GENERAL TWIN SEAL Operation, Maintenance & …exposicionesvirtuales.com/so_images/1983/manual-de-mantenimiento... · 3 general valve company bushings/one gland 72 - cap screw 62a

GENERAL TWIN SEAL™

Operation, Maintenance & Service Manual

SCOPEIncluded in the following pages you will findassembly drawings, exploded views, parts lists,assembly tips, operational descriptions androutine maintenance requirements for the currentdesign of the General Twin Seal™.

GENERAL VALVE COMPANY

TABLE OF CONTENTS

Integral Bushing/Retaining Ring Gland ............... 2Integral Bushing/Bolted Gland ............................ 2Bushings/One Gland ............................................ 3Bushings/Two Glands .......................................... 3Bearings/Dual Retention ..................................... 4Bearings/Internally & Externally Retained .......... 5Bearings/Internally Retained w/Two Glands ....... 5

Model 375 H ........................................................ 6Model 500 H & 625 H .......................................... 7Model 376G & 501G ............................................ 8Model 625G, 751G & 755G ................................ 10Model 1261G & 1261-7G.................................... 12Model 1276G ..................................................... 14Model 1500G ..................................................... 16

Understanding the DTR Bleed System .............. 18

Operation .......................................................... 20Maintenance ..................................................... 20Parts .................................................................. 20Where to find us ................................................ 20

V A L V E S

O P E R A T O R S

B L E E D S

M I S C E L L A N E O U S

2


71 - STUD

75 - HEX NUT

72 - CAP SCREW

6 - GLAND (SHOWN 90˚ OUT OF POSITION)

62A - O-RING & 62D BACKUP RING

76 B - PIPE PLUG (SHOWN 90˚ OUT OF POSITION)

62 B - O-RING

63 - PACKING

2 - BONNET

49 - GASKET

62C - O-RING

1 - BODY

5 - SLIP

4 - PLUG

3 - LOWER PLATE

76A - PIPE PLUG

49 - GASKET

62C - O-RING

INTEGRAL BUSHING/RETAINING RING GLAND

6 - GLAND

76 - RETAINING RING

62A - O-RING

62B - O-RING

63 - PACKING

2 - BONNET

49 - GASKET

62C - O-RING

72 - CAP SCREW

76B - PIPE PLUG

1 - BODY

5 - SLIP

4 - PLUG

49 - GASKET

62 - O-RING

3 - LOWER PLATE

76A - PIPE PLUG

The smallest of the twin seal valvesdo not require discrete bushings dueto minimal hydro seating forces withinthe valve. Also note that due to thesize of the operator, the gland is heldin by a retaining ring backed up bythe operator housing.

Typical Arrangement of

2" C8112" C8213" CA8113" CA821

These units do not require discretebushings due to small hydro seatingforces, incorporating a slightly largeroperator however, allows boltedglands to be employed.


4" C811

INTEGRAL BUSHING/BOLTED GLAND

3


BUSHINGS/ONE GLAND

72 - CAP SCREW

62A - O-RING

62A - BACKUP RING

6 - GLAND

62B - O-RING

71 - STUD

75 - HEX NUT

2 - BONNET

49 - GASKET

62C - O-RING

63 - PACKING

46 - BUSHING

5 - SLIP

4 - PLUG

1 - BODY

62C - O-RING

49 - GASKET

3 - LOWER PLATE

46 - BUSHING

71 - STUD

75 - HEX NUT

76A - PIPE PLUG

6˚ SIZE HOLELOCATED 90˚ FROMPOSITION SHOWN

76B - PIPE PLUG(SHOWN OUT OFPOSITION)

76A - PIPE PLUG76B - PIPE PLUG

(16” C811 ONLY)

62A - O-RING62D - BACKUP RING

76 - PIPE PLUG63 - PACKING46 - BUSHING

62C - O-RING62E - BACKUP RING

4 - PLUG5 - SLIP

62C - O-RING62E - BACKUP RING

63 - PACKING62B - O-RING

2 - C-PLATE62A - O-RING62D - BACKUP RING

6 - GLAND

72 - CAP SCREW6 - GLAND

62B - O-RING71 - STUD75 - NUT

2 - BONNET49 - GASKET1 - BODY

46 - BUSHING49 - GASKET76 - PIPE PLUG71 - STUD75 - NUT72 - CAP SCREW

3 - LOWER PLATE

Higher pressure class valves employthe balanced plug design to minimizeplug hydro forces which in turnrequires two glands.


3" C8513" C8614" C8516" C851


11/2"2"2"2"2"2"2"3"4"4"4"4"4"6"6"6"6"6"

6"6"6"8"8"8"8"8"8"8"

10"10"10"10"10"10"12"12"

C911C921C941C411C421C811C821C841C911C921C411C421CA811C821C911C921C411C421

12"12"12"12"14"14"14"16"16"16"16"18"18"20"20"20"24"24"

C811C821A1911C921C811C821C911C411C811C821C921C411C811C411C421CA811C411C421

C921C841C851C861C911C921C941C911C821C841C911C921C941C411C421C821C841CA811

This most popular General Twin Seal design employsbushings and requires a single gland.

BUSHINGS/TWO GLANDS

4


BEARINGS/DUAL RETENTION

BEARINGS/DUAL RETENTION 62A - O-RING

62D - BACKUP RING6A - GLAND

71G - STUD75C - NUT76D - GREASE INJECTOR71A - STUD75A - NUT76A - PIPE PLUG26C - BEARING RETAINER62J - O-RING49A - GASKET (20” CA911 ONLY)76C - PIPE PLUG62H - O-RING26B - BEARING RETAINER

73 - 12 PT CAP SCREW66 - BEARING5 - SLIP4 - PLUG1 - BODY

62F - O-RING62G - BACKUP RING

46 - SLIP PAD26B - BEARING RETAINER49B - GASKET (20” CA911 ONLY)

3 - LOWER PLATE71D - STUD75A - NUT95B - SUPPORT49D - GASKET (20” CA911 ONLY)71E - STUD75B - NUT62H - O-RING76D - GREASE INJECTOR26A - BEARING RETAINER

71F - STUD75C - NUT62B - O-RING63A - PACKING76E - NEEDLE VALVE76F - NIPPLE76H - ELBOW76J - NIPPLE76G - BUSHING71C - STUD75A - NUT95A - LIFTING LUG

2 - BONNET76A - PIPE PLUG62E - O-RING49C - GASKET (20” CA911 ONLY)6B - LANTERN RING

63B - PACKING62F - O-RING62G - BACKUP RING

73 - 12 PT CAP SCREW66 - BEARING

62J - O-RING62C - O-RING76B - PIPE PLUG71B - STUD75A - NUT62F - O-RING62G - BACKUP RING76E - NEEDLE VALVE76J - NIPPLE76G - BUSHING76C - PIPE PLUG

62A - O-RING

62D - BACKUP RING (2)

73D - 12 PT CAP SCREW

6A - GLAND

62L - O-RING 73C - 12 PT CAP SCREW

26B - BEARING RETAINER

76D - GREASE INJECTOR

76C - PIPE PLUG

49C - GASKET

62L - O-RING

2 - BONNET

49B - GASKET

62F - O-RING

62A - O-RING


4 - PLUG

5 - SLIP

1 - BODY

62A - O-RING


62K - O-RING

66 - BEARING

49D - GASKET

62H - O-RING

73B -12 PT CAP SCREW

26D - BEARING RETAINER

76D - GREASE INJECTOR

95A - SUPPORT

71C - STUD

75 - NUT

71B - STUD

75 - NUT

62B - O-RING

62E - BACKUP RING

63 - PACKING RING

6B - LANTERN RING76E - NEEDLE VALVE

76B - NIPPLE (2)

76H - ELBOW

76G - BUSHING

95B - LIFTING LUG

71D - STUD

75 - NUT

76C - PIPE PLUG

71A - STUD

75 - NUT

62G - O-RING

66 - BEARING

26C - BEARING RETAINER

76A - PIPE PLUG

26C - RETAINER PLATE

73A - 12 PT CAP SCREW

46 - SLIP PAD

62C - O-RING

49A - GASKET

76C - PIPE PLUG

3 - LOWER PLATE

76E - NEEDLE VALVE

76F - NIPPLE

76G - BUSHING

26A - BEARING RETAINER

76A - PIPE PLUG

This valve requiresbearings. The innerbearing retainer is slightlydifferent than the oneabove.


