - Flow

Through 0.150.12

Note : * Indicates two stages of Multi-Labyrinth Trim.

Gas Flow Velocity.It is Important that checks are made uponboth the inlet and velocities during sizing ofa control valve. Much attention is often givento the elimination of excessive outletvelocities which would result in the creationof shock waves, and consequent vibration ofthe valve plug, as sonic velocityapproached. This secondary source of noisegeneration and instability should not beunderestimated and within Table 5 is therecommended maximum Mach Numberswhich should not be exceeded if specifiednoise levels are to be achieved. However,high inlet velocities also may result inexcessive dynamic forces acting on exposedplugs and stems causing vibration and earlymechanical failure.

Procedure.a) Depending upon the processconditions given select one of theequations from Table 4. Calculate boththe inlet and outlet velocities for the sizeof valve selected.

b) Compare the calculated flow velocitywith the recommended limits in Table 5.

c) If the velocities are outside these limitsgiven then a solution could be one of thefollowing:-Fit fixed area baffle within the outlet of valvebody, to reduce gas specific volume andhence velocity.

Increase size of valve body.

Use limited discretion as there is no exactline between a correct and problem solution.

d) Calculation of valve outlet Mach No.The sonic velocity can be calculated fromthe expressions given for a given in Table4.

Mach No. = v/aWhere:- v is valve body velocity. and a is the sonic velocity.

(e) Recalculation of Cv if Body Size ChangeRecalculate Cv if body size has increased(due to eliminating excessive outlet velocity)thereby altering the Piping factor Fp.

(f) Select Appropriate TrimIdentify suitable trim from ranges available inorder to satisfy final calculated Cv and flowcharacteristics required.

Table 4. Gas / Vapour Velocity Equations and Units of Measurement.Formulae for mean

velocityStreamVelocity

v

InternalvalveDia. d

AbsolutePressure P

VolumeFlowrate

Q

Molecularweight

M

SpecificHt Ratio

K

AbsoluteTemp.

T

MassflowW

Specificvolume

u

v=0.051 u W D2

ft/sec inches lb/ hr ft3 /lb

v=354 u W d2

m/sec mm kg/ hr m3 kg

v=1.52*1033 QT d2P

ft/sec inches lbf/ in2a nft3/ hr o r

v=1.31 QT d2P

m/sec mm bar a nm3/ hr o k

v=0.547 W T d2PM

ft/sec inches lbf/ in2a lb/ lb mol o r lb/ hr

v=29.5 W T d2PM

m/sec mm bar a kg/ kg mol o k kg/ hr

a=68.1 (Kpu)0.5 ft/sec lbf/ in2a non-dim ft3/ lb

a=316.4 (Kpu)0.5 m/sec bar a non-dim m3/ kg

a=223 (KT/M)0.5 ft/sec lb/ lb mol non-dim o r

a=91.3 (KT/G)0.5 m/sec kg/ kg mol non-dim o k

Note : v is the mean velocity through the valve and a is the sonic velocity.Specific volume u is 1/1 the specific weight.

Table 4. Maximum Recommended Valve Body Velocities for Gas/Vapour Flows.Valve Type Valve Size Trim Style Maximum

Inlet VelocityMaximum

Outlet VelocityMaximum outlet Mach No.for predicted noise level.

Ins mm ft/s m/s ft/s m/s >95 dba 600 80 24 350 107 0.65 0.5 0.3

For other sizes consult factory.

Calculation for Cv for MixedPhaseFluids.This method of Cv calculation for two phaseflow assumes that the gas and liquid passthrough the controlling orifice within thevalve at the same velocity, and that thepressure within the valve is high enough toprevent cavitation or flashing of the liquidthereby creating a choked flow situation.The required Cv is determined by using anequivalent density for the liquid / gasmixture.

Liquid / Gas SizingThis method is intended for use withmixtures of a liquid and a non-condensablegas.When a liquid / gas mixture passes througha valve, the liquids density remains constantwhile the gas expands and reduces itsdensity. The formula below calculates amean density for inclusion in a simple Cvcalculation.

Imperial Units

Cv = W ------------(30)44.8 (p( 1 + vc) ) 0.5

where:-W = Total flowrate lb/hr1 = Upstream density lb/ft3vc = Vena contracta density lb/ft3p = Pressure drop lb/in2

Metric Units

Cv = W ------------(31)19.3 (p( 1 + vc) ) 0.5

where:-

W = Total flowrate kg/hr1 = Upstream density kg/m3vc = Vena contracta density kg/m3p = Pressure drop bar

The densities are given by :-

Upstream = 1 = Cv = 1 -----(32) XG1 VG1 + (1-XG1) VL

Vena = vc= 1 ----------------(33) XG1 VGVC + (1-XG1) VL

Where:-XG1 = fraction by weight of gas in the flowVG1 = specific vol. of gas at inlet ft3/lb (m3/kg)VL = specific vol. of liquid at inlet ft3/lb (m3/kg)VGVC= specific vol. of gas at vena contracta ft3/lb (m3/kg)

While the specific volume of gas at the venacontracta is given by:-

VGVC = VG1 ----------------- (34) 1 ( p / P1 FL2 )

P1 =inlet pressure lb/in2 abs (bara)FL =liquid pressure recovery factor see Table 1 also SGT 10/4.

Liquid / Vapour Sizing.

