ML20116H892

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Users Guide for Preslock,Gate Valve Pressure Locking Analysis Program Using the Commonwealth Edison Model
ML20116H892
Person / Time
Site: Prairie Island  Xcel Energy icon.png
Issue date: 01/02/1996
From:
NORTHERN STATES POWER CO.
To:
Shared Package
ML20116H586 List:
References
PROC-960102, NUDOCS 9608120303
Download: ML20116H892 (30)
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{{#Wiki_filter:O Page 1 USER'S GUIDE FOR PRESLOK, A GATE VALVE PRESSURE LOCKING ANALYSIS PROGRAM USING THE COMMONWEALTH EDISON MODEL REVISION 0 January 2,1996 While this information is presented in good faith and believed to be accurate, the Westinghouse Owner's Group does not guarantee satisfactory results from reliance upon such information. Nothing contamed herein is to be construed as a warranty, express or implied, regarding the performance, merchantability, fitness or any other matter with respect to the product, nor as a recommendation to use any product or process in conflict with any patent. "Ih: Westinghouse t Owner's Group reserves the right, without notice, to alter or improve the methode de.,cribed herein. [ ] l l i pleh1213.wpf 0119961358 9608120303 960006 PDR ADOCK 05000282 P PDR

e 9 Page 2 USER'S GUIDE FOR PRESLOK GATE VALVE PRESSURE LOCKING ANALYSIS PROGRAM USING THE COMMONWEALTH EDISON MODEL RECORD OF REVISION PAGE Rev.O OriginalIssue January 2,1996 i i j pish 1213.wpf 0119961358

Page 3 USER'S GUIDE FOR PRESLOK GATE VALVE PRESSURE LOCKING ANALYSIS PROGRAM USING THE COMMONWEALTH EDEON MODEL TABLE OF CONTENTS SECTION PAGE NO. TITLE PAGE 1 REVISION

SUMMARY

2 TABLE OF CONTENTS 3 INTRODUCTION 4 HARDWARE / SOFTWARE REQUIREMENTS 5 GETTING STARTED 6 RUNNING THE PRESLOK ANALYSIS 7 INPUT PREPARATION 9 THEORY I1 EXAMPLE USING PRESLOK VERSION 1 20 EXAMPLE USING PRESLOK VERSION 2 26 REFERENCES 32 I pish 1213.wpf 0119961358

I USER'S GUIDE FOR FRESLOK Page 4 INTRODUCTION Pressure locking is a phenomenon which can cause the unseating thmst for a gate valve to increase dramatically from its typical static unseating thmst. This can possibly result in the valve failing to open due to the actuator having insufficient thmst capability. Pressure locking can also result in valve damage in cases where the actuator thrust capability exceeds the valve stmetural capacity. For these reasons, a proper understanding of the conditions which may cause pressure locking, as well as a methodology for predicting the increase in unseating thrust for a pressure locked valve, are necessary. A method of analyzing gate valves to predict the increase in unseating thrust for a pressure locked valve has been developed by Commonwealth Edison, and has been presented by Mr. Brian Bunte (Ref.1). The Westinghouse Owner's Group; in the Pressure locking /Thennal Binding Task Team meeting en November 13 and 14, 1995, authorized the preparation of a MATHCAD program and accompanying user's manual to allow the uniform use of the Commonwealth Edison pressure locking analysis methodology. This manual is the result of that authorization. This manual and the program file for performing the analysis are available from the Westinghouse Owner's Group and may be obtained by contacting L. I. Ezekoye at (412) 374-6643 or W. E. Moore at (412) 374-6351. Please indicate whether the program is to be supplied on 3.5 inch diskettes or 5.25 inch diskettes. pleh1213.wpf 0119961358

l USER S GUIDE FOR PRESLOK Page 5 HARDWARE / SOFTWARE REQUIREMENTS The program has been written using the MATHCAD 5.0 for Windows progmm This program is available from MathSoft, Inc. 101 Main Street Cambridge, MA 02142 1-800-628-4223 or 617-577-1017 Fax: 617-577-8829 The program is also widely available from software vendors. The following hardware and software requirements for running the MATHEAD 5.0 for Windows program are extracted from the User's Guide which is supplied with the MATHCAD program: An 80386 or higher IBM

  • or compatible computer. A math coprocessor is e

not required, but its presence will significantly improve performance. m Microsoft* Windows" Version 3.1 or later or Windows NT. At least 4MB of RAM. All memory above 640K should be configured as a extended memory. a At least 14MB of free hard disk space for MATHCAD files. m An additional IMB on the hard disk where MATHCAD is installed. m At least 8MB of vinual memory. See the Windows user manual for how to specify vinual memory. a A monitor and graphics card compatible with Windows. m A mouse supponed by Windows. m Any printer supponed by Windows. The User's Guide supplied with the MATHCAD program should be followed for installation of the MATHCAD program onto your computer. The scope of this manual is to explain the usage of the PRESLOK analysis using the MATHCAD program. plsh1213.wpf 0119961358

