The most common layout for dry gas seals (DGS) in centrifugal pumps is the “back-to-back” double seal with a dual-sided seal face. This design has the unique capability to maintain seal integrity even when the supply of buffer gas is interrupted. Depending on the characteristics of the sealed fluid and the type of buffer gas used, the DGS system can be supplemented with an end labyrinth and an internal spiral groove seal. The materials used in the components of dry gas seal assemblies are selected for their resistance to the corrosive effects of the sealed medium.
Technical specifications:
- Sealed pressure: Up to 20 kg/cm²
- Temperature in the sealing area: Up to 250°C (special designs can handle up to 450°C)
- Peripheral speed of the rotating seal face: Up to 80 m/s
- Shaft diameter under the seal: Up to 200 mm
Advantages of using dry gas seals for centrifugal pumps:
- 100% Liquid Sealing: This is particularly important when handling volatile liquids where complete sealing ensures safety and process efficiency.
- Elimination of Contamination: DGS systems do not use buffer liquids, making them a preferred choice when maintaining the purity of the pumped medium and avoiding contamination is crucial.
- Reduced Energy Loss: Due to the absence of liquid friction, DGS systems offer significantly lower energy losses compared to liquid seals.
- Extended Seal Lifespan: The use of a gas film between the seal faces practically eliminates seal wear, resulting in a longer service life and reduced expenses for spare parts and repairs.
- Lower Expenses for Buffer Gas Control Systems: DGS systems have simpler and more economical buffer gas control systems, reducing operational costs.
- No Need for Water Flushing: Unlike some other systems, DGS systems do not require water flushing during operation, reducing water consumption.
- Seal Integrity in Reverse Pressure: In the event of a buffer gas supply failure, DGS systems maintain their functionality and prevent the leakage of the pumped liquid into the environment.
- Reversible Execution: Some DGS systems can be supplied in a reversible (bi-directional rotation) configuration, increasing their versatility and applicability.