36" CA811

As valve size increases sodoes the plug load,therefore, these sizesrequire bearings.


12" C94114" C84116" C92118" CA82120" CA82120" CA84120" C84120" C91120" CA91120" CA92124" CA81124" C81124" C82124" CA82128" C81130" C821

3

GREASE AT LEASTSEMI ANNUALLYTOP & BOTTOM

VENT WHILE INJECTINGGREASE TOP & BOTTOM

3

3



3

5


BEARINGS/INTERNALLY RETAINED W/TWO GLANDS

BEARINGS/INTERNALLY & EXTERNALLY RETAINED71C - STUD75B - NUT

72 - CAP SCREW62A - O-RING62F - BACKUP RING (2)6A - GLAND

71C - STUD75B - NUT76D - GREASE INJECTOR,

76K - NIPPLE & 76L - ELBOW

26B - BEARING RETAINER71B - STUD75A - NUT76B - PIPE PLUG (SLIP REM

90˚ OUT)62B - O-RING62D - BACKUP RING

49C - GASKET62G - O-RING

5 - SLIP1 - BODY

66 - BEARING62A - O-RING62F - BACKUP RING (2)49C - GASKET49B - GASKET71A - STUD75A - NUT71F - STUD75C - NUT

26C - ADAPTER76E - NEEDLE VALVE76J - NIPPLE76H - ELBOW76J - NIPPLE76G - BUSHING

76B - PIPE PLUG71E - STUD75A - NUT95A - LIFTING LUG

2 - BONNET63 - PACKING6B - LANTERN RING

49A - GASKET62C - O-RING76A - PIPE PLUG

66 - BEARING62A - O-RING62F - BACKUP RING (2)

4 - PLUG62A - O-RING62F - BACKUP RING (2)62G - O-RING

46 - SLIP PAD62E - O-RING

3 - LOWER PLATE95B - SUPPORT71D - STUD75A - NUT76B - PIPE PLUG

76D - GREASE INJECTOR26A - BEARING RETAINER76C - PIPE PLUG

76E - NEEDLE VALVE76F - NIPPLE76G - BUSHING

62A - RING62D - BACKUP RING62B - O-RING

2 - BONNET76B - GREASE INJECTOR76J - ELBOW76C - NIPPLE66 - BEARING

62F - O-RING71A - STUD75A - NUT

26 - BEARING RETAINER73 - SOC HD CAP SCREW

62C - O-RING62G - BACKUP RING

4 - PLUG26 - BEARING RETAINER73 - SOC HD CAP SCREW

62C - O-RING62G - BACKUP RING63 - PACKING

62B - O-RING76A - PIPE PLUG71A - STUD75A - NUT76D - NEEDLE VALVE76G - NIPPLE76F - ELBOW76H - NIPPLE76E - BUSHING

6 - GLAND71B - STUD75B - NUT63 - PACKING

76D - NEEDLE VALVE76G - NIPPLE76F - ELBOW76H - NIPPLE76E - BUSHING76A - PIPE PLUG

62E - O-RING62H - BACKUP RING (2)49 - GASKET1 - BODY5 - SLIP

62E - O-RING62H - BACKUP RING (2)62F - O-RING49 - GASKET86 - BEARING3 - LOWER PLATE

62A - O-RING62D - BACKUP RING76B - GREASE INJECTOR76J - ELBOW76C - NIPPLE

6 - GLAND71B - STUD75B - NUT


3

3


High pressures requirehydrostatically balanced plugsand two glands.


8" C85110" C851

These valve sizes require bearings.


10" CB84110" C94112" CB8413



3

6


1. Unscrew (17) and remove indicator flag (5). 2. Remove the stem protector (12). 3. Remove the handwheel nut (19), handwheel (6), key (7) and grease

retainer ring (10). 4. Remove the retainer ring (25) and pull out the upper stem (2) with

lower stem (3), bearing (15), roller (9) and indicator shaft sub-assembly (4) out through the top of the housing (1).

5. Remove set-screw (18) from bottom of lower stem and push indicatorshaft sub-assembly (4) out through the bottom of the lower stem.

6. Separate the stems and remove the retaining ring (24) and thebearing (15) from the upper stem.

7. Remove grease seal (14) and bushing (8) (if req'd) from top of upperstem (2).

8. Remove O-Ring (11) from inside of housing (1).

OPERATOR ASSEMBLY

TWIN SEAL™ MODEL 375 H

Cross Section

Exploded View

Item No.375 H

Part No. Description123456789

10111213141516171819202122232425

21-41922-41722-41827-41827-41928-40645-41146-42548-40550-40262-32

64-41564-41765-40266-409

72-574-674-9

75-43476-41177-40777-42377-45378-41378-414

Operator HousingUpper StemLower StemIndicator ShaftIndicator FlagHandwheelKeyBushingRollerGrease RetainerO-RingProtectorInsignia PlateGrease SealBall BearingCap ScrewScrewSet ScrewNutLube FittingGuide PinDrive PinRoll PinRetaining RingRetaining Ring

Req'd1111111111111114111111111

1. Install O-Ring (11) in housing (1). 2. Place the bearing (15) on the top of the upper stem (2). Install

retaining ring (24). 3. Apply a liberal coating of grease to all surfaces of upper stem (2) and

inside and outside of lower stem (3). 4. Thread the upper stem and lower stem together such that the drive

pin (22) in the upper stem comes against the shoulder at the TOP ofthe lower stem (3) and the detent recess in the upper stem is exactlyin line with roller opening in the lower stem.

NOTE: This operation may require several attempts as the threads aremultiple start and do not always assemble correctly with the first try.

5. Install the indicator shaft sub-assembly (4) up through both stems.Align the detent hole in the indicator disc with the threaded hole inthe lower stem and fasten with set screw (18). Set screw must bebelow the outside surface of the lower stem.

6. Place the roller (9) in the side opening of the lower stem. A liberalapplication of grease will hold the roller in position.

7. Place the stem assembly into the housing taking care that roller isaligned with roller groove in housing. Push the entire assembly downuntil the bearing rests on the shoulder in the housing.

8. Install the retaining ring (25) in the top of the housing (1). 9. Install grease retainer (10) in handwheel (6) and place handwheel

and key (7) on upper stem. Install bushing (8) and grease seal (14)in handwheel nut (19). Screw the nut on the upper stem and tightendown on handwheel securely.

10. Install stem protector (12).11. Install indicator flag (5) and secure with screw (17).

* not available separately

OPERATOR DIS-ASSEMBLY

375 H Is Used on Models:

2" C8112" C8213" CA8113" CA821

*

5

17

12

4

19

7

25

10

24

1522

9

1

23

18

21

16

14

8

6

11

4

9

18

21

15

22

25

20

17

19

11

13

23

16

7

1

3

2

5

12

14

8

6

10

24

7


1. Unscrew (26) and remove indicator flag (6).2. Remove the stem protector (18).3. Remove bearing retainer nut (27).4. Remove the handwheel (8) and key (11).5. Unbolt and remove the housing cover (5).6. Unbolt and remove the guide pin (9), with detent pin (10) and

spring (13).7. Pull the upper stem (2) with lower stem (4), roller (14), bearing (20)

and indicator shaft (7) out through the top of the housing (1). If thebearing is snug in the housing, replace the handwheel and key. Turnthe handwheel clockwise to raise the lower stem as far as possible.Insert a 3/8" diameter bar through the two holes in the bottom of thehousing. Turn the handwheel clockwise and jack the bearing clear ofthe housing.

