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

Question

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

Rhodie · Answer

From what I have learned at university, pressure in a  vessel is equal at all points of the interior surface. This means it does not matter where the measuring gauge is placed.

mustang · Answer

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

If you want to measure the pressure at the bottom of the vessel with the mercury manometer, make sure the pipe connecting the limb and vessel is filled with air. (just to avoid hydrostatic pressure by the fluid inside the connecting pipe). This would be difficult.

The best method I could think is, go for single limb manometer and keep the bottom of the limb and the bottom of the vessel are at the same level (head).

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

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