Bray 31U - Manual (Page 14)

Resilient Seated Butterfly Valves – Valve Sizing Coefficients
All information herein is proprietary and confidential and may not be copied or reproduced without the expressed written consent of BRAY INTERNATIONAL, Inc.
The technical data herein is for general information only. Product suitability should be based solely upon customer’s detailed knowledge and experience with their application.
Coefficients : 14
Valve Sizing Coefficients:
1. Valve Sizing Coefficients (Cv)
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Pages 14-15
1. Cv stands for Valve Sizing Coefficient, sometimes called the Flow Rate Coefficient.
2. Cv varies with the valve size, angle of opening and the manufacturer’s valve style.
3. Cv is defined as the volume of water in USGPM that will flow through a given restriction or valve
opening with a pressure drop of one (1) psi at room temperature.
2. Valve Sizing Coefficients (Kv)
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Pages 16-17
1. Kv stands for Valve Sizing Coefficient, sometimes called the Flow Rate Coefficient.
2. Kv varies with the valve size, angle of opening and the manufacturer’s valve style.
3. Kv is defined as the volume of water in Cubic Meters/Hour (m 3 /hr) that will flow through a given
restriction or valve opening with a pressure drop of one (1) bar at room temperature.