# How does placement of a pressure gauge in a tank of fluid affect the pressure readings?

This is not a real system but rather something I made up to understand how the placement of pressure gauge in a tank takes its readings.

Here’s a diagram of it-

The pressure gauge placed in the middle of the tank. Let’s say I’m working in gage pressure.

Which point in the tank does this pressure gauge measures until ?

Does it measure till the middle point only ?

For example - pressure at the level where pressure gauge is placed - P (vapor) + P (liquid at h=1m) = $120 + \rho g h$ = ____ kpa

• and what about the pressure due to the mercury column? – Solar Mike Aug 18 '18 at 9:17
• @SolarMike that is just to compare the pressure in the tank to the atmosphere isn’t it ? – user185692 Aug 18 '18 at 11:13
• Is it? Have you evaluated that? – Solar Mike Aug 18 '18 at 11:16

Yes, If you remove mercury manometer, then the pressure measured will be $P = 120000 + \rho *9.81 * (1m)$.