Percentage characteristics of control valves, linear characteristics, parabolic characteristics analysis

Percentage characteristics of control valves , linear characteristics , parabolic characteristics analysis

Regulators are used to regulate the pressure, flow, and temperature of the media. Receiving signal, automatically control the opening of the valve, so as to achieve media pressure, flow and temperature adjustment. Regulating valve points electric control valve, pneumatic control valve and self-regulating valve. Commonly used electric control valve and pneumatic control valve two.

The circulation capacity Cv is one of the main parameters for selecting the regulating valve. The definition of the flow capacity of the Shenzhen Euro valve regulating valve is: When the regulating valve is fully opened, the differential pressure across the valve is 0.1MPa , and the fluid density is 1g/cm3 . The flow rate of the hour flow path control valve, called flow capacity, also called the flow coefficient, is expressed in Cv in t/h .

We can determine the nominal diameter DN of the regulating valve based on the size of the flow capacity Cv value .

The flow characteristic of the regulating valve is the relationship between the relative flow of the medium flowing through the regulating valve and its opening degree under the condition that the pressure difference at both ends of the valve is kept constant. Shenzhen Ou valve valve flow characteristics of linear characteristics, equal percentage characteristics and parabolic characteristics of three. The significance of the three fluence properties is as follows:

( 1 ) equal percentage characteristics (logarithms)

The relative stroke and relative flow of equal percentage characteristics are not in a straight line. The change in the flow rate caused by the change in the unit stroke at each point of the stroke is proportional to the flow at this point, and the percentage of flow change is equal. Therefore, its advantage is that when the flow rate is small, the change in flow rate is small, and when the flow rate is large, the flow rate changes greatly, that is, at different opening degrees, the same adjustment accuracy is achieved.

( 2 ) Linear Characteristics (Linear)

Linear characteristics of the relative stroke and relative flow in a straight line. The change in flow caused by the change in unit travel 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 properties

The flow changes in proportion to the two sides of the stroke, and generally has an intermediate characteristic of linearity and equal percentage characteristics.

From the analysis of the above three characteristics, it can be seen that, in terms of its adjustment performance, the equal percentage characteristic is excellent, the adjustment thereof is stable, and the adjustment performance is good. The parabolic characteristic is better than the linear characteristic adjustment performance. According to the requirements of the application occasions, any one of the flow characteristics can be selected.