Sub Sec 47 - Velan_pressure Seals Vlvs

8/15/2019 Sub Sec 47 - Velan_pressure Seals Vlvs

1/99Main Menu Maintenance

Manuals

VEL–FPSM–99

PRESSURE SEAL VALVESMAINTENANCE MANUAL

Cast and Forged Steel, Gate, Globe, Parallel Slide and Check Valves

2– 24” (50-600 mm)

http://../1velan.pdfhttp://_manual.pdf/http://_manual.pdf/http://../1velan.pdfhttp://_manual.pdf/


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GENERAL INFORMATION PAGE

I INTRODUCTION ........................................................................................................................6

1.1 General Introduction ..............................................................................................................................6

1.2 Essential Features of Velan Valves........................................................................................................71.3 The Different Styles of Pressure Seal Valves ......................................................................................8

IIRECEIVING & PREPARATION FOR INSTALLATION ..............................................................................9

2.1 Receiving Inspection ..............................................................................................................................9

2.2 Quality Control Documentation ............................................................................................................9

2.3 Storage ....................................................................................................................................................9

2.4 Handling and Preparation ......................................................................................................................9

2.5 Special Instructions for Gate Valves ....................................................................................................9

2.6 Special Instructions for Globe Valves ................................................................................................10

2.7 Special Instructions for Check Valves ................................................................................................10

2.8 Special Instructions for Tilting Disc Check Valves ............................................................................112.9 Recheck for Bolt Tightness ..................................................................................................................11

2.10 Special Note on Live-loaded Bolting ..................................................................................................12

III WARNINGS ..........................................................................................................................13

IV GENERAL MAINTENANCE ........................................................................................................14

4.1 Trouble Shooting Chart........................................................................................................................15

4.2 Operation ..............................................................................................................................................154.2.1 General ......................................................................................................................................154.2.2 Smoothness of Operation ........................................................................................................15

4.3 Recommended Lubrication..................................................................................................................15

4.4 General Assembly Information ..........................................................................................................154.5 Bonnet/Gasket Torquing Procedure....................................................................................................16

4.5.1 General ......................................................................................................................................164.5.2 Application of Torque................................................................................................................16

V INFORMATION PERTINENT TO GATE, GLOBE, CHECK AND PARALLEL SLIDE VALVES ......................19

5.1 Packing ..................................................................................................................................................195.1.1 Number of Packing Rings Required ........................................................................................195.1.2 Packing Ring Removal On Line ................................................................................................195.1.3 Removal With Blowout..............................................................................................................205.1.4 Repacking With Graphite Packing Rings ................................................................................20

for Valves Without a Leak-off Connection ..................................................................................

5.1.4.1 Packing Consolidation Method................................................................................215.1.5 Repacking With Graphite Packing Rings ................................................................................22

for Valves With a Leak-off Connection ........................................................................................5.1.6 Packing Torques ......................................................................................................................225.1.7 Live-loading Packings................................................................................................................24

5.2 Detailed Maintenance ..........................................................................................................................245.2.1 Packing Chamber Leakage........................................................................................................245.2.2 Body/Bonnet (Gasket) Leakage ................................................................................................25

5.2.2.1 General ......................................................................................................................255.2.2.2 Leakage of Body-Bonnet Joint ................................................................................255.2.2.3 Body-Bonnet Joint - Seating Face Repairs ............................................................25

TABLE OF CONTENTS


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TABLE OF CONTENTS

5.2.3 Seat Leakage ..............................................................................................................................265.2.3.1 General ......................................................................................................................26

5.2.3.2 Wedge & Disc Repairs - Gate & Parallel Slide Valves............................................275.2.3.3 Seat Repairs ..............................................................................................................28

5.2.3.3.1 Gate & Parallel Slide Valves ....................................................................285.2.3.3.2 Globe, Needle, Stop & Piston Check Valves ..........................................28

5.2.3.4 Fitting Of Repaired Parts ..........................................................................................295.2.3.4.1 Gate Valves................................................................................................295.2.3.4.2 Parallel Slide Valves..................................................................................315.2.3.4.2 Globe, Stop Check and Piston Check Valves ..........................................32

5.2.3.5 Seat Tightness - Closing Torques............................................................................335.2.4 Backseat Repairs ........................................................................................................................34

5.3 Torque Values - Actuator, Yoke/Bonnet Bolting ................................................................................35

GATE VALVE PAGE

VI GATE VALVE ........................................................................................................................36

6.1 Types of Gate Valves............................................................................................................................36

6.2 Exploded View ......................................................................................................................................39

6.3 Partial Disassembly - Gasket Replacement ........................................................................................416.3.1 Style I ..........................................................................................................................................416.3.2 Style II and III ..............................................................................................................................41

6.4 Total Disassembly ................................................................................................................................416.4.1 General ......................................................................................................................................416.4.2 Disassembly of Body/Bonnet and Wedge/Stem ....................................................................41

6.4.2.1 Style I ........................................................................................................................416.4.2.2 Styles II and III ..........................................................................................................42

6.4.3 Disassembly of Top Works ......................................................................................................46

6.5 Assembly ..............................................................................................................................................476.5.1 Top Works Assembly ................................................................................................................476.5.2 Body/Bonnet and Wedge/Stem Assembly ..............................................................................47


GLOBE VALVE - INCLUDES STOP & PISTON CHECK VALVES PAGE

VII GLOBE VALVE ......................................................................................................................49

7.1 Types of Globe Valves..........................................................................................................................497.2 Exploded View ......................................................................................................................................53

7.3 Partial Disassembly - Gasket Replacement ........................................................................................54

7.3.1 Style I ..........................................................................................................................................547.3.2 Style II and III ..............................................................................................................................54

7.4 Total Disassembly of Globe and Stop Check Valves ........................................................................547.4.1 General ......................................................................................................................................547.4.2 Disassembly of Body/Bonnet and Disc/Stem/Union ..............................................................54


7.4.3 Disassembly of Top Works ................................................................................................................58

7.5 Total Disassembly of Piston Check Valve ..........................................................................................58

7.6 Assembly ..............................................................................................................................................597.6.1 Top Works Assembly ................................................................................................................597.6.2 Body/Bonnet and Disc/Stem Assembly ..................................................................................60


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TABLE OF CONTENTS


PARALLEL SLIDEVALVE PAGE

VIII PARALLEL SLIDE VALVE ........................................................................................................62

8.1 Types of Parallel Slide Valves..............................................................................................................62

8.2 Partial Disassembly - Gasket Replacement ........................................................................................648.2.1 Style I ..........................................................................................................................................648.2.2 Style II and III ..............................................................................................................................64

8.3 Total Disassembly ..............................................................................................................................648.3.1 General ......................................................................................................................................648.3.2 Disassembly of Body/Bonnet and Discs/Stem ........................................................................65


8.3.3 Disassembly of Top Works ......................................................................................................718.4 Assembly ..............................................................................................................................................72

8.4.1 Top Works Assembly ................................................................................................................728.4.2 Body/Bonnet and Discs/Stem Assembly..................................................................................72

CHECK VALVES - INCLUDES SWING CHECK & TILTING DISC VALVES PAGE

IX CHECK VALVES......................................................................................................................75

9.1 Types of Check Valves..........................................................................................................................75

9.2 Partial Disassembly - Gasket Replacement ........................................................................................78

9.3 Total Disassembly ................................................................................................................................799.3.1 Body/Bonnet Disassembly ........................................................................................................799.3.2 Disc Disassembly ......................................................................................................................80

9.3.2.1 Swing Check..............................................................................................................809.3.2.2 Tilting Disc ................................................................................................................82

9.4 Detailed Maintenance ..........................................................................................................................839.4.1 Body/Bonnet (Gasket) Leakage ................................................................................................83

9.4.1.1 General ......................................................................................................................839.4.1.2 Leakage of Body-Bonnet Joint ................................................................................83

9.4.2 Seat Leakage - Swing Check ....................................................................................................839.4.2.1 Swing Check Disc Repairs........................................................................................839.4.2.2 Swing Check Seat Repairs........................................................................................84

9.4.3 Seat Leakage - Tilting Disc ........................................................................................................849.4.3.1 Tilting Disc Disc Repairs ..........................................................................................849.4.3.2 Tilting Disc Seat Repairs ..........................................................................................84

9.5 Assembly ..............................................................................................................................................849.5.1 Disc Assembly Fit-Up ................................................................................................................84

9.5.1.1 Swing Check Disc Unit..............................................................................................849.5.1.2 Tilting Disc Unit ........................................................................................................85

9.5.2 Bearing Blue or Developer Test................................................................................................869.5.2.1 Swing Check..............................................................................................................869.5.2.2 Tilting Disc ................................................................................................................87

