The relationship between the flow rate of the dynamic balance electric valve and the pressure difference on both sides of the valve at different opening degrees is shown in the figure below. It can be seen from the figure that in order to achieve the required flow rate, the minimum working pressure difference needs to be met. When the degree of pressure is constant, when the actual pressure difference between the two ends of the whole valve is less than the minimum working pressure difference, the flow increases with the increase of the pressure difference between the two valves. When the minimum working pressure difference of the valve is reached, the flow through the valve will remain constant. , no longer changes with the increase in the differential pressure across the valve. Only when the opening of the regulating spool changes, does the flow change.
From the formula, it can be obtained that the flow through the valve is related to the opening degree of the valve and the pressure difference behind the valve, and the control system outputs the corresponding signal to the valve according to the load change to adjust the opening degree of the valve, so as to achieve the corresponding flow. Therefore, as long as the pressure difference before and after the valve can be adjusted constantly, it can be ensured that the change of flow is completely determined by the valve opening, that is, it corresponds to the load change, and is not affected by the system pressure fluctuation caused by the influence of other valve switches, so as to achieve dynamic Balanced effect. The adjustment of any branch will not interfere with other branches, and any branch will not be affected by the adjustment of other branches.
In the air-conditioning water system, in order to achieve a good control effect, the characteristics of the best control valve should be equal percentage characteristics, also known as logarithmic characteristics, this curve is also called the ideal characteristic curve of the valve. If an air-conditioning system cannot maintain a good linear relationship between the opening of the control valve and the heat dissipation of the air conditioner, it will cause frequent temperature fluctuations and long system stabilization time.