Pressure gauge that operates based on the principle of the comparison of a pressure with the barometric pressure of a column of fluid (Figure F 23). They are only suitable for measuring low pressures or differential pressures. Alcohol, water or mercury is used as the fluid.
Vertical column pressure gauges are generally read directly. They are reliable; their accuracy is approx. 0.3 % at room temperature.
Figure F 23: Vertical column pressure gauge