The relative stroke and the relative flow of equal percentage characteristics are not in a straight line relationship. At each point of the stroke, the change of the flow caused by the change of the unit stroke is proportional to the flow at this point, and the percentage of the flow change is equal. So its advantage is that when the flow is small, the flow change is small, and when the flow is large, the flow change is large, that is, it has the same adjustment accuracy at different opening degrees. The relative stroke of the linear characteristic and the relative flow are in a linear relationship. The flow change caused by the change of unit stroke is constant. When the flow is large, the relative value of the flow changes little, and when the flow is small, the relative value of the flow changes greatly. Regulating valves include throttle valves and pressure reducing valves, whose function is to adjust parameters such as pressure and flow of the medium.
Regulating valves are divided into nine categories according to their structure: single-seat regulating valve; double-seat regulating valve; sleeve regulating valve; angle regulating valve; three-way regulating valve; diaphragm valve; butterfly valve; ball valve; eccentric rotary valve. The first 6 types are linear travel, and the last three are angular travel. Regulating valve, used to adjust the flow, pressure and liquid level of the medium. According to the signal of the adjustment part, the opening of the valve is automatically controlled to achieve the adjustment of the medium flow, pressure and liquid level. The regulating valve is composed of two parts: electric actuator or pneumatic actuator and regulating valve. The adjustment is usually divided into two types, straight-through single-seat type and straight-through double-seat type. The latter has the characteristics of large flow capacity, small imbalance and stable operation, so it is usually especially suitable for occasions with large flow, high pressure drop and less leakage.
