Dual cooled slide ring shaft seal - has slide and counter ring pairs and pump driven by shaft to be sealed

摘要

A drive shaft passing through a wall into a pressurized working fluid envirment is sealed by two spaced slide ring/counter ring pairs which surround the shaft. An axially innermost one of the pairs extends radially from a first high pressure region related to the pressurized fluid environment to a second high pressure region of a sealing and cooling fluid recirculation loop serving both of the pairs. A built-in pump of the sealing device, driven by the shaft propels said sealing and cooling fluid and builds up the pressure at the second region so that such pressure is higher than the first pressure region by a pressure difference (DP). Flow restrictions are built into the recirculating loop so that the sum of pressure drops therein is at least equal to DP.