| 摘要 |
A method and apparatus for reducing undesirable noise generated by a vacuum pumping system. The vacuum system operates to reduce the pressure in a chamber to a first pressure value. The system then detects that the pressure at the vacuum pump system's inlet is about to change to a second higher pressure and, in response, the speed of a booster pump in the vacuum pump system is reduced below the rated speed for the pump. When the pressure at the vacuum pump's inlet is above the second pressure, the speed of the booster pump is increased to the rated speed. Thus, the booster pump is slowed down prior the pump system becoming exposed to a rapid increase in inlet pressure. |
