The Solution For The Valve Problems Plug Valves

Plug Valves

Double Block & Bleed Plug ValveThe Solution For The Valve Problems

Specification & Availability

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3Z Standards Twin Slip Double Block and Bleed ValveFigure # 124, 324, 624, 924, 1524

Rating : ANSI Class 150/300/600/900/1500Size : 2”~ 24”Temperature Range : -20˚F(-29˚C) TO + 350˚F(+176.7˚C)Connections : Flanged, Screwed, Welded (Butt, Socket)Wrench, enclosed gear operated or actuated

3Z Full Bore Twin Slip Double Block and Bleed Valves

Rating : ANSI Class 150/300/600/900/1500Size : 2”~ 24”Temperature Range : -20˚F(-29˚C) TO + 350˚F(+176.7˚C)Connections : Flanged, Screwed, Welded (Butt, Socket)Hand wheel, enclosed gear operated or actuated

3Z 4-Way Twin Slip Double Block and Bleed Valves

Rating : ANSI Class 150/300/600/900/1500Size : 2”~ 24”Temperature Range : -20˚F(-29˚C) TO + 350˚F(+176.7˚C)Connections : Flanged, Screwed, Welded (Butt, Socket)Hand wheel, enclosed gear operated or actuated

Materials of construction

BodyCarbon Steel

ASTM A216 WCB Chrome Plated

TopCover

Carbon Steel

ASTM A216 WCB or ASTM A283D Plated

BottomCover

Carbon Steel

ASTM A216 WCB or ASTM A283D Plated

Wedge Carbon SteelASTM A216 WCB

Electroless Nickel Plated

Slips Ductile Iron ASTM A536-65-45-12

GlandStainless

SteelASTM A276 410SS

PackingGraphite

Type-

O-Ring & Slip

Viton -

Studs /Nuts

Carbon Steel ASTM A193 B7 / ASTM A194 2H

Operation

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3Z Double Block & Bleed (DBB) ValveDesigned to meet Oil & Gas transmission, loading,unloading needs. Line sealing is achieved by body andwedges cut from each side of the plug with or withoutthe assistance of soft seat rings.

The sealing is positively made on each side of theplug(double block), and the media kept in the plugport area can be bled into upstream or to thecontainer to prevent from explosion. The Valve can beused for assuring metering accuracy and SCADAsystems.

1. ClosingThe small size Double Block and Bleed valves arehandwheel operated and the larger sizes are equippedwith waterproof of gearing but operate in the samemanner, proportionately requiring more turns. Turningthe handwheel rotates the wedge 90 degrees, aligningthe seating slips. The elastomer seal rings areintegrally bonded within the machined groves of eachslip.

2. CompressingAs the wedge lowers, it force the seating slipsoutwards, pushing the seals against the body andcompressing them with in the grooves. With the slipssolidly against the body, a secondary metal-to metalseat is formed on both sides of each seal, providingdouble protection. The wedging forces the seatingslips outwards against the valve body and isperpendicular to the seats and the body. Thiseliminates all scraping and rubbing forces on theseals.

3. OpeningWhen opening, the wedge moves upwards and thedove-tailed (slips) are pulled away from the body. Thewedge is guided by an upper and lower trunnion, andthe wedge is rotated 90 degrees, aligning the seatingslips. In the open position, the seals are completelyout of the flow. Again, This action eliminates allscraping and rubbing forces on the seals.

Plug

Seatingslip

dovetail

Resilentseal

Construction

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Handle & operator :This is designed for easy openingand closing, and minimizes thepossibility of line shock.

Indicator : This indicates the direction of the plug open or closed position.

Gland & packing : This is designed so that the depthof the stuffing box is sufficient toinsert both a fire safe graphitepacking and Viton O-ring or othercustomer specified material.

Plug & Trunnion : This is designed to insure thetrunnions (Upper &Lower)maintain correct alignment of theplug during opening and closingof the plug.

Slip & viton seal :The viton seal within the slipexecutes a double block and bleedfunction, it eliminates abrasion,because the slips Containing theViton seals pull away from thebody before the plug starts torotate.

Bottom cover :The bottom cover may be removedfor maintenance purpose.Replacement of the slips ispossible, while the valve remainsbolted in the pipeline (In LineReparability)

Cover Bolt

Cover

Body

O-RING & GASKET

Bleeding Systems

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Gauge

25PSIDifferentialCheck Valve

Flow Direction

Isolation ValveLeave openwhen in service

Bleed Valve

25 psiDifferentialCheck Value

IsolationValue(Ieave openwhen in service)

FlowDirection

The above system is designed to relieve any excess rise inpressure, within the body cavity, due to terminalexpansion of the liquid within the cavity, when the valveis in the closed position. The relief valve is set to open at25PSI or above and bleeds excess pressure to theupstream side.

