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Flange-Mounted Instrument Isolation

DBB Monoflange Valves

DBB monoflange valves combine the process flange interface, two block functions and a bleed path in a compact body close to the nozzle. They are selected to simplify pressure-instrument hook-ups where space, external joints, orientation and direct flange mounting matter.

Direct Flange MountTwo Block FunctionsCentral BleedInstrument Outlet

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DBB Monoflange Valves engineering collection

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Parent Collection

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Buyer Selection Matrix

Monoflange Interface Checks

Flange interface	Confirm nominal flange size, pressure class / rating, facing, bolt pattern and project flange standard.
Instrument outlet	State the exact thread or connector for the gauge, transmitter or downstream manifold.
Bleed connection	Specify bleed / vent size, thread, outlet direction and whether discharge must be piped away.
Stem orientation	Confirm access for all block and bleed stems after the monoflange is bolted to the process nozzle.
Material and packing	Match wetted materials and packing to corrosion, pressure and temperature requirements.

Selection Logic

Why the Flange Interface Is the First Monoflange Design Decision

A monoflange is installed directly at a flanged process take-off, so the process flange dimensions and rating are the fixed boundary conditions. The instrument outlet and bleed ports must then be arranged so technicians can operate the stems, connect tubing and route venting without interference. A correct flange rating alone is not enough if the orientation and outlet details are wrong.

Application and isolation function

Pressure / temperature boundary

Material compatibility

Connection interfaces

Operation and access

Testing and documentation

Project Application

RFQ Data for DBB Monoflange Valves

Send the flange size and class/rating, facing, instrument outlet connection, bleed connection, body/trim/packing material, design pressure/temperature, required stem orientation, process medium and any plugs, fittings, handles or locking requirements. If available, provide the instrument hook-up drawing and nozzle orientation.

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

DBB Monoflange Valves FAQ

What is a DBB monoflange used for?

It provides compact double-block-and-bleed isolation at a flanged process connection for gauges, transmitters and other instrument hook-ups.

What is the main difference between a monoflange and a line-size DBB valve?

A monoflange is built around a process flange and instrument outlet, while a line-size DBB valve is selected as part of the main piping flow path.

Why should stem orientation be shown on the RFQ?

Because the valve must remain operable after installation. Nearby piping, insulation and instrument tubing can block access if the stem arrangement is not checked.

RFQ Checklist

Information to Send for Review

Flange size and class / rating

Facing / flange standard

Instrument outlet

Bleed / vent connection

Block / bleed stem arrangement

Body / trim / packing material

Design pressure / temperature

Process medium

Mounting orientation

Accessories and test scope

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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