Sealing Water in Purifier – Purpose and Use Explained for Marine Engineers

The sealing water in purifier plays a crucial role in the operation of marine fuel oil purifiers. It is clean water introduced into the bowl before the purification process begins, creating a waterinterphase that separates the oil and water phases inside the rotating bowl.

This water seal prevents oil from escaping through the water outlet and ensures that the centrifugal separation process occurs correctly. Without sealing water, the interface between oil and water cannot form, and the purifier would discharge oil along with the separated water.

Purpose of Sealing Water in a Purifier

The main function of sealing water is to establish the oil-water interface inside the bowl. In a self-cleaning purifier, this stable interface allows the machine to continuously separate water, sludge, and solids from fuel oil.

Creates a stable interface between oil and water layers.
Prevents oil loss through the water outlet during operation.
Improves separation efficiency and discharge quality.
Protects the paring discs and prevents air entry into discharge lines.

When Is Sealing Water Used?

Sealing water is used only when the purifier operates in purifier mode (two-phase separation). It is not used in clarifier mode since that process separates solids only, without water removal. The sealing water is supplied just before fuel entry and retained during steady operation. It works closely with the closing or operating water system, which provides the hydraulic pressure needed for bowl locking and desludging cycles.

Working Process

During start-up, sealing water is first admitted through a control valve or solenoid-operated line into the bowl’s water space. When the purifier reaches full speed, fuel is introduced. The heavier sealing water remains at the periphery, forming a continuous water ring, while lighter oil collects inside this ring.

This configuration ensures the oil-water interface remains at the correct radius, maintained by the gravity disc. As the purifier continues to operate, separated water and sludge discharge periodically through the sludge ports.

Importance of Correct Sealing Water Flow

Insufficient sealing water → interface shifts inward → oil loss.
Excess sealing water → interface shifts outward → water contamination in oil outlet.
Correct flow ensures clean oil discharge and minimal water carryover.

Maintenance and Troubleshooting

Always use clean fresh water as sealing water to avoid scaling or deposits.
Check sealing water solenoid valves and pipelines for blockage or leakage.
Monitor the interface position during operation using discharge clarity.
Replace faulty control valves to maintain steady water admission.

FAQ

Q: Why is sealing water not used in clarifier mode?
A: In clarifier mode, only solids are removed — there’s no water phase to maintain. Therefore, sealing water is unnecessary and would interfere with solid separation.

Conclusion

The sealing water in purifier is a simple yet essential component for efficient fuel oil purification. It forms the foundation for a stable interface and ensures that clean oil is delivered to the engine without water contamination. Proper maintenance of sealing water systems ensures reliable purifier performance at sea.

Purpose of Sealing Water in Fuel Oil Purifier Operation