Kalsi Seals-brand rotary seals have been used in rotating control devices (RCDs) for many years. Prior to this year, however, usage has been restricted to lubricant overpressure type RCDs, where the lubricant supply provides seal lubricant at a pressure that is several hundred psi greater than the pressure of the wellbore. A pair of Kalsi Seals is required in such systems: One seal to retain the pressurized seal lubricant, and the other to partition the wellbore fluid from the seal lubricant.
Beginning in 2014, Kalsi Engineering now offers a new type of rotary seal named the KLS® that can be used with RCDs that have a simple gravity feed lubricator. It is a high performance spring loaded lip seal that has been tested with 1,000 psi at 540 feet/minute using a gravity fed 150 viscosity grade lubricant at a bulk temperature of 153°F. KLS Seals have also been tested at 1,500 psi and 136 feet/minute. This high level of performance is made possible by an extrusion resistant plastic liner and patented collapse-resistant hydrodynamic waves that pump a film of lubricant into the dynamic sealing interface during rotation. These high performance lip seals were developed for low cost RCDs that are used in situations where the cost of a lubricant overpressure system cannot be justified.