Double block and bleed valve Working

Double block and bleed valve Working

Double block and bleed valve is a one valve which comprises of 2 seating surfaces. It can give a seal against force from both control device ends when the valve is closed. The basic operating spec of this valve is that it vents or blends that cavity between the seating surfaces. The DBB valve was made so that the want of bolting down personal control devices can be rejected. A single control device can provide the twin isolation that decreases the cost by over sixty percent.


There is a bleed control device along with 2 block valves that work as a unit or a manifold. This get-together is installed to give a right isolation. The double block and block control devices are used for toxic or hazardous fluid processes or for the high-force systems and many more critical processes.


The DBB are used to maintain a right isolation while you the maintenance activities are being done in live process plant. The right isolation can be  done during the maintenance, shutdown or repairing works. At first, block valves are shut off. Additional, the close off side is expel to get ready for repairs. The process fluid trapped in the area between 2 block valves is thankful by the bleed control device assembly. In this way, the close off side is separated from procedure fluids via the isolation valves.


The DBB valve fluids applications in chemical injection link, gauge isolation, chemical seal isolation and instrument drain. The DBB need much lower weight and area but can perform the work of 3 different control devices i.e. 2 isolation control devices and one drain control devices.

Some readers might be confused about when are the DBB valves needed. So, basically, this control device is used when a vent control device is needed in between 2 isolation techniques.

Types of double block and bleed valve

Single block and bleed valve

A single DBB valve is used while the maintenance activities are going on in a live procedure plant. It supports to attain right isolation. Generally, one bleed control device and one block control device is made in the type of single get-together or it can be known as manifold. Now, this single BBD valve manifold is capable to get gladly fixed for the isolation objective.

Double block and bleed valve

In this kind of DBB valve, the role of isolation control devices or the block control devices is played by ball valves whereas ball or needle valves play the role of drain control devices or the bleed valves. This way, the bleed and block assembly are modified. This assembly is designed to use in the midstream, downstream or the upstream of gas and oil.

Integral double block and bleed valve

The integral DBB valves are employed for the initial isolation duties for liquid or gaseous service. These control devices are produced because of the area and weight saving specs of these valves. Additional, they are accessible in a big range of materials and sizes. You can simply get the head unit mixtures too in order to meet all your needs.