8. Remove the set-screw (16) and push the indicator shaft sub-assembly (7) out through the bottom of the lower stem.

9. Remove the lower stem (4) from the upper stem (2).10. Remove the retaining ring (30) and bearing (20) from the upper stem.11. Remove the O-Ring (16) from the inside of the housing, and grease

seal (19) and bushing (12) (if req'd) from the top of the upper stem (2).

OPERATOR ASSEMBLY

Item No.500 H


10111213141516171819202122232425262728293031

21-41122-40841-40522-40926-40827-40627-40428-40941-40341-40445-40146-42447-40148-40162-1762-18

64-41464-41165-40166-40272-472-572-6

72-2174-1

73-2875-42776-41177-40278-40393-413

Operator HousingUpper StemDrive PinLower StemHousing CapIndicator FlagIndicator ShaftHandwheelGuide PinDetent PinKeyBushingSpringRollerO-RingO-RingPlastic PlugProtectorGrease SealBall BearingCap ScrewCap ScrewCap ScrewCap ScrewSet ScrewScrewHex NutLube FittingCoupling PinRetaining RingCover

625 HPart No.

21-40722-41141-40622-41326-40527-40627-43828-40141-40341-40445-41346-42447-40148-40362-1762-22

64-40564-41265-40166-40372-472-6

72-1172-2174-374-6

75-42976-41177-40378-40493-413

TWIN SEAL™ MODEL 500 H & 625 H

Cross Section

Exploded View

1. Place the bearing (20) on upper stem (2). Install a retaining ring (30)to lock bearing in place.

2. Apply a liberal coat of grease to all surfaces of upper stem (2) belowthe bearing, and to all surfaces of the lower stem (4). Thread theupper stem (2) into the lower stem (4) such that the drive pin (3) inthe upper stem comes against the shoulder at the TOP of the lowerstem and the detent recess in upper stem is exactly in line with theroller opening in lower stem. This operation may require severalattempts as the threads are multiple start and do not alwaysassemble correctly with the first try.

3. Install the indicator shaft assembly (7) up through both stems. Alignthe detent hole in the indicator disc with the threaded hole in thelower stem and fasten with set-screw (25). Set-screw must be belowthe outside surface of the lower stem.

4. Install O-Ring (16) in housing (1). 5. Place roller (14) in opening of lower stem. A liberal application of

grease will hold it in position. 6. Place the stem assembly into the housing – taking care that roller is

aligned with roller groove in housing. Push entire assembly downuntil bearing rest on shoulder in housing.

7. Apply a smooth even coating of Permatex Number 3D to surface ofguide pin boss on housing (1).

8. Insert guide pin (14) with detent pin (10) and spring (13) to fullyengage slot in lower stem and secure with cap screws (21).

9. Apply a smooth even coating of Permatex Number 3D to top surfaceof housing (1).

10. Install O-Ring (15) in housing cover (5) and secure to housing (1)with cap screws (22).

11. Install the handwheel (8) and key (11).12. Install the bearing retainer nut (27) and tighten securely.13. Install grease seal (19) and bushing (12) in top of upper stem (2).14. Install stem protector (18).15. Install indicator flag (6) and secure with screw (26).


500 H Is Used on Models:2" C841 2" C9213" C841 3" C9114" C811 4" C9114" C821 4" C9216" CA811


625 H Is Used on Models:2" C851 2" C9412" C861 4" C9413" C851 6" C9113" C861 6" C9214" C8414" C8516" C8218" C81110" CA811

*

8


TWIN SEAL™ MODEL 376G & 501GCross Section Exploded View

83418

2321

2

94

5

27

21

1914

332

110

2715

262911

12

7

20

31

28

17

2425

6

24-444

A1613

A

B B

Section A-A

Section B-B

376 G Is Used on Models:

2" C811 2" C8213" CA811 3" CA821


2" C841 2" C9213" C841 3" C9114" C811 4" C9114" C821 4" C9216" CA811

49-648-020

24

2531

34

8

21

2

23

18

165

23

13

14

28

33

35

8

25

19

21

1

27

32

22

32

1015

1129

911

7

20

PLASTICSHIM

17

1224

6

26

25

4

3

30

30

9


TWIN SEAL™ MODEL 376G & 501G

1. Remove the indicator pin (34) and pull the indicator stem (8) upthrough the gear housing (2).

2. Remove the stop screw (35) and dowel pin (33). Drive out the uppercoupling pin (32) and remove the coupling (10).

3. Remove the cap screw (29), washer (11), handwheel (9) and key (12).4. Remove the four cap screws (27) and the gear housing cover (7).5. Remove four cap screws (27) and lift off the gear housing (2). It may

be necessary to turn the worm shaft counterclockwise to back theworm clear of the gear while lifting off the gear housing. The wormshaft (6) and the tapered bearing cup (24) and cone (25) on each endmay now be removed from the gear housing (2).

6. The operator stem (3), upper stem (4), bearings (23), and roller (16)may now be lifted out of the operator housing.

NOTE: The cam bushing (13) and stem bushing (14) are a press fitin the operator housing and should not be removed. Should the cambushing require replacement, the operator housing must be returnedto the factory.

1. Install O-Ring (21) in the stem bushing (14) in the Operator Housing (1).Place bearing (23) in the top of the operator housing (1).

2. Apply a liberal coating of grease to all surfaces of the operator stem (3) andthe upper stem (4). Thread the operator stem into the upper stem such thatthe dowel pin (5) comes against the shoulder at the BOTTOM of the upperstem and the detent recess in the operator stem is exactly in line with theroller opening at the bottom of the upper stem. This operation may requireseveral attempts as the threads are multiple start and do not alwaysassemble correctly with the first try.

3. Place the roller (16) in the opening of the upper stem (4) and the detentrecess of the operator stem (3). An application of grease will hold it inposition.

4. Position the operator housing such that when viewed from above, the raisedportion of the cam is in the lower left quadrant of the housing bore (seecross-section illustration). With the roller on the left side, place the upperstem, operator stem and roller (which have been assembled together–seesteps 2 & 3) into the operator housing (1), down through the stem bushing(14) and cam roller bushing (13) until the shoulder of the upper stem (4) isagainst the bearing (23).

5. Install bearing (23) in the gear housing (2). Install the O-Ring (21) in the topof the gear housing (2).

6. Install the tapered roller bearing cup (24) in the recess of the gear housingwith the large diameter of the taper facing out.

7. Install tapered roller bearing cup (24) and cone (25) on the handwheel end ofthe worm shaft (6). Place bearing cone (25) on the opposite end of the wormshaft with the large diameter of the taper against the shaft shoulder. Apply aliberal amount of grease to all parts.

8. Install the worm shaft in the gear housing. Make certain that the rear bearingcone has properly entered the rear bearing cup.

9. Install O-Rings (17) and (20) in the gear housing cover (7) and assemble tothe gear housing (2) with four of the cap screws (27). Run the screws in justenough to keep parts in place but do not tighten at this time.

10. Install O-Ring (19) in the top of the operator housing. Place the gear housingon the operator housing with the worm gear on the left side as viewed fromthe top (same side as the roller) and fasten with four of the cap screws (27).

NOTE: Worm shaft must be moved out slightly to allow parts to assemble.Tighten cap screws (27) in gear housing cover (7).

11. Assemble handwheel (9), key (12), washer (11) and cap screw (29) on theworm shaft.

12. Place a drift punch through the hole in the top of the operator stem to preventit from turning. With the punch at 90o to the worm shaft, turn the handwheelclockwise and run the upper stem down as far as it will go. Place thecoupling (10) on the bottom of the operator stem with the horizontal portionof the L-shaped groove at the bottom. Turn the coupling until the coupling pinhole in the operator stem is aligned with the top hole in the coupling, and thevertical groove without the ramp is aligned with the stop screw boss in thehousing. Drive the coupling (32) into the hole in the top of the coupling andthe bottom hole of the operator stem. Install the stop screw (35) and thedowel pin (33).