9.5.3 Paper or Light Test ....................................................................................................................879.5.3.1 Swing Check..............................................................................................................879.5.3.2 Tilting Disc ................................................................................................................88

9.5.4 Internal and Mid-Section Assembly - Swing Check................................................................889.5.5 Body-Bonnet and Cover Assembly - Swing Check & Tilting Disc ........................................89


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TABLE OF CONTENTS

APPENDIX PAGE

X APPENDIX ............................................................................................................................9010.1 Procedure for Removing Manual Gear Actuator ..............................................................................90

10.1.1 Style I ..........................................................................................................................................9010.1.2 Style II ........................................................................................................................................91

10.2 Procedure for Removing Motor Actuators ........................................................................................92

10.3 Procedure for Removing Motor Hydraulic or Pneumatic Actuators ................................................94

10.4 Spare Parts............................................................................................................................................95

10.5 Special Tools for Valve Assembly and Disassembly ........................................................................96

TERMS AND CONDITIONS OF SALE ................................................................................................99


6/996

I INTRODUCTION

T hi s manual ha

s been pr epar ed by V elan

engi neer s , d es i gner s and m

ai nt enanc e

per s onnel t o as s i s t y ou i n obt ai ni ng many y e

ar s

of s at i s f ac t or y s er v i c e f r om

y our pr es s ur e s eal v alv es . It

w i ll als o as s i s t y ou i n r es t or

i ng y our v alv e t o t he bes t

w or k i ng c ond i t i on w i t h a m

i ni mum of t i me and

ex pens e.

V elan v alv es ar e d es i gned a

nd manuf ac t ur ed bas ed on

many y ear s of r es ear c h and

pr od uc t d ev elopment and

ar e c ons t ant ly bei ng i mpr ov

ed . Bef or e begi nni ng any

ma j or w or k , w e r ec ommend

t hat y ou r ead t hi s book let

c ar ef ully at leas t onc e

t o und er s t and t he v alv e's

phy s i c al c ond i t i on.

P leas e not e t hat i f y ou d o no

t und er s t and t he r eas on

f or t he s er v i c e pr oblem, w e

s ugges t t hat y ou get i n

t ouc h w i t h y our loc al V elan

r epr es ent at i v e or c all t he

C us t omer Ser v i c e Manager

f or t ec hni c al as s i s t anc e.

Bef or e begi nni ng any ma j or

w or k , w e r ec ommend t hat

y ou c ar ef ully c hec k t he nam

eplat e on t he v alv e and

r ec or d t he f i gur e number t o

i d ent i f y t he t y pe and s i z e of

v alv e. See t he “ E ssent i a

l F eat ur es of V el an V al v es”

f or m on t he f ollow i ng page f or an ex plan

at i on of V elan

“ F i gur e N umber s” .

1.1 GENERAL INTRODUCTION


7/997

INTRODUCTION I

1.2 ESSENTIAL FEATURES OF VELAN VALVES

The figure numbers shown on this key are designed to cover essential features of Velan valves. Please use figure numbers to ensure prompt and accurate pro-

cessing of your order. A detailed description must accompany any special orders.

Gate, Globe and Check ValvesType of Connection Size of connection Class Type Body/Bonnet Style Body Material Trim Material

A B C D E F G

— —B 1 6 — 3 0 5 4 P — 0 2 T S

e.g.: is a 10" (250 mm) Class 1500 carbon steel pressure seal gate valve with TS trim and buttweld ends.

TYPE OF CONNECTIONAA Special C Combination R Flanged, ring joint W Socket weld

B Butt weld F Flanged, B16.5 U Undrilled flanges X Butt weld (intermediate class)

SIZE OF CONNECTIONB

Customers have the choice of specifying valve size as part of the valve figure (“B”) using the numbers below, or indicating valve size separately.

e.g.: B16-3054P-02TS (valve size is part of figure number), 10" (250mm) B-3054P-02TS (valve size is shown separately).

08 2" (50 mm) 12 4" (100 mm) 16 10" (250 mm) 21 18" (450 mm) 26 26" (650 mm) 34 34" (850 mm) 99 SPECIAL

09 21 ⁄ 2" (65 mm) 13 5" (125 mm) 18 12" (300 mm) 22 20" (500 mm) 28 28" (700 mm) 36 36" (900 mm)

10 3" (80 mm) 14 6" (150 mm) 19 14" (350 mm) 23 22" (550 mm) 30 30" (750 mm) 42 42" (1050 mm)

11 31 ⁄ 2" (90 mm) 15 8" (200 mm) 20 16" (400 mm) 24 24" (600 mm) 32 32" (800 mm) 48 48" (1200 mm)

Valve Type Figure Number Designation for Live-loading and Leak-offAdd a one-digit suffix to the figure number:

Standard Gate or globe 0 - for live-loading, double packing and leak-off Packed 2 -for live-loading onlyValves 3 - for double packing and leak-off only

e.g.: B16-3054P-02TS-0 is a 10" (250 mm) Class 1500 carbon steel pressure seal gate valve with TS trim, live-loading, double packing and leak-off.

CLASSC0– 150 1– 300 2– 600 3– 1500 4– 2500 5– 4500 7– 900 X– Special

TYPED

01 Flow control 05 Conv. port gate 07 Stop (globe) 09 Needle 14 Parallel Slide 34 Tilting disc check03 Piston check 06 Full port gate 08 Stop check 11 Swing check 23 Double disc gate 99 Special

BODY/ BONNET STYLEE4 – Vertical 6 – “Y” pattern (inclined) A – Special K – Pressure seal (cast)5 – Angle 8 – Elbow down B – Bolted bonnet (forged) P – Pressure seal (forged)

BODY MATERIALF01 - Special 09 - Chr. moly, F9, C12 15 - S/S, F347, CF8C 22 - Titanium Gr. 5 28 - S/S F317, CG8M 36 - S/S F321H 42 - Titanium Gr. 1202 - A105, WCB 10 - S/S, F316H 16 - S/S, F304H 23 - Alloy 20 29 - S/S F317L, CG3M 37 - Incoloy 43 - Titanium03 - Chr. moly, F1, WC1 11 - S/S, F304, CF8 18 - S/S, F321, CF8C 24 - LF1 31 - LCC 38 - LC1 45 - Nobium04 - Chr. moly, F5, C5 12 - S/S, F304L, CF3 19 - Monel M35 25 - LCB 32 - S/S F51 39 - LC2 44 - Ferralium 25505 - Chr. moly, F11, WC6 13 - S/S, F316, CF8M 20 - Inconel 625 26 - LF2 34 - F91 40 - Titanium Gr. 2/3 45 - S/S F5506 - Chr. moly, F22, WC9 14 - S/S, F316L, CF3M 21 - Hastelloy C 27 - LF3/LC3 35 - S/S F44, 254 SMO 41 - Titanium Gr. 7

TRIM MATERIALGCODE WEDGE / DISC SEATING SURFACE (1) SEAT SURFACE (1) STEM

AA Special Special Special

HC Hastelloy C Stellite 6 Hastelloy C

MS Stellite 6 Stellite 6 316

MY CF8M or 316 Stellite 6 316

TS Stellite 6 Stellite 6 410

XS Stellite 6 Stellite 6 Monel or Monel K

XX Monel Monel Monel

XY Monel Stellite 6 Monel

NA(2) 13% Chrome HRC 22 max. Stellite 6 13% CR HRC 22 max.

NB(2) Stellite or CF8M Stellite 6 SS 316

NC(2) Monel Stellite 6 Monel or Monel K

1. Base material is either the same as body or solid trim at manufacturer's option. 2. NACE service valves are supplied with bolting with maximum hardness ofRc. 22. Use NS for special NACE trim and specify details on order.

N A C E

H 2 S

S E R V I C E ( 2 )


8/99

I INTRODUCTION

1.3 THE DIFFERENT STYLESOF PRESSURE SEAL VALVES

Velan pressure seal valves have in the past beenbuilt in three basic styles for a large range of sizes

and pressure classes. These basic styles (shownin Fig. 1.3A, 1.3B and 1.3C) apply to gate, parallelslide, globe and stop check valves. In a continuousinnovative effort to improve pressure seal valvedesign, Velan is presently phasing in a live-loadedbolted bonnet configuration as its standard.An example of this is illustrated in Fig. 1.3D .

1. Style I (Fig. 1.3A)

Turning the bonnet retainer clockwisedevelops the upward force for tightening thepressure seal gasket. The internal fluid pres-sure also forces the bonnet upward toward theyoke, increasing the pressure on the gasket.

