Howden, a compressor technology company that is part of Chart Industries, said its KSN screw compressor seal system has been field-validated for more than five years worldwide. The redesign is intended to improve reliability and service life by refining the seal drive arrangement and face geometry. In industrial applications, the system has completed operating cycles of more than 40,000 hours, the company said.
Seal redesign targets reliability and service life
Howden describes the KSN seal system as one of its most significant product improvements of the past decade. As part of a continuing development effort, the company’s engineers reviewed the seal drive arrangement and the geometry of the seal faces, then tested the design internally under pressure conditions more demanding than those typically found in the field.
The main change transmits the driving force for the primary seal faces through steel components, reducing wear on parts involved in the drive process. Howden also improved face flatness to help retain the fluid film. The company says the adjustments allow the seal system to run without failure for at least two years, and longer when operating and maintenance procedures are followed.
Principal technical features
The KSN design combines materials and mechanical changes intended to support stable operation across a range of compressor duties.
- Silicon carbide faces: The material is designed to prevent face blistering, improve wear resistance and extend the operating temperature range.
- Reinforced drive structure: Steel retaining components on the seal faces reduce drive wear, and an external retainer is included.
- Balanced closing force: Spring force is balanced to maintain correct closing pressure. The direct-drive arrangement avoids direct contact with the shaft drive.
- Installation flexibility: A cushioned stationary-seat O-ring design allows greater alignment tolerance. Some variants, including models 163 and 204, use FFKM O-rings.
- Backward compatibility: KSN seals are fully interchangeable with earlier seals, simplifying upgrades.
Compressor and seal model compatibility
The KSN seal is offered for several Howden WRV and XRV screw compressor series. The matching seal model varies by compressor size and Mark version.
| Compressor model | KSN seal model |
|---|---|
| WRV / XRV 163 (all versions) | KSN163 |
| WRV 204 (Mark 1-4) | KSN204-2/3/4 |
| WRV 204 (Mark 5) | KSN204-5 |
| WRV 204 (Mark 6) / XRV 204 (all versions) | KSN204 |
| WRV 255 (Mark 1-5) | KSN255-4 |
| WRV 255 (Mark 6) | KSN255-6 |
| WRV 321 (Mark 1-5) | KSN321-4 |
| WRV 321 (Mark 6) | KSN321-6 |
| WRV 365 (all versions) | KSN365 |
After-sales support and installation
As the original equipment manufacturer, Howden provides after-sales support for the life of the equipment. The service includes original spare parts, expert maintenance, engineering troubleshooting and documented service records, according to the company.
Installation instructions are supplied with each seal. Howden also offers customized seal installation training when requested, the company said, to help operators maintain the equipment in proper working condition.