NOTE: The coupling (10) has an L-shaped groove on both sides. Thevertical portion of one of the grooves has a ramp at the top. The couplingmust be installed such that the side without the ramp is adjacent to, andengages the stop screw. (The ramp is used to actuate the automatic bodybleed valve when installed.)

13. Install O-Ring (21) in the top of the gear housing and O-Ring (18) in the topof the lower stem (3). Place the indicator stem (8) on the top of the operatorstem and down through the gear housing. Install the indicator pin (34).


Item No.376G


1011121314151617181920212223242526272829303132333435

111111111111111111112

2221841112111

21-58321-58422-52423-56077-46524-45126-63227-54528-44132-47644-46545-43146-55746-55846-55948-40562-7162-83

62-39862-91

62-371–––

66-48366-48166-48269-41472-5

72-1672-21

76-89176-61277-42277-48077-45198-790

Operator HousingGear HousingOperator StemUpper StemPinWorm ShaftGear Housing CoverStem IndicatorHandwheelCouplingHandwheel WasherKeyCam BushingStem BushingPilot BushingRollerO-RingO-RingO-RingO-RingO-RingCaplugBall BearingCup BearingCone BearingSpinner HandleCap ScrewCap ScrewCap ScrewPlugLube FittingCoupling PinDowel PinIndicator PinStop Screw

501GPart No.

21-55521-55422-50823-52577-46424-44526-58027-50428-44232-46944-45345-43146-50146-502

–––48-40162-3462-7062-7962-9162-33964-42466-47666-47766-47869-414

72-572-1072-2676-59476-61277-41777-41877-44098-663

Req'd

OPERATOR DIS-ASSEMBLY OPERATOR ASSEMBLY

*

10


26 2832 13

17

34

18

29

218

7

11

3924

2516

10

27

19

43

3 12

14

31

35

23

15/4230/40

23

36

9

27

6

2

4

5

20

38

4437

1

TWIN SEAL™ MODEL 625G, 751G & 755GCross Section Exploded View

34

1718

7

8

3221

26, 28

41


6" C851 6" C941

8" CA841

2416

33

113913253691027

29

2435

1

22

12

2340, 30

43

619

5

2031143

3815, 42


6" C841 8" C9118" C821 10" C91110" C82112" C81114" C811


2" C851 2" C9412" C861 4" C9413" C851 6" C9113" C861 6" C9214" C8414" C8516" C8218" C81110" CA811

22

11


Item No.751 G


1011121314151617181920212223242526272829303132333435363738394041424344

21-62321-40522-55522-55441-40123-40324-40426-40126-40326-41127-40627-43528-40241-49841-41042-40144-40145-40245-40648-41362-13

62-20964-40264-41165-40166-40166-41066-45869-414

–––72-472-572-672-872-972-1472-2174-474-6

73-13076-61278-40678-40893-413

Housing OperatorHSG GearStem LowerStem UpperPin DriveGear WormShaft WormCap BearingCover Gear HousingCarrier BearingIndicator FlagIndicator ShaftHandwheelPin GuidePin CouplingNut HexWasherKey WoodruffKey StraightRollerO-RingO-RingPlastic PlugProtectorSeal GreaseBearing ConeBearing BallBearing CupHandle SpinnerStudScrew CapScrew CapScrew CapScrew CapScrew CapScrew CapScrew CapScrew SetScrewNut HexFitting LubeRing RetainingRing RetainingCover

625 GPart No.

21-42221-40822-44022-43941-40623-40224-40426-40126-41326-41227-40627-42928-40441-40777-40375-46244-40145-40245-40348-40362-1362-22

64-40564-41165-40166-40166-41266-45869-41472-1172-472-5

72-1072-872-9

72-1472-2174-374-6–––

76-612–––

78-40493-413

755 GPart No.

21-62321-44322-55522-55441-40123-40624-40326-40126-40326-42327-40627-43528-40241-49841-41042-40144-40145-40245-40648-41362-13

62-20964-40264-41165-40166-40166-41066-45869-414

–––72-472-5–––72-872-972-2672-2173-2874-6

73-13076-61278-40678-40893-413

TWIN SEAL™ MODEL 625G, 751G & 755GOPERATOR DIS-ASSEMBLY 20. Install bearing (27) in bearing carrier (10). NOTE: The widest surface of the outer

race goes against the shoulder in the bearing carrier.21. Apply a smooth even coating of Form-A-Gasket over top surface of gear housing

(2).22. Place bearing carrier (10) on top of gear housing (2). Install two cap screws (36)

180° apart to temporarily align the bearing carrier. They need only be partiallyscrewed in.

23. Install lock nut (16) on upper stem and tighten snug with a wrench. Remove the twocap screws (36).

24. Install the grease seal (25) in the gear housing cover (9). Slide the cover over theindicator shaft (12) and secure to top of gear housing (2) with cap screws(36).

25. Install stem protector (24).26. Install indicator (11) and secure with socket head cap screw (39).

*

not available separately

*

OPERATOR ASSEMBLY

1. Unscrew (39) and remove indicator flag (11). 2. Remove Stem protector (24). 3. Unbolt and remove gear housing cover (9). 4. Remove bearing retainer nut (16). 5. Remove bearing carrier (10) and upper bearing (27). 6. Remove upper retaining ring (43). 7. Remove cap screw (34), washer (17), handwheel (13) and key (18). 8. Unbolt and remove bearing cap (8).

CAUTION: DO NOT DAMAGE PLASTIC SHIMS. 9. Screw out the worm shaft (7). Front bearing cone (26) and cup (28) and rear bearing

cone (26) will come out with the worm shaft. Rear bearing cup (28) can then beremoved from gear housing (2).

10. Remove the worm gear (6) and key (19).11. Unbolt and remove the gear housing (2).12. Unbolt and remove the guide pin (14).13. Pull the upper stem (4) with lower stem (3), roller (20), lower bearing (27) and indicator

shaft (12) out through the top of the housing (1). If the bearing is snug in the housing,install the worm gear with its key on the upper stem upside down (hub up). Turn thegear counter clockwise to raise the lower stem as far as possible. Insert a 1/2"diameter bar through the two holes in the bottom of the housing. Using a pipe wrenchon the gear hub, turn clockwise and jack the bearing clear of the housing.

14. Remove the set-screw (38) and push the indicator shaft sub-assembly (12) out throughthe bottom of the lower stem.

15. Remove the lower stem (3) from the upper stem (4).16. Remove the retaining ring (43) and lower bearing (27) from the upper stem.

1. Place one of the two bearings (27) on upper stem (4).NOTE: This bearing is assembled such that the wide surface of the inner race seatson the upper stem shoulder.Install a retaining ring (43) to lock the bearing in place.NOTE: The retaining ring comes against narrow surface of inner race.

2. Apply liberal coat of grease to all surfaces of the upper stem below the bearing. Threadthe upper stem (4) into the lower stem (3) such that stop pin (5) in the upper stemcomes against the shoulder at the TOP of the lower stem and the detent recess in upperstem is exactly in line with the roller opening in lower stem. This operation may requireseveral attempts as the threads are multiple start and do not always assemble correctlywith the first try.

3. Install the indicator shaft assembly (12) up through both stems. Align the detenthole in the indicator disc with the threaded hole in the lower stem and fasten withset-screw (38). Set-screw must be below the outside surface of the lower stem.

4. Install O-Ring (22) in housing (1). 5. Place roller (20) in opening of lower stem. A liberal application of grease will hold it

in position. 6. Place the stem assembly into the housing–taking care that roller is aligned with

roller groove in housing. Push entire assembly down until bearing rests on shoulderin housing.