USER'S GUIDE FOR PRESLOK Page 6 GETTING STARTED The PRESLOK files are supplied to you on either a 3.5 inch or a 5.25 inch diskette, per your request. It is recommended that the first step to use the fdes is to copy a " working version" of the files to your hard disk so that the diskette can be retained as a record copy. The fdes which are included are as follows: preslokl.med MATHCAD program using the closing valve factor as an

input, preslok2.med MATHCAD program using the coefficient of friction between disk and seat as an input.

plinputl.dat ASCII filc of input data required by version 16f the PRESLOK program. plinput2.dat ASCII file of input data required by version 2 of the l PRESLOK progam. j The next step to use the program is to create a data file to transfer the input values for the variables to the PRESLOK analysis program. The PRESLOK program is j expecting these vanables to appear in text file in plain ASCII format with the name "plinputl.dat" for use with version 1 or "plinput2.dat" for use with version 2. The various numbers in the "plinputl.dat" or "plinput2.dat" file can be sepamted by spaces, commas, or camage returns, and may appear as integers, floating point numbers, or as E-format numbers such as 2.35E-2. An ASCII text fde can be created using the Windows utility Notepad, or by numerous other methods. This file should be located in the same directory as the PRESLOK rde, since when the PRESLOK fue is loaded, that directory will become the MATHCAD default directory. The user is also referred to the chapter on " Data Files" in the MATHCAD User's. Guide if further explanation of the use of the ".dat" fde is needed. Sample data files are included in the program diskette which can be used simply by changing the input values to the proper values for your analysis. Altemately, other file names can be used for the input data by changing the input file name on the page 1 of the PRESLOK program to the file name desired. pish 1213.wpf 0119961358

USER'S GUIDE FOR PRESLOK Page 7 RUNNING THE PRESLOK ANALYSIS At this point it is assumed that the user has the MATHCAD 5.0 program loaded onto j his computer, and that the PRESLOK Version 1 or PRESLOK Version 2 file and the "plinputl.dat" or "plinput2.dat" file are available to the computer in the same l diactory. To mn the PRESLOK analysis, the user should perform the following steps: 1. Double click on the MATHCAD 5.0 icon to start the MATFCAD program. j 2. Go to the File pulldown menu and click on Open (or click on the Open File icon on the Tool Bar.) 3. In the Open dialogue box, select the directory containing the preslokt.med or preslok2.mcd file and select the desired version of the program. Then click on OK. 4. The PRESLOK program will pick up the input values from the plinputl.dat or plinput2.dat file and perform the analysis if the program is in the automatic mode (Automatic Mode has a check mark next to it in the Math pulldown j menu.) If the MATHCAD program is not in the automatic mode, it can be forced to perform the calculation by clicking on the Calculate Document function in the Math pulldown menu. Results may be inspected by using the scroll bar on the right hand side of the display to scroll through the display as desired. 5. To change the inputs, open the Windows utility Notepad and open the plinputl.dat or plinput2.dat file. Make the desired changes to the file and then save it. To have MATHCAD re-perform the analysis with the new input values, open the Math pulldown menu and click on Calculate Document. This j alternate use of Notepad and the MATHCAD function Calculate Document should be repeated until the analysis is correct. 6 The output may be printed using the Print command in the pulldown menu under File or using the print icon in the Tool Bar. The user is referred to the i MATECAD User's Guide if any changes am desired to the Page Setup or the Printer Setup. Note that valve identifiers or other identifying titles may be added to the output by using the MATHCAD text entry methods given in the MATHCAD User's Guide. If the user desires to add the identifier / title to each page, the use of a header is recommended. The header can be defined through the Headers / Footers command in the Edit pulldown menu or through the Header command in the Page Setup dialogue box. See the Documents and Windows pish 1213.wpf 0119961358

USER'S GUIDE FOR PRESLOK Page 8 RUNNING THE PRESLOK ANALYSE (continued) section of the MATHCAD User's Guide for further information about Headers. 7. The program may be exited using the Exit command in the File pulldown menu. L b \\ i c I \\ \\ + O - Seat Angle - Hub Length Disk = =, Thickness FIGURE 1 Disk Geometry i ptsh1213.wpf 0119961358

4 USER'S GUIDE FOR PRESLOK Page 9 INPUT PREPARATION The following inputs are required for the use of the PRESLOK analysis using version 3 i 1 of the program: e Pressure Conditions at the time of the pressure locking event. This includes the upstream, downstream, and bonnet pressure. Bonnet Pressure: P psi w,, Upstream Pressure: P, psi Downstream Pressure: P Psi down i Valve Disk Geometry. This includes the hub radius, hub length, mean seat a radius, average disk thickness, and seat angle. j l Disk Thickness: t inches Seat Radius: a inches Hub Radius: b inches Hub Length: Hub inches g Seat Angle: degrees The disk thickness recommended for use in these calculations is the thickness at the centerline of the disk vertically. See Figure 1. This will normally be a value which is intermediate between the minimum and maximum thickness of the dir.k and this is the thickness which has been used in the comparisons of test measurements which Commonwealth Edison is making with the analytical results. It is noted that the magnitude of the pressure locking force increases with the thickness of the disk, so that use of the maximum disk thickness would yield conservative results. The pressure locking forces predicted by using the maximum value of disk thickness are likely to be unreasonably high though. The seat radius used in these calculations is the mean seat radius which corresponds to the radius at which one half of the seat area would be outside the mean seat radius and one half of the seat area would be inside the mean radius. Thus, given the inner and outer seat diameters, the mean seat radius is OD* + ID

