METHOD AND MECHANISM FOR CONTROLLING RETURN OIL IN CIRCULATING OIL SUPPLIER DEVICE

PURPOSE: To provide a method and mechanism for controlling return oil in a circulating oil supplier device capable of collecting by a collecting pan the oil with its supply amount fluctuating, without having a tank in the underground. CONSTITUTION: A device comprises a main tank 1, supply oil pipe 3 with a supply oil pump 2 interposed, oil collecting pan arraged under a processing part 4 and a return oil pipe 6 with a return oil pump 8 interposed, also to change an oil amount supplied to the processing part from the main tank. A liquid level gage 11 is inserted into the return oil pipe, to control a rotational speed of the return oil pump based on a signal generated from the liquid level gage, and since an oil level height in the return oil pipe is obtained always in a fixed range of HL-LL, overflowing with oil from the oil collecting pan or operating the return oil pump reced is eliminated, and the oil can be collected.