Trademark of SISTAGHHIGH PERFORMANCE DOUBLE BLOCK AND BLEED KNIFE GATE VALVE

The unique WEY Model DB serves as both a Double Block & Bleedvalve and a Line Blind. This unique design has two gates operatedby one actuator. The gates seal against a combination metal and resilient seat for bi-directional bubble-tight shut-off. The chest andseating areas of the valve are self cleaning. The top “transverse”seal is re-packable while in service under full pressure. The valve istested and rated for ZERO leakage (liquid or gas) downstream andto atmosphere.

MODEL DB CHARACTERISTICS

� Solid 316 SS cast lugged body� 316 SS hard chrome finished gate� Aflas seals as standard� 2" – 24" size� 150 psi CWP design� 2" – 12" 150 psi shut-off� 14" – 24" 90 psi shut-off� Other body, gate and seal materials available� All styles of actuators available

The WEY Model DB reduces the number of valves required for a traditional double block & bleed application. Reducingthe number of valves required eliminates additional leak paths due to multiple flange connections and costs associatedwith extra valves and piping requirements. The illustration below compares a typical double block & bleed installationwith one utilizing a WEY Model DB.

TYPICAL DBB INSTALLATION WEY MODEL DBB

DRAIN / BLEED LINEDRAIN / BLEED LINE

ISOLATEDOBJECT / TANK

ISOLATEDOBJECT / TANK

# 1 – Vent center section to Atmosphere.

# 2 – Connect center sectionto flush or purge.

# 3 – Pressurize center sectionto pressure higher thaneither side of the valve.

Note: Leak detector (“sniffer”)can be used with any of the three protection options.

FUEL TERMINAL STORAGE TANKS

The Model DB is used to isolate product from the main trunk lines. The valve allows the operator to check for leakage all in a single valve with a relatively narrow face to face. The double block & bleed feature ensures no cross contamination of fuels. A small amount of contamination can ruin a tank of fuel resulting in the loss of hundreds of thousands of dollars for a single tank.

RECLAIM WATER CHEST ISOLATION

The Model DB is used to isolate the main mill water to the paper machine. The Model DB was selected toavoid cutting pipe and welding in additional flanges for multiple valves. They also avoided the need toshut down the system and disassemble piping to insert a line blind.

LIME KILN FILTER ISOLATION

The Model DB was selected for this application for safety reasons. It was critical to have positive isolationduring the process of acid cleaning the pressure filter. Time and money were saved by eliminating theneed for using line blinds reducing the isolation time for the cleaning process.

CONFINED SPACE ENTRY

OSHA requirements dictate the use of a double block and bleed set-up in these applications for safetyreasons. The Model DB meets this requirement with a small package that allows the valve to be installedin cramped piping systems eliminating the need for additional valves, flanges and spool pieces.

TTHREE METHODS OF PROTECTION

TTYPICAL APPLICATIONS

PORT#3

PORT#1

PORT#2THREECENTERSECTIONPORTS

TWOGATES

OSHA“CRABCLAW”

LOCK-OUTDEVICE

IISO 9001 CERTIFIED

MMODEL DB DOUBLE BLOCK AND BLEED

D I M E N S I O N S

3"

4"

*6"

8"

10"

12"

14"

16"

18"

20"

24"

30"

3

4

6

8

10

12

14

16

18

20

24

30

3.23

3.42

3.93

4.45

4.72

5.03

5.31

5.82

6.18

7.24

7.55

8.79

6.00

7.50

9.50

11.75

14.25

17.00

18.75

21.25

22.75

25.00

29.50

36.00

5/8"

5/8"

3/4"

3/4"

7/8"

7/8"

1"

1"

1-1/8"

1-1/8"

1-1/4"

1-1/4"

12.44

15.47

19.57

22.72

26.65

29.80

–

–

–

–

–

–

7.87

11.81

15.75

15.75

15.75

19.69

–

–

–

–

–

–

–

–

18.15

21.29

24.84

28.93

33.42

35.74

40.75

44.66

53.75

63.77

–

–

11.50

11.50

11.50

14.75

14.75

14.75

14.75

16.75

23.50

23.50

3/8"

3/8"

1/2"

1/2"

1/2"

1/2"

1/2"

1/2"

1/2"

1/2"

1/2"

1/2"

–

–

12

12

16

16

18

18

18

24

24

24

18.42

22.44

28.93

34.05

41.06

46.37

52.99

58.18

63.81

74.25

86.25

97.50

6"

8"

10"

10"

12"

12"

14"

16"

18"

20"

24"

26"

–

0.86

0.94

1.12

0.75

0.83

0.78

0.94

0.98

1.37

1.22

0.98

–

4

4

4

8

8

8

8

12

12

12

20

7.50

9.00

11.00

13.5

16.0

19.0

21.0

23.5

25.0

27.5

32.0

38.7

VALVE

SIZE A B C D E F G H J KNPT L M N O P

FOR OPTIONAL CYLINDER SIZES AND DIMENSIONS CONSULT THE FACTORY

*VALVE SHOWND=CYLINDER PORT SIZE 4"-12" TYP. SISTAG CYL.N=CYLINDER DIAMETER NOT ACTUAL OUTSIDE DIMENSIONNOTE: STANDARD CYLINDERS ARE SHOWN. (OTHER SIZES ARE AVAILABLE)O=DEPTH OF BLIND TAPPED HOLES IN CHEST AREA OF VALVEP=NUMBER OF BLIND TAPPED HOLES IN CHEST AREA OF VALVE

NOTE:(3:1) BEVEL GEARS ARE RECOMMENDED FOR 6"-10" VALVES(4:1) BEVEL GEARS ARE RECOMMENDED FOR 12"-20" VALVES(6:1) BEVEL GEARS ARE RECOMMENDED FOR 24" AND LARGER VALVESCONSULT FACTORY FOR SPECIAL APPLICATIONS

c 2007 Wey Valve, Inc. Bulletin No. DB0707

P.O. Box 387Nettleton, MS 38858Phone 662-963-2020Fax 662-963-2025e-mail: info@weyvalve.comVisit our website: www.weyvalve.com

Trademark of SISTAG

REPRESENTED BY:

Model VKSquare and Rectangle Valves

Model HDHigh Pressure Knife Gate Valve

(to 1440 psi)

Model HSIHigh Speed

Isolation Valve

OTHER SPECIALTY WEY VALVES

ALL INFORMATION IN THIS PUBLICATION PRESENTED FOR REFERENCE ONLY AND SUBJECT TO CHANGE

OTHER WEY VALVE PRODUCTS

Model VL(Lugged Design)

Model VS(Semi-Lugged Design)

Model NA1(Full Flange Design)

Model A3(Full Flange 300 psi Design)

Model T13(Transmitter Isolation)

Model SG(Shear Gate)