There is no reliable data for accurate sizingof mixture in their own vapour as difficultiesarise due to the transfer of energy and massbetween the liquid and vapour phases.However, the formulae used for theliquid/gas calculations may be adapted toproduce an acceptable estimation by basingthe vena contracta density on the fraction byweight of vapour downstream of the valve.The example below illustrates this method.

Two Phase Sizing Example.A valve working on hydrocarbon liquid issubjected to two phase flashing under thefollowing conditions of operation. Calculatethe valve Cv.

Flow rate liquid = 1125 usgpmFlow rate vapour XG1 = 4.5% by weight at

InletFlow rate vapour XG2 = 15.8% by weight at Outlet

P1 = 391 lb/in2 absP2 = 205 lb/in2 absP = 186 lb/in2k = 1.16Cp = 0.4 BthU/lb oRPv = 391 lb/in2S.G. = 0.5 (liquid)T = 565oR

Pipe size = 8ins Schedule 40S.G. = 1.0 (vapour)Pc = 592 lb/in2FL = 0.95

(a) Calculate total weight of flow at valveinlet.

Liquid phase flow = 1125 x 60 x 10 x 0.5 =

1.201

281,250 lb/hr

vapour phase flow = 294,503 lb/hr

(b) Liquid critical pressure ration FF

FF = 0.96 0.28 (391/592)0.5 = 0.732

(c) P allowable = FL2 (P1 FF x Pv)= 0.902 (391 0.732 x 391)= 94.5 lb/in2

(d) Calculate the upstream density 1 usingequation (32)

Upstream = 1 = 1XG1 VG1 + (1 XG1) VL

XG1 is given and equals 0.045

VG1 can be derived from gas equation PV =WRT as follows:-

VG1 = V/W = R T / P and R = Ro / M

Where:-Ro is the universal gas constant = 1545 ftlb/lbmoloRM = Molecular weight

VG1 = Ro T1 = 1545 x 565 =0.535 ft3/lb 144 MP1 144 x 29 x 391

VL = 1 = 1 =0.032 ft3/lb 62.4xS.G. 62.4x0.5

1 = 1 =18.3 lb/ft3 0.045x0.535 + (1-0.045) x 0.032

(e) Calculate vena contracta density vc fromequation (33) modified to utilize XG2 thefraction by weight of vapour downstream ofthe valve.

Vena = vc = 1 XG2 VGVC + (1 XG2) VL

XG2 is given and equals 0.158

VGVC vena contracta specific volume VGVCcan derived from equation (34)

VGVC = VG1

1 ( p / P1 FL2 )

VGVC = 0.535 = 0.731

1 ( 94.5/391.0.902 )

vc = 1 = 7.02 lb/ft3 0.158.0.731+(1-0.158) 0.032

(f) From equation (30) Cv can be calculatedas follows:-Cv = w 44.8 (p (1 + vc) ) 0.5

Cv = 294503 = 134.5 44.8 (94.5 ( 18.303 + 7.02 ) )0.5

Multi-Phase Velocity Calculation.Using this example the Multi-Phasevelocities can be calculated using thefollowing procedure.

1) As the flash fraction (x) is given, then theliquid and vapour phase velocities can becalculated. A measure of the different phasevelocities is given by the slip ratio (s). This isthe ratio between the vapour phase andliquid phase velocities. From this equation itis evident that as the flash fraction increasesso does the slip ratio, and hence the vapourflow velocity.

s = ( x L / v + 1 x )0.5where:- L is the liquid density and v thedownstream vapour density.

s = (0.158.31.25/7.020+1-0.158)0.5= 1.243

2) Calculate the downstream vapour Qv2 andliquid phase volume QL flowrates by dividingby the appropriate density.

Qv2 = Wv / v and QL = WL / LQv2 = 0.158. 294503 / 7.020 = 6,628ft3/hr

QL = 0.842. 294503 / 31.25 = 7,935 ft3/hr

3) Calculate the downstream vapour volumeratio XvXv = Qv2 = 6,628 = 0.455 Qv2 + QL 6,628 + 7935

4) Determine the void fraction (Vf) andphase flow areas AL and Av

Vf = Xv = 0.455

(Xv +(1-Xv)s) (0.455+(1-0.455)1.243)

Vf = 0.401

Liquid phase flow area AL =(1 - Vf) x totalflow area

Vapour phase flow area AV = Vf x total flowarea

Assuming a Series 5000 size 4ins valve isselected in order to accommodate trim witha design Cv 120 (calculated Cv 95.1). Thisvalve would have a total outlet flow area of0.087 ft2

5) Determine the liquid phase flow velocityVLVL = QL = 7935

AL 3600 0.599 x 0.087 x 3600

VL = 42.29 ft/sec

6) Determine the vapour phase velocity VvVv = Qv = 6628

Av 3600 0.401 x 0.087 x 3600

Vv = 52.77 ft/sec

Both these calculated velocities would bewithin the limits given in Tables 2 and 5 forSeries 5000 cage guided trims.

Notes

Severn GloconTechnical ManualFlow Characteristics

Contents.Quick-Opening Flow-Lift Characteristics.Linear Flow Lift Characteristics.Equal Percentage Flow LiftCharacteristics.Modified Equal Percentage or ParabolicFlow Lift Characteristics.

