Short definition
Control engineering deals with the automatic influencing of physical variables through continuous feedback between the actual and setpoint values. It works in closed control loops, in which the controlled variable is constantly measured, compared with the setpoint and corrected by means of corrective interventions. This automatic compensation of disturbance variables is the fundamental difference between closed-loop control and open-loop control. In membrane filtration systems, control technology stabilizes critical process parameters such as pressure, flow rate, temperature and concentration with high precision.
Functional principle
The Control loop consists of a controlled system (process), measuring device (sensor), controller (algorithm) and actuator. The controller continuously calculates the manipulated variable based on the control deviation. Classic PID controllers use proportional, integral and differential components for optimum dynamics. Modern approaches include cascade control for coupled variables, feedforward control for disturbance compensation and model predictive control (MPC) for complex multi-size systems. The parameters are set using mathematical modelling or experimental identification with subsequent optimization.
Areas of application
Control technology is essential for stable operating conditions in membrane filtration systems despite fluctuating raw water quality, temperature influences or fouling effects. It enables consistent product quality through precise parameter control and protects membranes from damage caused by excess or low pressure. Adaptive controllers automatically compensate for gradual process changes such as increasing membrane resistance.
Typical areas of application:
- Transmembrane pressure control for constant permeate flow
- Cascaded flow control with frequency converter pumps
- Temperature control for thermosensitive products
- pH value control during dry cleaning
- Concentration control through adaptive permeate recirculation
Summary
Control technology is indispensable for high-quality, reproducible filtration results and maximum process stability. It reduces rejects, optimizes energy consumption and significantly extends membrane service life. For plant operators, it means economical operation thanks to minimized process fluctuations, reduced operating costs and compliance with strict quality requirements in regulated industries.
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