Switchable liquid filter

摘要

A switchable liquid filter equipped with two filter housings has a change-over cock equipped with a rotatable cock plug in a cock borehole into which an inlet channel, an outlet channel and a discharge channel open at separate levels from each filter housing. Check valves opening by spring force against the effluent direction are arranged in the discharge channels, which check valves are moved into the closed position above the geodetic pressure stemming alone from the liquid column in the filter but below the operating pressure of the liquid to be filtered. A separate filling point permits the previously emptied filter housing to be filled with only a partially opened inlet channel and shut-off outlet channel and closed discharge channel. A constantly open venting device contains a calibrated throttle cross-section. A transverse borehole which connects the discharge channels to the outlet channel of the shut-off filter housing permits the filtrate chamber also to be drained.