Introduction.The valves flow characteristic is therelationship of valve capacity to valve travel.The shape and movement of the valve plugsurface development, relative to the staticseat ring, determines the flow / liftcharacteristic. Normally valve plugs aredesigned for set positional control, i.e.on/off, or for throttling duty where the valveplug may be positioned at any point withinthe working range dictated by the processrequirements.The inherent characteristic can be designedinto the valve trim so that the valve gain willvary in a prescribed way with the valvecapacity thereby theoretically controllingloop gain at all ladings and set points.However, this characterization at the valve isoften modified by the flow loop with its ownin built resistance and characteristics. Inaddition actuator non-linearity and varyingtime constant can adversely affect thesmooth characterization, produced withinthe mechanical limitations of the flowcontrolling trim profiles.Clearly, the same valve working oncompressible fluid if switched to anincompressible one will exhibit a differentflow characteristic.Also when a valve chokes due to sonicvelocity in the case of a gas or withcavitation or flashing when flowing a liquid,the flow-lift characteristic at that point isaffected. Therefore care needs to beexercised in relying on the flow liftcharacterization to give full control of thevalve gain characteristics over a wideoperating range.There are four main inherent flow-liftcharacteristics for control valves, they arequick opening, linear, equal percentage,modified equal percentage pr parabolic.These curves are shown in figure 1.

Technical Manual Section SGT 10/3

Figure 1. Control Valve FlowCharacteristic Curves.

SEVERNGLOCON

Quick Opening Characteristic.This trim profile provides the maximumchange in flowrate at low valve travels,within a fairly linear relationship. Thiscontrasts with the higher levels of valvetravel, where the change in flowrate nearszero.

Application.In a control valve the quick openingcharacteristic is used primarily for on-offservice, where the flow must be establishedquickly as the valve begins to open. Atypical application would be as a relief valve.

Design.The valve plug may be shaped to providesome smoothing of the flow with valveopening. In essence when the lift on the plugequals some 25% of the seat boredimension the two areas are equal. Inconsequence the any flow increase, forfurther valve lift will decrease sharply.

Linear Flow Characteristic.The linear flow characteristic curve showsthat the flow rate is directly proportional tovalve travel. This proportional relationshipproduces a characteristic with a constantslope, so that with constant pressure drop,the valve gain is the same at all flows.

Application.The linear characteristic valve is commonlyspecified for liquid level control and for someflow control applications where constantgain is required.

Design.With equal increments in valve travelresulting in equal increments of flow thefollowing simple equation may be used toexpress the linear flow characteristic.

Q = KxWhere:-

Q = Flow Rate.K = Constant depending upon units.x = Valve travel.

Equal Percentage Characteristics.The equal percentage flow characteristicproduces flow changes which are equalpercentages of the existing flow, for equalincrements of valve travel. The change inflowrate is always proportional to the flowrate that exists just before the change invalve position is made, this means a givenchange in valve travel always produces thesame equal percentage change in existingflow.

Figure 2. Construction of a Quick OpenFlow Characteristic Plug.

Application.Control valves with an equal percentageflow characteristic are probably the mostfrequently specified, for pressure control asit is considered their particular gaincharacteristics are the most tolerant and arelikely to provide stable control at low lifts.They are suitable for other applicationswhere a large percentage of the pressuredrop is normally absorbed by the systemitself, with only a relatively small percentageavailable at the control valve.Equal percentage characteristics shouldalso be considered where a high variation inthe pressure drops could occur.

Design.The formula, which describes the equalpercentage flow characteristic, is:-

Q = Qo emx

Where:-Q = FlowrateQo = Minimum controllable flow.x = Valve positionm = In R/T = constant for a particular valve.R = Valve rangeablity = Qm / QoIn = Natural LogarithmT = Maximum valve travel.Qm = Maximum flow rate.

These parameters can be combined toproduce several common variations of equalpercentage flow equation, which are ofexponential nature:-

Q = Qo e(x/t)InR

Q = QoR(x/t)

Q = QmR{(x/t)-1}

Figure 3 Profile of CharacterisedContoured Plug

Modified Equal Percentage or ParabolicCharacteristics.The modified equal percentage or parabolicflow characteristic curve falls between thelinear and equal percentage characteristics.

Application.For economic reasons this flowcharacteristic is most commonly used onsmall capacity trims where the physical sizecan make machining of the full equalpercentage characteristic impractical.Therefore the applications are mainly onpressure control, or where highly varyingpressure drop conditions can be expected.

Design.The exposed flow area of the valve trimparts varies as a parabolic function of thevalve travel. Assuming that the flow isproportional to the flow area the flowequation can be expressed as:-

Q = Kx2

Where:-Q = Flow rate.K = Constant depending upon units.x = Valve travel.

The slope of this flow curve maintains thesame constant proportionality to the valvetravel at every flow condition.

Flow Characterisation of Cage GuidedValves.

In conventional contoured plug valve, as theplug is moved through its travel range by theactuator, the throttling flow area changes asdictated by the contoured shape on the plug.