  • a=h 8

pish 1213.wpf 0119961358

USER'S GUIDE FOR PRESLOK Page 10 When the hub cross-section is not reasonably circular (e.g. many Westinghouse gate valve designs), then an effective hub radius is used which corresponds to a circle of equal area to the hub cross-sectional area. Hub Area y,3 it The hub length is the distance from the inside face of the hub to the inside face of the hub at the hub radius, as shown on Figure 1. The seat angle is as shown on Figure 1. Valve Disk Material Properties. This includes the modulus of elasticity and the m Poisson's ratio for the disk base material, at the temperature being considered. Poisson's Ratio: v dimensionless Modulus of Elasticity: E psi a Valve Stem Diameter Stem Diameter: D,,,, inches This is the stem diameter in the region of the stem which is inside the packing. m Static Unseating Thrust Static Pullout Force: F,, pounds This is the static pullout force obtained from testing of the valve for which the calculation is being performed. m Closing Valve Factor Valve Factor: VF dimensionless It is suggested that this valve factor be the factor obtained from test measurements of closing the valve being considered in a DP test, if possible. To use version 2 of the program instead of version 1, the closing valve factor VF is replaced by the co-efficient of friction to be considered between the disk and the seat, and the input data file is named plinput2.dat. All other inputs remain the same as for version 1. The different input value is a Coefficient of Friction between Disk and Seat Seat to Disk Coefficient of Friction: p dimensionless pish 1213 wpf 0119961407

USER'S GUIDE FOR PRESLOK Page 11 THEORY ASSUMPTIONS 1 l. The valve disk is assumed to act as two ideal disks connected by a hub. That 1 is, the disks are assumed to be round, of uniform thickness, and perpendicular 1 to a cylindrical, concentric hub. A line perpendicular to the hub centerline i and at the middle of the hub length is an axis of symmetry for the wedge. The equations in reference 2 for this idealized structure are assumed to conservatively model the actualload due to pressure forces. This assumption is considered conservative since inspection of the disk drawings show large fillets between the disk hub and seats which should make the valve disk stiffer than assumed in the reference 2 equations. 2. The coefficient of friction between the valve seat and disk is assumed to be the same under pressure locking conditions as it is under DP conditions. This assumption is considered to be justified based on bench marking of the calculations against Comed and EPRI pressure locking test data for similar flex-wedge gate valves. 3. The upstream, downstream, and bonnet pressure values are considered to be known. DESIGN INPUTS The following design inputs are used in calculating the force required to unseat a pressure locked MOV: Pressure Conditions at the time of the pressure locking event. This includes a the upstream, downstream, and bonnet pressure. Bonnet Pressure: P psi Upstream Pressure: P psi op Downstream Pressure: P psi down Valve Disk Geometry. This includes the hub radius, hub length, mean seat e radius, and average disk thickness. Disk Thickness: t inches Seat Radius: a inches Hub Radius: b inches pish 1213 wpf 0119961407

USER'S GUIDE FOR PRESLOK Page 12 Hub Length: Hub inches y Seat Angle: 0 degrees The disk thickness recommended for use in these calculations is the thickness at the centerline of the disk vertically. See Figure 1. This will normally be a value which is intermediate between the minimum and maximum thickness of the disk, and this is the thickness which has been used in the comparisons of test measurements which Commonwealth Edison is making with the analytical results. It is noted that the magnitude of the pressure locking force increases with the thickness of the disk, so that use of the maximum disk thickness would yield conservative results. The pressure locking forces predicted by using the maximum value of disk thickness are likely to be unreasonably high j though. t The seat radius used in these calculations is the mean seat radius which corresponds to the radius at which one half of the seat area would be outside the mean seat radius and one half of the seat area would be inside the mean radius. Thus, given the inner and outer seat diameters, the mean seat radius is l t 2 2 OD . fp j a=h 8 [ i -When the hub cross-section is not reasonably circular (e.g. many Westinghouse gate valve designs), then an effective hub radius is used which corresponds to a circle of equal area to the hub cross-sectional area. i Hub Area y,S i 8 E The hub length is the distance from the inside face of the hub to the inside face of the hub at the hub radius, as shown on Figure 1. The seat angle is as shown on Figure 1. m Valve Disk Material Properties. This includes the modulus of elasticity and the Poisson's ratio for the disk base material. j Poisson's Ratio: v dimensionless Modulus of Elasticity: E psi e Valve Stem Diameter Stem Diameter: D,,,, inches p6sh1213 wpf 0119961407

