Abstract: Pumps used in liquid chromatography applications employ actuators for pressurizing and moving liquid. An actuator includes a pump head having a chamber, a gland, a movable rod extending through the gland into the chamber of the pump head, and a plunger seal disposed in the gland around the rod for sealing against fluidic leakage from the chamber. The plunger seal has an annular flange that provides an OD (outer diameter) seal against the gland. The flange defines a seal cavity. The pump head further includes an outlet port and an outlet channel. One end of the outlet channel is in communication with the outlet port and the other end of the outlet channel opens into the seal cavity of the plunger seal. The outlet channel provides a flow path for liquid in the chamber to travel towards the outlet port in response to movement of the rod.