There are various kinds of valves that are sold at https://www.kp-lok.com/product/double-block-and-bleed-valves one of which is a ball valveand it is mainly used for the isolation in different kinds of applications which needed a barrier to operate independently of the major pressure barrier. It is mainly used because it require operational safety i.e. cleanliness of the fluid, zero leakages, gas service, etc. A valve that has an independent second barrier is mostly referred to as Double Isolation and Bleed valve which is also close to the double block and bleed valve.
There is a significant difference between DBB and DIB valve according to most engineers in the industry and various statistical data has also shown that various engineering group and different industries make use of DBB valve as the generic term but sometimes use of DIB valve in some instances where their application is required or specified by the engineer.
In the oil and gas sector, the valve which is widely used by engineers and also specified by API is double block and bleed valve. The major fact which will help in understanding this can be found in various journals and literatures about pipelines, it also clarifies the differences between the double block and bleed valve as well as double block and bleed valve. A single valve or DBB is a valve which has two distinct resting platforms that, when in closed position, it guides against the pressure which is coming from the two valve sideby bleeding the hollow space which is within the resting surfaces. The research which was recently done provide an information which shows that valves won’t provide isolation whenever only one side is under pressure. However, the definition of API regarding double block and bleed valve indicates that it is one valve which has two different resting platform, each of which is in close position, and this ensure there is seal so as to prevent the pressure from one direction, by bleeding the hollow space between the seating surfaces. The research also stated that the feature can either be provided in a single direction or two different directions as the case may be or due to the need and sector.
The double block and bleed valve would help in the prevention of fluid from getting access into the area where work is being done, the two in-line valves would be closed while the bladder would be in opened position. This will make sure that the double block and bleed valve verify the primary seal by the bleeding cavity i.e. the space which is between the upstream and downstream valve spaces, if there is any leakage between and such pass through the first valve, the bladder would ensure it is drained off before the cavity get pressurized as a result of it. In addition to that, it can also be used for measuring the cavity for leakage. if the bleeder were to be plugged in the downstream valve, it would allow the passage of fluid. Thus, the second barrier is in place and if the first barrier is unable to stop the leakage which result from the flow of the cavity which is between.
Apart from using it as a block valve where there is need to have line maintenance, the double block and bleed valve likewise have applications in the metering industry, oil and gas industry, service industry etc. this kind of valve can also be designed for a metering service which differs from the design feature for the former because the design for the metering service is different from the design features for metering service application is mainly driven by the zero percent leakage. This is because a close valve which is leaking can create an errors in the metering measurement.