USER'S GUIDE FOR PRESLOK Page 13 This is the stem diameter in the region of the stem which is inside the packing. m Static Unseating Thrust Static Pullout Force: F pounds po This is the static pullout force obtained from testing of the valve for which the calctlation is being performed. m Coefficient of Friction between Disk and Seat Seat to Disk Coefficient of Friction: p dimensionless The analysis program is presented in two versions, one of which requires that the coefficient of friction to be used between the disk and the seat be input dirc:stly, and the other which allows the input of the closing valve factor instead. For the version which allows the input of the closing valve factor, the coefficient of friction is calculated as follows: cos 6 y, yy. 1 + VF sin 0 CALCULATIONS The methodology for calculating the thrust required to open the MOVs under the pressure locking scenario is based on the Reference 2 (Roark's) engineering handbook. The methodology determines the total force required to open the valve,under a pressure locking scenario by solving for the four components to this force. The four components of the force are the pressure locking component, the static unseating component, the piston effect component, and the " reverse piston effect" component. These magnitudes of these components are determined using the following steps: Pressure Locking Component of Force Reauired to Open the Valve The valve disk _is modeled as two plates attached at the center by a hub which is concentric with the valve disk. A plane of symmetry is assumed between the valve disks. This plane of symmetry is considered fixed in the analysis. ptsh1213 wpf 0119961407

.. - -.. _. _ - _ _ _ - ~ { l USER'S GUIDE FOR PRESLOK Page 14 1 L, H== Of H 1 e Symmetry 1 + a a j w Modeled As: -l " Symmetry "f j m 1 W i +- I i ] W l Based on this geometry, the following constants are calculated using the reference 2 equations: Average DP Across Disk \\ P +P EP l DP** = P""' 2 Disk Stiffness Constants i E t' f D= l 12 -(1 -v ) 2 G= 4 2 -(1 + v) I 4 b d pish 1213 wpf 0119961407 a a

  • W 4

.+i-.. ll .h. + m .a. ~ -.., 4 ++-.ad+h,+e

    • -.+#~T 8

USER'S GUIDE FOR PRESLOK Page 15 Geometry Factors t 32 r r is' l-1+2in f C" 2 4 ras r s b > >. C b ' b '* 1In a ' + b'* 1 + 3 4a.sas rb> sas t b t2' C, = l '1 + v + (1 -v )I 2. taa j i C, = p f 1 + v,g 1 -v 3_[pf } j i al 2 1b4 4 \\ c, / J Deflection Due To Pressure Force l The pressure force is assumed to act uniformly upon the inner stuface of the disk j between the hub diameter and the outer disk diameter. The outer edge of the disk is assumed to be unisapeded and allowed to deflect away from the pressure force. In addition, the disk hub is allowed to stretch. The total displacement at the outer edge i of the valve disk due to shear and bending and due to hub stretch are calculated using the reference 2 equations. Corresponding Equations Additional Geometry Factors (r0 = b for Case 2L) i r 42 r 34 r 32' r 32' r i L,=1{1+4E-53 7 7 7 7 2 2+ E in i S ka s \\al \\a) La) \\r) o l i r ' r '2 1 +(1 + v)ln a 1 1 1-v 1-o o L,7 = 4 4 rai. ra, g r s. o T l pish 1213 wpf 0119961407 I 1

--.=-_aa 4-.___, _ah- --_A h _a +4--+ wMa a a e- - -u-= =w +- AL e, USER'S GUIDE FOR PRESLOK Page 16 Moment Factors (r0 = b for Case 2L) i 2 -DP" a C', (a2-r).t; 2 M,, = o EAculd be "4 Q,. 2.b (a 2_7 2 s,.. 4.,_ a er.,,-y Ant s;5 Pagre-Pmloct Muge-Goso). y, nuesh se w cmvp ca(e. Ho. V-ec-wok. Bending Deflection due to Pressure W2u% DP" a* 2 3 M " M,,3 2 + Q, a C, - L,, a C J Shear Deflection due to Pressure (r0 = b for Case 2L) y' 821 f 1 f f e K* = -0.3 - 2 in S -1+ 1 - 2 In b rbs ras r <b,. K, DP, a' In " g.a Deflection from Hub Stretch due to Pressure g=x(a2 _ 3 ).pp 2 P m ym = - Total Deflection due to Pressure ye

  • Jg
  • yn + ya,an An evenly distributed force is assumed to act between the valve seat and the outer edge of the valve disk. This force acts to deflect the outer diameter of the valve disk inward and to compress the disk hub. The pressure force is reacted to by an increase in this contact force between the valve disk and seats. The valve body seats are conservatively assumed to be fixed. Therefore, the deflection due to the known pressure load must be balanced by the deflection due to the unknown seat load. The deflection due to the pressure force was previously calculated. Now, the reference 2 l

ptsh1213 wpf 0119961407 i

USER'S GUIDE FOR PRESLOK Page 17 , equations are used to deterrnine the contact force between the seat and disk which results in a deflection which is equal and opposite to the deflection due to the pressure l force. This is done by first calculating the amount deflection created by a unit load of seat contact force (w = 1 lb/in). The equilibrium contact load is then determined l by dividing the deflection caused by the unit contact load into the previously calculated deflection due to the pressure force. The equations are provided below: Additional Geometry Factors (For Case IL, to = a,..L = L = 0 3 9 'f r '2 In a ' !bY ro o L +1 + -l -1 3 4a s a, gr, ta) o 1 + v.b '#' I~" fr 32

