| 摘要 |
PCT No. PCT/JP93/00572 Sec. 371 Date Feb. 1, 1994 Sec. 102(e) Date Feb. 1, 1994 PCT Filed Apr. 28, 1993 PCT Pub. No. WO93/22094 PCT Pub. Date Nov. 11, 1993.In an ion exchange treatment method for producing or regenerating an aqueous EDM fluid to be used for electric discharge machining, raw water is supplied under pressure to a column (4) charged with ion-exchange resins, and passed through a resin phase in the column (4), at a conspicuously large space velocity, for example, at least 20 h-1. Thereby, "harmful ions" to electric discharge machining are preferentially and selectively removed without excessively reducing electric conductivity of treated water at the outlet of the resin phase. The raw water is circulated through the resin phase, with the ion exchange treatment including such a large space velocity, until overall electric conductivity of treated water in a storage tank (17) is reduced to a desire value. The raw water is prevented from excessive ion exchange treatment to increase the volume of treated water per unit volume of resins, resulting in the longer useful life of resins. |
