Apparatus for cleaning the working liquid of an EDM or ECM machine

An apparatus comprising:

• means for cleaning a machining liquid of an electroerosive or electrochemical machining device, including,
• a device for sedimenting contaminants from the machining liquid, said sedimenting device having a liquid entrance and a liquid exit;
• a filter unit comprising a housing that is subdivided by a stationary membrane filter into a concentrate chamber and a permeate chamber;
• a pump for supplying fluid from the liquid exit of the sedimenting device to the concentrate chamber;
• a conduit for supplying liquid from the permeate chamber to the machining device, said conduit containing a shut off valve;
• a collecting means for collecting the liquid from the machining device, said collecting means being connected with said liquid entrance of said sedimenting device;
• a pressure means connected with said permeate chamber for backwashing said membrane filter;
• means for selectively connecting said concentrate chamber with said liquid entrance of said sedimenting device during backwashing of said membrane filter;
• and
• an ultrasonic vibrator mounted on said filter unit, said vibrator having a radiating surface submerged in the liquid for vibrating said membrane filter, said pump being dimensioned so that, during filtering, an entire output flow of said pump is passed through said membrane filter.