  1. 0 o

4,a 1- + 2 sri 4 ga, ) l a Bending Deflection due to Seat Load (r = a) o 3 'C . ' r C, rC a 2 o o 3 y -Q +L 3 D , C, i b b Shear Deflection due to Seat Load (r = a) o f r* r K* = - 1.2-In E a rbi 7 l l yu = K, a Deflection from Hub Compression Due to Seat Load (w = 1,.. Compressive force = 2 x a) , _ 2 x a ' #"hw' ,W nb < 2E 1 Total Deflection from Unit Seat Load (w = 1) l y,

  • y n + ys,
  • y m pe Therefore, the equilibrium contact load distribution (Ib/in) and the corresponding load applied to each seat is calculated using the relationship below:

l plsh1213 wpf 0119961407 1

USER'S GUIDE FOR PRESLOK Page 18 y l w,p = y,, where y, is calculatedfor w = 1 Load per seat = 2xaY ry,, Determining The Disk To Seat Friction Coefficient Several methods can be used to determine an appropriate seat to disk friction coefficient. The coefficient of friction between the seat and disk is perhaps best detemtined based on the open valve factor from a DP test. However, due to the difficulty sometimes encountered in obtaining a good, consistent valve of the opening valve factor from testing, the PRESLOK program is written to accept a closing valve factor or a co-efficient of friction directly. The equation used to calculate the coefficient of friction from the closing valve factor is given in the Design Inputs section of this User's Manual. The stem force required to overcome the contact load between the seat and disk which opposes the pressure force is equal to: (seat load) x [p cos 0 - sin 0 ] x 2 (for two disk faces). Static Unseatine Force The static unseating force represents the opening packing load and the pullout force due to wedging of the valve disk during closure. These loads are superimposed on the loads due to the pressure forces which occur during pressure locking. The value for this force is based on static test data for the MOVs. Piston Effect The piston effect due to valve internal pressure exceeding outside pressure is calculated using the standard industry equation. This force assists movement of the valve stem in the open direction. j

  • D*

(P - P,) Fp,, y = w Reverse Piston Effect (Fvert) The reverse piston effect is the term used in this calculation to refer to the pressure i l pish 1213 wpf 0119961407

USER'S GUIDE FOR PRESLOK Page 19 force acting downward against the valve disk. This force is equal to the differential pressure across the valve disk times the area of the valve disk times the sine of the seat angle times 2 (for two disk faces). 2 F, = n a sin e -{2 P - P, - Pw) w i Pbonnet l ) i 8 scat P P inlet outlet i m Pbonnet Total Force Reauired to Overcome Pressure Lockine As mentioned previously, the total stem force (tension) required to overcome pressure locking is the sum of the four components discussed above. All of the terms are positive with the exception of the piston effect component. The acceptance criteria recommended for use in this calculation is that the available motor operator thrust capability be at least 120% of that required to unseat the MOV under pressure locking conditions. The 20'7c rnargin is provided to allow for 1 uncertainty in the measurement of stem factor, open valve factor, static unseating thrust as well as other effects such as stem factor variation and motor-to-motor torque capability variations. All of these effects are random in nature. plsh1213 wpf 0119961407

USER'S GUIDE FOR PRESLOK Page 20 EXAMPLE OF AN ANALYSIS PERFORMED WITH PRESLOK, VERSION 1 The following is an image of the input file plinputl.dat used to run an example problem on version 1 of the PRESLOK analysis program: 1005 380 350 2 4.36 1.25 0.5 5 0.3 27.6E6 1.875 15409 0.52 The input file corresponds to input values as shown: Bonnet Pressure: Phonnet = 1005 psi Upstream Pressure: P,p = 380 psi Downstream Pressure: Pdown = 350 psi Disk Thickness: t = 2.00 inches Seat Radius: a = 4.36 inches Hub Radius: b = 1.25 inches Hub Length: L = 0.50 inches Seat Angle: 0 = 5 degrees Poisson's Ratio: v = 0.3 (dimensionless) Modulus of Elasticity: E = 27,600,000 psi Stem Diameter: D,, = 1.875 inches 33 Static Pullout Force: F, = 15,409 pounds p Valve Factor: VF = 0.52 (dimensionless) The next five pages contain the output of the PRESLOK program, Version 1, using the above input. ptsh1213.wpf 0113961410 ~.

USER'S GUIDE TO PRESLOK Page 21 Prcgrcm PRESLOK, Vcrsi:n 1 Revision 0 December 22,1995 This Mathcad Program is designed to calculate the estimated opening force under pressure locking scenarios for flex-wedge gate valves using a calculational methodology that accounts for wedge stiffness resisting pressure locking forces. This program was prepared by the Westinghouse Owner's Group based upon the calculational methods developed by Commonwealth Edison. While this information is presented in good faith and believed to be accurate, the Westinghouse Owner's Group does not guarantee satisfactory results from reliance upon such information. Nothing contained herein is to be construed as a warranty, express or implied, regarding the performance, merchantability, fitness or any other matter with respect to the product, nor as a recommendation to use any product or process in conflict with any patent. The Westinghouse Owner's Group reserves the right, without notice, to alter or improve the methods described herein. This section of the program reads the thirteen items of input data from the plinput1.dat

file, i := 0. 12 input := READ (plinputl) i P bonnet = input ' Psi v := inpur o

8 P up := inputypsi E := input 9 ysi P down := input Psi D stem := input 10'i" 2 t := inputyin F po := input plbf 3 a := input,cin VF := input12 j b := inputyin Hub length := input 'In 6 0 := inputydeg l l l i PRESLOK. Ver.1. Rev. 0 12/22/95 Westinghouse Owner's Group l12/96 4:27:58 PM Page I of5