2. Style II (Fig. 1.3B)

When the cap screw is turned clockwise, theupward force on the bonnet retainer pulls thebonnet upward against the pressure seal

Figure 1.3B Style II

Capscrew

gasket. The internal fluid pressure also forcesthe bonnet upward toward the thrust ring,increasing the pressure on the gasket.

3. Style III (Fig. 1.3C)

The upward tightening force for the pressureseal gasket is achieved by tightening the nutson the studs in the bonnet which protrudethrough the bonnet retainer. The internal fluidpressure also forces the bonnet upwardtoward the thrust ring, increasing the pressureon the gasket.

4. Live-loaded bolted bonnet (Fig. 1.3D)

(with spring washers)

Compression of the pressure seal gasket isachieved by tightening the nuts on the studs inthe bonnet which protrude through the bonnet

retainer and by the internal fluid pressure.The Belleville washers allow for greater ener-gy storage and consequently, automaticallyreapply bolt load to the gasket when hydropressure is removed or pressure is reduced.

Figure 1.3D Live-loaded bolted bonnet

Bellevillewashers

Figure 1.3A Style I

Bonnetretainer

Figure 1.3C Style III

Nut

8


9/999

2.1 RECEIVING INSPECTION

All valves must be examined for signs of damagethat may have occurred during transportation.

Any damage should by analyzed and a reportshould be issued. Serious damage should bereported to your local Velan representative or tothe Customer Service Manager so that a suitablearrangement for repairs can be madewithout delay.

2.2 QUALITY CONTROL DOCUMENTATION

For valves purchased with Quality Control (QC)certification, check the package of documents tosee that the Quality Control certificates are com-

plete as per the purchase order.

2.3 STORAGE

Valves should be stored in a suitably shelteredplace to prevent contamination by weather, dirtor dampness. The valve is shipped with endprotectors on the inlet and outlet which shouldstay on the valve until it is ready for installation.

NOTE: If actuators are involved, please

refer to the applicable manufacturer’s instruc-

tions for storage.WARNING: During installation, welding and

construction stage the valve mid-section

around the packing flange and stem should

be protected at all times; as foreign debries

from welding, grinding, etc. can fall in

between the tapered area of the packing

flange and stem that can cause extensive

damage to stem and associated parts during

valve cycling. In any case, prior to cycling,

the area between the stem, packing flange

and gland bushing must be thoroughly

cleaned off of all foreign matter.

2.4 HANDLING AND PREPARATION

On large valves, a hoist is needed to assistinstallation. A sling should be placed under the

valve body so that the unit can be lifted verticallyto its final destination. End protectors must beremoved from all types of valves and connectionsmust be checked for cleanliness. Any visible for-eign matter must be removed from end connec-tions on flanged and weld-end valves. The weld-end preparation must be cleaned properly with asuitable solvent such as acetone or alcohol. Donot use solvents containing chloride or fluoride.

2.5 SPECIAL INSTRUCTIONSFOR GATE VALVES

The flow through gate valves can be from eitherend. There may be exceptions to this if bypasspiping is welded to the valve body or if a pressurerelief hole is drilled in one side of the valve gate.Check your piping layout drawing to ensure cor-rect position and direction of flow. Gate valvesshould be installed and welded into the pipelinewith the wedge or disc in the fully closed position.If the valve is left open or partially open, it coulddistort and leak during operation. Also, leavingthe valve in a fully closed position helps preventweld spatter from falling directly onto the mating

faces of the seats.

The preferred orientation of a gate valve isupright. The valve may be installed in otherorientations, but any deviation from vertical is acompromise. Installation upside down is notrecommended because of possible dirt build-up inthe bonnet. It is best to consult Velan Engineeringdepartment during quotation review process as toremedial measures required (hardfacing of guides)when valves over 12” are tilted beyond 45˚ fromthe stem vertical orientation.

NOTE: Gate valves should not be used forthrottling to control the flow, they are

normally fully open or fully closed. If left in

partially open position could result in severe

damage to body seats, wedge, stem & guide

rails.

RECEIVING & PREPARATION FOR INSTALLATION II


10/9910

II RECEIVING & PREPARATION FOR INSTALLATION

Flow

45°max. 45°max.

45°max.

Figure 2.7 Check valve: Angle of incline and roll angle

2.6 SPECIAL INSTRUCTIONSFOR GLOBE VALVES

Globe valves are usually installed with the inlet

below the valve seat. This must be checked care-fully to prevent incorrect installation. If throttlingservice is particularly severe, Velan recommendsthat the valve be installed so that the flow entersover the top of the seat and goes down through it.This maintains the valve in a more stable condi-tion, the amount of wear is minimized and there isless external noise. Valve operation also becomeseasier because less torque is required to closethe valve.

Globe type valves should be installed and weldedwith the disc in a fully closed position to prevent

damage to the valve during installation. Leavingthe disc in a fully closed position also preventsweld spatter from falling directly onto the matingfaces of the seat and disc.

PRECAUTION: Allow time for welding tocool before trying the valve for the firsttime in the pipeline.

2.7 SPECIAL INSTRUCTIONSFOR CHECK VALVES

Check valves must be installed with the inlet in

direction of arrow. This must be checked carefullybefore installing the valve. Placing a check valvein the opposite direction to the flow will preventthe disc from swinging free and will therefore pre-vent normal operation of the valve.

NOTE: All check valves should be installed at

least ten pipe diameters away from upstream

pumps, elbows, fittings or equipment. If

closer installation is required, please consult

the Velan Customer Service Manager.

CAUTION: Velan piston check and stopcheck valves without springs should beinstalled with the bonnet up, and the angleof incline of the line should be no morethan 45° from horizontal. Also, the rollangle of the valve bonnet should be nomore than 45° from side to side


11/9911

RECEIVING & PREPARATION FOR INSTALLATION II

2.8 SPECIAL INSTRUCTIONS FOR TILTINGDISC CHECK VALVES

Tilting disc check valves can be installed

horizontally or vertically according to the designspecifications and with the inlet in the directionof the arrow. However, for vertical installationspecial disc machining is required and priorknowledge of design condition is necessary toensure correct applications. Placing a check valvein the opposite direction to the flow will preventthe disc from swinging free and will thereforeprevent normal operation of the valve.

NOTE: All check valves should be installed at

least ten pipe diameters away from upstream

pumps, elbows, fittings or equipment. If clos-

er installation is required, please consult theVelan Customer Service Manager.

2.9 RECHECK FOR BOLT TIGHTNESS

In order to ensure a pressure seal between thevalve’s body and bonnet, it is essential that bolttightness be verified. Whenever possible firmlybackseat the valve and bring up the line pressureas close as possible to normal operating pressureand temperature. Recheck and retighten the gas-ket bolts (i.e., body/bonnet bolts) as necessary to

the values given in Tables 4.5 on pages 17. Thefollowing procedure is used:

1. If possible fully open and firmly back seatthe valve.

2. Remove one nut or cap screw at a time,lubricate stud and nut thoroughly with anapproved anti-seize compound and torque torecommended values shown in tables 4.5 .

3. Remove opposite nut or cap screw and repeatprocedure until all nuts or cap screws havebeen retorqued.

4. Recheck bolt torque by going once aroundclockwise.

NOTE: If gasket must be replaced, followBody-Bonnet Torquing Procedure, Section 4.5 .

NOTE:

a) Pressure seal design without live load

bonnet (no spring washers):

The gasket bolt tightness must be

rechecked after operating test pressureand temperature has been achieved.Without live-loading, bolt tightness will belost, when the system loses pressure.

b) Pressure seal design with live load bonnet:A live-loaded bonnet bolt may also losesome bolt load, due to vibration in transitor bolt creep. It is advisable that live-loadedbonnets be checked for bolt torque atoperating pressure. Once torqued atoperating pressure, no future tightening of gasket bolting will be necessary, unless thevalve has been dismantled, in which case,

the gasket bolts must be torqued to valuesgiven in Tables 4.5A & B on page 17 andbolt tightness rechecked after operatingtest pressure and temperature has beenachieved.

CAUTION: If the pressure seal gasketis not pulled up concentric to the body

/bonnet top-bore axis, under lowerpressure the gasket may not be properlyseated. Consequently, leakage mayoccur. Moreover, non-uniform contact

may be the source of leaks in the future.Therefore, when possible, backseat thevalve fully when pulling up the pressureseal gasket bolts. The packing bolts mustalso be verified against Table 5.1A & B on page 23.


12/9912

II RECEIVING & PREPARATION FOR INSTALLATION

4. Standard design now on market.(Fig. 2.11C)

5. Velan solution with live-loading, ensuresautomatically zero leakage over large range

of pressures.

The torque requirements on various live-loadedconfigurations differ from the standard boltingtorque requirements and may require alteringcertain parts (e.g., packing flanges and bonnetretainers in case of retro-fit live-loading).For further details regarding specific applicationsby size and pressure class please contactCustomer Service Manager.

