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### Manometer Application Equation for Pressure

Fluids Flow Engineering
Hydraulic & Pneumatic Design Engineering

U-Tube Manometer Equation and Calculator

A Manometer is an instrument for measuring gas or vapor pressure- especially at low levels. Manometer's are used to measure the difference between dynamic and static pressures and may be configured as a u-tube, a single tube, or inverted depending on the application.

U-tube manometer measuring pressure relative to atmosphere (gauge pressure) equation.

p = pmgh

Where:
pm = density of manometer fluid (kg/m3 , lb/in3)
h = manometer reading or height difference (m, in)
g = acceleration due to gravity (9.81 m/s2 , 32.174 ft/s2)
p = Measured pressure ( N/m2, lb/in2)

U-tube manometer - differential pressure Equation

p = p1 - p2 = ( pm - pf) g h

Where:
p1 - p2 = Pressure Difference
pm = density of manometer fluid (kg/m3 , lb/in3)
pf = density of measured fluid. (kg/m3 , lb/in3)
h = manometer reading or height difference (m, in)
g = acceleration due to gravity (9.81 m/s2 , 32.174 ft/s2)
p = Measured Pressure Difference ( N/m2, lb/in2)

Single-leg manometer - Gauge Pressure Equation

Measured pressure p = pmgh

Where:
p = Measured Pressure Difference ( N/m2, lb/in2)
pm = density of manometer fluid (kg/m3 , lb/in3)
h = manometer reading or height difference (m, in)
g = acceleration due to gravity (9.81 m/s2 , 32.174 ft/s2)

Inclined single-leg manometer Measured Pressure Equation

Measured pressure p = pmgL sinθ

Where:
p = Measured Pressure Difference ( N/m2, lb/in2)
pm = density of manometer fluid (kg/m3 , lb/in3)
g = acceleration due to gravity (9.81 m/s2 , 32.174 ft/s2)
L = Length (m, in)
θ = Angle

Inverted U-tube manometer Equation

Pressure difference (p1 - p2) = (pf - pm)gh

Where:
p = p1 - p2 = Pressure Difference ( N/m2, lb/in2)
pm = density of manometer fluid (kg/m3 , lb/in3)
pf = density of measured fluid. (kg/m3 , lb/in3)
h = manometer reading or height difference (m, in)
g = acceleration due to gravity (9.81 m/s2 , 32.174 ft/s2)

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