The flow characteristic of the regulating valve is the relationship between the relative flow rate of the regulated
medium flowing through the regulating valve and the relative opening of the regulating valve under the condition
that the pressure difference at both ends of the valve remains constant. The regulating valve is divided into four
flow characteristics: equal percentage, straightness, fast opening and parabolic linearity.
How it works:
1, equal percentage characteristics: the relative stroke and relative flow rate of equal percentage characteristics
are not directly related, and the flow change caused by the change of unit stroke at each point of the stroke is
proportional to the flow rate at this point. Therefore, the advantage of equal percentage is that the flow hour
flow change is small, the flow is large, the flow change is large, in different degrees of opening, with the same
accuracy; Widely used, strong adaptability.
2, linear characteristics: linear characteristics of the relative stroke and relative flow into a linear relationship.
The change of flow rate 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. Poor adaptability;
3, parabolic characteristics: the parabolic characteristics are proportional to the square of the stroke, and the
characteristics are between linear and equal percentage characteristics. The adjustment performance is ideal,
but the disc processing is difficult;
(Tonghe regulating valve belongs to parabolic characteristics.)
4, fast opening: when the valve stroke is small, the flow rate will increase greatly, and it will soon reach the
maximum. Fast opening is mostly seen in ball valves, mainly used for cutting off work, and mostly used for
two-position adjustment and program control;From the above analysis, the adjustment performance of equal
percentage characteristic is the best, the adjustment stability is good, and the adjustment performance of
parabolic characteristic is better than that of linear characteristic. Tonghe regulating valve belongs to
parabolic characteristic flow regulating valve. When configuring the regulator for a real system, it is also
necessary to conduct a detailed analysis of the entire piping loop and consider various factors comprehensively.
Only in this way can the regulating valve be correctly selected to ensure the control quality of the regulating system.
