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Flow Meter Types

Flow meters are vital test equipment that can be used to determine the mass and volumetric flow of a liquid or gas. As a highly versatile instrument, flow meters are called many different names depending on their industrial use, including flow gauge, flow indicator, liquid meter, and flow rate sensor. Regardless of their specific application, all flow meters are designed with the purpose of measuring fluids with greater precision and accuracy than traditional methods. Flow meters can measure the volume of a material along with its speed or mass and calculate characteristics like mass, flow, absolute pressure, differential pressure, viscosity, and temperature. There are many types of flow meters available with the most common of them listed here.

Differential Pressure Flow Meters

This type of flow meter relies on the Bernoulli equation which states that as the speed of flow of a fluid increases, its pressure decreases. In using this principle, the meter measures the flow of fluid in its regular state and where it has just changed direction. By comparing the pressure at these two points, the meter is able to calculate several flow characteristics of the fluid. The types within this category are orifice plates, flow nozzles, venturi flow meters, and rotameters. All of these devices work by constricting the diameter of flow at a certain point. As the simplest of the types, orifice meters are straightforward and easy to install, consisting mainly of a plate with a hole in the center that can be placed inside a pipe. On the other end, venturi flow meters are more involved and use an altered pipe itself, which more gradually decreases so there is far less friction.

Velocity Flow Meters

Velocity flow meters calculate flow speed by measuring the depth and average air velocity of the flow. Using these measurements, engineers can maintain necessary flow throughout the stream. Typically, velocity flow meters have a greater range than differential pressure devices; therefore, they can be used in a larger number of operations. The major types of velocity flow meters include pilot tubes, calorimetric, turbines, and other electromagnetic variations.

Pitot tube flow meters find the velocity of flow by translating its kinetic energy into potential energy. The device does this by using a small tube which allows the fluid to stagnate. Pitot tube meters are commonly used in ventilation and HVAC systems.

Calorimetric flow meters use the laws of heat transport by comparing the difference in temperature of a heating element and the flow downstream from it. The flow rate will affect how much heat is transferred and be indicated by the sensor.

Turbine flow meters use flow to measure the speed of the turbine and are used with clean and viscous liquids with extremely high accuracy. They have a multi-blade rotor mounted at right angles to the flow. Outputs are a sine wave or square wave frequency.

Electromagnetic flow meters are volumetric and use Faraday’s law of electromagnetic induction to find fluid velocity. They include an electric coil placed at one end of a pipe and measure the amount of current that was transferred to the other end.

Vortex flow meters measure flow rate by putting a blockage in the flow path and forcing fluid around it. The flow around it causes two symmetrical vortices on the opposite side which changes the pressure. The sensor between the vortices measures pressure changes.


Overall, these are just some of the types of flow meters available, but they represent a wide variety of different measurement techniques. In general, flow meters are useful for finding fluid characteristics such as pressure and velocity. As such, they are an essential piece in aircraft construction which is used to convey vital information to the pilot and crew. If you are in the search for high quality aircraft parts, such as top-grade flow meters, and more, you can rely on ASAP Domain 360 for a premium selection of aircraft parts. Browse our online catalogs of available parts at your leisure on our website. Upon finding any item of interest, you may request a competitive quote for your comparisons at any time using our Instant RFQ service. Begin procuring the parts you need today with unbeatable cost and shipping solutions when you source with ASAP Domain 360!


August 1, 2022


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