Valve sizing

Open the calculator #

Use the standalone valve-sizing calculator, or select a valve body on your drawing and open Properties → Engineering data → Valve sizing….

The drawing dialog and public calculator use the same calculation module. The dialog offers a direct way to insert results into the selected valve’s custom properties. Conditions must be entered in the calculator; free-text engineering fields are not imported automatically.

Enter the service conditions #

1. Choose Liquid or Gas or vapour.
2. Select a valve style, then review the displayed factors. If the selected body has no matching preset, the drawing dialog says it is using globe values.
3. Enter flow rate, inlet pressure P₁, outlet pressure P₂, temperature and viscosity. Select the units beside each applicable field.
4. For liquids, enter density, vapour pressure and critical pressure. For gases, enter molecular mass, specific heat ratio, compressibility and the pressure ratio factor.
5. Enter valve size and, where applicable, upstream and downstream pipe internal diameters. Review the pressure recovery and valve style factors.

The P₁ and P₂ are gauge pressures checkbox changes how those two values are interpreted. Vapour pressure and critical pressure remain absolute inputs. Keep the chosen flow basis consistent with the conditions you are entering.

Read the result #

The result panel shows Cv, Kv, flow regime and whether the calculated flow is choked. It also displays intermediate factors and any calculation warnings. Invalid or incomplete inputs show an error instead of an insertable result.

Presets are starting values. The form lets you enter the manufacturer’s factors for the valve being evaluated. Keep the service conditions and calculation warnings with your result when comparing cases.

The standalone calculator also offers a rated coefficient and a manufacturer travel table. Those controls are separate from the smaller dialog used to save a result on the drawing.

Save a result on the drawing #

1. In the drawing’s sizing dialog, choose Insert into properties.
2. Review Cv and Kv as number properties and Sizing as a one-line calculation basis.
3. Choose Save engineering data in the Properties panel.

Inserting a new result updates properties with those three names and preserves other custom properties. Closing the calculator without inserting does not attach a result. Running the standalone calculator does not update a drawing.