Abstract: An apparatus comprises a rotatable shaft. A bush has a circumference with the bush being disposed about the shaft. The bush has a plurality of openings disposed throughout the circumference. Each of the plurality of openings is spaced from the remaining openings. A slot, having a first end and a second end, is disposed between the shaft and the bush. The first end is exposed to fluid having a first pressure. The second end is exposed to fluid having a second pressure which is less than the first pressure. The plurality of openings is exposed to fluid having a third pressure which is less than the first pressure and greater than the second pressure such that fluid flowing from the plurality of openings into the slot exits exclusively from the second end of the slot.