DBB ball valves /Double block and bleed ball valves/Double isolation and bleed ball valves use all the design features and benefits of a single DBB trunnion ball valve, but more special in its double isolation performance. The body is generally is manufactured from forged or bar stock material to ensure a high integrity pressure envelope for the valve body (housing). ● Double secure isolation more reliable to safety factor ● Zero leakage performance credibility ● Bleed and depressurize pipeline system ● Less installation space and less weight in pipeline ● Easy one step operation in one union body ● Less cost in material and labor ● Inline repair or maintenance check allowable by not shut down plant,improve plant efficiency ● Fire safe API607 ● Anti-static design API608 ● Cavity self relief ● Double block and bleed ● Seals: o ring/graphite for general service /graphite for high temperature service/ lip seal+graphite for cryogenic service ● Seat: soft/metal seated for general service, metal seated for high temperature service ● Seat design: Self relieving or double piston effect seats ● Valve seat bi-direction sealing ● Bonnet: extend stem for high temperature/cryogenic service Emergency grease injection device for soft seated trunnion ball valve. For the valve size about DN150 trunnion ball valve, both the stem and seat has the grease injection device, for size below DN125,the valve chamber has the grease injection device. In case of the seat sealing or stem o ring damaged, the emergency grease injection will seal the damaged area and prevent the medium leakage. QL DBB ball valves could be designed with soft seat or metal-to-metal seat. Metal seated for high temperature or particle medium. The sealing is reliable and suitable for the severe working conditions. Application
QL has the ranges of DBB ball Valves suitable for Oil & Gas production, processing, transportation, distribution, chemical and petrochemical refining including system isolation, pressure level and flow measurement, instrument drain, chemical injection and sampling for smaller sizes. QL ball valves designated in highest performance and produced in strictest quality. Contact our sales engineer for your specific fluid needs.