Figure 2.11C Graphically illustrates the storedbolt energy in live-loaded bolting.

New Generation of Live-Loaded Pressure Seal Design(Fig. 2.11B)

1. Automatically reapplies bolt load to the

gasket when hydro pressure is removed or

pressure is reduced.

2. When torqued once at installation under

operating pressure no future tightening will

be required.

3. Live-loading compensates for large bonnet

movement.

Figure 2.11A

Figure 2.11B

2.10 SPECIAL NOTE ONLIVE LOADED BOLTING

As a result of continuous design improvements

and application requirements, Velan is phasing-inlive-loaded bolting as a standard feature in futuredesigns and as an option in certain existing designs.At the present time, live-loading is available in6 - 24” (150 - 600 mm) (Class 1500) and 8 - 24”(200 - 600 mm) (Class 2500). For applications insmaller sizes, please contact your local Velanrepresentative.

Standard Pressure Seal Design (Fig. 2.11A)

1. Bonnet tends to move up or down as pres-

sure changes.

2. Bolt load nominal to create initial seal.

3. Gasket deforms during hydrotest, bolts lose

torque and must be retightened after

hydro-test.


13/9913

WARNING III

FOR SAFETY REASONS,

it is important to take these precautions

Personnel making any adjustments on the valves should wear safety equipment normally used to work with fluid in the line

where the valve is installed.

Before removing the yoke bushing under pressure, the valve should be in

fully open position in order to prevent injuries.

Before removing a valve from a line, line pressure must be relieved withno exception.

Velan valves can be equipped with a variety of manual gear, electric motor,hydraulic or pneumatic actuators. Generally, all pressure must be relieved from

both sides of the valve before the actuator is removed.

A valve in the fully open position (backseated), should not be jammed-tight (over- torqued), to avoid thermal binding. It is our recommendation that the valve be

removed 1 / 4 turn of the handwheel from the fully open position. This will also

ensure that packing tightness is verifiable. In gear-operated valves, because of the

backlash, it is difficult sometimes to ensure this position.

Valve standards, such as API and MSS, caution users that successful completionof a backseat test should not be construed as a recommendation by the manufactur-

er that a valve may be repacked while it is under pressure. The backseat may

be used as a means of stopping or reducing packing leakage until the packing

can be replaced under no pressure. Removal of packing with the valve under

pressure is at the owner’s risk.

Do not attempt to force out the pressure seal gasket by using a crane, hoist, chain-block, etc. The gasket may be tight inside

the valve body and if pulled using a crane, jack, or other

means, it may suddenly release, causing

personal injury and/or extensive damage.


14/99


15/9915

GENERAL MAINTENANCE IV

4.2 OPERATION

4.2.1 General

All valves require examination before beingput into operation. In addition, valves should beinspected regularly during operation and shouldreceive prompt attention when trouble arises.As a general rule, valves should be subjectedto scheduled maintenance.

4.2.2 Smoothness of Operation

Stem threads, gearing and other workingcomponents outside the fluid area should belubricated frequently and at least once every six

months. Specific lubricants and frequency of application are shown in the recommendedlubrication table of Section 4.3 . Valves that arenot operated frequently and which may remainopen or closed for long periods of time shouldbe worked (even if only partially) about once amonth.

IMPORTANT: Excessive handwheel effort can

indicate the following:

1. Improperly lubricated or damaged valvestem.

2. Valve packing compression too tight (check

torque Table 5.1A) .

3. Faulty or damaged valve parts.

4. Foreign debries on stem threads and/orpacking area

4.4 GENERAL ASSEMBLY INFORMATION

1. The most important fact to be considered is

the cleanliness of all parts. All rust and dirt

should be removed from all parts with a wirebrush or emery cloth. Oil and grease should

be removed with suitable solvents.

2. All threaded parts (cap screws, nuts, studs)

must be well relubricated. The stem and yoke

nut threads should be clean of old grease

before the new application. Recommended

lubricants can be found in Section 4.3 . Use

correct lubricant for each individual part.

3. Repaired or replacement parts must be

checked to see that all repair procedures

have been done and that all replacement

parts (e.g., packing rings, gasket, etc.) have

been checked for size so that they will fit into

the valve being serviced.

4. All orientation marks assigned during

disassembly must be observed so that correct

orientation is maintained. Where applicable,

orientation marks should be made on parts

near the body serial number (e.g., wedge,

disc, seat, etc.).

Recommended lubricant subject to change without notice.

Table 4.3 Recommended lubrication

4.3 RECOMMENDED LUBRICATION

PART LUBRICATION APPLICATION FREQUENCY

Stem Exxon: Ronex MP, Castrol MP Directly to When threadsthreads or equivalent MP group (up to 6500F) threads appear dry

Ronex Extra duty 2 (above 6500F)

Yoke nut Exxon: Ronex MP, Castrol MP Inject through Concurrentlyor equivalent MP group (up to 6500F) grease fitting with stemRonex Extra duty 2 (above 6500F) at hub of yoke thread lubrication

All threaded parts - Anti-seize compound No. 425-A Thin coat on On valveexcept (Crane) or equivalent threads assembly onlystem and yoke nut - Nickel Anti-Seize to MIL-A-90TE

or MOLYKOTE P37


16/99

frequent temperature and/or pressure cycling.For further details, refer to Section 2.11, Special Note on Live-Loaded Bolting . For torque valuesconsult Table 4.5B. For Belleville spring washerconfiguration refer to Fig. 4.5C & D.

16

IV GENERAL MAINTENANCE

4.5 BONNET/GASKET TORQUING PROCEDURE

4.5.1 General

1. Clean all studs and nuts. Visually inspectall threads to ensure removal of all foreignmatter, rust, corrosion, burrs and previouslubricants.

2. Liberally cover the stud threads and thesurface under the nut head with FELPROtype C5A Hi-Temp or nuclear grade (neverSEEZ 5000) nickel base antiseize compoundor approved equivalent. Also, lubricate thefemale threads of the nuts and nut flats andwipe off any excess lubricant that mayadhere to any of the stainless steel partswith recommended solvents.

Recommended solvents for this work are:a) unused or redistilled acetoneb) alcohol

3. After tightening bolts by hand, follow thebolt tightening sequence shown in Fig. 4.5A.This sequence depends on the quantity of bolts used. The drawing illustrates the logicalsequence one should follow.

IMPORTANT: To maintain proper alignment,whenever possible valve should be fullybackseated prior to retightening bolts.

If the type of valve you are servicing is apressure seal, Style I, the bolt tighteningsequence shown in Fig. 4.5A will not apply.The bonnet retainer nut must be torqueddown using a crawfoot wrench as in Fig. 4.5B and torque to value shown in Table 4.5A.

4.5.2 Application of Torque

When applying the torque to the bolts, each boltshould be torqued in steps of approximately 20%of the final torque shown in Table 4.5A or B torque values with or without live-loading.

If possible, after the final torque has been appliedto the screwed bonnet retainer, cap screw orpull-up bolts, bring up the line pressure as closeas possible to normal operating pressure andtemperature. Recheck and retighten the bolts if necessary.

IMPORTANT: It is possible to retro-fit certainsizes of Velan pressure seal valves with longerbolts and Belleville spring washers to achieve alive-loading of the bonnet bolts. This isapplicable when the system undergoes

6

3

2 8

7 1

5

4

Figure 4.5A Bolt tightening sequence

Figure 4.5B Crawfoot Wrench for 2 - 2 1 ⁄ 2 ” (50-65 mm) for screwed bonnet retainer


17/9917

IV GENERAL MAINTENANCE

Table 4.5A Bonnet/Gasket Torque Values Without Live-Loading

BOLTING MATERIAL

STUD SIZE B7, B16, 630, A–574 660

ft⋅lb Nm ft⋅lb Nm3 ⁄ 8” – 16UNC 20 27 20 277 ⁄ 16” – 14UNC 30 41 30 411 ⁄ 2” – 13UNC 50 68 45 619 ⁄ 16” – 12UNC 70 95 62 845 ⁄ 8” – 11UNC 95 129 85 1153 ⁄ 4” – 10UNC 170 231 150 2037 ⁄ 8” – 9UNC 270 366 240 326

1 – 8UN 410 556 360 488

11 ⁄ 8” – 8UN 600 814 535 726

11 ⁄ 4” – 8UN 845 1146 750 1017

13 ⁄ 8” – 8UN 1150 1560 1020 1383

11 ⁄ 2” – 8UN 1520 2062 1350 1831

VALVE SIZE SCREWED BONNET RETAINER MATERIAL

inches mm SA–36, A–515, A–479

2 – 21 ⁄ 2” 50 - 65 350 ft⋅lb 475 Nm

3 - 4” 75 - 100 650 ft⋅lb 880 Nm

NOTE: (1) For graphite gasket use the following values.a. If the valve is not pressurized, use 125% of above torque values.b. If pressurized to design pressure (operating) use 50% of the above values.c. For pressures between zero and the design pressure, the torque to be used is approximated by linear interpolation.

