可单独作低真空泵用，也可与其他高真空泵组合作前级泵用；
Used either solely as Rough Pumps, or in combination with other high vacuum pumps as Backing Pumps.
在适当的压强下，工艺室被接通高真空泵系统抽气，以继续降低工艺室的压强。
At the appropriate pressure, the chamber is opened to a high-vacuum pumping system that continues to reduce the pressure of the process chamber.
由于罗茨泵是一种无内压缩的真空泵，通常压缩比很低，故高、中真空泵需要前级泵。
As the Roots pump is a non-vacuum inside the compression, the compression ratio is usually very low, so high, medium and vacuum pumps need to pump before.
设计了一种用于真空制盐的新型高真空组合技术，介绍了该技术的装置流程、工作原理及凉水塔、真空泵等设备的功能。
A high vacuum composite technique for the production of salt under vacuum was designed, its unit flow, working principle, function of cooling tower and vacuum pump were introduced.
设计了一种用于真空制盐的新型高真空组合技术，介绍了该技术的装置流程、工作原理及凉水塔、真空泵等设备的功能。
A high vacuum composite technique for the production of salt under vacuum was designed, its unit flow, working principle, function of cooling tower and vacuum pump were introduced.
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