7. Apply a smooth even coating of Permatex Form-a-Gasket to surface of guide pinboss on housing (1).

8. Insert guide pin (14) to full engage slot in lower stem and secure with cap screws(31).

9. Place gear key (19) in key way of upper stem.10. Install tapered roller bearing cup (28) in rear bearing recess of gear housing (2) with

large diameter of taper facing out.11. Install tapered roller bearing cup (28) and cone (26) on handwheel end of worm

shaft (7). Place bearing cone (26) on opposite end with large diameter of taperagainst shaft shoulder.

12. Install worm shaft in gear housing. Make certain that rear bearing cone hasproperly entered rear bearing cup (28).

13. Install O-Ring (21) in bearing cap (8).14. Apply a smooth even coating of Permatex Number 3D to bearing cover boss on gear

housing. Fasten bearing cap (8) in place with cap-screws (32). Be sure to installthe plastic shims between gear housing and bearing cap.

15. Install worm gear (6) in gear housing with hub down. (Toward smaller opening).16. Apply Form-A-Gasket to top flange of operator housing (1). Place gear housing (2)

with assembled parts on top of operator housing guiding worm gear keyway overkey (19) in upper stem (3).

17. Install retaining ring (43) to secure worm gear (6).18. Fasten gear housing (2) to operator housing (1) with cap screws (35). CAUTION:

NOTE THAT THE SHORT CAP SCREW (33) IS INSTALLED DIRECTLY UNDERTHE CENTER OF THE WORM SHAFT (7).

19. Fill gear housing (2) with grease up to top of worm gear.

12


TWIN SEAL™ MODEL 1261G & 1261-7G

Cross Section Exploded View

29 34

1116176

308

2839

2827

2

2827

378

2210337

2415255

182

3111

3642

35402613

121932134

3821

411423


12" C821 8" C92114" C821 10" CA92116" C811 12" CA91118" C811 14" C91120" CA811 16" C911

1261-7G Is Used on Models:

8" C851 12" CA92110" CB841 18" C91112" CB841 20" CA91116" CA82118" CA82124" CA811

30

8

17

3416

29

11

2028

276

2827

33

24

25

5

2

39

26

26

18

3

4

13

32234114

35

1

21

937

22

7

15

39

40

12

19

38

10

3642

31

2341

43 NOT SHOWN

13


TWIN SEAL™ MODEL 1261G & 1261-7G

1. Unscrew (37) and remove indicator flag (9). 2. Remove indicator shaft protector (22). 3. Unbolt and remove gear housing cover (7). 4. Remove upper stem nut (15). 5. Remove upper bearing (25). 6. Remove cap screw (34), handwheel washer (16), handwheel (11) and woodruff

key (17). 7. Unbolt and remove bearing cap (8). CAUTION: DO NOT DAMAGE PLASTIC

SHIMS. 8. Screw out worm shaft (6). Front bearing cone (27) and cup (28) and rear bearing

cone (27) will come out with the worm shaft. Rear bearing cup (28) can then beremoved from gear housing.

9. Remove the worm gear (5) and key (18).10. Unbolt and remove the gear housing (2).11. Remove the retaining ring (40).12. Unbolt and remove the guide pin (13).13. Pull the upper stem (3) with the lower stem (4), roller (19), two bearings (26) and

indicator shaft (10) out through the top of the housing (1). If the bearings are snugin the housing, install the worm gear (5) with its key (18) on the upper stem upsidedown (hub up). Turn the gear counter-clockwise to raise the lower stem as far aspossible. Insert a 11/2" diameter bar through the two holes in the bottom of thehousing. Using a pipe wrench on the gear hub, turn clockwise and jack the bearingclear of the housing.

14. Remove the socket head cap screw (38) and push the indicator shaft sub-assembly (10) out through the bottom on the lower stem (4).

15. Remove the lower stem (4) from the upper stem (3).16. Remove the bearings (26) from the upper stem (3).

1. Install the two bearings (26) at top of upper stem (3). NOTE: These are radialthrust bearings and must be installed such that the widest surfaces ofthe inner raceways are back to back. INCORRECT INSTALLATION WILLRESULT IN SERIOUS DAMAGE.

2. Install the bearing retaining ring (40). 3. Apply a liberal coating of grease to all surfaces of the upper stem (3). 4. Thread the upper stem (3) into the lower stem (4) such that the drive pin

in the upper stem comes against the shoulder at the TOP of the lower stemand the detent recess in the upper stem is exactly in line with the roller opening inthe lower stem. This operation may require several attempts as the threads aremultiple start.

5. Install the indicator shaft sub-assembly (10) up through both stems. 6. Install O-ring (21) in housing (1). 7. Place the roller (48) in the side opening of the lower stem (4). 8. Place the stem assembly into the housing (1) taking care that the roller (48)

is aligned with the roller groove in the housing. Push the assembly down untilthe lower bearing (26) rests on the shoulder in the housing.

9. Apply a smooth even coating of Permatex Form-A-Gasket to the surface of theguide pin boss on the housing (1).

10. Insert the guide pin (13) to full engage the slot in the lower stem (4) and fasten withcap screws (32).

11. Place gear key (18) in keyway of upper stem (3).12. Install tapered roller bearing cup (28) in rear bearing recess of gear housing (2)

with large diameter of taper facing out.13. Install tapered roller bearing cup (28) and cone (27) on handwheel end of worm

shaft (6).14. Install worm shaft (6) in gear housing (2). Make certain that rear bearing cone (27)

has properly entered the rear bearing cup (28).15. Install O-ring (20) in bearing cap (8).16. Apply a smooth coating of Permatex Form-A-Gasket to bearing cap boss on gear

housing (2). Fasten bearing cap in place with cap screws (30). Be sure to installthe plastic shims between the gear housing and the bearing cap.

17. Install worm gear (6) in gear housing (2) hub down (toward smallest opening).18. Place the gear housing (2) with assembled parts on top of the operator housing

guiding the worm gear keyway over key (18) in upper stem (3).

19. Install the ball bearing (25) on the upper stem (3) and secure with nut (15).20. Apply a smooth coating of Permatex Form-A-Gasket to top of operator housing.21. Fasten the gear housing (2) to the operator housing with cap screws (35

and 3). CAUTION: NOTE THAT THE SHORT CAP SCREW (72B) ISINSTALLED DIRECTLY UNDER THE CENTER OF THE WORM.

22. Fill the gear housing (2) with grease up to the top of the worm gear (5).23. Apply a smooth coating of Permatex Form-A-Gasket to top surface of gear housing (2).24. Install grease seal (24) in gear housing cover (7). Slide cover over indicator shaft (10)

and ball bearing (25) and secure to top of operator housing with cap screws (33).25. Install the indicator shaft protector (22).26. Install the indicator flag (9) and secure with screw (37).27. Install handwheel (11) with woodruff key (17), washer (16) and cap screw (34).



OPERATOR ASSEMBLY

Item No.1261 G Part No. Description

123456789

10111213141516171819202122232425262728293031323334353637383940414243

Item No.1111111111111111111111

2112221412817211212111

21-62121-51822-55222-55323-47224-42826-51326-51427-40627-48828-40241-40241-49641-41142-40344-40145-40245-40448-41262-13

62-20864-41164-41665-40166-40466-41166-46566-46669-41472-272-372-472-772-8

72-1372-2173-2873-28

76-41278-40578-40793-413

–––

Operator HousingGear HousingUpper StemLower StemWorm GearWorm ShaftGear Housing CoverBearing CapIndicator FlagIndicator ShaftHandwheelDrive Pin*Guide PinCoupling PinNutHandwheel WasherWoodruff KeyKeyRollerO-RingO-RingProtectorPlastic PlugGrease SealBall BearingBall BearingBearing ConeBearing CupSpinner HandleCap ScrewCap ScrewCap ScrewCap ScrewCap ScrewCap ScrewCap ScrewScrewSet ScrewLube FittingRetaining RingRetaining RingCoverAdapter

1261 7G Part No.