USER'S GUIDE TO PRESLOK Page 22' i Pr:grcm PRESLOK, Versi:n 1 INPUTS: Bonnet Pressure P bonnet = 005 psi Upstream Pressure P = 380 psi up Downstream Pressure P down =350 psi Disk Thickness t = 2 in (taken at centerline of the hub verticaHy) Seat Radius a =4.36 in (corresponding to mean seat diameter) Hub Radius (taken at plane of symmetry, b = 1.25 in perpendicular to the hub, radius of circle of equivalent area for non-circular hubs) Seat Angle 0 = 5 deg Poisson's Ratio (disk material at temperature) y r.0.3 Modulus of Elasticity (disk material at temperature) E = 2.7610 psi Static Pullout Force F po = 15409 lbf (measured value from diagnostic test) Close Valve Factor VF = 0.52 Stem Diameter D stem = 1.875 in i Hub Length Hub length =0.5 in (from inside face of disk to inside face of disk) i i l l PRESLOK. Ver.1. Rev. 0 12122195 Westinghouse Owner's Group ll2/96 4:28:44 PM Page 2 of5

r ) I USER'S GUIDE TO PRESLOK Page 23 Prcgrcm PRESLOK, Vcrsian 1 j PRESSURE FORCE CALCULATIONS

  • ' ' doefficient of friction between disk and seat:

cos(0) i

= VF-

= 0.496 1 + VF sin (0) Average DP across disks: l P up + P down DPavg := P bonnet DPavg = 640 psi 2 Disk Stiffness Constants 1 E-(t)3 7 D := D = 2.022 10 Ibf in 12-(1 - v ) E 7 G := G = 1.06210 psi 2-(1 + v) Geometry Factors: 1-b*I1 + 2 inl a\\ \\ l\\ l 1 C 3 := -- C 2 =0.1781 \\ 4, \\a) \\ b ~ \\ )). Ih Inl ai l Ih b b b C +1 '-1 C 3 =0.0311 3 := 4 a .+ ,(aj (b) (a) l32. I 1 + v + (1 - v) b C C g =0.6788 8 := 2 (a) (3 2. l) 1-v l-b C 9 =0.2789 b 1+v a C Inl !+ 9 = a-2 (b) 4 (a) Ih I In.ah lai a a L +1 '+- -1 L 3=0 3 := 4 a , \\ a) (a) \\a) li 1-v la32' - a 1+v -In a 1-! L L 9=0 9 := a-2 (a) 4 (aj .+ PRESLOK Ver.1. Rev.012/22/95 Westinghouse Owner's Group 112l% 4:29:24 PM Page3 ofS l l

USER'S GUIDE TO PRESLOK Page 24 Program PRESLOK, Voision 1 Gecmetry Factors: (continued) 1 I e4 b '-5b - 4 bh Ibi l\\ Ih I f In' ai 2+1 L g i = 0.0069 L i g := 64 (aj (a/ ta/ (a/ (b), 1 l I\\*' Ii 1 + (1 + v) In' a\\ ' f b b - l 1 1-v 1 L ;7 = 4 L 17 =0.1526 l l 4 (a) (a/ (bj., Moment 2 C -DPavg a 9 2 2 M tb := -a-b -L M tb =-5265 lbf 17 C 8 2ab l l Q := DPavg b a-b Q b =4466.5 lbf 2 2 2b in l Deflection due to pressure and bending: 2 3 DPavg a# l y bq := M rb - C 2 + Q ',D a -4 C 3- 'L il bq =-3.9041 10 in b D Deflection due to pressure and shear stress: 2In a\\1-1+:b*. I I\\ K sa := -0.3-K sa =-0.4743 (bj (aj 2 K DPavg a sa ysq:= y sq =-2.7177 10, in Deflection due to hub stretch: force := x-(a - b ) DPavg 2 2 P P force Hub length Y stretch " ~5 2 x6 (2 E) Y stretch = 6.4731 10 in Total Deflection due to pressure forces: ~# yq := y bq + Y sq - Y stretch Yq =-7.2691 10 in PRESLOK. Ver.1, Rev. 0 12122/95 Westinghouse Owner's Group 1/2/96 4:30.95 PM Page 4 of5

USER'S GUIDE TO PRESLOK Page 25 Pr:grcm PRESLOK, Versi:n 1 Deflection due to seat contact force and shear stress (per Ibf/in.): l (y ( 1.2 ' g

