Flow through the valve can be calculated as follows: where: Q - flow through the valve, m3 / s; Kv - flow capacity of the valve, and the valve opening corresponding; △ P - pressure before and after the valve difference, bar.
Obtained by the formula after the pressure difference before and after the size of the flow of the valve and the valve opening degree and valve, and the control system outputs a corresponding signal to the valve to adjust the valve opening degree so as to achieve the corresponding flow according to the load change. Constant adjustment valve differential pressure △ P can guarantee the change of the flow is completely determined by the valve opening, that corresponds with the load changes from other valve switch affect system pressure fluctuations, which to achieve the effect of dynamic equilibrium. Any loop adjustment none other loop interference while loop will not be any other loop regulation.
In HVAC applications, since the coil static characteristics of the exponential characteristic, and therefore in order to achieve a good controlled effect, the best characteristics of the regulating valve should be equal percentage characteristic, also known as a logarithmic characteristic, this curve also known as the valve The ideal characteristic curve. An air-conditioning system can not keep a good linear relationship between the regulating valve opening degree and cooling equipment heat dissipation will cause frequent fluctuations controlled room temperature, the system is stable for too long.
Homeostasis electric control valve is different from the conventional electric valve, is the integration of the product with the electric control of dynamic equilibrium, the dynamic pressure balancing constant electric directly to adjust the pressure difference across the valve, can be achieved to adjust the pressure difference across the valve in the entire adjustment process constant, the valve authority is always 1, can realize the ideal characteristic curve, in order to achieve the ideal temperature control effect. The electric valve in the different degree of opening of the flow on both sides of the differential pressure of the valve of dynamic equilibrium of the curve shown in Figure 2, can be seen from the diagram in order to achieve the desired flow rate of the need to meet the minimum working pressure, when the adjustment spool opening degree is constant, the actual pressure of the both ends of the entire valve is less than the minimum working pressure, flow rate with the increase in the pressure differential across the valve increases, when the the valve minimum working pressure is reached, the flow through the valve will remain constant, no with the increase of the differential pressure across the valve. Only when the degree of opening of the adjusting spool change, the flow rate before change.
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