21-62121-51822-55222-55323-47224-42826-51326-51427-40627-48828-40241-40241-49641-41142-40344-40145-40245-40448-41262-13

62-20864-41164-41665-40166-40466-41166-46566-46669-41472-272-372-472-772-8

72-1372-2174-6

74-1276-41278-40578-40793-41326-712

14


TWIN SEAL™ MODEL 1276G

Cross Section

9

31

19

34

2218

4136

10

3630

29

79

26513

113912

24178

635

27

2028

214

43

23

45

15 3

38

2

4032

1

33

254237

16

Exploded View

39

24

26

17

6

3

3029

7

1930

29

41

3118

34

36

22

13

14

21

2

40

10

32

43

40

12

44

11

35

8

27

41

36

9

28

20

5

4

38

33

25

1545

37

1

23

16

42


10" C851 16" C92116" CA841 20" CB92120" CA82124" CA82130" CC811

49-649-20SHIM

(NOT SHOWN)

15


22. Fill the gear housing with grease up to the top of the worm gear.23. Apply a smooth even coating of Permatex Number 3D around top surface of

gear housing.24. Install the grease seal (26) in the gear housing cover (8). Slide the cover over

the indicator shaft (12) and the ball bearing (27) and secure to the top of theoperator housing with cap screws (35).

25. Install the stem protector (24) and secure the indicator flag (11) in place withset screw (39).

26. Install the handwheel (13) with key (19), washer (18), cap screw (34) andspinner handle (31).


TWIN SEAL™ MODEL 1276G

1. Turn handwheel counter clockwise to full open position.2. Remove set-screw (39) and indicator flag (11).3. Remove the stem protector (24).4. Unbolt and remove the gear housing cover (8).5. Remove the bearing retainer nut (17) and ball bearing (27).6. Remove cap screw (34), washer (18), handwheel (13) and key (19).7. Unbolt and remove the bearing caps (9) and (10). CAUTION: DO NOT

DAMAGE THE PLASTIC SHIMS UNDER FRONT BEARING CAP (10).8. Remove worm shaft (7) and taper bearings consisting of cone (29) and cup (30).9. Remove worm gear (6) and key (20).10. Unbolt and remove the gear housing (3).11. Unbolt and remove the guide pin (16).12. Pull the upper stem (5) and lower stem (4) with bearings (28) and roller (21)

out through the top of the upper housing (2). If bearings are snug in the upperhousing, remove the upper and lower stems with the roller through the bottomof the lower housing (1). Unbolt the upper and lower housing and remove thebearings with a suitable puller.

13. Separate the upper and lower stems and remove indicator shaft assembly (12).

1. Install the two bearings (28) at the top end of the upper stem (5). NOTE:These are radial thrust bearings and must be installed such that the widestsurfaces of the inner race ways are back to back. INCORRECT INSTALLA-TION WILL RESULT IN SERIOUS DAMAGE.

2. Apply a smooth even coating of Permatex Number 3D to the bottom flange ofthe upper housing (2) and fasten to the lower housing (1) with studs (32) andnuts (40). The dowel pin (43) is a press fit in the lower housing and a slip fit inthe upper housing. Its function is to properly align the roller grooves.

3. Apply a liberal coating of grease to all surfaces of upper stem (5) and lower stem (4).4. Thread the two stems together such that the drive pin (14) in the upper stem

comes against the shoulder at the top of the lower stem and the detent recessin the upper stem is exactly in line with the roller opening in the lower stem.This operation may require several attempts as the threads are multiple startand do not always assemble correctly with the first try.

5. Install the indicator shaft sub-assembly up through both stems and secure withthe roll pin (44) in the bottom of the lower stem.

6. Install O-ring (23) in the lower housing (1).7. Place the roller (21) in the side opening of the lower stem (4). A liberal

application of grease will hold it in place.8. Place the stems with bearings and roller assembled down through the top of

the upper housing until the lower of the two bearings (28) rests on theshoulder in the upper housing.

9. Apply a smooth even coating of Permatex Form-a-Gasket to the surface of theguide pin boss on the lower housing (1).

10. Insert the guide pin (16) to fully engage the slot in the lower stem and fastenwith cap screws (33).

11. Place the gear key (20) in the keyway of the upper stem (5).12. Place the tapered roller bearing cones (29) on each end of the worm shaft (7)

with the large diameter of the cone taper against each shaft shoulder.13. Assemble the cups (30) on the cones (29).14. Apply a smooth even coating of Permatex Number 3D to the surfaces of the

bearing retainer bosses on the gear housing (3).15. Fasten the blind bearing cap (9) in place with cap screws (36).16. Install the worm shaft (7) in the gear housing.17. Install the O-Ring (22) in the bearing cap (10) and fasten in place with cap

screws (36). Be sure to re-install the plastic shims between the gear housingand the bearing cap.

18. Install worm gear (6) in gear housing with hub down. (Toward smallest opening).19. Apply a smooth coating of Permatex Number 3D to top flange of upper housing.20. Place the gear housing with assembled parts on top of the upper housing

guiding the worm gear keyway over the key (20) in the upper stem, and fastento the upper housing with cap screws (38).

21. Install ball bearing (27) over upper stem and secure with nut (17).

Item No.1276 GPart No. Description

123456789

101112131415161718192021222324252627282930313233343536373839404142434445

21-59421-59521-50522-53322-53423-46124-42526-48726-48826-48927-40627-54128-43241-47341-47641-48042-40344-40145-40245-42848-40962-20

62-21564-41264-41665-40166-40466-45266-45466-46369-41471-4772-572-8

72-2672-64

73-11173-13174-6

75-40676-41276-53677-45477-48178-407

Lower HousingUpper HousingGear HousingLower StemUpper StemWorm GearWorm ShaftGear Housing CoverBearing CapBearing CapIndicator FlagIndicator ShaftHandwheelDrive Pin*Coupling PinGuide PinNutWasherKeyKeyRollerO-RingO-RingProtectorPlastic PlugGrease SealBall BearingBall BearingBearing ConeBearing CupSpinner HandleStudCap ScrewCap ScrewCap ScrewCap ScrewCap ScrewCap ScrewScrewNutLube FittingPipe PlugDowel PinRollpinRetaining Ring

Req'd1111111111111111111111114112221

12218

126

121

2421112

OPERATOR DISASSEMBLY

OPERATOR ASSEMBLY

*

16


11

39

24

37

45

1543

12

23

44

4

33

16

40

32

1

42

215

2

28

38

1927

6

39

40

26

8

35

TWIN SEAL™ MODEL 1500 G

Cross Section Exploded View

39

24

26

17

6

3

3029

7

1930

29

41

3118

34

36

22

13

14

21

10

11

35

8

27

41

36

9

28

20

5

4

41

29

10

19

31

1834

3022

7

936

Handwheel not shown

**SHIELDS(NOT SHOWN)

25-93-42425-93-492

46


20" C841 16" C94130" CC82136" CA811

17


TWIN SEAL™ MODEL 1500 G

1. Turn worm shaft counter-clockwise to full open position.2. Remove set screw (39) and indicator flag (11)3. Remove the stem protector (24).4. Unbolt and remove the gear housing cover (8).5. Remove the set screw (39), and upper stem nut (17).6. Remove the ball bearing (27).7. Unbolt and remove bearing cap (10). CAUTION: DO NOT DAMAGE THE

PLASTIC SHIMS UNDER MOTOR ADAPTER.8. Remove the worm shaft (7) and taper bearings consisting of cones (29) and

cups (30).9. Remove worm gear (6) and key (20).10. Unbolt and remove the gear housing (3).11. Unbolt and remove the guide pin (16).12. Pull the upper stem (5) and lower stem (4) with bearings (28), bearing retainer

and roller (21) out through the top of the upper housing (2). If bearings aresnug in the upper housing, remove the upper and lower stems with the rollerthrough the bottom of the lower housing. Unbolt the upper and lower housingsand remove the bearings with a suitable puller.

13. Separate the upper and lower stems and remove the nut (43) and indicatorshaft (12).

1. Install the two bearings (28) and bearing retainer at the top end of the upperstem (5). NOTE: These are radial thrust bearings and must be installed suchthat the widest surfaces of the inner raceways are back to back. INCORRECTINSTALLATION WILL RESULT IN SERIOUS DAMAGE.

