Double Block and Bleed Monoflange Valve Manifold

Double Block and Bleed Monoflange Valve Manifold Product Overview

The SIYelectric Double Block and Bleed Monoflange Valve Manifold, also called a DBB monoflange valve manifold, is an instrument valve assembly used for pressure isolation, pressure release, venting, draining, and safe maintenance of field instruments.

It is typically installed between the process connection and a pressure measuring instrument, such as a pressure transmitter, pressure gauge, pressure switch, or other process instrumentation device.

A proper double block and bleed structure usually provides two isolation valves and one bleed valve in a compact monoflange body. The two block valves isolate the instrument from the process line, while the bleed valve allows trapped pressure to be released before calibration, inspection, or instrument removal.

This design is especially suitable for applications where safety, compact installation, and leakage reduction are important.

Product Description

In many industrial pressure measurement points, a pressure instrument needs to be isolated from the process before maintenance. If only a single isolation valve is used, the operator has less protection when dealing with high-pressure, flammable, toxic, or hazardous media.

The double block and bleed monoflange manifold provides a more secure arrangement. The double block valves create two isolation barriers between the process and the instrument, while the bleed valve allows the trapped pressure between the isolation points to be released safely.

Compared with installing several separate valves and pipe fittings, the monoflange design combines the required valve functions into one compact body. This helps simplify the instrument connection, reduce installation space, reduce possible leakage points, and improve maintenance convenience.

It is widely used in pressure measurement, process monitoring, instrument protection, calibration, and safe shutdown applications.

Key Features

Double Block and Bleed Design

The manifold provides double isolation and controlled pressure release. This helps improve safety when instruments need to be inspected, calibrated, removed, or replaced.

Compact Monoflange Structure

The monoflange body reduces the need for multiple separate fittings and valves. It is suitable for compact instrument installations and high-pressure process connections.

Suitable for Pressure Instruments

Commonly used with pressure transmitters, pressure gauges, pressure switches, smart pressure transmitters, and other field instruments.

Pressure Venting and Draining

The bleed valve can be used to release trapped pressure, drain residual media, or connect maintenance equipment according to site requirements.

Reduced Leakage Points

By integrating multiple valve functions into one body, the manifold helps reduce threaded joints and potential leakage paths.

Reliable Sealing Design

A non-rotating stem design and secure gland structure help improve sealing reliability and reduce wear during operation.

Material and Connection Options

Available with different materials, flange standards, pressure ratings, thread types, and vent connection options according to process conditions.

Technical Specifications

Applications

Oil and Gas Industry

Pressure measurement and isolation
Used in upstream, midstream, and downstream oil and gas applications, including production units, pipelines, separators, gas processing systems, and refinery pressure measurement points.

Safe venting and maintenance
The DBB monoflange valve manifold allows operators to isolate the pressure instrument and release trapped pressure before maintenance, improving safety in high-pressure or hazardous service.

Chemical and Petrochemical Plants

Process pressure monitoring
Applied in reactors, pumps, distillation columns, storage tanks, chemical pipelines, dosing systems, and process units where stable pressure measurement is required.

Hazardous media isolation
Suitable for applications involving corrosive, toxic, flammable, or high-pressure media where safer instrument isolation is important.

Power Generation

Steam and water systems
Used in boiler systems, feedwater lines, condensate systems, turbine auxiliary systems, and other pressure monitoring points in power plants.

Instrument protection
The manifold helps protect pressure transmitters and gauges during commissioning, shutdown, calibration, and routine inspection.

Water Treatment and Distribution

Pressure monitoring in pipelines
Used in filtration systems, pumping stations, water treatment equipment, distribution pipelines, and desalination systems.

Local instrument maintenance
Allows pressure gauges or transmitters to be isolated locally, helping reduce maintenance difficulty and system interruption.

HVAC and Utility Systems

Heating and cooling system measurement
Suitable for chilled water, hot water, compressed air, gas, and utility pressure measurement points.

Convenient service access
The compact DBB structure provides isolation and pressure release functions for instrument maintenance.

Laboratories and Test Systems

Pressure test and fluid control systems
Used in test benches, pilot plants, calibration systems, and laboratory process equipment where reliable pressure isolation and venting are required.

Advantages

• Double block and bleed structure provides two-stage isolation and controlled pressure release.
• Compact monoflange design reduces separate fittings and saves installation space.
• Suitable for pressure transmitters, pressure gauges, and pressure switches.
• Helps reduce leakage points compared with multiple separate valve assemblies.
• Useful for high-pressure, hazardous, flammable, or corrosive media applications.
• Supports safer calibration, inspection, instrument removal, and maintenance.
• Non-rotating stem design helps reduce seat wear and improve service life.
• Secure gland structure supports stable sealing performance.
• Hastelloy tip option can improve corrosion resistance in demanding media.
• 100% pneumatic testing can be provided before shipment according to order requirements.

Selection Notes

When selecting a Double Block and Bleed Monoflange Valve Manifold, confirm the following details:

1. Instrument type
   Confirm whether it will be used with a pressure transmitter, pressure gauge, pressure switch, or other field instrument.
2. Process connection
   Confirm flange size, flange standard, pressure class, sealing face, and instrument connection type.
3. Pressure and temperature
   Confirm the maximum working pressure and operating temperature of the process.
4. Medium compatibility
   Select body material, stem tip material, seat material, and sealing structure according to the medium.
5. Vent or drain requirement
   Confirm whether the bleed connection will be used for venting, draining, calibration, or pressure release.
6. Safety requirement
   For oil and gas, petrochemical, or hazardous applications, confirm whether special testing, material certificates, or project standards are required.
7. Installation space
   Monoflange manifolds are useful where compact installation and fewer leakage points are preferred.