Kalsi Engineering introduced the 673 series Axially Constrained Seal (ACS) in a blog entry in October of last year. We have continued testing this advanced rotary seal in conditions that the 462 series ACS would never be considered for.
The ACS is a partitioning seal used in applications having the pressure of the seal/bearing lubricant substantially balanced to the pressure of the environment fluid. It was designed to eliminate the need to provide seal lubricant over-pressure or use a spring loaded seal carrier (see Chapter D9 of our rotary seal handbook). A lubricant viscosity of ISO 460 or greater is recommended for 462 series seals. This viscosity requirement makes 462 series seals unsuitable for some applications.
We recently completed a series of characterization tests on the 673 ACS that simulate the conditions an ACS would see as the partitioning seal in a rotating control device (RCD), and in Kalsi Engineering’s high pressure washpipe assembly. In all three tests, the rotary seals were exposed to a water based drilling fluid with 2% sand content by volume, and the seal lubricant and drilling fluid were maintained at 0 psi.
The RCD tests ran with an ISO 150 VG lubricant maintained at 180°F. The shaft was rotated at 540 feet/minute, which represents 200 rpm on a 10.375-inch RCD mandrel. The seals were in excellent condition at the conclusion of the 200-hour tests, as seen in the first photo.
The washpipe assembly test ran with an ISO 46 VG lubricant maintained at 160°F. The shaft was rotated at 250 feet/minute, which represents a 3-inch bore washpipe rotating at 200 rpm. The test seal was in excellent condition at the conclusion of the 100 hour test, as seen in the second photo.
The ability of the 673 ACS to operate with low viscosity lubricants at high speeds accommodates the use of a simple diaphragm type lubricant reservoir system. This eliminates the need for complicated lubricant overpressure systems, or axially spring loaded rotary seals.
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