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Two-Ball DBB Isolation

Double Ball DBB Valves

Double ball DBB valves use two separate ball closure elements in one assembly with a bleed or vent point between them. This page is for buyers who specifically need a two-ball architecture, rather than a generic DBB label, and need to define how each ball, seat and cavity should behave in service.

Two Ball ClosuresIntermediate BleedIndependent OperatorsProject-Specified Seat Design

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Double Ball DBB Valves engineering collection

Related Collections

Compare Related DBB Designs

Use the related collection pages to keep valve architecture, installation function and buyer intent separate.

COMPACT CONSTRUCTION

Compact Construction

Integral DBB Valves

Compare integral DBB construction when installed length and reduction of external joints are the main design drivers.

Compact DBB body

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BALL SUPPORT

Ball Support

Trunnion Mounted DBB Valves

For pipeline duties, compare trunnion-mounted DBB architecture and seat/cavity pressure requirements.

Trunnion DBB

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PARENT COLLECTION

Parent Collection

Double Block & Bleed Valves

Return to the full DBB family to compare instrument and monoflange designs as well.

All DBB families

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Buyer Selection Matrix

Two-Ball DBB Design Decisions

Ball support	Specify floating or trunnion-supported ball construction where required; do not leave the support concept ambiguous.
Operator independence	Confirm whether each isolation ball needs a separate lever, gear or actuator and the required operating sequence.
Intermediate cavity	Define the bleed / vent connection and how trapped pressure between the two balls is handled.
Seat arrangement	State seat materials, sealing direction / philosophy and any project requirement for upstream/downstream isolation.
Bore and pigging	If the line must be piggable, state the full-bore requirement and dimensional restrictions in the RFQ.

Selection Logic

The Two-Ball Layout Gives Buyers a Clear Isolation Architecture

Two ball closures make the isolation arrangement physically obvious: one closure on each side of an intermediate cavity that can be bled or vented. But the performance still depends on ball support, seat design, cavity relief, bore, operator configuration and test criteria. Those details should be written into the datasheet instead of assumed from the product name.

Application and isolation function

Pressure / temperature boundary

Material compatibility

Connection interfaces

Operation and access

Testing and documentation

Project Application

What to Send for a Double Ball DBB Quotation

Provide size, class, design code if specified, full/reduced bore, floating or trunnion preference, body and trim materials, seat material, end connections, bleed connection, operation, flow direction if relevant, service pressure/temperature and test/document requirements. For automated units, add actuator fail position, power source, controls and accessories.

For final selection, use the project valve specification, piping class, instrument hook-up drawing or approved datasheet as the controlling document.

Factory & Quality Evidence

Review Supplier Evidence Before PO

Buyers can review YINKE VALVE factory information, quality documents, sample inspection records and project references before technical and commercial confirmation.

Factory & Production Quality & Certificates Project References Send RFQ

Buyer Questions

Double Ball DBB Valves FAQ

Is a double ball DBB valve always trunnion mounted?

No. Double ball describes the number of ball closure elements. The support design should be specified separately.

Why is the intermediate bleed important?

It provides a defined point to depressurize, drain or verify the cavity between the two isolation closures, subject to the project operating procedure.

Can a double ball DBB valve be full bore?

Yes, full-bore configurations are possible, but the RFQ should explicitly state the bore requirement and any pigging or pressure-drop constraint.

RFQ Checklist

Information to Send for Review

Two-ball architecture

Floating / trunnion support

Size and pressure class

Full / reduced bore

Seat design and material

Intermediate bleed connection

End connection / facing

Operator for each closure

Service conditions

Test / inspection / documents

Technical data is confirmed against the final quotation, approved drawings and project specification.

Need a DBB Valve Quotation?

Send the valve list, datasheet, P&ID or instrument hook-up drawing for technical and commercial review.

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