(2) Torque tolerance ±10%.(3) For temperatures above 750°F (400°C) use 75% of the values.

(4) Above Torque Values are with the bolts lubricated.

Table 4.5B Bonnet/Gasket Torque Values With Live-Loading (Spring Washers)

BOLTING MATERIAL

STUD SIZE B7, B16, 630, A–574

ft⋅lb N⋅m1 ⁄ 2” – 13UNC 60 815 ⁄ 8” – 11UNC 120 1633 ⁄ 4” – 10UNC 200 2717 ⁄ 8” – 9UNC 320 434

1 – 8UN 490 664

11 ⁄ 8” – 8UN 710 963

11 ⁄ 4” – 8UN 1000 1360

NOTE: (1) For graphite gasket use the following values.a. If the valve is not pressurized, use 125% of above torque values.b. If pressurized to design pressure (operating) use 50% of the above values.c. For pressures between zero and the design pressure, the torque to be used is approximated by linear interpolation.

(2) The torque values listed above are for standard Velan valve designs with live loading.(3) Torque tolerances ±10%.(4) Above Torque Values are with the bolts lubricated.


18/9918

GENERAL MAINTENANCE IV

On sizes of bolts larger than 1-1 / 8”, special torquemultipliers with ratios 1:7 or 1:6 should be usedfor torquing.

PRECAUTION:

1. If tightening sequence is not followed,

it is possible that the gasket will not becompressed evenly, and may result ingasket leakage.

2. Over-torquing can cause deformationof the body/cover retainer and/or gasketretaining ring, causing valve to leak.

3. Do not use impacting devices to tightenup the bolting on the body/bonnet(cover). Use suitable mechanicaldevices for tightening.

4. When the valve is positioned such that

the stem is horizontal, care should betaken to prevent the bonnet from tiltingto one side by gravity. To maintainconcentricity, first open valve fully,backseat firmly and repack. Torque insteps of 20% of the final torque valueand ensure that the gland bushing slidessmoothly into the packing chamber.

5. Use hand torque wrenches. If torquewrenches are not suitable, use standardwrenches and the following guidelines

will apply:BOLT SIZE LENGTH OF WRENCH

inches mm

3 / 8” 5” 1251 / 2” 6” 1509 / 16” 9” 2255 / 8” 12” 3003 / 4” 18” 4507 / 8” 24” 6001” 30” 750

1 1 / 8” 36” 900

Figure 4.5C Belleville spring washerconfiguration

Figure 4.5D Belleville spring washerconfiguration

(3) bellevillespring washer

(5) bellevillespring washer


19/9919

5.1 PACKING

5.1.1 Number of Packing Rings Required

(see Figs 5.1A & B)

All Velan pressure seal gate, globe and parallelslide valves require seven packing rings(Fig 5.1C) . For valves equipped with a leak-off connection, four packings are placed below thelantern ring and three above (Fig. 5.1D) .

5.1.2 Packing Ring Removal on Line

Follow warning instructions in Section III beforereplacing packing rings on line.

1. Remove the packing flange nuts and, if fit withlive-loading, remove Belleville spring washers.

2. Lift packing flange and gland bushing as highas possible and secure.

3. For braided packing rings: Fig. 5.1C and D usespecial flexible removal tools (cork screw tip)Fig. 5.1E screw into the packing ring and pullout. For graphite ribbon packing Fig 5.1C and D with special “C”-saw tool Fig. 5.1F cut throughthe packings, apply downward pressure asyou work the tool in a back and forth motion.Blow out packing remains using instrument air

or suck out with a vaccum cleaner. Care mustbe taken not to scratch the stem or the walls of the packing chamber during the removal of the packing rings.

4. If the valve is equipped with a leak-off pipe,there is a lantern ring after the third packingring. To remove the lantern ring, insert twohooks into the holes at the top of the lanternring or insert screw-in extracting wires wheretapped holes are provided. These tappedholes are 6-32 for valves 21 ⁄ 2 - 4”(65 -100 mm)and 8-32 UNC for valves 6”(150 mm) and

larger.5. After the lantern ring is lifted, the last four

packing rings can be removed using theprocedure described in step 3.

NOTE: All of our designs can be equippedwith a blowout plug option. If this connectionis provided, the packing rings can be removedby applying gas or hydraulic pressure frombelow as shown in Fig. 5.1G . See Section 5.1.3.

Figure 5.1A Graphite ribbon packing

Figure 5.1B Braided graphite packing ring

Figure 5.1C Seven packings shown

Lanternring

BraidedpackingGraphite

ribbonpacking

Graphiteribbonpacking

Braidedpacking

Braidedpacking

Braided

packing

Figure 5.1D Lantern ring configuration

INFORMATION PERTINENT TO GATE, GLOBE, CHECK & V

PARALLEL SLIDE VALVES


20/99

4. Remove blowout plug and gasket.Attach the pressure source to the connection.The packing rings will be pushed out of

the packing chamber.NOTE: When applying gas pressure, thisoperation will happen quite quickly and it ispossible that trapped liquid will spray out.

5. All packing rings can be removed simultane-ously. This is a fast and efficient operation.

5.1.4 Repacking with Graphite Packing Rings forValves without Leak-off Connection

1. Before repacking, check the stem and

the packing chamber wall for damage.

Packing Chamber: Scratches (damage) nodeeper than 0.010” (0.25 mm) per side can

be removed by polishing the surfaces with a

buffing wheel (120 - 220 grit) or by machining

the entire packing chamber surface.

The surface finish should be 16 RMS or better.

Stem: Scratches (damage) no deeper than

0.010” (0.25 mm) per side can be removed by

machining the entire stem. Smooth portion

up to the back seat. Surface finish should be

16 RMS or better.

2. Insert the first packing ring (braided graphite

type, end ring) manually and place as deepinto the packing chamber as possiblefollowed by 1 graphite ribbon (intermediatepacking ring). Refer to Fig. 5.1H .

Figure 5.1G Removal with blowout

Figure 5.1H Repacking without leak-offconnection

Packingflange

Gland bushing

Packing ring

20

V INFORMATION PERTINENT TO GATE, GLOBE, CHECK &


Figure 5.1F ”C”-saw packing removal tool

Figure 5.1E Flexible packing removal tool cork screw tip

5.1.3 Removal with Blowout (Fig. 5.1G)

1. Fully open the valve and tighten the stemfirmly against the backseat.

2. Loosen packing flange nut and live-loadingassemblies (if so equipped).

3. If valve is equipped with a leakoff pipe, blockoff connection.


21/99

Split packing

adaptor

21

INFORMATION PERTINENT TO GATE, GLOBE, CHECK & VPARALLEL SLIDE VALVES

Figure 5.1I Repacking with split packing ring

repeat the procedure above until all intermediate

graphite ribbon packings have been torqued

NOTE:

a) The split lap joints of each consecutive ringmust be staggered at 120° so that the fourthring installed has its lap back at the startingpoint (Fig. 5.1J) . Subsequent packing ringsshould be repacked in the same manner untilthe special packing adaptors are no longerrequired and the standard gland bushing canbe used.

b) In case valves are equipped with live-loading(Belleville spring washers), remove springwashers during precompression of packingrings, and reinstall at final torque.

6. Remove the nuts and split packing adaptor and

insert the last end ring (braided graphite type),

lower gland bushing and check for bushing

positive engagement with packing chamber.

NOTE: As a rule of thumb 1 ⁄ 4” (6 mm) min.

engagement is required. Lower the gland flange,

relubricate the gland studs/nuts using anti-seize

compound and torque to values shown in

Table 5.1A and/or project drawing.

7. Cycle the valve once for approximately the length

of the packing chamber. First cycle open then

close and retighten packing flange nuts to the

required torque value Table 5.1A.

NOTE: If above procedure using split bushings

cannot be followed, use alternate procedure,

refer to Section 5.1.4.1.

5.1.4.1 Packing Consolidation Method

1. Insert the first packing ring, braid graphite type

(end ring) and place as deep into the packing

chamber as possible, followed by five graphite

ribbon (intermediate packing rings)

refer to Fig. 5.1C.

NOTE: The split lap joints of each consecutive

ring should be staggered at approximately

120 degrees apart.

2. Install the last packing braided graphite type

(end ring). Lower the gland bushing and check

for positive engagement with packing chamber.