However, in valves fitted with cage guidedtrims the plug is a symmetrical cylinder andthe flow characterization is determined bythe shape or sequencing of the flowopenings in the wall of the surroundingcage.As the plug is moved away from the seatring, the apertures in the guide areuncovered to permit flow. Standard cagesare produced with flow ports and theseported trims with discrete large aperturescan be characterized accurately to produceany of the four main flow rate / travelrelationships.Cage designs for low noise or anti cavitationapplications utilize high numbers of flowholes or apertures in order to break downthe main flow within the trim into multi-streams, to instigate low pressure recoveryand velocity control flow regimes. The shapeand positioning of these flow aperturesclearly has a direct influence on thecharacteristic produced, which in certaincases may well be compromised by otheraspects of the design requirements.Main control of the characterization isattributable to the plug uncovering the flowapertures in the primary cage guide. Inmulti-cage trims the characterization can befurther changed by the influence of theattached outer cages.This is due to the series resistance to flow,with the primary cage guide being the onlycontroller or variable restrictor. Therefore asthe flow increases the resistance of theouter cages rises, with a direct effect on theflow rate / travel relationship.The flow / lift curve from the multi-hole cagetrim is generally characterized by having anumber of steps rather than the smoothshape given by the contoured plug.

Figure 4 Characterised Cage Trims.

Flow Characterisation of Disc or PlateStack Trims.This type of trim is normally specified for thehigher duty applications, as multi-stagepressure let down can be readily built intothe design.The long and thin aspect of the rectangularshaped flow apertures in the discs, togetherwith the large number of plates making updisc stack reduce the problems ofcharacterization highlighted for the multi-sleeve cage designs which normally usedrilled holes to control the flow rates.

Inherent and Installed FlowCharacterisation.The objective of valve flow characterizationis to vary the gain of the valve tocompensate for changes in process gainwith changing load. The gain or sensitivity ofa valve is measured by how its flow outputvaries in relation to changes in input signalor valve travel. A high gain valve is one inwhich high changes in flow result from smallchanges in valve travel.Contouring the valve plug or characterisingtrim cages will provide a predeterminedinherent relationship by changing theexposed flow areas with valve travel. Clearlyvariations in flow can also result fromchanges in pressure drop, with no change invalve travel. In practice where the controlvalve is installed within a process systemthe pressure drop is seldom constant, due todynamic pressure losses, and the flow /travel that results is called the installedcharacteristic. This contrasts with the flow /travel relationship when constant pressuredrop is applied which is the inherentcharacteristic.An assessment of the effects on the valvecontrollability and control accuracy providedby the installed flow characteristic curvecould be made using a valve gain curve.This gain curve for the installed valvedescribes the changes that take place inrelative flow rate (Q) divided by the changein relative travel (x).

i.e. Gain = dQ / dx

It follows that by taking into account therelative control signal and the relationshipbetween relative inherent flow characteristicand installed valve gain, the optimum flowcharacteristic for a process can bedetermined.

Figure 5. Section of Typical Stacked Disctrim.

Severn GloconTechnical ManualPressure Recovery Factors

Contents.

Valve Lift v Pressure Recovery Charts.Nomenclature.Pressure Recovery Formulae.Pressure Recovery Tables and Charts.

Introduction.As the flow passes from the control valveinlet towards the trim entry, the staticpressure reduces due to frictional andturning losses. Fluid approaching the trimhas to accelerate in order to pass throughthe area contraction presented by the trimentry geometry. This acceleration continuesuntil a point just downstream from the trimoutlet where the maximum stream velocity isreached, this is recognized as the venacontracta.Down stream of the vena contracta the flowarea expands, resulting in a reduction in flowstream velocity and consequent rise in staticpressure. The amount of pressure recoveryis a function of the control valve and trimdesign and is quantified as the valvepressure recovery factor FL.This factor is used within the control valveliquid sizing formulae, and the relationship ofthe actual p to the pvc is an importantfactor in determining the point at whichcavitation of flashing would start.Severn Glocon use a single parameter mrto indicate the operating limit, or cavitationindex, of each particular product. Thismanufacturers recommended single value isapplicable at the full open position for sizingpurposes, and is a product of the pressurerecovery factor FL and a valve / trim modifierratio Kic which has been determined fromtest data.In common with FL the pressure recovery,the value of mr changes with the valveopening.In gas sizing the limiting pressure dropplimit for different types of valve and trimcombinations, before choked flow isreached, is determined from the pressuredrop ratio XT.This ratio is multiplied by the specific heatratio FK (Air = 1) to account for differentflowing gases. The valve and trim pressurerecovery factors for the Severn Gloconproduct range are given in the followingtables and charts.

Figure 1. Typical Flow Path through aControl Valve.

Figure 2. Pressure Variations within aControl Valve.

SEVERNGLOCON

Nomenclature used within this publication.

Unit Definition Imperial MetricFd Valve Style Modifier ------------ ----------FF Critical Pressure Ratio ------------ ----------Fk Ratio of Specific Heat Factor = K/1.4 ------------ ----------FL Pressure Recovery Factor ------------ ----------Kie Incipient Cavitation Coefficient ------------ ----------P1 Upstream Pressure lbf/in2 A bar AP2 Downstream Pressure lbf/in2 A bar APv Vapour Pressure at inlet conditions lbf/in2 A bar APc Thermodynamic Critical Pressure lbf/in2 A bar Ap Pressure Drop Across Valve lbf/in2 barPvc Apparent Pressure at vena contracta lbf/in2 A bar AX Pressure Drop Ratio p / P1 ------------ ----------XT Pressure Drop Ratio Factor ------------ ----------Y Expansion Factor (Gas / Liquid Ratio) ------------ ----------Z Compressibility Factor ------------ ---------- Cavitation Index ------------ ---------- mr Manufacturers Recommended Valve style cavitation index. ------------ ----------

Associated Formulae using Valve TrimRecovery Factors.Liquids.(a) The amount of pressure recovery is afunction of the control valve trim design andis quantified as the valve pressure recoveryfactor FL.

