Block and Bleed Manifold
What
is Block and Bleed - DBB
A block and bleed manifold is a hydraulic manifold that combines
one or more block/isolate valves, usually ball valves, and one or
more bleed/vent valves, usually ball or needle valves, into one
component, for interface with other components (pressure measurement
transmitters, gauges, switches, etc.) of a hydraulic (fluid) system.
DBB Purpose
The purpose of the block and bleed manifold is to isolate or block
the flow of fluid in the system, so the fluid from upstream of the
manifold does not reach other components of the system that are
downstream, then bleed off or vent the remaining fluid from the
system on the downstream side of the manifold. For example, a block
and bleed manifold would be used to stop the flow of fluids to some
component, then vent the fluid from that component’s side of the
manifold, in order to effect some kind of work
(maintenance/repair/replacement) on that component.
Isolation Manifold
A block and bleed manifold with one block valve and one bleed valve
is also known as an isolation valve or block and bleed valve; a
block and bleed manifold with multiple valves is also known as an
isolation manifold. Also used in combustionable gas trains in many
industrial applications. Double Block and Bleed Valves replace
existing traditional techniques employed by pipeline engineers to
generate a double block and bleed configuration in the pipeline.
Cartridge Type DBB
Cartridge Type Standard Length Double Block and Bleed Valves have a
patented design which incorporates two ball valves and a bleed valve
into one compact cartridge type unit with ANSI B16.5 tapped flanged
connections. The major benefit of this design configuration is that
the valve has the same face-to-face dimension as a single block ball
valve (as specified in API 6D and ANSI B16.10), which means the
valve can easily be installed into an existing pipeline without the
need for any pipeline re-working.
Single Unit DBB Advantage
Three Piece Non Standard Length Double Block and Bleed Valves (DBB
Valves) feature the traditional style of flange-by-flange type valve
and is available with ANSI B16.5 flanges, hub connections and welded
ends to suit the pipeline system it is to be installed in. It
features all the benefits of the single unit DBB valve, with the
added benefit of a bespoke face-to-face dimension if required. The
single unit DBB design also has operational advantages, there are
significantly fewer potential leak paths within the double block and
bleed section of the pipeline.
DBB Reduced Space
Because the valves are full bore with an uninterrupted flow orifice
they have got a negligible pressure drop across the unit. The
pipelines where these valves are installed can also be pigged
without any problems. There are several advantages in using a Double
Block and Bleed Valve. Significantly, because all the valve
components are housed in a single unit, the space required for the
installation is dramatically reduced thus freeing up room for other
pieces of essential equipment.
Quickly Establish Safe Work Environment
Considering the operations and procedures executed before an
operator can intervene, the Double Block and Bleed manifold offers
further advantages over the traditional hook up. Due to the volume
of the cavity between the two balls being so small, the operator is
afforded the opportunity to evacuate this space efficiently thereby
quickly establishing a safe working environment.