The intelligent electric control valve features PI control functionality

Thread Content

The intelligent electric control valve is a pressure-balancing type control valve equipped with the RQM series of intelligent electric actuators. It features a compact overall structure, low weight, good stability, and a high level of protection, which makes it widely used in automatic control systems in large thermal power plants, chemical plants, water treatment and sewage treatment facilities, natural gas fields, steel mills, and other similar applications. When the intelligent electric control valve performs PI regulation using a transmitter signal, the microcomputer first compares the transmitter signal with the setpoint signal, calculates according to the pre-set PI parameters, and then sends a control signal to the actuator to adjust the valve until the signals are in balance. The PI regulation function is a cost-effective and high-performing sampling control system that does not require a conventional PID controller; it directly accepts signals from field transmitters to carry out tasks that are difficult to achieve with analog continuous control systems. Some industrial processes have very long time lags (such as furnaces used for temperature control), which result in large errors and slow responses in the system. By using microcomputers for sampling and control, the performance of the low-pass control can be improved. Adjusting the flow characteristics: When a smart electric control valve has its flow characteristics adjusted, the microcomputer in the servo amplifier processes the signals according to pre-set parameter values, thereby establishing the desired numerical relationship between the input signal and the valve displacement and enabling nonlinear adjustments. This makes it simple and easy to select and change the flow characteristics, which is important for control systems. The method of altering flow characteristics by changing the shape of the valve core or the cam is considered outdated. Moreover, for angle-of-rotation valves such as butterfly valves, it is not possible to change their flow characteristics by altering the shape of the valve element. The use of an intelligent actuator can change this situation, as it is already an intelligent butterfly valve. Product features of intelligent electric control valves: 1. The valve body features a flow channel with a constant cross-section and low flow resistance, designed based on fluid dynamics principles, resulting in a 30% increase in the rated flow coefficient ； 2. It has a wide adjustable range; the inherent adjustable ratio is 50, and the flow characteristics can be linear or equal percentage ； 3. The electric two-seat control valve has low unbalanced force, good stability, and can operate with a large pressure difference ； 4. The regulating cut-off type features a valve core with a soft-seal structure, making it less prone to leakage ； 5. Electronic electric control valves can directly have their valve opening controlled by current signals, without the need for a servo amplifier ； 6. The bellows-sealed control valve provides a tight seal around the moving valve stem, preventing fluid leakage.