Mass Flow Controller

A mass flow controller (MFC) is a device that measures and automatically controls the flow rate of a gas or liquid in terms of mass (weight) per unit time, regardless of temperature and pressure variations.Key Features and Operation Components: An MFC consists of a mass flow sensor, a proportional control valve, and internal circuitry/electronics (often with a built-in PID controller). Operating Principle: The sensor measures the actual mass flow rate. This measurement is continuously compared to a desired flow rate setpoint (an electrical signal from an operator or external system). If there's a difference, the control valve's position is adjusted automatically via a feedback loop to match the actual flow to the setpoint, ensuring stability and accuracy. Mass vs. Volumetric Flow: Unlike volumetric flow, which changes with temperature and pressure fluctuations, mass flow measurements remain consistent. This provides more accurate and repeatable results for industrial processes. Types: MFCs can be analog or digital. Digital controllers are often more flexible, able to control multiple gases with onboard databases and offering a range of communication interfaces (RS-232, RS-485, etc.). Sensor Technologies: Common sensor types include thermal (capillary or inline), Coriolis, and differential pressure-based technologies, each suited for different applications and fluids.