A flow meter, abbreviated as FM, is a device used to measure the rate of flow or quantity of a fluid (liquid or gas) that passes through a particular point in a system.  Flow meters are essential in various industries and applications where monitoring and controlling the flow of fluids are critical.  They provide valuable information about the flow rate, helping in processes such as regulation, optimization, and billing.  There are several types of flow meters, each employing different principles for measurement.

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Flow Meter Design Classification

Differential Pressure Flow Meter

• Orifice Plate  -  Uses a plate with a hole to create a pressure drop.
• Venturi Tube  -  Similar to an orifice plate but more streamlined.
• Flow Nozzle  -  Includes a contoured inlet to improve accuracy.

Positive Displacement Flow Meter

• Piston Meter  -  Measure the volumetric flow in a chamber.
• Oval Gear Meter  -  Count the rotation of gears in the flow stream.
• Rotary Vane Meter  -  Use rotating vanes to measure flow.

Velocity Flow Meter

• Turbine Flow Meter  -  Measure flow through the rotation of a turbine.
• Electromagnetic Flow Meter  -  Use Faraday's law to measure flow.
• Ultrasonic Flow Meter  -  Use ultrasonic waves to measure flow velocity.

Mass Flow Meter

• Coriolis Flow Meter  -  Measure mass flow based on the Coriolis effect.
• Thermal Mass Flow Meter  -  Measure mass flow by heating a sensor.

Vortex Shedding Flow Meter  -  Create vortices in the flow, and the frequency is proportional to flow rate.

Variable Area Flow Meter (Rotameter)  -  Use a float in a tapered tube; the position of the float indicates flow rate.

Paddlewheel Flow Meter  -  Use a rotating paddlewheel in the flow to measure velocity.

Pulse Flow Meter  -  Generate electrical pulses proportional to the flow rate.

The selection of a flow meter depends on factors such as the type of fluid, flow rate, accuracy requirements, and the specific application.   Each type has its advantages and limitations, and the appropriate choice depends on the characteristics of the fluid being measured and the goals of the measurement.

Metering Systems

Metering systems can be simple or complex, a single piece of equipment or a skid.  A single piece of equipment would be something that fit between two pieces of pipe like a venturi tubes or flow nozzles.  A metering skid is a fabricated frame where equipment is installed on such as a meter run, transmitters, control valves and control panels.  The skid can be self contained, part of a system, portable or stationary.