Where:- FL2 = P1 P2 / P1 Pvcand Pvc = Pv FFwhere:- FF = Fluid critical pressure ratiofactor which is [0.96 0.28[Pv/Pc]0.5]

(b) The Cavitation index values mr , whichSevern Glocon recommended and use, area product of the valve pressure recoveryfactor FL2 and an incipient cavitationcoefficient Kie determined from the testingprogrammes carried out on the differentvalve/trim styles.

mr = (P1 Pv) = 1 (P1 P2) FL2 Kie

This single index allows the engineerselecting the valve / trim, to quickly assessthe suitability of a product. If the value of mrcalculated for the application is below that ofthe product selected then cavitationproblems may well occur.

(c) Determination of the limiting pressuredrop, for a valve trim combination is carriedout by calculating the p limit using thefollowing equation. This corresponds to thecommencement of critical flow, and ismaximum valve used in the calculation ofValve Cv.p limit = FL2 (P1 Pvc) = FL2 (P1-Pv FF)

Gasesa) Determination of the Limiting PressureDrop in a gas valve applications is carriedout in the following manner:-

Calculate the specific heat factor Fk relativeto air from the following equation.

Fk = k/1.4 where k is gas specific heat ratio.

Calculate the ratio of actual pressure drop toabsolute inlet pressure X from

X = p/P1Therefore p limit occurs when X = Fk XTWhere XT is the pressure drop ratio, for theselected Valve/Trim combination, taken fromthe appropriate Table shown within thisManual.

b) Determination of Valve sizing pressuredrop. If the pressure drop across the valve isless than or equal to the limiting pressuredrop p limit then the flow is normal and theactual sizing pressure drop p sizing is takenas the actual value given.

If the value of p sizing > p limit then p mustbe taken as the value determine fro p limit.c) The gas expansion factor Y, used in thedetermination of valve Cv, can be calculatedfrom:-

Y = 1 X

3Fk XT

Pressure Recovery Ratios for Series 2000 Split Body Valves

Valve Ratio % Travel Trickle Flowed - OverSeries 2410 % 10 20 30 40 50 60 70 80 90 100Globe / Corner FL

FL2Kie mrXT

0.940.880.921.230.88

0.940.880.921.230.85

0.940.880.921.230.81

0.930.860.921.260.79

0.930.860.921.260.78

0.930.860.921.260.78

0.930.860.921.260.78

0.930.860.921.260.78

0.930.860.921.260.78

0.930.860.921.260.78

Valve Ratio % Travel Trickle Flowed - UnderSeries 2410 % 10 20 30 40 50 60 70 80 90 100Globe / Corner FL

FL2Kie mrXT

0.940.880.921.230.89

0.940.880.921.230.89

0.940.880.921.230.87

0.930.860.921.260.87

0.930.860.921.260.87

0.930.860.921.260.85

0.930.860.921.260.85

0.930.860.921.260.85

0.930.860.921.260.85

0.930.860.921.260.85

Valve Ratio % Travel Contoured Flowed - OverSeries 2410 % 10 20 30 40 50 60 70 80 90 100Globe / Corner FL

FL2Kie mrXT

0.680.460.812.670.47

0.720.520.812.380.49

0.760.580.812.140.53

0.790.620.811.980.57

0.790.620.811.980.57

0.800.640.811.930.66

0.800.640.811.930.66

0.800.640.811.930.66

0.800.640.811.930.66

0.800.640.811.930.66

Valve Ratio % Travel Contoured Flowed - UnderSeries 2410 % 10 20 30 40 50 60 70 80 90 100Globe / Corner FL

FL2Kie mrXT

0.950.900.801.390.82

0.930.860.801.450.79

0.920.850.801.480.78

0.910.830.801.510.75

0.890.790.801.580.75

0.890.790.801.590.73

0.880.770.801.610.73

0.860.760.801.650.73

0.860.740.801.690.73

0.850.720.801.730.73

Valve Ratio % Travel Seat Cage Flowed Under or OverSeries 2410 % 10 20 30 40 50 60 70 80 90 100

Globe / Corner FLFL2Kie mrXT

0.970.940.801.330.96

0.960.920.801.360.95

0.950.900.801.390.94

0.940.880.801.410.94

0.930.860.801.450.93

0.920.850.801.480.93

0.910.830.801.540.92

0.900.810.801.540.92

0.900.810.801.540.92

0.890.790.801.580.91

Valve Ratio % Travel Contoured 3 WaySeries % 10 20 30 40 50 60 70 80 90 10024203-wayMixing

andDiverting

FLFL2Kie mrXT

0.680.460.812.670.47

0.720.520.812.380.49

0.760.580.812.140.53

0.790.620.811.980.57

0.790.620.811.980.57

0.800.640.811.930.66

0.800.640.811.930.66

0.800.640.811.930.66

0.800.640.811.930.66

0.800.640.811.930.66

Pressure Recovery Ratios for Series 2000 Split Body Valves

Valve Ratio % Travel Trickle Flowed - OverSeries 2430 % 10 20 30 40 50 60 70 80 90 100

