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Description of the role of electromagnetic flowmeter regulating valve

The inherent flow characteristic of the regulating valve refers to the rate of change of the flow rate through the valve with the opening when the differential pressure at both ends of the valve is constant. Physically speaking, the inherent flow characteristics of the valve indicate how the effective flow area of the valve changes with the change of the bet, such as quick opening, linear, equal score and parabola, etc. .
The electromagnetic flowmeter regulating valve is used to regulate the flow, pressure and level of the medium. According to the adjustment part signal, the opening of the valve is automatically controlled to achieve the adjustment of the medium flow, pressure and liquid level. The regulating valve is divided into an electric regulating valve, a pneumatic regulating valve and a hydraulic regulating valve.
(1) The fast opening characteristic is within the range of the opening degree, and the rate of change of the flow rate with the opening degree is the largest, and as the opening degree is increased, the rate of change of the flow rate is drastically reduced.
(2) The linear characteristic is in the range of 0–100% opening, and the rate of change of the flow rate with the opening degree is constant.
(3) The equal percentage characteristic increases within the range of the opening degree, and the rate of change of the flow rate with the opening degree is small, but as the valve opening degree increases, the rate of change increases sharply. The flow characteristic of the electromagnetic flowmeter regulating valve is the relationship between the relative flow rate of the medium flowing through the regulating valve and its opening degree under the condition that the pressure difference between the two ends of the valve is kept constant. The flow characteristics of the regulating valve are linear, equal percentage and parabolic. The significance of the three fluence characteristics is as follows:
The relative travel of the linear characteristic (linear) is linear with respect to the relative flow. The change in flow caused by changes in unit stroke is constant. When the flow rate is large, the relative value of the flow rate of the electromagnetic flowmeter changes little, and when the flow rate is small, the relative value of the flow rate changes greatly.
The relative stroke and relative flow of the equal percentage characteristic (logarithmic) are not linear. The change in flow caused by the change in unit stroke at each point of the stroke is proportional to the flow at this point, and the percentage change in flow is equal. Therefore, its advantage is that the flow rate is small, the flow change is small, and when the flow rate is large, the flow rate changes greatly, that is, the same adjustment precision is obtained at different opening degrees.
The parabolic characteristic flow varies proportionally to the quadratic of the stroke and generally has intermediate characteristics of linear and equal percentage characteristics.
In terms of adjustment performance, the equal percentage characteristic is optimal, the regulation is stable, and the adjustment performance is good. Parabolic characteristics are better than linear characteristics, and any of the flow characteristics can be selected according to the requirements of the application.

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