NOTE: The gland bushing should enter thepacking chamber as a rule of thumb approx.1 ⁄ 4” (6 mm) minimum engagement.

3. Insert the split packing adaptor. Push thepacking rings to the bottom of the chamber,making sure that the lap joint is not reversedduring the operation.

4. Place the gland bushing and packing flangeinto position (Fig. 5.1I) and compress thebottom packing by tightening the nuts to 130%of the torque value shown in Table 5.1A or B.

NOTE: Ensure gland bolts/nuts are well

lubricated with anti-seize compound.5. Remove the nuts and split packing adaptors,

insert the next graphite ribbon packing and

Figure 5.1J Seven packings installed


22/9922



3. Place the packing flange into position referto Fig. 5.1J . Ensure gland bolt/nuts are welllubricated with anti-seize compound.

Compress the packing by tightening the nutsto the torque value shown in Table 5.1A.

4. Cycle the valve for approximately the length of the packing chamber, first open then close andretighten to required final torque (Table 5.1A) .Do this procedure as many times as necessary(approximately 4-5 times) until all packingbecome fully consolidated (no more loss of torque).

NOTE: For motor operated valves (mov) usemov manual override handwheel to cycleopen and close.

5.1.5 Repacking with Graphite Rings for Valves withLeak-off Connection (Fig. 5.1K)

1. Follow the same procedure as described insteps one through four of the previous sectionSection 5.1.4 , Repacking with Graphite PackingRings for valves without leak-off connection.

2. Insert next intermediate graphite ribbonpacking ring and repeat the procedure above.

3. Insert (1) braided graphite packing ring.Lower the lantern ring ensuring that it lines upwith the leak-off connection and repeat theprocedure above.

4. Place (1) braided and (1) graphite ribbon

packing ring above the lantern ring and

precompress to 130% of torque value of

Table 5.1A.

NOTE: In case valves are equipped with

live-loading (Belleville spring washers) remove

spring washers during precompression of

packing rings, and reinstall at final torque.

5. Insert (1) last end ring braided graphite type

lower gland bushing and check for positive

engagement. As a rule of thumb approx. 1 ⁄ 4”

(6 mm) engagement is required. Carefully

align the gland bushing and packing flange.

Relubricate gland bolts/nuts and torque

down to values shown in Table 5.1A and/orproject drawing.

6. Cycle the valves once for approximately the

length of the packing chamber. When cycling

is completed, retighten packing flange nuts to

required final torque (Table 5.1A or B) .

NOTE: If above procedure using split bushings

cannot be followed, use alternate procedure as

described in Section 5.1.4.1, except install four

packing rings below the lantern ring and three

packings above, refer to Fig. 5.1D.

5.1.6 Packing Torques

Step 1: Clean all studs and nuts. Visually

inspect all threads to ensure removal

of all foreign matter, rust, corrosion,

burrs and previous lubricants.

Step 2: Liberally cover the stud and nut

threads and the bottom of nut flats

with an anti-seize compound such as

nickel base Never-SEEZ 5000, FELPRO

type C5A Hi-Temp or approved

equivalent.Step 3: Tighten the packing flange nuts a little

at a time on each side, then torque in

accordance with valve type, size,

pressure class and packing type as

shown in Table 5.1A.

NOTE: Values in Table 5.1A and B are

approximate for standard Velan valves.

Whenever possible, refer to project

engineering drawings for individual valves

and their required torques.

Leak-offpipe

Lanternring

Figure 5.1K Leak-off connection


23/9923

GLOBE GLOBE GLOBE “Y”- PATTERN INCLINED GLOBE

SIZE 600 - 900 1500 2500 1500 2500

ft⋅lb N⋅m ft⋅lb N⋅m ft⋅lb N⋅m ft⋅lb N⋅m ft⋅lb N⋅m

2” (50 mm) 21 28 21 28 25 34 25 34 25 342-1 ⁄ 2” (65 mm) 21 28 21 28 25 34 25 34 25 34

3” (75 mm) 23 31 25 34 25 34 25 34 25 34

4” (100 mm) 32 43 32 43 25 34 25 34 25 34

6” (150 mm) 81 110 81 110 81 110 81 110 90 122

8” (200 mm) 112 152 112 152 122 165 93 126 93 126

10” (250 mm) 132 179 141 191 122 165 151 205 151 205

12” (300 mm) 132 179 190 258 – – 190 258 151 205

14” (350 mm) 132 179 190 258 – – 190 258 151 205

16” (400 mm) 151 205 – – – – 244 331 – –

18” (450 mm) – – – – – – 244 331 – –

20” (500 mm) – – – – – – 255 346 – –

GATE FORGED GATE FORGED GATE FORGED GATE CAST PARALLEL SLIDE FORGED

SIZE 600 - 900 1500 2500 600 600 - 1500 2500

ft⋅lb N⋅m ft⋅lb N⋅m ft⋅lb N⋅m ft⋅lb N⋅m ft⋅lb N⋅m ft⋅lb N⋅m

2” (50 mm) 21 28 21 28 21 28 12 16 21 28 23 31

2-1 ⁄ 2” (65 mm) 21 28 21 28 25 34 16 22 21 28 23 31

3” (75 mm) 23 31 23 31 25 34 16 22 23 31 23 31

4” (100 mm) 32 43 32 43 25 34 24 33 32 43 23 31

6” (150 mm) 51 69 51 69 77 104 48 65 51 69 52 71

8” (200 mm) 102 138 102 138 102 138 60 81 102 138 102 138

10” (250 mm) 125 170 125 170 102 138 67 91 122 165 102 138

12” (300 mm) 125 170 125 170 125 170 84 114 122 165 122 165

14” (350 mm) 125 170 125 170 125 170 143 194 122 165 122 165

16” (400 mm) 141 191 197 267 197 267 184 250 122 165 141 191

18” (450 mm) 147 199 197 267 209 283 209 283 132 179 141 191

20” (500 mm) 186 252 209 283 209 283 209 283 170 231 141 191

24” (600 mm) 221 300 255 346 255 346 209 283 190 258 212 288

26” (650 mm) 221 300 – – – – – – – – – –

INFORMATION PERTINENT TO GATE, GLOBE, CHECK & VPARALLEL SLIDE VALVES

NOTE:

(1) Globes 12” (300mm) and up and “Y” - Pattern 6” (250 mm) are cast.

(2) For other materials and/or valve sizs contact the Velan Service Department.

(3) Torques tolerance ±10%.

(4) Above torque values are with the gland stud and nuts lubricated.

Table 5.1A Packing flange stud / nut torques for graphite packings

Table 5.1B Packing flange stud / nut torques for graphite packings


24/99



5.1.7 Live-Loading Packing

Installation of the packing rings follows theprocedures described in Sections 5.1.4 & 5.1.5 (‘without’ and ‘with’ a leak-off connection,respectively). The Belleville washers are notto be used while compressing individual packinginto the packing chamber. However, if “packingconsolidation method” is used as described inSection 5.1.4.1 the Belleville spring washers(live -loading) must be in place prior to applyingpacking torque.

IMPORTANT: approximately 1 ⁄ 4” (6mm)engagement of the gland bushing into thepacking chamber is essential to ensure thatthe packing does not blowout.

Velan’s standard live-loaded packing configurationfor pressure seal valves is illustrated in Fig. 5.1L.

Assembly Procedure:

1. On each gland stud, place spacer ring onthe packing flange, a guide sleeve, a stack of Belleville spring washers (either single or

24

double stack depending on application), anda gland nut, refer to Fig. 5.1L.

2. Tighten the gland nuts a little at a time on

each side up to the torque values indicated inTable 5.1A or B.

NOTE: Make sure that the Belleville washersdo not slide laterally while tightening.

5.2 DETAILED MAINTENANCE

5.2.1 Packing Chamber Leakage

If moisture or dripping occurs around the stem of the ID packing chamber, the following points mustbe investigated before removing the packing:

1. Check if the packing flange is torqueddown to the correct torque as shown inTable 5.1A or B.

2. Check if the live-load arrangement is incorrect order. Compare your live-loadingarrangement with Fig. 5.1L. If it is not correct,open the valve to the backseat position andtighten up on the backseat firmly.

Figure 5.1L Live loaded packing

Guidesleeve

Guidesleeve

Single stacked Double stacked


25/99



3. Check if the gland bushing is bindingagainst the packing chamber wall or stem.If so, fully open the valve and tighten thestem against the backseat firmly. Loosen thepacking flange and realign the gland bushing.Tighten up the packing flange a little at a timeon each side, then torque down to the correcttorque as shown in Table 5.1A or B .

