BOURDON Vacuum Gauge
The inside of a tube which is bent into a circular arc (the so-called Bourdon tube)
is connected to the vacuum system. Due to the effect of the external atmospheric
pressure, the end of the tube bends more or less during the evacuation process.
This actuates the pointer arrangement which is attached to this point. The
corresponding pressure can be read off on a linear scale. With Bourdon gauges it
is possible to roughly determine pressures between 10 mbar (7.5 Torr) and
atmospheric pressure.