Angle FLFL2Kie mrXT

0.940.880.921.230.88

0.940.880.921.230.85

0.940.880.921.230.81

0.930.860.921.260.79

0.930.860.921.260.78

0.930.860.921.260.78

0.930.860.921.260.78

0.930.860.921.260.78

0.930.860.921.260.78

0.930.860.921.260.78

Valve Ratio % Travel Trickle Flowed - UnderSeries 2430 % 10 20 30 40 50 60 70 80 90 100

Angle FLFL2Kie mrXT

0.940.880.921.230.89

0.940.880.921.230.89

0.940.880.921.230.87

0.930.860.921.260.87

0.930.860.921.260.87

0.930.860.921.260.85

0.930.860.921.260.85

0.930.860.921.260.85

0.930.860.921.260.85

0.930.860.921.260.85

Valve Ratio % Travel Contoured Flowed - OverSeries 2430 % 10 20 30 40 50 60 70 80 90 100

Angle FLFL2Kie mrXT

0.870.760.841.570.78

0.820.670.841.770.72

0.790.620.841.910.68

0.780.610.841.960.66

0.750.560.842.120.66

0.720.520.842.300.66

0.710.500.842.360.66

0.710.500.842.360.66

0.710.500.842.360.66

0.710.500.842.360.66

Valve Ratio % Travel Contoured Flowed - UnderSeries 2430 % 10 20 30 40 50 60 70 80 90 100

Angle FLFL2Kie mrXT

0.960.920.801.360.82

0.950.900.801.390.77

0.940.880.801.410.75

0.930.860.801.450.73

0.920.850.801.480.71

0.910.830.801.510.71

0.900.810.801.540.71

0.890.790.801.580.71

0.890.790.801.580.71

0.890.790.801.580.71

Valve Ratio % Travel Seat Cage Flowed Under or OverSeries 2430 % 10 20 30 40 50 60 70 80 90 100

Angle FLFL2Kie mrXT

0.970.940.901.180.93

0.960.920.901.210.93

0.950.900.901.230.93

0.940.880.901.260.93

0.930.860.901.280.93

0.920.850.901.310.92

0.910.830.901.340.91

0.910.830.901.340.91

0.910.830.901.340.91

0.910.830.901.340.91

Pressure Recovery Ratios for Series 3000 & 4000 Cryogenic Valves

Valve Ratio % Travel Contoured Flowed - OverSeries 3410 % 10 20 30 40 50 60 70 80 90 100

Globe FLFL2Kie mrXT

0.680.460.812.670.47

0.720.520.812.380.49

0.760.580.812.140.53

0.790.620.811.980.57

0.790.620.811.980.57

0.800.640.811.930.66

0.800.640.811.930.66

0.800.640.811.930.66

0.800.640.811.930.66

0.800.640.811.930.66

Valve Ratio % Travel Contoured Flowed - UnderSeries 3410 % 10 20 30 40 50 60 70 80 90 100

Globe FLFL2Kie mrXT

0.950.900.801.390.82

0.930.860.801.450.79

0.920.850.801.480.78

0.910.830.801.510.75

0.890.790.801.580.75

0.890.790.801.580.73

0.880.770.801.610.73

0.870.760.801.650.73

0.860.740.801.690.73

0.850.720.801.730.73

Valve Ratio % Travel Cage Flowed Under or OverSeries 3410 % 10 20 30 40 50 60 70 80 90 100

Globe FLFL2Kie mrXT

0.970.940.801.330.96

0.960.920.801.360.95

0.950.900.801.390.94

0.940.880.801.410.94

0.930.860.801.450.93

0.920.850.801.480.93

0.910.830.801.510.92

0.900.810.801.540.92

0.900.810.801.540.92

0.890.790.801.580.91

Pressure Recovery Ratios for Series 5000 Multi-Purpose Valves

Valve Ratio % Travel Trickle Flowed - OverSeries 5410 % 10 20 30 40 50 60 70 80 90 100

Globe FLFL2Kie mrXT

0.940.880.921.230.85

0.940.880.921.230.83

0.940.880.921.230.81

0.930.860.921.260.79

0.930.860.921.260.79

0.930.860.921.260.78

0.930.860.921.260.78

0.930.860.921.260.78

0.930.860.921.260.78

0.930.860.921.260.78

Valve Ratio % Travel Trickle Flowed - UnderSeries 5410 % 10 20 30 40 50 60 70 80 90 100

Globe FLFL2Kie mrXT

0.940.880.921.230.91

0.940.880.921.230.90

0.940.880.921.230.89

0.930.860.921.260.88

0.930.860.921.260.88

0.930.860.921.260.86

0.930.860.921.260.86

0.930.860.921.260.85

0.930.860.921.260.85

0.930.860.921.260.85

Valve Ratio % Travel Contoured Flowed - OverSeries 5410 % 10 20 30 40 50 60 70 80 90 100

Globe FLFL2Kie mrXT

0.530.280.814.400.62

0.550.300.814.080.65

0.680.460.812.670.65

0.850.720.811.710.67

0.870.760.811.630.67

0.870.760.811.630.70

0.860.740.811.670.70

0.850.720.811.710.70

0.850.720.811.710.70

0.850.720.811.710.70

Valve Ratio % Travel Contoured Flowed - UnderSeries 5410 % 10 20 30 40 50 60 70 80 90 100

