⒈The main control parameters of electric control valve are nominal diameter, nominal design pressure, allowable temperature range of medium, flow coefficient, etc.

⒉Special control valves should be selected for strict situations where the flow rate is proportional to the opening height. Ball valves and butterfly valves can be selected when they are roughly adjusted.

⒊

The sealing performance of the valve is one of the main indicators to evaluate the quality of the valve. The sealing performance of the valve mainly includes two aspects: internal leakage and external leakage. Internal leakage refers to the degree of sealing of the medium between the seat and the closure. Leakage refers to the leakage of the filling part of the stem, the leakage of the middle gasket part and the leakage of the valve body caused by casting defects. Leaks are not allowed to occur.

⒋The ideal flow characteristics of the control valve include fast opening, parabola, linearity and equal percentage. It is necessary to select the control valve with appropriate flow characteristics according to the actual flow characteristics.

Source: Baidu Encyclopedia