Pneumatic control valve flow characteristic introduction

The flow characteristic of the pneumatic control valve are linear, constant percentage and parabolic.The meanings of the three flow characteristics are as follows:

(1) Equal percentage flow characteristic
The relative stroke of percentage characteristic (logarithm) and the relative flow are not in a linear relationship. At each point of the stroke, the change of flow caused by the change of unit stroke is in direct proportion to the flow at this point, and the percentage of flow change is the same.So its advantage is the flow hour, the flow change is small, when the flow is large, the flow change is large, that is, in different degrees of opening, has the same adjustment precision.

(2) linear flow characteristic
Linear characteristics of the relative travel and relative flow into a linear relationship.The change of flow caused by the change of unit stroke is constant.When the flow rate is large, the relative value of the flow rate changes little; when the flow rate is small, the relative value of the flow rate changes greatly.

(3) Parabolic characteristic
The parabolic characteristic flow varies in proportion to the two sides of the stroke, and generally has the intermediate characteristic of linear and equal percentage characteristics.
From the analysis of the above Pneumatic control valve three flow characteristics, it can be seen that, in terms of its regulating performance, the constant percentage characteristic is the optimal, and its regulating performance is stable and good.And the parabola characteristic is better than the linear characteristic adjustment performance, can be used according to the requirements of different occasions, choose any one of the flow characteristics.