After a multi-year test program, Kalsi Engineering is pleased to announce the new KLS high pressure lip seal. These spring-loaded lip seals are for applications with unidirectional rotation. Initial testing was performed at a surface speed of 543 feet per minute (2.76 m/s) with pressures up to 1,000 psi (6.89 MPa). Subsequent testing was performed at a surface speed of 137 feet per minute (0.7 m/s) and a fluid pressure of 1,500 psi (10.34 MPa).
The ability to perform well under such high differential pressure is the result of hydrodynamic interfacial lubrication provided by the patented wave geometry on the low pressure end of the seal. Conventional PTFE lip seals with the same general cross-sectional design, but without the waves, failed in a few hours at only 500 psi (3.45 MPa) and a surface speed of 543 feet per minute (2.76 m/s).
When used to retain clean pressurized fluids, only one KLS seal is required, and the seal lubricant can be supplied from a simple unpressurized lubricator. For example, if the seal is located below the bearings, the seal can simply utilize the bearing lubricant.
The ability of lip seals to exclude abrasives diminishes as pressure increases. Because of this, two KLS seals are recommended for excluding abrasive fluids. In this arrangement, the outboard seal excludes the abrasive fluid, and the inboard seal retains a barrier lubricant between the seals that is balanced to the pressure of the abrasive fluid pressure. For information on implementing KLS lip seals in rotating control devices without lubricant overpressure, see Chapter E6 of our seal handbook.