Globe FLFL2Kie mrXT

0.960.920.801.360.86

0.950.900.801.390.85

0.940.880.801.410.83

0.930.860.801.450.80

0.920.850.801.480.80

0.920.850.801.480.78

0.910.830.801.510.75

0.900.810.801.540.75

0.900.810.801.540.75

0.900.810.801.540.75

Valve Ratio % Travel Ported Cage Flowed - OverSeries 5410 % 10 20 30 40 50 60 70 80 90 100

Globe FLFL2Kie mrXT

0.560.310.903.540.47

0.720.520.902.140.65

0.820.670.901.650.75

0.860.740.901.500.77

0.870.760.901.470.79

0.880.770.901.430.79

0.880.770.901.430.79

0.880.770.901.430.79

0.880.770.901.430.79

0.880.770.901.430.79

Valve Ratio % Travel Ported Cage Flowed - UnderSeries 5410 % 10 20 30 40 50 60 70 80 90 100

Globe FLFL2Kie mrXT

0.960.920.901.210.87

0.940.880.901.260.84

0.920.850.901.310.84

0.900.810.901.370.81

0.890.790.901.400.81

0.880.770.901.430.79

0.880.770.901.430.79

0.880.770.901.430.79

0.880.770.901.430.79

0.000.770.901.430.79

Pressure Recovery Ratios for Series 5000 Multi-Purpose Valves

Valve Ratio % Travel Single Cage Flowed Under or OverSeries 5410 % 10 20 30 40 50 60 70 80 90 100

Globe FLFL2Kie mrXT

0.970.940.951.120.88

0.970.940.951.120.88

0.960.920.951.140.88

0.960.920.951.140.88

0.960.920.951.140.88

0.950.900.951.170.88

0.950.900.951.170.88

0.940.880.951.190.88

0.940.880.951.190.88

0.940.880.951.190.88

Valve Ratio % Travel Double Cage Flowed Under or OverSeries 5410 % 10 20 30 40 50 60 70 80 90 100

Globe FLFL2Kie mrXT

0.970.940.951.120.90

0.970.940.951.120.90

0.960.920.951.140.90

0.960.920.951.140.90

0.960.920.951.140.90

0.950.900.951.170.90

0.950.900.951.170.90

0.950.900.951.170.90

0.950.900.951.170.90

0.950.900.951.170.90

Valve Ratio % Travel Triple Cage Flowed Under or OverSeries 5410 % 10 20 30 40 50 60 70 80 90 100

Globe FLFL2Kie mrXT

0.970.940.951.120.92

0.970.940.951.120.92

0.960.920.951.140.92

0.960.920.951.140.92

0.960.920.951.140.92

0.960.920.951.140.92

0.960.920.951.140.92

0.960.920.951.140.92

0.960.920.951.140.92

0.960.920.951.140.92

Valve Ratio % Travel Quad - Cage Flowed Under or OverSeries 5410 % 10 20 30 40 50 60 70 80 90 100

Globe FLFL2Kie mrXT

0.980.960.951.100.96

0.980.960.951.100.95

0.980.960.951.100.94

0.980.960.951.100.94

0.970.940.951.120.94

0.970.940.951.120.94

0.970.940.951.120.94

0.970.940.951.120.94

0.970.940.951.120.94

0.970.940.951.120.94

Valve Ratio % Travel Multi-Labyrinth Trim *(MLT) Flowed Under or OverSeries 5410 % 10 20 30 40 50 60 70 80 90 100

Globe FLFL2Kie mrXT

0.990.980.971.050.98

0.990.980.971.050.98

0.990.980.971.050.98

0.990.980.971.050.98

0.990.980.971.050.98

0.990.980.971.050.98

0.990.980.971.050.98

0.990.980.971.050.98

0.990.980.971.050.98

0.990.980.971.050.98

* 2 stages of MLT Trim

Valve Ratio % Travel Contoured 3 WaySeries 5410 % 10 20 30 40 50 60 70 80 90 100

Globe FLFL2Kie mrXT

0.530.280.814.400.62

0.550.300.814.080.65

0.680.460.812.670.65

0.850.720.811.710.67

0.870.760.811.630.67

0.870.760.811.630.70

0.860.740.811.670.70

0.850.720.811.710.70

0.850.720.811.710.70

0.850.720.811.710.70

Pressure Recovery Ratios for Series 5000 Multi-Purpose Valves

Valve Ratio % Travel Trickle Flowed - OverSeries 5430 % 10 20 30 40 50 60 70 80 90 100

Angle FLFL2Kie mrXT

0.940.880.921.230.85

0.940.880.921.230.83

0.940.880.921.230.81

0.930.860.921.260.79

0.930.860.921.260.79

0.930.860.921.260.78

0.930.860.921.260.78

0.930.860.921.260.78

0.930.860.921.260.78

0.930.860.921.260.78

Valve Ratio % Travel Trickle Flowed - UnderSeries 5430 % 10 20 30 40 50 60 70 80 90 100

Angle FLFL2Kie mrXT

0.940.880.921.230.91

0.940.880.921.230.90

0.940.880.921.230.89

0.930.860.921.260.88

0.930.860.921.260.88

0.930.860.921.260.86

0.930.860.921.260.86

0.930.860.921.260.85

0.930.860.921.260.85

0.930.860.921.260.85

Valve Ratio % Travel Contoured Flowed - OverSeries 5430 % 10 20 30 40 50 60 70 80 90 100