2. Apply a smooth even coating of Form-A-Gasket to the bottom flange of theupper housing (2) and fasten to the lower housing (1) with studs (32) andnuts (40).

3. Apply a liberal coating of grease to all surfaces of the upper stem (5) and lowerstem (4).

4. Thread the two stems together such that the drive pin in the upper stemcomes against the shoulder at the top of the lower stem and the detent recessin the upper stem is exactly in line with the roller opening in the lower stem.This operation may require several attempts as the threads are multiple startand do not always assemble correctly with the first try.

5. Install the indicator shaft (12) up through both stems and secure with nut (43)in the bottom of the lower stem.

6. Install 0-ring (23) in the lower housing.7. Place the roller (21) in the side opening of the lower stem (4). A liberal

application of grease will hold it in place.8. Place the stems with bearings (28), bearing retainer and roller (21) assembled

down through the top of the upper housing until the lower of the two bearingsrests on the shoulder in the upper housing.

9. Apply a smooth even coating of Form-A-Gasket to the surface of the guide pinboss on the lower housing.

10. Insert the guide pin (16) to fully engage the slot in the lower stem and fastenwith cap screws (33).

11. Place the gear key (20) in the keyway of the upper stem.12. Place the tapered roller bearing cones (29) on each end of the worm shaft (7)

with the large diameter of the cone taper against each shaft shoulder.13. Assemble the cups (30) on the cones.14. Install the worm shaft in the gear housing.15. Apply a smooth even coating of Form-A-Gasket to motor adapter mounting

surface of the gear housing.16. Install o-ring (22) in the bearing cap (10) and fasten to gear housing with

screws (36). Be sure to re-install the plastic shims between the gear housingand motor adapter.

17. Install worm gear (6) in gear housing with hub down (toward smaller opening).18. Apply a smooth even coating of Form-A-Gasket to the top flange of the upper

housing.19. Place the gear housing with assembled parts on top of the upper housing

guiding the worm gear keyway over the key (20) in the upper stem and fastento the upper housing with cap screws (38).

20. Install ball bearing (27) over upper stem and secure with upper stem nut.21. Install insert and set screw into upper stem nut.22. Fill the gear housing with grease up to the top of the worm gear.23. Apply a smooth even coating of Form-A-Gasket around top surface of the

gear housing.24. Install the grease seal (26) in the gear housing cover (8). Slide the cover over

the indicator shaft (12) and ball bearing (27) and secure to the top of the gearhousing with cap screws (35).

25. Install stem protector (24) and secure indicator flag (11) in place with setscrew (39).


Item No.1500 GPart No. Description

12345678910111213141516171819202122232425262728293031323334353637383940414243444546

21-57221-57121-57322-51022-50923-41124-42526-51526-48826-48927-40627-45028-43241-47432-41041-47475-44144-40145-40245-41448-40862-2062-8964-412

**65-40166-42466-42566-45466-46369-41471-10972-572-872-2672-6473-8773-12474-6

75-40876-41276-47075-44172-2175-44232-452

Lower HousingUpper HousingGear HousingLower StemUpper StemWorm GearWorm ShaftGear Housing CoverBearing CapBearing CapIndicator FlagIndicator ShaftHandwheelDrive Pin*Coupling PinGuide PinNutWasherKeyKeyRollerO-RingO-RingProtectorOper. ShieldGrease SealBall BearingBall BearingBearing ConeBearing CupSpinner HandleStudCap ScrewCap ScrewCap ScrewCap ScrewCap ScrewCap ScrewScrewNutLube FittingPipe PlugNutCapscrewCoupling Pin NutSpacer

Req'd1111111111111111111111112111221122181212121242113021

OPERATOR DISASSEMBLY

OPERATOR ASSEMBLY

*

18


UNDERSTANDING THE DTR BLEED SYSTEM

SCOPE

This specification addresses the proper functioning, trouble shooting, and repair of the General TwinSeal differential (pressure) thermal relief (DTR) bleed system.

BACKGROUND

When the General Twin Seal valve is seated and completely filled with aliquid, any slight variation in temperature due to the sun’s rays or ambientthermal fluctuations will cause drastic changes in body cavity pressureresulting from thermal expansion.

Valves filled with 330 API fuel oil have exhibited a 75 PSI increase inpressure with a temperature rise of only 1° F. Putting this into perspective,a normal daily 30°F swing in ambient temperature may cause an increaseof body cavity pressure of 2250 PSI.

While results vary under actual service conditions depending on media,pressure vessel rigidity, and presence of entraned gas it is known thatdangerously high pressures will build up in liquid filled positive shut offvalves.

Therefore, the General Twin Seal in liquid service requires a pressurerelief device.

The differential (pressure) thermal relief (DTR) system is one suchautomatic “device" and should be included on every automated valve.

HOW IT WORKS

The differential (pressure) thermal relief (DTR) system is arranged as shownbelow. A variety of components are used in the DTR. As shown here, onecan see that the relief valve mounted at the tee outlet on the bonnet pipesover pressure to up-stream throat of thevalve. The standard re-lief valve is set to openat 25 PSI on all valvesregardless of workingpressure. With thevalve closed, the reliefvalve will open at 25PSI above upstreampressure. This systemfunctions only when thevalve is closed.

A manual body bleedvalve is included on theGeneral Twin Seal asstandard. This bleedvalve installed in therelief system is openedafter the Twin Seal isclosed. Seal effective-ness can be immedi-ately evaluated, after allowing a few seconds for stabilization of cavity vol-ume due to entrained air or gas. The bleed valve must be closed before theTwin Seal is reopened.

An isolation valve installed in the upstream throat tap is also included on thestandard DTR. It must be left open to permit relief system to relieve pressureupstream.

The isolation valve willbe used only for main-tenance and troubleshooting which will beexplained later.

Valve is to be CLOSEDONLY FOR REPAIR. Ifclosed during normaloperation the automaticportion of the relief sys-tem (relief/check valve)will be defeated. (Theoutlet of the relief valvewould close when clos-ing the isolation valve).

The remaining compo-nents of the bleed sys-tem i.e., tube fittings,nipples, pipe fittingsetc., are not functionally

involved in “how it works” but may be involved in “why it doesn’t work” whichwill be discussed later.

FLOW

DOWNSTREAMTHROAT TAPUPSTREAM

THROAT TAP

ISOLATIONVALVE

RELIEF VALVE

TEE

MANUAL BLEED

BLEED HOLElocated in bonnet onall valves except asnoted below.

BODY CAVITY TAP

Manual bleed with differential thermal relief (DTR) system discharged to flow line

19


SLIPS RETRACTSUFFICIENTLY FARTO DISLODGE SEALSFROM BODY

UNSEATING CONTINUES

PRESSUREEQUALIZES

UNSEATING BEGINS

SLIPS RETRACT“SQUEEZING” THETRAPPED VOLUME ANDTHUS ADDING TO THECAVITY PRESSURE

LINE PRESSUREREMAINS CONSTANT

LINE PRESSUREDINDEPENDENT OF

BODY CAVITYPRESSURE

PRESSURE BUILDS AS ARESULT OF THERMALEXPANSION OF A TRAPPEDVOLUME OF LIQUID

Electrically powered actuators or motor operators are configured normallyto bypass or ignore the opening torque limiter as the valve just beginsunseating.

If the motor operated General Twin Seal has experienced any thermal ex-pansion the pressure in the body cavity may have increased significantlyabove line pressure (see figure below) which would hydrostatically causeunseat load resistance. Worse yet, as these slips are pulled inwardly by theascending plug the trapped body cavity volume is squeezed like an accor-dion.