In

,\\ a y3,=- sw "-N' tG (_i f3. in) Deflection due to seat contact force and bending (per Ibf/in.): I 3\\ '(C \\ 'fa C g\\ ~fy g 2 g Y bw =-6.012 10,

n

-L 9 C 3 *L y bw * - ( D ).(C 8/.\\ D / .(b/ lbf) 3 l mi Deflection due to hub compression: J 1 I xa Hub 2 length ~8 in Ycmpt*- cmpt =-5.055 10 2 2E j (in j Total deflection due to seat contact force (per Ibf/in.): -7 in i Y w := y bw

  • Y sw
  • Y cmpr Y w =-9.597 10

) imj Seat Contact Force for which deflection is equal to i previously calculated deflection from pressure forces: Y l l q F := 2 x a-F s = 20750.5 lbf 3 Yw l UNSEATING FORCES F is included in measured static pullout Force packing K 2 F D P p ston

  • 7 stem bonnet F p ston = 2775 lbf 2

ven := x a sin (0)-(2 P bonnet up down) F -P -P F ven =6662.4 lbf F preslock := 2 F -(p cos(0) - sin (0)) F preslock = 16871 lbf s l y'sw = 43.079 10'7 m F total := - F piston + F ven + F preslock + F po \\"' F total = 36167.4 lbf PRESLOK.Ver.1, Rev.012122195 Westinghouse Owner's Group 1/2/96 4:30:57PM Page5 of5 l l

USER'S GUIDE FOR PRESLOK Page 26 EXAMPLE OF AN ANALYSIS PERFORMED WITH PRESLOK, VERSION 2 The following is an image of the input file plinput2.dat used to run an example problem on version 2 of the PRESLOK analysis program: 1005 380 350 2 4.36 1.25 0.5 5 0.3 27.6E6 1.875 15409 0.496 The input file corresponds to input values as shown: Bonnet Pressure: Phonnet = 1005 psi Upstream Pressure: P,p = 380 psi Downstream Pressure: Pdown = 350 psi Disk Thickness: t = 2.00 inches Seat Radius: a = 4.36 inches Hub Radius: b = 1.25 inches Hub Length: L = 0.50 inches Seat Angle: 0 = 5 degrees Poisson's Ratio: v = 0.3 (dimensionless) Modulus of Elasticity: E = 27,600,000 psi l Stem Diameter: D,,, = 1.875 inches 3 Static Pullout Force: Fpo = 15.409 pounds Seat to Disk Coefficient of Friction: p = 0.496 (dimensionless) The next five pages contain the output of the PRESLOK program, Version 2, using the above input. o pish 1213 wpf 0119961410

[ 1 i l USER'S GUIDE FOR PRESLOCK Page 27 ~ Program PRESLOK, Version 2 Revision 0 December 22,1995 1 This Mathcad Program is designed to calculate the estimated opening force under pressure locking scenarios for flex-wedge gate valves using a calculational methodology that accounts for wedge stiffness resisting pressure locking forces. This program was prepared by the Westinghouse Owner's Group based upon the calculational methods developed by Commonwealth Edison. While this information is presented in good faith and believed to be accurate, the Westinghouse Owners Group does not guarantee satisfactory results from reliance upon such information. Nothing contained herein is to be construed as a warranty, express or implied, regarding the performance, merchantability, fitness or any other matter with respect to the product, nor as a recommendation to use any graduct or process in conflict with any patent. The Westinghouse Owners Group reserves the right, without notice, to alter or improve the methods described herein. i This section of the program reads the thirteen items of input data from the plinput2.dat file. i := 0. 12 input; := READ (plinput2) P bonnet := input ' Psi y := input o g P up input psi E := input psi i 9 P down := input ' Psi D stem := input 10'i" 2 t = input in F = input lbf 3 po ti a := inpurgin

= input12 b := input 'I" s

Hub length := inPutgin 1 0 := inputydeg PRESLOK. Ver. 2. Rev. 0 12/22/95 Westinghouse Owner's Group 1121 % 4:35:50 PM Page 1 of5

USER'S GUIDE FOR PRESLOCK Page 28' Program PRESLOK, Version 2 INPUTS: Bonnet Pressure P bonnet = 1005 psi Upstream Pressure P = 380 psi up Downstream Pressure P down = 350 psi Disk Thickness t = 2 in (taken at centerline of the hub vertically) Seat Radius a = 4.36 in j (corresponding to mean seat diameter) 'j Hub Radius (taken at plane of symmetry, b = 1.25 in perpendicular to the hub, radius of circle l of equivalent area for non-circular hubs) Seat Angle 0 = 5 deg Poisson's Ratio (disk material at temperature) v = 0.3 7 Modulus of Elasticity (disk material at temperature) E = 2.76 10 psi Static Pullout Force F = 3.5409 lbf po (measured value from diagnostic test) Coefficient of Friction between disk and seat: =0'.496 Stem Diameter D stem = 1.875 in ) Hub Length Hub length =0.5 in (from inside face of disk to inside face of disk) PRESLOK. Ver. 2. Rev. 0 12122/95 Westinghouse Owner's Group 1121 % 4:36:20 PM Page 2 of5 1

l [ USER'S GUIDE FOR PRESLOCK Pag 229 Pr:gr m PRESLOK, Vcrsi:n 2 PRESSURE FORCE CALCULATIONS Average DP across disks: DPavg = P bonnet - up+P down P DPavg = 640 psi 2 Disk Stiffness Constants E-(t)3 7 D:= D = 2.02210 lbf in 2 12 1-v 1 E 7 G := G = 1.06210 psi i 2-(1 + v) Geometry Factors: 2*4' I - ' b\\

