What is Valve Flow Coefficient (Cv)?

Valve Flow Coefficient (Cv) is a valve’s capacity for a liquid or gas to flow through it.  Basically, the larger the opening in a valve, the larger the Cv.  As a valve is opened more and more, the Cv increases until the valve is fully open, where it reaches its highest possible Cv, or 100% open Cv. See flow curve chart below. The fully open Cv (100% open) for this valve is 52.

Cv is technically defined as:  The volume (in US gallons) of water at 60°F that will flow per minute through a valve with a pressure drop of 1 psi across the valve.

For determining what size valve should be used for a particular application, Cv can be calculated using the sizing program at https://kimray.com/sizing, then a list of applicable valves is displayed, based on the calculated Cv.

Breck Swigart serves as a Product Manager at Kimray, and is responsible for Kimray’s line of pneumatic valves, pneumatic pilots, regulators and temperature controllers. He collaborates with Kimray’s engineering, manufacturing, and quality teams to optimize the performance of our products and make a difference for our customers.