1. Equal percentage characteristic (logarithm): the relative stroke and relative flow of equal percentage characteristic are not in a straight line. At each stroke point, the flow change caused by unit stroke change is proportional to the flow at that point. The proportion of flow change parts is equal. Therefore, it has the advantage of small flow change when the flow is small, and large flow change when the flow is large, that is, under different opening degrees, it has the same adjustment accuracy.

2. Linear: the relative stroke of linear characteristics is connected with the relative flow in a straight line. The flow change caused by unit stroke change is constant. When the flow is large, the change of the relative value of the flow is small. When the flow is small, the change of the relative value of the flow is large.

3. Parabolic characteristics: the flow changes with the two directions of travel, and generally has the central characteristics of linear and equal percentage characteristics.

It can be seen from the analysis of the above three characteristics that, in terms of its conditioning performance, the equal percentage characteristic * * * is stable and has good conditioning performance. Parabolic characteristics are superior to linear characteristics. Any flow characteristic can be selected according to the application requirements.