  • I' 1 + 2 In a\\ \\

1 I f C C 3 =0.1781 (a) ( (b//, 1 Ih fh I\\ b b b - - +1 In a C -1 C 3 =0.0311 3*4a ,(a) (bj (aj + l32. b I C C 8 =0.6788 1 + V + ( 1 - V)- 8 := 2 (a) l32' b 1+v fa\\ 1-v 1-b C 9 =0.2789 C Ini 9 := a-2 (bj 4 (a), + I\\ f\\ fa\\ a a a L 3 := 4 a l +1 Ini !+ -1 L 3 =0 , (a) (a) (aj f32. In'ah f 1-v a 1+v l-'a L 9=0 L 9 := a-2 (aj 4 (aj + PRESLOK, Ver. 2. Rev. 0 12/22/95 Westinghouse Owner's Group ll21% 4:37:0$ PM Page3 ofS

l I USER'S GUIDE FOR PRESLOCK Pcg2 30

  • Program PRESLOK, Version 2 i

Geometry Factors: (continued) t - 4 b\\

  • 2 +

b\\. In a\\ I I f - 1

  • 4 b\\' - 5 b\\

l f 1 L l L g i = 0.0069 g i = 64 (a/ (a) (a) (a/ (bl. 1 l )2 Ii 1 + ( 1 + v ) In ,3-f 1 1 1-v 1 b b L L 17 =0.1526 17'= 4 4 (a) (a) (bj. Moment 2 C 9 2 ~ -DPavg a -bg-L M tb =-5265 lbf M tb

  • 17 C 8 2ab Q

= DPavg Q =4466.5 lbf 2 2 -a-b b b 2b in Deflection due to pressure and bending: Y bq := M tb g C 2 + Q g,3 2 DPavg a# a ~4 b C L 3-D ii y bq =-3.9041 10 in Deflection due to pressure and shear stress: l f\\ 1. 2in a\\'-1+b K = - 0.3-K sa =-0.4743 sa (b) (a) 2 K DPavg a sa y sq

  • Y sq =-2.7177 10, in tG l

Deflection due to hub stretch: force := x-(a _ b ) DPavg 2 2 P P force Hub length Y stretch = xb (2 E) Y retch = 6.4731 10'5 2 in t Total Deflection due to pressure forces: q =-7.2691 10'# in yq := y bq + Y sq - Y stretch Y PRESLOK, Ver. 2. Rev. 0 12/22/95 Westinghouse Owner's Group 1/2l% 4 37:44 PM Paged ofS

1 USER'S GUIDE FOR PRESLOCK Page 31 Pr: gram PRESLOK, V rsi:n 2 Deflection due to seat contact force and shear stress (per Ibf/in.): ..s fa\\ l l.21 In ai a l ysw =- I*" ~ tG 5 libfi i\\ n) Deflection due to seat contact force and bending (per Ibf/in.) l3) (C ) la C ) lai a 2 9 -7 in -L 9 C 3 +L Ybw

  • g (C g),( b/

3 Y bw =-6.012 10 \\ in / Deflection due to hub compression: I na Hub 2 length 8 in Ycmpr"- N 2 2E cmpr /lbf) (b j (in / Total deflection due to seat contact force (per Ibf/in.): -7 in y w := y bw

  • Y ::w
  • Y cmpt Y w =-9.597 10

\\ \\ (in / Seat Contact Force for which deflection is equal to previously calculated deflection from pressure forces: Y4 F = 2 n a-F =20750.5 lbf s s Yw UNSEATING FORCES Fpacking is included in measured static pullout Force F D P p ston := stem bonnet F piston =2775 lbf 2 vert := x a sin (0)-(2 P bonnet -P -P down) F F ven =6662.4 lbf up F preslock := 2 F -( cos(0)- sin (0)) F preslock = 16889.1 lbf s F total := - F piston + F vert + F preslock + Fpo po = 15409 lbf F F total = 36185.5 lbf PRESLOK. Ver. 2. Rev. 0 12122/95 Westinghouse Owner's Group 1/2/96 4:38:21 PM Page 5 of5

USER'S GUIDE FOR PRESLOK Page 32 l REFERENCES 1. Bunte, Brian, " Comed Pressure Locking Methodology and Test Program," i presented at the NRC Region 3 Workshop on Pressure Locking and Thermal Binding, November 7,1995, i 1 2. Roark, Raymond J., and Young, Warren C., Formulasfor Stress and Strain, Fifth Edition, McGraw-Hill Book Company,1975. 3. Liberal use has also been made of a draft of a report being prepared by Mr. Brian Bunte of Commonwealth Edison Company, tentatively titled " Pressure Locking / Thermal Binding Report." I l l i l c i ( ptsh1213xpf 0119961410

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