Depending on the gas composition, compressor geometry, and operating parameters, a dry gas sealing unit can include one or multiple sealing stages. There are several common layout solutions for such units, namely.
Single Sealing
This is the simplest sealing arrangement consisting of a single sealing stage. It is used for sealing non-hazardous and non-toxic gases with pressures up to 80 kg/cm². This sealing can be supplemented with an end labyrinth.
Dual Back-to-Back Sealing
This configuration includes two sealing stages positioned back to back. It is typically used when there could be a vacuum ahead of the seal, or when an inert gas is supplied as a buffer to the seal, and its leakage into the compressor needs to be limited. This type of sealing can also be supplemented with an end labyrinth.
Dual Sequential Sealing
This sealing arrangement comprises two sealing stages positioned sequentially. This scheme is most frequently used in chemical, petrochemical, and gas industries where hazardous and toxic gases are involved. This type of sealing can also be supplemented with interstage and end labyrinths.
Materials used in dry gas sealing units (housing components, sealing pairs, secondary seals, etc.) are selected based on their resistance to the sealed medium’s corrosion.
Technical specifications of the seals:
- Sealed pressure: up to 250 kg/cm²
- Temperature in the sealing area: up to 250°C
- Peripheral speed of the rotating seat: up to 160 m/sec
- Shaft diameter under the seal: up to 300 mm
In cases where any of these parameters are exceeded, special (non-standard) solutions can be applied.
Advantages in terms of reliability and durability:
- Elimination of complex equipment: Complex and unreliable components of oil sealing systems such as high-pressure oil pumps, limited-life oil sealing units, pressure differential regulators, oil traps, degassers, and others are excluded.
- Adaptability to changing conditions: Key elements, such as sealing pairs and their design, are engineered to automatically respond to changes in compressor operating parameters, ensuring continued functionality even in emergency situations, thus increasing device reliability.
- Wear prevention: The absence of contact between sealing pairs during operation reduces wear and extends the sealing’s service life, ensuring reliable operation for more than 12 years.
Advantages in terms of maintenance:
- Elimination of complex maintenance processes for oil sealing systems: Tedious procedures like oil changes, pump and associated equipment repairs, and a complete system overhaul are eliminated.
- Simple technical maintenance of dry gas sealing systems: This involves visual inspection of the working pairs, replacement of O-rings and dampers (within 1-4 years), replacement of clogged filter elements, and routine calibration of measuring instruments. This means that maintenance tasks are simple and quick, with minimal downtime.
- Easy assembly, disassembly, installation, and removal of dry gas sealing unit components: All these processes are convenient and straightforward, and they can be completed in a short period, ensuring efficient equipment maintenance.
