Shaft seal with pressure equalizing shuttle

摘要

An apparatus is provided for equalizing pressure between a lubrication fluid for lubricating a pump and a combustion fluid located at a low pressure side of the pump wherein the pump has a rotatable shaft. The apparatus includes a wall defining a bore within the pump wherein a first end of the bore is configured to receive a lubrication fluid and a second end of the bore is configured to receive combustion fluid. An equalizing element is disposed within the bore for separating the lubrication fluid and the combustion fluid and may be at least partially movable in response to pressure differences caused, e.g., by differences in thermal expansion between the lubrication fluid and the combustion fluid.