The difference between extreme vacuum in plateaus and plains
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I have a question: In flat areas, the ultimate vacuum achieved by water-ring Roots vacuum pump systems is 267 Pa. When using the same vacuum pump unit in the Yunnan-Guizhou region or on the Qinghai-Tibet Plateau, is there any difference in the ultimate vacuum achieved? How to calculate the achievable ultimate vacuum?
Personal understanding: Firstly, the output of motors in high-altitude areas decreases. If it is assumed that the motor output remains unchanged, then due to the lower atmospheric pressure, the ultimate vacuum pressure also decreases
Of course there is a relationship. Under normal conditions, atmospheric pressure is 101354 Pa; as the altitude increases, the vacuum level inevitably decreases. How much it decreases depends on the altitude
No change. The absolute pressure remains the same absolute pressure. Using gauge pressure will give incorrect results; it’s sufficient to use absolute pressure gauge
Personally, I don’t think there will be much change; the capabilities of the equipment remain the same
Theoretically, it should be the extreme vacuum that decreases, as the saturated vapor pressure of water increases in high-altitude areas.
It depends on the absolute pressure; gauge pressure cannot be used
The vacuum level that can be easily achieved by ordinary water ring pumps in plain areas requires a Roots vacuum pump system in high-altitude areas. I just don’t know how to map it out specifically
It is likely related to different types of vacuum pumps; positive-displacement pumps such as Roots and water ring pumps achieve a slightly higher ultimate vacuum, because as the altitude increases, the amount of gas that flows back decreases, which results in a lower ultimate pressure – hence an increased ultimate vacuum.