| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent cavitation and noises due to the cavitation in a decompression system using a water-sealing vacuum pump and an air ejector.SOLUTION: The decompression system comprises a water-sealing vacuum pump 3; an air ejector 4 arranged in an air intake passage 9 of the vacuum pump 3; and a seal water temperature sensor 21 for detecting the temperature of the seal water for the vacuum pump 3. The vacuum pump 3 is reducing a pressure by reducing a discharge velocity by the vacuum pump 3 as the pressure approaches a set pressure so as to prevent a suction side pressure PS2 of the vacuum pump 3 from becoming the level equal to or less than a set pressure (cavitation generation pressure), which is higher, by a preset value, than a saturation vapor pressure at a detection temperature TH detected by the seal water temperature sensor 21, and at a set timing, the air ejector 4 is started to further reduce the pressure.</p> |
