DBB Plug Valves: Uses in Aviation Kerosene Refueling

Double Block and Bleed (DBB) Plug Valves are key shutoff devices in the aviation kerosene refueling industry. Their unique performance fits the needs of aviation kerosene—like its flammability, high purity requirements, and strict refueling scenarios. Below are the specific applications:

I. Core Application Scenarios

1. Airport Refueling Pipeline Systems
Airport aviation kerosene refueling pipelines often switch between different storage tanks or refueling stations. The double-block and double-bleed functions of orbit plug valves cut off the medium accurately. This prevents mixing of different batches of aviation kerosene.
For example, large hub airports widely use these DBB valves in their pipeline systems. When a tank is being refueled, DBB plug valves block residual medium. At the same time, bleed valves quickly drain any leaked medium. This ensures fuel purity.

2. Fuel Truck-Aircraft Connection Links
When refueling aircraft with fuel trucks, valves need to respond quickly and seal reliably. This stops kerosene leaks.
Twin seal orbit plug valves have low switching torque. They are easy to operate and switch on/off fast. Their soft seal achieves zero leakage. And their hard seal prevents massive leakage in extreme situations (such as fires). This boosts refueling safety.

3. Aviation Kerosene Storage Tank Outlet Pipelines
The tank outlet is a key node for controlling kerosene delivery.
The full-bore design of general plug valves ensures smooth kerosene delivery. This guarantees efficient refueling. The valve body is hard chrome-plated. It resists corrosion and has a smooth surface. This reduces impurity buildup from kerosene and lowers the chance of valve failure. It also ensures stable fluid supply from the storage tank to the refueling system.

II. Usage Precautions

1. Regularly Test Sealing Performance
Though DBB plug valves have excellent sealing, their soft seals may age after long-term use. You need to check for internal leaks through the bleed valve regularly. If aged parts are found, replace them promptly to ensure sealing reliability.

2. Match Medium Characteristics
Choose special valves designed for aviation kerosene's traits. The sealing material must be compatible with aviation kerosene. This avoids seal failure or medium contamination caused by incompatible materials.

III. Advantages Over Traditional Valves
In the aviation kerosene refueling field, general twin seal plug valves have clear advantages over traditional valves (like gate valves and ball valves). The main advantages are as follows:

(I) Better Sealing and Safety Performance

1. Dual Seal Protection
General twin seal valves use a combined soft and hard seal design. Under normal working conditions, the soft seal achieves zero leakage. This prevents safety risks from kerosene volatilization or leakage. If a fire damages the soft seal, the hard seal immediately takes over as the main seal. It stops massive leakage and reduces accident risks.
Traditional gate valves have good fire resistance. But their hard seals can hardly maintain zero leakage for a long time. Ball valves with soft seals lack fire protection.

2. Prevent Medium Mixing
The DBB structure has two isolation valves to block medium flow. A bleed valve is set between them. If the isolation valves leak, the leaked medium can be drained through the bleed valve. This prevents mixing of different batches of aviation kerosene and ensures kerosene purity.
Most traditional valves have a single seal. They are less effective at preventing cross-contamination.

3. Valve Cavity Pressure Relief to Avoid Abnormal Pressure Rise
Compliant with API 6D standards, when used with liquid media, orbit plug valve automatically balances pressure differences caused by ambient temperature changes. It prevents abnormal pressure rise inside the valve cavity. This lowers the risk of valve damage or leakage.
Most traditional valves lack this feature. They easily malfunction due to abnormal pressure.

(II) Easier Maintenance

1. Online Maintenance Without Shutdown
If the disc seal is damaged or the actuator malfunctions, you don't need to remove the DBB plug valve from the pipeline. Just take off the bottom cover and replace the slide to finish maintenance. You can also inspect the actuator while the pipeline is under pressure.
Repairing traditional valves requires disconnecting the pipeline. This shuts down the aviation fuel refueling system and affects operational efficiency.

2. Simple and Intuitive Internal Leak Detection
When the pressure relief system is closed, open the needle valve connected to the end cover. If there is an internal leak, the medium will flow out through the needle valve. This makes detection easy.
Checking the sealing effect of closed traditional valves is difficult. It requires complex procedures or special equipment.

(III) Better Flow and Operational Performance

1. Full-Bore Design, Zero Flow Resistance
The full-bore design of the valve body and plug ensures zero flow resistance for aviation kerosene delivery. This guarantees efficient refueling. It also makes pipeline cleaning easier and reduces impurity buildup (ball valves have similar cleaning advantages).
Traditional reduced-bore valves have flow resistance. They affect delivery efficiency and make pipeline cleaning hard.

2. Low Switching Torque, Easy Operation
During opening and closing, the general plug valve’s body and slide seal surfaces do not rub. This results in low switching torque and easy operation. It allows fast on/off switching. This is ideal for scenarios that need quick responses—like fuel truck-aircraft connections.
Some traditional valves (such as large gate valves) have high switching torque. They are hard to operate and respond slowly.

(IV) Longer Service Life

1. No Wear on Seal Surfaces
During opening and closing, the general twin seal valve body and slide seal surfaces do not touch. This eliminates friction and wear, extending the seal's service life.
Traditional valves (like ball valves and gate valves) easily have seal surface wear during opening and closing. This leads to a rapid drop in sealing performance over time.

2. Corrosion and Erosion Resistance
Twin Seal Orbit General Valve body's inner cavity is hard chrome-plated. This forms a hard, smooth sealing area. It can withstand erosion and corrosion from long-term aviation kerosene delivery. It reduces impurity adhesion and the chance of valve failure.
Traditional valves have poor corrosion and erosion resistance for their inner cavity materials. They are easily shortened in service life by medium erosion.