WHY IT IS ESPECIALLY IMPORTANT ON MOTOR OPERTED VALVES

In order to check that your bleed system is properly working, install or ob-serve a proper pressure gauge upstream of the valve. Seat the General TwinSealTM, verify integrity. Hook up a hand pump with ~ proper pressure gaug-ing to the manual body bleed. With the hand pump reservoir full of compat-ible fluid open MBV, begin pumping slowly observing body cavity pressure.Note it should not exceed upstream pressure by more than 25 PSI. If this isso, the DTR relief has been verified.

Manually operated valves (operated locally) allow access to their manualbody bleed valves which may be vented slightly to relieve this pumping ac-tion as well as thermal build up. If this center cavity cannot be vented to theatmosphere for environmental or safety reasons, the DTR may be required.Optionally, a manual body bleed alone may be acceptable.

Other remotely power operated valves, i.e. hydraulic, pneumatic, DC, etc.,may display stall problems during unseat if no automatic pressure protection(DTR) is installed, therefore DTR is required in these applications also. Butstall torque does not represent same damaging concern.

CONCERNS OF OTHER TYPES OF ACTUATORS

MANUALLY OPERATED VALVES

Symptom Problem Solution

Valve stalls as it unseats Isolation valve closed Open isolation valve -close only to repair

Relief check valve Close isolation valveinstalled backwards seat valve bleed and

drain valve removecheck/reliet reversereinstall close bleedopen isolation valve

Check valve plugged Same as above butforeign material replace or clean

Tubing/piping leaking Loose fittings/nipple Close isolation valvedamaged bleed close valve bleed and

drain valve, repair asrequired open isolationvalve close bleed

This pumps the body cavity pressure even higher adding directly to the ther-mal expansion pressure until something gives, such as...

1) The slip seals retract or2) The motor stalls or3) Something breaks or4) The DTR relieves

Since our slip seals are so dependably bubble tight and motor stall may beas high as 6 times maximum rated torque (remember the torque limiter is outof the unseat circuit) we see that electric motor operators MUST have AU-TOMATIC pressure protection which is, as shown previously, exactly whatthe DTR does best. Torque switch settings on electric actuators should beset higher on the opening direction than the closing direction.l

General Valve Company

a PCC Flow Technologies CompanyMain office: 800 Koomey Road • Brookshire Texas 77423

Tel: (281) 934-6013 • Toll-free: (800) 926-2288Fax: (281) 934-6058 • Toll-free: (800) 765-2266 http://www.general-valve.com

West Coast Factory: 2817 Cherry Avenue • Long Beach, California 90806Tel: (562) 426-5280 • Toll-free: (800) 624-8261 Fax: (562) 595-0296

Operation, Maintenance & Service Manual


The Twin Seal Valve requires no day-to-day maintenance, however, there are someservices which may be needed occasionally.

1. Annually, drain plugs in the lower plate should be removed and the residueflushed and drained from the lower plate. In cold climates, before freezingweather sets in, any possible collection of water below valve plug or plugtrunnion should be drained out through the lower plate drain plugs.

a. Keep the valve operator housing full of lubricant to displace and preventmoisture from accumulating and freezing. The operator is provided with agrease fitting. Lubricant should be injected with the Twin Seal Valve in theopen position only. Under ordinary conditions, a few pumps of the greasegun semi-annually is sufficient. Use lithium 12 hydroxy stearate or lithiumbase molydisulfide grease.

b. If applicable, temporarily remove ABBV cover and guide pin. Liberally applygrease in this area semi-annually.

2. If at any time the body bleed should indicate a leak which cannot be stoppedwith ordinary force on handwheel (no cheaters necessary), this may becorrected by one of the following:

a) Operate valve through open-close cycle while fluid is flowing to flush out valvebody. After several flushing attempts, close Twin Seal Valve and check bodybleed again. If body bleed still indicates valve leakage, proceed to b).

The General Twin Seal Valve is a non-lubricated, resilient seal, plug-type valve whichhas a mechanical means of freeing the plug before it is rotated from the closed tothe open position. In opening the valve, the plug is raised, thus retracting theseating segments or slips through their tapered dovetail connections. Only after theslips are fully retracted perpendicularly from the body seat is the plug rotated to theopen position.

Conversely, in closing the valve, the plug and slips are rotated freely, with no seal-to-body contact, until the slips are positioned over the ports. Then the plug is drivendown between the slips and the tapered surfaces wedge out the slips for a positiveupstream as well as downstream shut-off. For maximum upstream sealing, Do notback off. Do not use cheaters.

The small Twin Seal Valves are handwheel operated, and require up to 3 turns toopen or close. Up to 23/4 turns expand or retract the slips, while 1/4 turn rotates theplug. Large valves operate in a similar manner, except that they have enclosedweather-proof worm gearing.

At the top of the valve, a position indicator flag shows the exact plug position. Itappears in line with the flow when the valve is open, and perpendicular to the flowwhen the valve is closed.

Since Twin Seal valves hold bubble-tight, for ease of opening in liquid service, it isimportant to prevent trapped body pressure from exceeding the working pressure ofthe valve. Therefore, a relief system is required to prevent pressure buildup in thebody cavity.

On gear-operated models the handwheel position may be changed as follows:

A) Place valve in full open position. B) Remove gear housing cap screws. C) Turnhandwheel to further open the valve–this will turn gear housing. Continue untilhandwheel comes to desired position and gear housing mounting holes are aligned.D) Replace gear housing mounting cap screws. Be sure short cap screw isinserted below worm shaft.

20

OPERATION

MAINTENANCE

HANDWHEEL REPOSITIONING

PARTS

©1998 GENERAL VALVE Bulletin 132 All specifications and materials are subject to change without notice.GENERAL TWIN SEAL, GVM, REZILON, VFR, GVX, BEST VALVE BEST VALUE, WHEN LEAKS MATTER, SEATAND RESEAT, HGO, GOSP AND SAFETY BLEED are registered trademarks of General Valve Company. VITONand TEFLON are registered trademarks of DU PONT. Printed in the USA Rev. 3/2000

b) If your valve is supplied with a DTR system, it is possible that the relief valvemay be leaking. Check this by temporarily closing the line isolation valve. Ifthe leak stops, repair or replace the relief valve. If this is not the case, theslips need inspection.

c) To inspect or replace slips the line must be drained. Then place TwinSeal valve in open position (check body bleed valve for zero line pressure)and remove lower plate (lower plate can be driven off by closing valve,inserting a wedge and then opening valve again). Slips can be removedfrom plug and inspected or replaced if damaged. Be sure to save the oldslips and return to General Valve Company for exchange credit. It isrecommended to replace the lower plate O-ring and gasket any time thelower plate is removed and slips are replaced.

If lower plate is not accessible for replacing seating slips, the valve operator andbonnet can be removed (Check body bleed for zero line pressure before removingbonnet) and slips replaced from the top of the valve.

3. If stem packing needs replacement, it can be changed as follows:a) Remove operator as described in #4 below.b) Remove packing gland and replace inner and outer O-rings and

backup ring.c) Remove packing rings and replace carefully.d) Replace packing gland.e) Replace operator as described in #4.

4. To change operator:a) Shut down line pressure.b) Close Twin Seal Valve extra tightly.c) Open bleed valve for zero pressure when removing operator.d) Drive out coupling pin (towards guide pin boss).e) Remove housing mounting bolts and lift operator off.f) Replace new operator in reverse order (insert coupling pin from

same side as guide pin boss.)g) Close bleed valve.h) Check operation of valve.

Genuine factory replacement parts are available from General Valve Company,which inventories original equipment parts.

Slips, O-rings and packing are packaged in kits that make ordering simple. Besure to specify size, series, part number on slip, and type of resilient seal materialin your order of replacement slips.

To perform on-site maintenance, a mechanic should keep slip kits and soft goodkits on site. Most kits can be shipped from stock, typically within 48 hours afterreceipt of order.

General Valve Company also offers major valve remanufacturing, emergencyrepairs, money-saving reconditioned slips, technical assistance by phone,maintenance contracts, startup service and service training seminars.

GENERAL TWIN SEAL

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