This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Vacuum symbols library.svg Several symbols of vacuum system components including vacuum pumps valves gauges etc The symbols probably are not standardized in the World Please make sure that they are commonly used in your country's vacuum engineering diagrams before you use them in any serious document date