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Monometers are devices that are used to measure hydrostatic pressure based off of a fluid level. There are different types of monometers that can be used.

Piezometer Tube

A piezometer tube is the simplest monometer that can be used. It consists of a fluid reservoir and a tube opened to atmosphere. Equation 1 would be used to measured the pressure in the tubes fluid reservoir.

(Eq 1) $P_A=γ_1h_1$

γ = Specific Weight

U-Tube Manometer

There are two types of U-Tube Monometers. The first type is a monometer that has a fluid reservoir and the end open to atmosphere. It is common to have two different type of fluids within the manometer, one fluid in the reservoir, and another type of fluid within the U. To calculate the pressure in the reservoir equation 2 would be used.

(Eq 2) $P_A=γ_2h_2-γ_1h_1$

γ = Specific Weight

P = Pressure

The other type of U-Tube monometer that could be used is a monometer that has two fluid reservoirs interconnected. To calculate the pressure differences between the two reservoirs refer to equation 3.

(Eq 3)  $P_A-P_B=γ_2h_2+γ_3h_3-γ_1h_1$

Incline Tube Manometer

An incline manometer is a manometer that uses an incline to measure a small pressure change. To calculate the pressure change for an incline tube manometer refer to equation 4.

(Eq 4) $P_A-P_B=γ_2l_2sinθ+γ_3h_3-γ_1h_1$

γ = Specific Weight

P = Pressure

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