To deaerate a cooling liquid used at a time of metal processing.
An ultrasonic vibrator 6 is mounted on a container and oscillation output is applied to the ultrasonic vibrator 6 from an oscillator 7, and further, power is applied to the oscillator 7 from a power supply device 8 and the cooling liquid 9 discharged from a metal processing apparatus is supplied to the container 5 from a piping 10 and, when the cooling liquid 9 is irradiated with ultrasonic waves generated from the ultrasonic vibrator 6, air bubbles 9a are generated from the cooling liquid 9 to be discharged from an exhaust pipe 11 and the cooling liquid 9 from which air bubbles 9a are removed is further supplied to a magnet part from a piping 12 of the container 5. Since air bubbles can be sufficiently removed from the cooling liquid, the cooling liquid is smoothly circulated to enhance natural cooling effect and the cooling effect is enhanced and the life of a processing jig of the metal processing apparatus is extended and the number of rotations of the processing jig can be increased.
KONDO RIYOUJI
MIURA HIROKI
