Flow controllers, commonly known as mass flow controllers, are electrical devices that measure and control the flow of gases and liquids. The instrument is specifically designed for a particular type of gas or liquid under a designated flow rate range.
Flow controllers are evaluated in a particular way to enhance them to have a repeatable flow rate set in which they transmit through an electric signal. Change in pressure or any external factor does not affect the way they operate.

How does a flow controller operate

Mass flow controller rates are put in two forms where pressure and temperature of the mass flow affect the volumetric flow. It operates under many industrial environments where it is used when there is a need to obtain accurate flow rate measurement.

Mass flow controllers are simple and easy to install and operate; hence one installs them without calling for an expert. At the water line point, many valves link directly to the faucet.

Ways in which flow controllers control the flow

1. Linear control

Flow controller devices with linear control utilize classical control and include proportional, regulation, derivative, and integral methods. The proper output control signal can be generated due to signal amplification, conditioning, or filtering.

2. Limit control

It introduces limits or set points in which a signal starts or stops when the flow reaches that point. The off and on control is usually a fair and direct control type.

3. Proportional, derivative, and integral control

All these flow controls require a real-time feedback system. It is a control method that monitors and controls the error found between the actual value and the variable value desired and adjusts the flow control how it is required. This type of flow control utilizes program instruction, enabling it to provide automatic loop performance, which is closed for the loop control process.

4. Proportional control

It is a type of flow control where the signal is proportional to the error between the feedback signal and the reference point.

5. Proportional integral control

It is also known as automatic offset control. The error signal is joined to remove offset errors.

6. Proportional derivative control

The flow rate change is determined by differentiating signal error. It usually raises the response speed of the controller. It may bring noise which causes instability in the system.

Functions of flow controllers

i) Indication of rates and control

A flow controller monitors, controls, and indicates the media or material flow rate in a system.

ii) Indication of totalizer and control

Flow controllers indicate and totalize, or material amount or variable process.

Flow controller specification

The flow controller specification includes; the user interface, controller functions, output type, and channels.


Flow controllers perform many functions where they use different inputs and outputs depending on the type of applications. The gas or liquid supply should be within a specific range of pressure for the measurement to be accurate.