There are different techniques to use in gas flow measurement. Some of the flow meters can be used to measure both the gaseous and liquid fluids. Here are some flow meters that are used to measure gaseous flow.

Thermal Flow Meters:

**Thermal flowmeters** use fluid flow rate measurement heat. There are two types of thermal flow meters. First one, this type measures the current needed for a heated component to keep a set temperature. Particles contact the element as the fluid flows, and dissipate or carry heat away. As the flow rate rises, it is necessary to maintain the component at a set temperature with more current. This current requirement is proportional to the mass flow rate.

In second heat technique, the temperature is measured from two points. As the fluid flows downstream over the component it holds the heat, the downstream temperature sensor increases and the upstream sensor temperature decreases. The temperature shift is linked to the mass flow of the fluid.

Coriolis flow meter:

The **Coriolis flow meter** utilizes the impact of Coriolis to assess a fluid’s mass flow. The fluid passes through curved single or dual pipes. The tube(s) will be vibrated. The Coriolis force acts on the fluid particles perpendicular to the vibration and the direction of the flow.

Laminar DP Flow Meters:

The pressure drop generated within a **laminar flow** component is used by differential pressure-based flow meters to evaluate a fluid’s mass flow rate. By dividing it into a range of thin, parallel channels, a laminar flow component transforms turbulent flow into the laminar flow.A differential pressure sensor is used to measure the reduction in pressure or pressure drop across the channel.

A differential pressure sensor is used to measure the reduction in pressure or pressure drop across the channel. With density correction at a given temperature and pressure, the volumetric flow rate can also be converted to a mass flow rate.

Ultrasonic Flow Meters:

Sound waves are used by **ultrasonic flow meters** to evaluate a fluid’s flow rate. Doppler flow meters convey ultrasonic waves of sound into the fluid. These waves are expressed in the fluid from particles and bubbles. The change in frequency between the wave transmitted and the wave received can be used to evaluate the fluid flow velocity.

Variable Area Flow Meters/Rotameter:

**Rotameters**, use a tube and float to measure flow. Equilibrium will be achieved when the float counterbalance gravity is pressed and buoyant. On a calibrated measurement reference, the height of the float in the pipe is then used to display a flow rate.