A flow meter is a devise that is used to measure the flow rate of a fluid moving through a pipe. It does this by placing a restriction in the path of the fluid’s flow. The pressure difference is before and at the obstruction is measured, and from a combination of Bernoulli’s equation and the continuity equation the flow rate can be determined using equation 1.

**(Eq 1) ** $Q=A_2\sqrt{ \frac{2(P_1-P_2)} {ρ\left[ 1- \left[1- \left( \frac{A_2}{A_1} \right)^2 \right] \right]} }$

Q = Flow Rate

A = Cross-Sectional Area

P = Pressure

ρ = Density