4. After retightening, cycle the valve oncefor approximetely the length of the packingchamber, cycle first open then close andretighten nuts to original torque value (Table 5.1A) . Slacken the nuts slightly if torque is toohigh. If steps 1 through 4 do not stop leakage,proceed with the removal and replacement of the packing rings.

5.2.2 Body/Bonnet (Gasket) Leakage

5.2.2.1 General

To maintain the tightness of a factory-testedpressure seal valve, it is essential to apply sufficientbolt tension at all times by having the proper torqueon the nuts or cap screws. The original torquemight be lost due to vibration, relaxation of materialcaused by frequent temperature and pressurefluctuations, or by creep in high temperatureapplications. Joint bolt tension should be checkedat approximetely one-year intervals and, if

necessary, retighten bolts in accordance withSection 2.9 Recheck For Bolt Tightness.

5.2.2.2 Leakage of Body-Bonnet Joint

Whenever possible, begin by opening the valvefully and backseat firmly. Tighten under linepressure the screwed bonnet retaining ring - Style I,Fig. 1.3A or cap screw - Style II, Fig. 1.3B or studand nut - Style III, Fig. 1.3C , to values shown inTable 4.5A. Wait three to five minutes before

CAUTION: You must determine theeffectiveness of the backseat seal as you

dismantle the live-loading arrangement.If leakage occurs during disassembly, linepressure must be shut off. Reassemblelive-loading arrangement in correct order,then torque down to the correct torque asshown in Table 5.1A or B .

determining if the leakage has stopped. The partscould have become loose during transportation orstorage. If tightening does not stop the leakage,

the pressure seal gasket is probably damaged andthe valve must be opened for examination. Such aleak can be caused by any of the following:

1. Imperfect seal between bonnet and gasket

An incomplete seal can be caused bycorrosion or dirt chips or other foreignmatter pushed between the seating surfacesof the body or bonnet and the seating facesof the pressure seal gasket. An imperfect sealbetween the seal ring and the inside contactsurface of the body can be caused by animperfect surface caused by metal failure,

sometimes after valve installation and use.All Velan bodies and bonnets are of forgedquality, eliminating the possibility of surfaceporosity, and the contact area of all pressureseal bodies has been hardface deposited(stainless steel) as an added precaution.Although the surface has a smooth finishand is die-penetrant inspected, surfaceindications can develop in service whichcan cause subsequent leakage.

2. Seal ring leakage

This may be caused by external flow on thesealing edge of the ring.

3. Reusing the pressure seal ringVelan recommends that the pressure seal ringnot be reused. Spare rings should be kept onhand before opening the valve. If the pressureseal ring is removed from the body, it must becarefully examined for imperfections andscore marks. These marks, usually madeduring the removal operation, may causeleaks if the ring is reused. The seal ring, madeof soft iron (silver-plated) or graphite, must behandled with great care to prevent scoring of internal and external surfaces.

5.2.2.3 Body-Bonnet Joint - Seating Face Repairs

1. First, it is necessary to make a visualinspection of the body and bonnet gasketcontact area. Wash the two contact areaswith a suitable solvent and dry with a cleanrag. Leak indications can be discovered bycorrelating marks on the body or bonnetseating areas with the corresponding clueson the OD and ID of the pressure seal gasketwhich has been removed from the valve.

25


26/99


27/9927



leak may be the result of a distorted seat causedby improper welding of the valve into the pipeline,or by stress relieving temperatures that may have

been used during installation. Leaks can alsodevelop from failure to close the valve tightly,resulting in high-velocity flow through a smallopening. The hardfacing material (e.g., Stellite 6)is corrosion and erosion-resistant, but grooves, pitmarks or other surface irregularities may still formon the mating surfaces. Valves which leak shouldbe repaired as quickly as possible to preventgreater damage caused by high velocity.

5.2.3.2 Wedge And Disc Repairs - Gate And ParallelSlide Valves

1. Disassemble valve as described in Section 6.4.2 for gate valves and Section 8.3.2 forparallel slide valves, and inspect the wedgeor disc for scratches or damage.

2. If seating faces are scratched, the wedge mustbe lapped. Slight pitting, grooving orindentations no deeper than 0.005” (0.1 mm)can be removed by lapping. If defects cannotbe corrected by lapping, wedge or disc shouldbe ground or machined. Velan recommendsthat a maximum of 0.015” (0.4 mm) on eachside be removed from a 10-degree seatedwedge and 0.010” (0.25 mm) on each sidefor a 7-degree seated wedge.

3. For parallel slide disc gate Velan recommendsmaximum removal of 0.040” (1 mm) per disc.

NOTE: I f more than 0.030” (0.76 mm) totalmust be removed from both discs and seatsof a parallel slide valve than the retainer plate(45) must also be ground, milled or machinedto compensate for gap allowance, refer toSection 8.4.2 steps 2, 3, 4 & 5 and Fig. 8.3I ,Disc type II & V retaining plate (45),Disc type IV retaining ring (45) andDisc type III Hex. head bolt (56A).

4. For the lapping, a flat plate, preferably castiron, should be used and an abrasive lappingcompound mixed with olive oil should beevenly distributed over the plate as shown inFig. 5.2D . Only light, even pressure should beapplied to the plate, lap to figure 8 and lift thewedge or disc as often as possible to preventaccumulation of particles in one area and toallow for proper distribution of the lappingcompound. The lapping plate should beturned slightly once in a while to maintain aflat surface. The part should be lapped untilseating faces are smooth. Velan recommends

the use of Clover Compound (silicone carbide)Grade E, medium coarse or C, fine grit forfinishing or an approved equivalent.

5. Thoroughly clean off the lapping compoundwith a suitable cleaning fluid such as acetone oralcohol. Do not use solvents containing chlorideor fluoride.

6. Grinding the wedge or disc using automaticgrinding machine can save considerable timerefer to Fig. 5.2E. For major damages use 60-80grit diamond or micron alumina stick on abrasivediscs. For minor damage use 120-180 grit andfor finishing 220 grit and up can be used. Forfurther details contact our customer service dept.

PRECAUTION: Lapping may be slow dueto the erosion-resistant surface, but toomuch lapping must be avoided.

Figure 5.2D Lapping of wedge

Figure 5.2E Wedge or disc Automatic Grinding Machine


28/9928

lapping plate in a circular motion on seat

face. Lift the plate as often as possible to

prevent accumulation of particles in one area

and to allow for proper distribution of thelapping compound. Lap until both seats have

smooth faces and then clean off the lapping

compound very thoroughly with a suitable

cleaning fluid such as acetone or alcohol.

Figure 5.2G Lapping plate



2. In those cases where the automatic grinding

and lapping machine is not employed, seat

faces must be repaired using a lapping plate.

The plate should be made of cast iron if

possible and should be large enough to cover

the face of the seat (Fig. 5.2G) . Apply lapping

compound mixed with olive oil and distribute

evenly over the plate. Lap seat by moving

5.2.3.3 Seat Repairs

5.2.3.3.1 Gate and Parallel Slide Valves

1. If seating faces are damaged, the body seatmust be repaired by lapping. Slight pitting,

scratches or indentations no deeper than

0.005” (0.12 mm) can be removed by lapping.

If defects cannot be corrected by lapping, the

seats should be ground using specialized

automatic grinding/lapping equipment. Velan

recommends a maximum of 0.015” (0.4 mm)

per side that can be removed from a 10 degree

seated valve, and 0.010” (0.25 mm) per side on

a 7 degree seated valve. For parallel slide

valve a maximum of 0.040” (1 mm) per seat

can be removed, see “NOTE” in Section 5.2.3.2

step (3) Grinding the seats using automatic

grinding equipment can save considerable

time refer to Fig. 5.2F.

Figure 5.2F Automatic grinding lapping machine for gate valve seats

and wedges

5.2.3.3.2 Globe, Needle, Stop and Piston Check Valves

1. Disassemble the valve as described in

Section 7.4.2 for globe and stop check valves

and Section 7.5 for piston check valves.

Inspect the disc and the seat for scratches,

pitting marks or other damage.

2. If there are indentations or pitting marks

no deeper than 0.005” (0.12 mm), a cast ironlapping disc (Fig. 5.2H) with the proper seat

angle must be used with a suitable lapping

compound to roughen the surface first. With

the use of a new or refurbished original disc

(Fig 5.2I) and a fine lapping compound, lap

the disc and seat together one final time.

NOTE: For body seat damage exceeding

0.005” (0.12mm) up to maximum of 0.030”

(0.76mm) can be removed from a Globe or a

needle valve having a seat angle of 15 degrees.


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Figure 5.2H Cast iron lapping disc

Cast ironlapping disc

For globe stop check and piston check valves

having a seat angle of 30 degrees max. of

0.040” (1 mm) can be removed by grinding

or machining with automatic equipment.

