DBB ball valve

DBB ball valve introduction

DBB ball valve (double block and bleed ball valve) is like having three valves in one.
API 6D defines a double block and bleed ball valve as a "single valve with two seating surfaces that, in the closed position, provides a seal against pressure from both ends of the valve with a means of vending/bleeding the cavity between the seating surfaces."
There are a couple different styles of double block and bleed valves. One style has two independently seating valves inside, with a bleed or drain valve. This configuration is referred to as a double isolation and bleed (DIB). The DIB valve can isolate either side of the valve (bi-directionally) to vent or bleed the cavity and isolate piping.
 
This trunnion mounted DBB ball valve from provides double block and bleed in a single valve. This style can isolate piping on both sides of the valve (uni-directionally) to vent/bleed the valve cavity between the seats.
Using a single double block and bleed valve system versus 3 separate valves saves installation time, weight on the piping system, and space. It also cuts down the number of leak paths to the atmosphere, reducing the risk of hazards when transferring liquids dangerous to humans or the environment.
 

DBB ball valve design feature

Normal diameter: 1/2 - 24 Inch (DN15 - DN600).
Pressure range: 150 - 3000 LB/ 15000 PSI.
Working temperature: -46℃ - +350℃.
DBB ball valve (ball/needle/ball), Reduce Bore.
Design: EEMUA 182, ASME B16.34.
Body Pattern: One Piece or three Pieces
Body: Carbon Steel, Stainless Steel, Alloy Steel.
End Connection: Flanged x Flanged,Flanged x F-NPT.
Face to face: as per manufacturer's standard.
Test and inspection: EEMUA 182, API 598.
Operation: lever.

DBB ball valve application

DBB ball valve (Double block and bleed ball valve) is most commonly used in the oil and gas industry, but can also be helpful in many other industries.
It's typically used where bleeding the valve cavity is required, where piping needs isolation for maintenance, or for any of these other scenarios:
Prevent product contamination
Remove equipment from service for cleaning or repair
Meter calibration