Double block and bleed valves are used to get positive isolation when doing maintenance activities in a live process plant. Typically 2 block valves and a bleed control device are produced as single get-together and this twin block and bleed control device manifold can be gladly installed for isolation objective,click here.
Double block and bleed valves are generally used for critical process service, such as top force toxic or system, hazardous or hydrocarbon process fluids. For non-critical service, one DBB assemblies must be used.
To do right isolation while doing repair, maintenance or close off activities, double block and bleed can be used in the subsequent way. Both the block control devices are closed first. The shutdown side of the bleed and block assembly is vented/drained/purged to make ready for maintenance. The bleed in the control device assembly is used to relieve the trapped procedure fluid from area between the 2 block valves. This way 2 isolation control devices separate the close off side from procedure fluids.
DBB valves are also generally used with blind spacers or spectacle blind to give right isolation. Double block and bleed valve assembles permit fewer potential leakage paths matched to traditional multiple control device installations, thus rising safety of the design.
Generally, ball valves are used as isolation or block valves and needle or ball control devices are used as drain control devices or bleed valves in the bleed and block assembly.
Cartridge type standard length DBB valves have an original design with2 ball valves and a bleed control device into one solid valves and fittings houston cartridge type item with ANSI B16.5 flanged tapped links. This configuration permits the valve assembly to have same face-to-face dimensions like a one block ball control device, thus permitting more area for other gadgets to be installed on the same time.
What application need a double block and bleed control deviec?
DBB are most generally used in the gas and oil industry, but can also be supportive in many other industries.
It is typically used where bleeding the control device cavity is needed, where piping needs isolation for maintenance, or for any of these other scenarios:
· Stop product contamination
· Get rid of equipment from service for repair or cleaning
· Meter calibration
· Storage and transmission
· Liquid service near municipalities or waterways
· Chemical sampling and injection
· Primary process steam
· Isolate instrumentation such as force indicators and lever gauges
What to look for when picking a double block and bleed valve?
As with any control device, during selection, one should consider the fluid features, force temperature. Perhaps most vitally, anyway, is how the control device will be used. With a number of designs offered, regard as which of these will fit your needs and process best.
If you are not sure which DBB valve is best for your process, discuss to an engineer. They can support determine which one will get your aims top.