Check Valve Dimensions Chart - China Manufacturer

Nominal Diameter vs Flow Coefficient (Cv) Across Pressure Classes

This chart titled "Nominal Diameter vs Flow Coefficient (Cv) Across Pressure Classes" visualizes typical check valve flow behavior for common nominal diameters (DN) under three ANSI/ASME-equivalent pressure classes: 150, 300, and 600. The horizontal axis lists nominal diameters in millimeters: 15, 25, 40, 50, 80, 100, 150, 200. The vertical axis shows the flow coefficient (Cv), an industry metric indicating the volume of water at 60°F that passes through a valve per minute at a one psi pressure drop. Data series are illustrative estimates that reflect expected trends: Cv increases nonlinearly with diameter, and higher pressure classes often require thicker components or narrower internal passages that can slightly reduce Cv for a given nominal size. Interpreting the lines, smaller diameters (15–50 mm) show steep Cv growth per incremental DN, while larger sizes (80–200 mm) produce more gradual Cv gains. The Pressure Class 150 series generally gives the highest Cv values at each size, followed by 300 then 600, which models the typical trade-off between pressure containment and flow performance. Designers can use these curves to approximate how changing a valve size or selecting a different pressure rating will impact flow capacity. Engineers should treat these plotted numbers as conceptual guidance rather than certified catalog data. Actual Cv depends on detailed geometry (seat style, lift, internal profiling), fluid properties, and operating conditions. For precise selection and system calculations, consult manufacturer tables or perform empirical testing. However, this visualization helps compare relative effects of nominal diameter and pressure class on check valve flow, aiding preliminary sizing, pump selection checks, and early-stage design decisions where rapid estimates are valuable. Use this chart during conceptual discussions, but validate with full fluid dynamic analysis and vendor specifications before final procurement; minor geometry changes can shift Cv significantly and affect system head loss calculations. And maintenance.