Angle FLFL2Kie mrXT

0.890.790.841.500.47

0.830.690.841.730.53

0.790.620.841.910.57

0.780.610.841.960.63

0.750.560.842.120.63

0.730.530.842.230.67

0.720.520.842.300.67

0.720.520.842.300.67

0.720.520.842.300.67

0.720.520.842.300.67

Valve Ratio % Travel Contoured Flowed - UnderSeries 5430 % 10 20 30 40 50 60 70 80 90 100

Angle FLFL2Kie mrXT

0.960.920.801.360.85

0.950.900.801.390.85

0.940.880.801.410.80

0.930.860.801.450.80

0.920.850.801.480.80

0.920.850.801.480.78

0.910.830.801.510.78

0.900.810.801.540.75

0.900.810.801.540.75

0.900.810.801.540.75

Valve Ratio % Travel Ported Cage Flowed - OverSeries 5430 % 10 20 30 40 50 60 70 80 90 100

Angle FLFL2Kie mrXT

0.900.810.901.370.84

0.900.810.901.370.83

0.890.790.901.400.81

0.890.790.901.400.80

0.880.770.901.430.79

0.880.770.901.430.79

0.870.760.901.470.79

0.870.760.901.470.79

0.870.760.901.470.79

0.870.760.901.470.79

Valve Ratio % Travel Ported Cage Flowed - UnderSeries 5430 % 10 20 30 40 50 60 70 80 90 100

Angle FLFL2Kie mrXT

0.940.880.901.260.85

0.940.880.901.260.83

0.930.860.901.280.83

0.930.860.901.280.82

0.920.850.901.310.81

0.920.850.901.310.79

0.910.830.901.340.79

0.910.830.901.340.79

0.910.830.901.340.79

0.910.830.901.340.79

Pressure Recovery Ratios for Series 5000 Multi Purpose Valves

Valve Ratio % Travel Single Cage Flowed Under or OverSeries 5430 % 10 20 30 40 50 60 70 80 90 100

Angle FLFL2Kie mrXT

0.970.940.951.120.89

0.970.940.951.120.89

0.960.920.951.140.87

0.960.920.951.140.87

0.960.920.951.140.87

0.950.900.951.170.86

0.950.900.951.170.86

0.940.880.951.190.86

0.940.880.951.190.86

0.940.880.951.190.86

Valve Ratio % Travel Double Cage Flowed Under or OverSeries 5430 % 10 20 30 40 50 60 70 80 90 100

Angle FLFL2Kie mrXT

0.970.940.951.120.91

0.970.940.951.120.91

0.960.920.951.140.90

0.960.920.951.140.90

0.960.920.951.140.89

0.950.900.951.170.89

0.950.900.951.170.89

0.950.900.951.170.89

0.950.900.951.170.89

0.950.900.951.170.89

Valve Ratio % Travel Triple Cage Flowed Under or OverSeries 5430 % 10 20 30 40 50 60 70 80 90 100

Angle FLFL2Kie mrXT

0.970.940.951.120.92

0.970.940.951.120.92

0.970.940.951.120.92

0.970.940.951.120.91

0.970.940.951.120.91

0.960.920.951.140.91

0.960.920.951.140.91

0.960.920.951.140.91

0.960.920.951.140.91

0.960.920.951.140.91

Valve Ratio % Travel Quad - Cage Flowed Under or OverSeries 5430 % 10 20 30 40 50 60 70 80 90 100

Angle FLFL2Kie mrXT

0.980.960.951.100.94

0.980.960.951.100.94

0.980.960.951.100.94

0.980.960.951.100.93

0.970.940.951.120.93

0.970.940.951.120.93

0.970.940.951.120.93

0.970.940.951.120.93

0.970.940.951.120.93

0.970.940.951.120.93

Valve Ratio % Travel Multi-Labyrinth Trim *(MLT) Flowed Under or OverSeries 5430 % 10 20 30 40 50 60 70 80 90 100

Angle FLFL2Kie mrXT

0.990.980.971.050.98

0.990.980.971.050.98

0.990.980.971.050.98

0.990.980.971.050.98

0.990.980.971.050.98

0.990.980.971.050.98

0.990.980.971.050.98

0.990.980.971.050.98

0.990.980.971.050.98

0.990.980.971.050.98

Pressure Recovery Ratios for Series 6000 Corrosive Service Valves

Valve Ratio % Travel Contoured Flowed OverSeries 6000 % 10 20 30 40 50 60 70 80 90 100

GlobePTFE Lined

FLFL2Kie mrXT

0.630.400.753.360.63

0.650.420.753.160.65

0.750.560.752.370.68

0.780.610.752.190.68

0.850.720.751.850.68

0.850.720.751.850.70

0.850.720.751.850.70

0.850.720.751.850.70

0.850.720.751.850.70

0.850.720.751.850.70

Valve Ratio % Travel Contoured Flowed UnderSeries 6000 % 10 20 30 40 50 60 70 80 90 100

GlobePTFE Lined

FLFL2Kie mrXT

0.750.560.752.370.69

0.780.610.752.190.69

0.780.610.752.190.67

0.800.640.752.080.67

0.810.660.752.030.65

0.900.810.751.650.65

0.900.810.751.650.65

0.900.810.751.650.65

0.900.810.751.650.65

0.900.810.751.650.65

Valve Ratio % Travel Contoured F