| 摘要 |
PURPOSE:To prevent the putrefaction of a metal processing oil with its emulsion kept intact, also with little increase in its temperature in the storage tank, by efficiently treating the oil under a specific condition. CONSTITUTION:A metal processing oil is partly drawn from its storage tank 1, being fed to a heating equipment 7 through a succession of the pipe 5 and the pump 6, followed by heating at 48-60 deg.C for a short time (for instance, at 50 deg.C for ca, 5-8min; at 60 deg.C for ca, 30-90sec). Subsequently, the resultant oil is returned through the pipe 8 to the tank 1. The cycle during which the total amount of the processing oil is subjected to heating treatment is (non)continuously repeated every 3-20 (pref. 5-15) hrs., said treatment being terminated after confirming that the number of aerobic bacteria in the oil has reduced to <=1X10<6>/ml. EFFECT:Free from any degradation in workplace environment, furthermore, with no selectivity for the strains of microorganisms to be killed, therefore also effective for anaerobic bacteria, sulfuric acid-reducing ones, etc. in addn. to aerobic bacteria. |
