BDRP Rotary Shaft Seals
BDRP™ seals are direct compression-type rotary seals developed specifically to be hydrodynamically lubricated when high differential pressure acts from either side. This feature makes it a candidate for use as a hydraulic swivel seal or as a rotary control device seal (RCD seal). This feature also allows it to be used with a simple gravity fed lubricant reservoir. No complicated lubricant overpressure system is required.
During rotation, the waves of the BDRP seal hydrodynamically wedge a lubricant film between the shaft and the plastic ID layer of the seal. This hydrodynamic interfacial lubrication reduces friction, wear, and friction-generated temperature, and enables the good high pressure performance of the BDRP seal.
When using a BDRP seal as a hydraulic swivel seal, two seals are required to define a single hydraulic circuit, three seals are required to define two hydraulic circuits, four seals are used to define three hydraulic circuits, and so on.
When using a BDR seal as an rotary control device seal (RCD seal), an outboard barrier seal is required, with the region between the two seals being filled with a barrier lubricant that is balanced to the pressure of the well. The barrier seal excludes the abrasive drilling fluid but is exposed to zero differential pressure while the BDRP seal retains the pressure of the barrier lubricant.
Chapter C07 of the Kalsi Seal Handbook provides additional details of the BDRP seal and implementation guidelines for the use of this rotary seal in hydraulic swivels and rotary control devices (RCDs). The most current testing and performance results can be obtained by contacting our helpful Kalsi Seals engineering team.