The existing Westinghouse EH System Hydraulic Power Unit (HPU) is equipped with four (4) pump discharge filters (2 per pump). These filters are rated at 10 micron nominal (15 micron absolute) filter capacity.
In order to assure reliable operation of the servo valves on the hydraulic actuators the fluid should be filtered to at least 5 microns absolute.
Replacing the existing filter elements with finer filters would restrict the pump output flows leading to potential erratic operation of the unit.
Barry Sibul Company offers a simple and non-invasive modification to the HPU which allows for the addition of finer pump discharge filters without effecting pump performance.
The modification consists of simply removing the existing filter housing caps, screwing on new filter housing extension tubes, inserting new 3 micron stainless steel mesh filter elements followed by screwing on new filter housing caps.
Features of the Westinghouse EH System HPU Filter Modification