Electric diaphragm pump flow characteristic is refers to the medium flow through the valve of the relative flow and displacement (relative opening degree of valves), the connection between the ideal flow characteristic mainly has straight lines, such as percentage (log), parabolic and quick opening four. The most common ideal traffic characteristics are straight lines, equal percentages (logarithms), and three kinds of fast driving. Parabolic flow characteristic between straight line and equal percentage, the percentage of properties such as generally available to replace, and quick opening feature is mainly used for two control and program control, so the choice of diaphragm pump characteristic is, in fact, the choice of straight lines and equal percentage flow characteristics.

The selection of flow characteristics of electric diaphragm pump can be calculated theoretically, but the methods and equations used are complicated. Adopt the rule of experience, which should be considered in the following aspects:

1. Analyze and select the adjustment quality of the regulating system;

2. Considering the situation of process piping;

3. Analysis of load changes.