Werner Alber: Die Durchflussregelung misst das Volumen eines Gases pro Zeiteinheit und reagiert empfindlich auf Druck- und Temperaturschwankungen. Die Massendurchflussregelung erfasst dagegen die tatsächliche Gasmasse und sorgt unabhängig von Umgebungsbedingungen für konstante Werte – ideal für präzise Anwendungen wie in der Medizintechnik oder Halbleiterfertigung.
Kurz gesagt: Während die Durchflussregelung auf das Volumen fokussiert ist, stellt die Massendurchflussregelung sicher, dass stets die gleiche Masse an Gas durch das System strömt – unabhängig von äußeren Einflüssen.
Werner Alber: Stellen Sie sich vor, Sie müssen in einem Prozess immer die gleiche Menge an Gas zuführen. Wenn Sie einen klassischen volumetrischen Durchflussregler auf 10 l/min einstellen, erhalten Sie nur unter bestimmten Bedingungen exakt die gleiche Gasmenge. Steigt die Temperatur, dehnt sich das Gas aus – bei 10 l/min ist dann weniger Gasmasse enthalten. Umgekehrt führt ein höherer Druck dazu, dass sich in 10 Litern mehr Moleküle befinden. Ein Massendurchflussregler bestimmt die Masse des strömenden Mediums. Da die Masse eines Gases – im Gegensatz zum Volumen – nicht von Druck oder Temperatur beeinflusst wird, ermöglicht dies eine hochpräzise und stabile Regelung. Dadurch bleibt die Gasmenge konstant, wiederholgenau und effizient. Im Gegensatz zu einfach gesteuerten Drosselventilen regeln Mass Flow Controllers den Massenstrom und stabilisieren ihn aktiv, um gleichbleibende Prozessbedingungen zu gewährleisten. Das macht ihn zur idealen Lösung für Anwendungen, die eine hohe Präzision, Dynamik und Prozesssicherheit erfordern.
Werner Alber: A mass flow controller (MFC) can detect the gas flow using various physical methods. The most commonly used method is the thermal (calorimetric) principle, especially for gas applications. The heat loss and heat transfer methods are the ones that are typically used. Pressure differential-based processes are also becoming increasingly common, as they enable a faster reaction compared to thermal principles. Also worth mentioning is the Coriolis principle, which measures the mass flow rate directly. Which measuring principle is selected always depends on the specific requirements of the application.
Werner Alber: A mass flow controller consists of three central components: Sensors, control electronics and a proportional valve as a final control element. The sensors record the mass flow rate based on a specific measuring principle. The measured values are processed by the control electronics, which compare them with the setpoint value. Deviations are detected immediately and passed on to the regulator, which acts as a final control element to regulate the flow rate accordingly.
At Festo, we use piezo technology, since it allows us to control very dynamically, energy-efficiently and virtually wear-free. It is this precise coordination of all components that facilitates an exact, stable and reproducible flow control. The entire process is controlled by a higher-level control unit that synchronises all components and makes continuous adjustments.
Werner Alber: Piezo technology offers crucial advantages in mass flow controllers compared to conventional solenoid valves. It facilitates high-precision, energy-efficient and low-wear flow control. Piezo valves have a ceramic bending element that deforms when voltage is applied, thus opening or closing the valve. A major advantage is the extremely low energy consumption. Once the valve is in position, the piezo actuator requires almost no energy as no holding current is required. This not only reduces the power requirement, but also prevents unwanted heat development in temperature-controlled environments.
In addition, piezo valves are completely silent, as no coils or mechanical switching processes are required. This is particularly beneficial in environments where acoustic malfunctions have to be avoided. Their high control accuracy and fast response time support the sensitive, infinitely variable control of the mass flow rate. Thanks to their compact design, mass flow controllers with piezo valves are very space-saving to integrate, making them ideal for mobile or confined applications. They are also durable, as they contain hardly any moving parts and are virtually wear-free.
Werner Alber: The key to efficient mass flow control lies in precision, energy efficiency and seamless integration. Companies should check at an early stage what precision and response times their processes require. A key optimisation approach is the use of energy-efficient final control elements.
Piezo technology significantly reduces power consumption, eliminates heat generation and enables precise, wear-free control. Companies should also use intelligent diagnostics functions to make maintenance more predictable and processes more stable.
A next recommended step would involve a system analysis. Where do losses occur? Which components are working inefficiently? Specific advice or a test run with modern mass flow controllers quickly provides information on any optimisation potential. Digital, scalable solutions increase efficiency, process reliability and flexibility in the long term.
Thanks to Werner Alber for the informative interview and his in-depth insights into the world of mass flow control. His expertise has highlighted how precise control, digital networking and piezo technology can increase efficiency and process reliability in numerous industries. Companies that rely on modern mass flow control benefit from greater precision, more efficient energy use and optimised process reliability, all of which are decisive factors for future-proof automation.