For valve disc seating surface damage greater

than 0.005” (0.12mm) up to a maximum of 0.030”(0.76mm) per side can be removed for

globe and needle disc having an angle of 12

degrees. For globe and stop check and piston

check disc having an angle of 27 degrees,

maximum of 0.040” (1mm) per side can be

removed by machining. Chuck and center

the disc in a lathe machine, remove only as

needed up to the maximum indicated above.

The repaired disc should be mated final

lapped with the body seat as shown in Fig 5.2I.

IMPORTANT: A guiding plate for the stemis required to maintain alignment during thelapping operation. Refer to Fig 5.2I. It shouldbe made of wood or any other suitable materialto the same gasket dimensions as the bonnet.The section of the plate where the stemextends through should be made 1 ⁄ 64” (0.4 mm)larger than the stem diameter.

3. Place a small quantity of lapping compoundmixed with olive oil and evenly distribute onthe two mating surfaces.

4. It is important to apply slight pressure whenlapping seats and to rotate in reciprocally.For best results, use an air or electric handtool with adjustable speed and reciprocalmovement. The lap should be lifted frequently

and turned to a new starting position so thatthe lapping will be rotated over a new area.

5. In order to ensure that light pressure is appliedevenly, it is necessary, on large valves, due toweight to suspend the disc and stem assemblyfrom a coil spring as shown in Fig. 5.2H .

6. Automatic grinding and lapping of seat facescan be done by specialized equipment whichcan save considerable time, refer to Fig. 5.2J .For major damages the use of 60-80 gritdiamond or Micron alumina abrasive discs issuggested. For minor damage use 120-180 grit

and for finishing 220 grit and up can be used.For further details contact our Customer ServiceDepartment.

5.2.3.4 Fitting of Repaired Parts

5.2.3.4.1 Gate Valves

1. After the seating faces of the wedge, discs orseats have been relapped and cleaned, a blueink test is recommended before reassembly.

Figure 5.2I Original stem-disc assembly

Originalstem-discassembly

Figure 5.2J Automatic reseater machine for grinding / lapping globe seats


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Figure 5.2L Wedge dimensions

F igure 5.2M

Full seating

circumference

B

t

d

Top wedge dimension

Bottomwedge

dimension

Serial number of body

Serial number of body

NOTE:

Seat dimension Bshould betransferredto wedgedimensionb± 0.005" (0.1 mm)

D

b

T

T= (t-B) × D + Bd



Figure 5.2K Blue ink test

A blue ink should be distributed smoothly and

equally over the full circumferential surface of both sides of the wedge (Fig. 5.2K) . Place the

side of the wedge or disc possessing the body

serial number, together with the side of the seat

also possessing the body serial number; (These

sides should have been marked-up during valve

disassembly as discussed in Section 4.4,

General Assembly Information ). Preassemble

the yoke and stem nut. Engage the stem threads

with stem nut. Slide the wedge T-slot into the

stem T-head. Using a chain hoist slowly lower

the entire yoke - wedge into the body. Secure the

yoke to body. Close the valve manually using the

handwheel and tighten firmly. Release the tensionby backing off handwheel a few turns. Lift out of

the valve body and check for positive contact.

If above procedure cannot be followed use

alternate method as follows: slide stem T-head

into the wedge T-slot. Slowly lower the stem and

wedge into the body. Tap a few times on top of

stem using a plastic, brass or lead hammer. Lift

out the stem and wedge and check for positive

contact.

2. If a part cannot be repaired, new parts must be

fitted and installed. All spare part wedges are

supplied slightly oversized. In order to fit, theymust be ground or machined followed by a blue

ink test to confirm 100% seating contact, and

then finally lapped. Refer to Fig. 5.2L.

NOTE: If the outside diameter of hardface and

top and bottom face-to-face dimensions of the

old wedge are given to Velan, it is possible that

there will be very little or no fitting required at

the site when replacing the part.

3. In some cases the original seat angle may belost when the seat is ground in the body.Therefore the wedge must be shimmed

while the seat is being ground or machined.Shim only as much as required to obtain a fullfit over the full circumference of the seatingfaces. Determine new wedge dimensions perFig. 5.2L . Figure 5.2M illustrates a wedge witha full seating circumference, which is essentialwhenever fitting a wedge.


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4. When fitting a wedge, it is also importantthat the clearance between the wedge andthe wedge guide slots be checked with a feelergauge at four locations, as shown in Fig. 5.2N.Ideally, the clearance on both sides should bethe same, however, a minimum clearance of 0.005” (0.1 mm) at any position along the

length of the guide must be maintained.

5.2.3.4.2 Parallel Slide Valves

1. After the seating faces of the disc andseat have been relapped and cleaned witha suitable cleaning fluid such as acetone oralcohol, it is essential that the results beverified using a blue ink test, check for fullcircumferential contact. A light coating of blue ink should be distributed smoothly andequally over the seating diameter of the disc.To maintain the disc concentric with the seat,place shim stock at the bottom of the valvebody and lower the disc. Using a wood disc,a stud and nut and tension against the oppo-site seat, refer to Fig. 5.2O.

NOTE: Ensure that the same match markeddisc and seat are being checked.

2. Release bolt tension and remove stud and nut,lift out the disc and check for positive contact(full seating circumference) Fig. 5.2P illustratesa disc with a full seating circumference, whichis essential whenever fitting a disc.

NOTE: Damages to the seat and disc exceeding0.060” (1.5mm) may require new part to bereplaced.

1 2

3 4

Figure 5.2N Clearance verification

NOTE: Numbers refer to four locations to be checkedby feeler gauge



stud & nut

shim stock

wood disc

Figure 5.2O Paralllel slidePreparation for blue ink test

Figure 5.2P

Parallel slide full seating circumference


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5.2.3.4.3 Globe, Stop Check and Piston Check Valves

1. After the seating faces of the disc andseat have been relapped and cleaned with

a suitable cleaning fluid such as acetone oralcohol, it is essential that the results beverified using a blue ink test check for fullcircumferential contact. A blue ink shouldbe distributed smoothly and equally over theseating diameter of the disc. For globe andstop check valves, preassemble the yoke andstem nut. Engage the stem threads with stemnut, lower the disc into the body, lower theyoke assembly into the body and secure.Close the valve firmly by manual handwheel.Release stem tension by backing off handwheela few turns. Lift out and check for positivecontact.

If this procedure is not possible, use alternateprocedure as follows: lower the disc into thebody, using a brass bar, place in center of discand tap a few times with a plastic, brass or leadhammer. Lift the disc out of the valve body andcheck for positive contact.

NOTE: This procedure should also be used onpiston check valves.

Figure 5.2R illustrates a disc with a full seatingcircumference, which is essential whenever

fitting a disc.2. When fitting the disc, it is also important that

the body inside diameter be checked forsufficient clearance to allow the disc to move



Figure 5.2R Tapered disc -Full seatingcircumference

Figure 5.2S Tapered disc - Hardface deposit

Figure 5.2Q Tapered disc - Thrust pad

freely up and down. We recommend a visualexamination of the body wall. Any groovesor scratches should be polished with a fine

emery cloth or buffing wheel 60-120 grit.3. Verification of contact between the valve

disc and the stem is made by a radius onthe end of the valve stem and is designedto give center loading for the disc as closelyas possible. A hard thrust pad (Fig. 5.2Q) ,which can be found in some designs, willhelp prevent galling. On valves without athrust pad, the bearing surface in the disc hasa hardface deposit on it (Fig. 5.2S) . If particlesget caught between the end of the valve stemand the disc, the center of the stem could bedestroyed.

Thrustpad

Hardfacedeposit


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surfaces of the stem and the disc must bechecked first in leaky valves in order to ensurethat the disc-stem contact is in proper

condition.

5.2.3.5 Seat Tightness - Closing Torques

Even with a brand new valve, seat tightness willonly be achieved when sufficient load has beenapplied to the wedge or disc. This load varieswith the pressure differential against which thevalve has to be closed or opened.

As a guideline, Diagram 5.2A can be used toestimate the torque required to open or closea valve against a given differential pressure.

The torque calculated is that torque which has tobe applied directly to the valve stem and does nottake into account any mechanical advantage suchas that achieved with a gear actuator, etc.

NOTE: Diagram 5.2A serves only as a generalguide line to determine approximate closingand opening torques required. It is not to be

used in e.g. motor actuator, bevel gear orpneumatic actuator sizing.

CAUTION: The use of wheel wrenches,cheater bars, etc., is quite common.However, it must be emphasized thatthese devices should be used withdiscretion, and then only to achieveapproximately the torque as calculatedfrom Diagram

Sub Sec 47 - Velan_pressure Seals Vlvs

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