| 摘要 |
PURPOSE: To eliminate the need for water and dust proof of a drive/control circuit and electric parts by generating a negative pressure without using a vacuum pump, realizing a lower price and a smaller size, no noise, and unnecessitating maintenance. CONSTITUTION: In a water channel returning from the first water supply terminal 43 to a water storage tank 42 of the channel circulating between a water storage tank 42 and the first water supply terminal 43, an aspirator 45 is inserted, and a suction port 45-3 of the aspirator 45 is connected to a vacuum buffer tank 57, and then a deaerating unit 51 and subtanks 55 and 56 are connected to the vacuum buffer tank 57. |
