# How do you calculate the CV value of a valve?

Jul 13, 2021

## How do you calculate the CV value of a valve?

Cv by definition is the number of gallons per minute (GPM) a valve will flow with a 1 psi pressure drop across the valve. For example a valve with a Cv of 10 will flow 10 GPM with a 1 psi pressure drop. The formula used to select the valve Cv with the specified differential pressure is: Cv=GPM/((SQ RT(P)).

### What happens if pressure drop is too high?

Excessive pressure drop will result in poor system performance and excessive energy consumption. Flow restrictions of any type in a system require higher operating pressures than are needed, resulting in higher energy consumption.

#### How do you calculate flow rate with pressure and diameter?

Divide the pipe’s internal diameter by 2. For example, if the pipe has an internal diameter of 0.1 meters: 0.1 ÷ 2 = 0.05 m This is the pipe’s radius. Square this radius: 0.05² = 0.0025 m². Multiply the result by pi, which is approximately 3.142: 0.0025 × 3.142 = 0.007855 m².

How do you calculate pressure from flow rate?

The flow rate, in turn, at a known pipe cross-sectional area, determines the fluid’s flow rate. Subtract static pressure from the total pressure. If the pipe has a total pressure of 0.035 kilopascals and a static pressure of 0.01 kilopascals: 0.035 – 0.01 = 0.025 kilopascals.

How do you find velocity with diameter and flow rate?

1: Flow rate is the volume of fluid per unit time flowing past a point through the area A. re the shaded cylinder of fluid flows past point P in a uniform pipe in time t. The volume of the cylinder is Ad and the average velocity is ¯v=d/t so that the flow rate is Q=Ad/t=A¯v.