Note : System will only function when valve is closed andthe isolation valve is open.

Automatic Body Bleed Valve to Atmosphere orUpstream (Customer Option)The check valve is operated by a plunger that opens thebleed valve by a coupling cam, during the closing of thevalve. The valve may be operated by hand or an actuator.

This system incorporates a complete automatic system byremoving the need for human intervention. An isolationvalve is fixed in the open position to prevent the need forchecking the seal.

Design Features

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Zero Leakage

Valves selection is very important in the petroleumindustry. An incorrect valve may cause loss of income,pollution of product, and increase of product linemaintenance costs. Multi-product system valvesshould be designed to withstand frequent cycling andprovide a tight seal shut off. The double block andbleed valve was developed to cater for pump ormetering station, tank farms, marine loading docksand blending plants.

No Abrasion

The 3Z Twin Slip Double Block and Bleed valve cancompletely isolate a line without leakage. The valvedesign is such that the seals do not come into contactwith the valve body at any time while opening orclosing of the valve. The seals come in contact withthe body at the last moment force. This pressure forceis perpendicular to the seating area and a shearingforce is thus eliminated. When the valve is in theopening position, the seals are separated from thebody, and are maintained at this state during wedgerotation. This eliminates abrasion forces from the sealsand extends seal life.

Double Block & Bleed

With the 3Z Twin Slip Double Block and Bleed valve,there is an up-stream and down-stream seal, as wellas a bleed point in between. This one D.B.B. may besubstituted for two valves with one spool (drain). Thespool sends any leaking fluid from the valve to thetank. The bleed system on the 3Z double block andbleed is provided to prove zero leakage. The ensuresthat if any leakage was to occur, it would beeliminated via the bleed. This in turn, guaranteescomplete and total product segregation.

High Integrity Shutoff

When the valve is closed the elastomeric seal rings arepushed against the seats each side of the valve body,The force is directed at a perpendicular direction bythe wedging action of the slips. The elastomer sealson the slips are secured within a machined grove by abonding agent. As for being fire-safe, the outsidesurface around the seals (on the slips) is a finishedsurface of metal, that is pushed against the metalbody seat. This results in both an elastomeric andmetal-to-metal bubble tight seal.

In Line Repairability

It is possible to inspect and replace the sealing slipswith the valve still in line. The valve has a top andbottom bolted flange that is removable while thevalve remains bolted in place.

Applications

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3Z Double Block and Bleed valves are widely used for critical areas such as refinery, distribution center, Loadingarm and air ports.

Loading Arm Tank Farm

Metering Station Air Port

Tank Terminals Pipe Line

Cryogenic Application (Construction)

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NO PART NAME Q’TY MATERIAL1 BODY 1 STAINLESS STEEL2 TOP COVER 1 STAINLESS STEEL3 BOTTOM COVER 1 STAINLESS STEEL4 PLUG 1 STAINLESS STEEL5 SLIP 2 STAINLESS STEEL6 SLIP INSERT 2 PFA7 PACKING GLAND 1 STAINLESS STEEL8 PIN(ANTISTATIC DEVICE) 1 ALLOY STEEL9 GASKET 1S STAINLESS STEEL/GRAPHIT10 MECHANISM OPERATOR 1S STAINLESS STEEL11 BLEED SYSTEMS 1S STAINLESS STEEL12 PACKING GLAND BOLT 1S STAINLESS STEEL13 BOTTOM DRAIN PIPE PLUG 2 STAINLESS STEEL14 COVER BOLT 1S STAINLESS STEEL15 OPERATOR HOUSING BOLT 1S STAINLESS STEEL16 GEAR OPERATOR 1S DUCTILE IRON17 BODY O-RING 1S PTFE18 INNER GLAND O-RING 1 PTFE19 OUTER GLAND O-RING 1 PTFE20 PACKING SET 1S GRAPHITE 21 STEM 1 STAINLESS STEEL22 ACTUATOR 1 COMMERCIAL23 UNDER BONNET 1 STAINLESS STEEL24 EXTENSION STEM 1 STAINLESS STEEL25 EXTENSION BONNET 1 STAINLESS STEEL26 TOP BONNET 1 STAINLESS STEEL

Cryogenic Application (At Site)

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Loading Arm of LNG Terminal at one of the Middle East Country

After Cryogenic Test at Factory Actual Installation withHeavy Insulation

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