Pneumatic Diaphragm Valve flow characteristic refers to the relationship between the relative flow of the medium flows through the valve and displacement (valve relative opening degree). the ideal flow characteristics are mainly straight lines, equal percentage (logarithm), parabola, and quick open, characteristic curves and spool shape. The ideal flow characteristics that commonly used are only straight line, equal percentage (logarithm), quick open three kinds. Parabolic flow characteristic is between the equal percentage and straight lines, generally can take the equal percentage features to replace, while the quick opening feature is mainly used for two-conditioning and process control, and therefore the choice of pneumatic diaphragm valves feature is actually straight lines and equal percentage flow characteristics selection.
      Rubber lined diaphragm valve, fluorine lined diaphragm Valve flow characteristic selection can be calculated theoretically, but the methods and equations used are very complex. At present, mainly using experience criteria, specifically from the following aspects to consider: