The universal method of valve sizing is by the Kv or Cv method. Both these flow coefficients give a positive indication of a valve's capacity to handle flow. Each line size MINIMATIC control valve has a single fixed Kv value shown in the relative detail pages in this catalogue.
For practical purposes Northvale Korting uses simplified sizing formulas. More complex formulas for steam and gas will give only minor variations and are only appropriate for severe service conditions.
Having calculated the Kv coefficient required from the following formula the appropriate control valve size can be selected from the graphs, taking into account the maximum and minimum flow requirements. MINIMATIC control valves have modest turndown ratios and it is good practice to select a valve size which is 80-90% of its full stroke at max Kv requirement and not less than 10% at minimum Kv requirement.