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Types of flow measurement instruments in industrial automation

There are several types of flowmeters used to measure the flow rate or quantity of fluids gases or solids moving through a system. Some commonly used types of flowmeters include: 1. Differential Pressure (DP) Flowmeters: These flowmeters measure the pressure drop across a restriction in the flow path to determine the flow rate. Examples include Orifice Plate Venturi Tube and Pitot Tube flowmeters. 2. Turbine Flowmeters: These flowmeters use a turbine rotor placed in the flow stream. The spinning rotor generates electrical signals that are proportional to the velocity and flow rate. They are commonly used for measuring liquid flow in clean low-viscosity fluids. 3. Electromagnetic Flowmeters: These flowmeters use Faraday’s law of electromagnetic induction to measure the flow rate of conductive fluids. They consist of a flow tube and electrodes to detect the voltage generated by the fluid passing through a magnetic field. 4. Ultrasonic Flowmeters: These flowmeters use ultrasonic waves to measure the flow rate of liquids or gases. They employ either the Doppler effect (measuring the change in frequency) or the transit-time method (measuring the time taken for sound waves to travel). 5. Coriolis Flowmeters: These flowmeters operate based on the Coriolis effect which measures the change in oscillation caused by the fluid passing through a vibrating tube. The measurement of the change in oscillation provides the flow rate and density information. 6. Positive Displacement (PD) Flowmeters: These flowmeters measure the volumetric flow rate by repeatedly filling and emptying a chamber with a known volume. Examples include Piston Oval Gear and Gear Flowmeters. 7. Vortex Flowmeters: These flowmeters utilize the principle of the Von Kármán vortex street where vortices form downstream of an obstruction placed in a flowing fluid. The frequency of the vortices is proportional to the flow rate and can be measured to determine the flow rate. 8. Thermal Flowmeters: These flowmeters measure the flow rate of gas by utilizing the change in temperature caused by the flow. They often have two temperature sensors one heated and one non-heated to detect the rate of cooling. These are just a few examples of the many types of flowmeters available for various applications. The selection of a suitable flowmeter depends on factors such as the type of fluid flow conditions process requirements and accuracy needed for measurement.