| 摘要 |
PROBLEM TO BE SOLVED: To shorten oil feed time, by restricting the number of times that additional oil feed is carried out after the detection of foam. SOLUTION: An oil feed nozzle 33 has a photo-interrupter for detecting foam formed on a liquid surface due to oil feed, and an ultrasonic sensor 28 for detecting the liquid surface. The control circuit 35 of the oil feeder 21 judges whether the number of times that a liquid surface is detected by the ultrasonic sensor 28 after the start of oil feed by the valve-opening operation of the oil feed nozzle 33 has reached a preset number of times or not, and judges whether an interval between liquid-surface detections by the ultrasonic sensor 28 is within a specific time or not. When it judges that the number of times that the liquid surface is detected has reached the specific number of times and that the interval between the liquid-surface detections is within the specific time, the oil feed is stopped to stop fill-up oil feed. Therefore, by the restriction of the number of times that additional oil feed is carried out during the fill-up oil feed, oil feed time from the start of the oil feed to the finish of the fill-up oil feed can be shortened.
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