Difference between controller and meter
Mass flow meter is only equipped with a mass flow sensor and displays the flow rate output, while a mass flow controller has a build-in control valve as well as a sensor, which allows it to control the flow rate.
The mass flow controller controls the flow rate on a feedback control principle by adjusting the valve position with PID control based on the current flow output of the sensor.
Comparison of Mass Flow Controllers and Meters
  Mass Flow Controllers |  | |
|---|---|---|
| Purpose | Mass flow control | Mass flow measurement |
| Main parts | Mass flow sensor, control valve | Mass flow sensors |
| Advantage | Automatic control of flow rate is possible | Low pressure loss |
| Disadvantage | Pressure loss is more than the mass flow meter | Flow control is not possible. |
What are mass flow controllers used for?
Mass flow controllers are generally used to control gas or liquid flow rates in deposition processes for semiconductor, flat panel, solar cell manufacturing etc. Specifically, it is used to control the flow rate of reactive gases in CVD, the plasma sources of PVD and etching gases of the front end of the semiconductor manufacturing process.
Mass flow controllers are used not only in the deposition processes, but also in various fields that require highly accurate flow control. For examples, analysis equipment, evaluation equipment, fuel cells, combustion gas control, biotechnology, medical, food, laboratory equipment, factory equipment, etc. Mass flow controllers play an important role in a variety of applications that require precise fluid control.
What is the role of the mass flow meter?
Mass flow meter measures the mass of the flow rate. In case of gas, it is used to measure the cumulative flow rate (the total amount) of used gas, or to measure the flow rate of gas controlled by a mass flow controller to double check the results or to serve as a standard reference unit. Additionally, the liquid mass flow meter can send a control signal to a standalone control valve (CV-1000) or a vaporizer built-in control valve.
- Gas Usage Management
- Double check of the flow rate controlled by a mass flow controller
- Flow control of liquid control valves and vaporizer control valves