Processing Magazine

State-of-the-art barrier seal

February 19, 2007

John Crane has announced the availability of the Type 83 Barrier seal, a dual-segmented carbon ring seal designed to prevent the migration of bearing oil to the dry gas seal cartridge on turbo-compressor equipment.The Type 83 builds on the success of the Type 82 product line—a dual-segmented carbon ring seal that features a specially designed joint between the carbon segments to minimize buffer consumption and bearing oil migration. The new design uses a unique spring design, which makes building and field assembly much easier. Further, the design has been modified to allow the seal to continue operating with low consumption in case of excessive changes in the sealing environment. If the barrier seal supply gas is lost and bearing oil migrates into the sealing cavity, the Type 83 has an additional sealing dam that helps to prevent migration to the dry gas seal (DGS). When the barrier seal supply is restored, the Type 83 moves the oil back toward the bearings, unlike competing products that could move oil in both directions. Normally applied as a double seal with an inert gas, this new barrier seal can be applied to agitators, blowers and fans. The Type 83 acts as a segmented carbon ring separation seal that works in conjunction with the Type 28 DGS, resulting in a total sealing system that ensures separation of bearing oil and process gas in compressors. The segments within the seal use a special design to direct the flow of barrier gas throughout the seal to prevent oil from migrating to the DGS.