# How do you calculate Cv for a butterfly valve?

## How do you calculate Cv for a butterfly valve?

Cv = 1,16 Kv Kv = 0,86 Cv *Kv = 0.86 Cv Cv = 1.16 Kv We recommend butterfly valves to be sized at 600 opening of the valves. Up to 600 the valve charateristic is nearly equal percentage, while from 600 to 900 it is linear or “quick opening”.

How do you size a butterfly valve?

How to Determine Butterfly Valve Dimensions

1. Length A – Length of butterfly valve body + stem endpoint.
2. Length B – Length from centerline x-axis to valve end.
3. Length C – thickness of the valve body.
4. Length F – length of the key.
5. Length H – diameter of stem.
6. Length J – Hole size.
8. L – number of holes.

What is Cv in control valve sizing?

Valve Flow Coefficient (Cv) is the flow capability of a control valve at fully open conditions relative to the pressure drop across the valve. It is defined as the volume of water (GPM in the US) at 60°F that will flow through a fully open valve with a pressure differential of 1 psi across the valve.

### How do you measure Cv valves?

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)).

Does higher Cv mean higher flow?

The valve flow coefficient (Cv) is a number which represents a valve’s ability to pass flow. The bigger the Cv, the more flow a valve can pass with a given pressure drop.

How do you calculate CV value?

The formula for the coefficient of variation is: Coefficient of Variation = (Standard Deviation / Mean) * 100. In symbols: CV = (SD/x̄) * 100. Multiplying the coefficient by 100 is an optional step to get a percentage, as opposed to a decimal.

#### How is valve size measured?

Another crucial, but easy to measure dimension is the valve’s overall length. By simply measuring from the tip of the valvestem to the face of the valve with a set of calipers, you can get the valve’s overall length.

How do I find my CV?

What is rated CV and calculated CV?

Thus, rated Cv is Cv attained at full open position. In my opinion, calculated Cv is a Cv value calculated at particular conditions (P1, P2, flow rate, specific gravity etc.). Conditions can give you min Cv, max Cv or a Cv value somewhere between those two. So when selecting a valve min and max Cv are of importance.

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