The flow characteristics of the electric control valve include linear characteristics, equal percentage characteristics and parabolic characteristics:
(1) Equal percentage characteristic (logarithm) The relative stroke and relative flow of equal percentage characteristic are not straight lines. At each point of the stroke, the change in flow caused by the change in unit stroke is proportional to the flow at that point, and the percentage of the change in flow is equal. Therefore, its advantage is that when the flow rate is small, the flow rate change is small, and when the flow rate is large, the flow rate change is greater, that is, the adjustment accuracy is the same at different opening degrees.
(2) Linear characteristic (Linear) The relative stroke and relative flow of linear characteristic have a linear relationship. The change in flow rate caused by the change in unit stroke is constant. When the flow rate is large, the relative value of the flow rate changes very little, and when the flow rate is small, the relative value of the flow rate changes greatly.
(3) Parabolic characteristic flow changes proportionally to both sides of the stroke, and usually has an intermediate characteristic of linear and equal percentage characteristic. From the analysis of the above three characteristics, it can be seen that in terms of its adjustment performance, the equal percentage characteristic is the best, its adjustment is stable, and its adjustment performance is good. The parabolic characteristic is better than the linear characteristic. Any flow characteristics can be selected according to application requirements.
