Method and apparatus for reclaiming used working fluid

A method of reclaiming a used working fluid produced after a working fluid which contains abrasive grains dispersed therein is used for abrasive machining on a workpiece, wherein cutting chips produced during said abrasive machining are removed from said used working fluid, said method comprising the steps of:

• circulating said used working fluid in a circulating path including a cross flow filter having a first chamber and a second chamber which are defined by a cross flow filtration film, said cross flow filtration film having pores which are sufficiently smaller than an average grain size of said abrasive grains and are sufficiently larger than an average grain size of said cutting chips;
• cross flow filtering said used working fluid while said used working fluid is fed to flow over the surface of said cross flow filtration film, such that a portion of said used working fluid is discharged through said cross flow filtration film, as a waste fluid, into said second chamber of said cross flow filter together with said cutting chips, for reducing an amount of said cutting chips in said used working fluid flowing in said circulating path;
• supplying a medium liquid which does not contain said abrasive grains and said cutting chips, to said circulating path, such that at least a portion of said medium liquid is fed to said first chamber via said second chamber of said cross flow filter, said medium liquid being supplied to said circulating path by an amount equal to an amount of said waste fluid which has been discharged into said second chamber in said step of cross flow filtering said used working fluid;
• and
• recovering a reclaimed working fluid from said circulating path, said reclaimed working fluid including said medium liquid in an amount equal to that of said medium liquid initially included in said used working fluid.

An apparatus for reclaiming a used working fluid produced after a working fluid which contains abrasive grains dispersed therein is used for abrasive machining on a workpiece, wherein cutting chips produced during said abrasive machining are removed from said used working fluid, said apparatus comprising:

• a first reservoir for storing said used working fluid;
• a cross flow filter having a first chamber and a second chamber which are defined by a cross flow filtration film, said cross flow filtering film having pores which are sufficiently smaller than an average grain size of said abrasive grains and are sufficiently larger than an average grain size of said cutting chips;
• a circulating path which is partially defined by said first reservoir and said cross flow filter;
• a circulating device for circulating said used working fluid in said circulating path, while said used working fluid is fed to flow over the surface of said cross flow filtration film, so that a portion of said used working fluid is cross-flow filtered through said cross flow filtration film, and discharged with said cutting chips as a waste fluid, into said second chamber of said cross flow filter;
• and
• a recovering device for recovering a reclaimed working fluid from said circulating path.