Mass Flow Controller
Float and rope level gauge
March 4, 2018Mass Flow Controller Mass Flow Controller is a device used for the precise control and measurement of fluid flow (liquid or gas) . The operation of most MFC gas or liquid, is based on heat transfer in a specified volume .
The simple schematic below shows the basis for fluid flow measurement of MFC gas or liquid . It is based on heat transfer :
The process of fluid flow control (MFC) for gas or liquid using the heat transfer method is schematically shown in the image below .
In a fixed volume and at a specified temperature, the fluid flow is allowed to pass through. .
When selecting and purchasing a MFC gas or liquid device, the following factors should be considered :
Type of gas :
Each MFC is calibrated for a specific gas. Therefore, before purchasing any MFC for gas or liquid, it should be ensured that the type of gas is specified for the MFC calibration .
Maximum pressure :
Each MFC has a maximum pressure rating. Operating above this pressure can cause serious damage to the MFC. If using an MFC at high pressures, pressure-reducing regulators or special MFCs designed for high-pressure operation can be used .
Minimum pressure differential :
The **drift pressure differential** DP of each MFC requires a minimum value for proper operation. DP is the pressure differential between the fluid's input and output .
Control conditions :
The operation of the MFC for gas or liquid can be controlled using an analog, digital, or manual system .
Analog Controller : Some MFCs are controlled and displayed in analog form. In this case, the outputs (4-20 mA, Vdc 5-0, or Vdc 10-0) allow the user to control or display the output parameters .
Digital Controller : In this case, the MFC has digital signal outputs for connecting to a computer or has digital signal outputs for connecting to a computer or PLC .
Local Controller : In this case, a digital display is present on the MFC, allowing the user to control and display the fluid flow .
Material :
Due to the corrosive and toxic nature of some fluids, it is necessary to select the material of the MFC and connections from specific alloys.
