Difference in Ball Valve Design between DIB-1 And DIB-2

In industrial fluid control, DIB double block and bleed ball valves are renowned for their high sealing performance and safety. Among them, DIB-1 and DIB-2 are suitable for different working conditions due to their design differences.

In terms of structure, DIB-1 adopts a double piston effect seat (DPE). Both seats can achieve bi-directional sealing. Whether the medium enters from the upstream or downstream, reliable isolation can be ensured. However, DIB-2 combines a single piston effect seat (SPE) with DPE. The single piston seat can only bear force unidirectionally. During installation, it needs to be placed at the inlet end to achieve automatic pressure relief in the middle cavity.

The differences in sealing and pressure relief functions are remarkable. DIB-1 has no automatic pressure relief ability and requires an external pressure relief valve to prevent overpressure in the middle cavity. However, with its bi-directional sealing of the double seats, it performs excellently in the transportation of high-risk media. DIB-2 relies on the single piston seat at the inlet end. When the valve is closed and the pressure in the middle cavity is too high, it will automatically relieve pressure. Although there is a unidirectional sealing seat, the DPE seat at the outlet end can still guarantee the downstream sealing performance.

The installation and application scenarios also have their own focuses. DIB-1 has no installation direction restrictions and is suitable for natural gas and chemical pipelines with extremely high sealing requirements. DIB-2 needs to be installed strictly according to the direction. It is commonly used in oil pipelines with large pressure changes and LNG pipelines with harsh working conditions to balance the requirements of pressure and sealing.