Double-block-and-discharge ball valve (DBB ball valve, also known as double-block-and-discharge valve) is a safety valve with dual isolation and discharge functions. Its core function is to provide reliable isolation, active discharge and efficient maintenance for industrial pipeline systems. The specific functions are as follows:
1. Double seal isolation (double shut-off)
Bidirectional seal blocking:
Built-in two independent seal pairs (such as ball + valve seat combination), which can simultaneously block the bidirectional flow of the medium and achieve zero leakage sealing;
Replace the traditional series double valve design, simplify the pipeline layout, and reduce leakage points.
Fire safety guarantee:
When the soft seal (PTFE) fails, the metal hard seal is automatically activated to maintain the basic sealing under fire conditions.
2. Cavity pressure relief (discharge function)
Automatic pressure relief and explosion prevention:
The middle cavity between the two sealing pairs is equipped with a discharge port (connecting a needle valve/ball valve), which can manually or automatically discharge the residual medium;
Avoid overpressure in the valve cavity due to increased ambient temperature and protect the pipeline system.
Safety detection channel:
Detect the integrity of the two sealing pairs through the discharge port (if there is internal leakage, the medium will be discharged from the discharge port) without disassembling the valve.
3. Core advantages of operation and maintenance
| Functions | Value | Applications |
|---|---|---|
| Online Maintenance | When the seal/actuator is damaged, it can be replaced under pressure | Oil and gas pipelines, chemical continuous production |
| Pipeline Pressure Reduction Integration | Replace independent pressure reducing system, saving installation space and cost | Tank area pipeline network, LNG receiving station |
| Cleaning sewage | Regularly open and close valves to remove impurities deposited in pipelines | Pipeline for conveying medium containing particles |
4. Typical application areas
Oil and gas storage and transportation: safe cutoff of aviation kerosene, natural gas, and liquefied gas pipelines;
Chemical process: highly corrosive media (need to be matched with anti-corrosion materials) and high-pressure reaction systems;
Energy system: steam/water pipelines in thermal power plants, petroleum refining equipment.
Prohibited scenarios: ultra-low temperature (<-46°C) or strong acid (such as hydrochloric acid) media
