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Flow meters are measuring tools used to increase efficiency and help companies calculate profit gain or loss. Most often, they are used to infer mass flow using calculations made by flow meters and flow monitor instruments, based on the various flow measurements they took. However, they measure many other things as well, such as material volume, speed, absolute pressure, differential pressure, viscosity, and temperature. Some flow meters are built with specially selected materials that will maximize results.

Popular flow meter types include water flow meters, flow switches, fuel flow meters, peak flow meters, air flow meters, and ultrasonic flow meters. Since flow meter techniques and designs are so varied, they are used by many different industries, such HVAC, chemical and raw materials, automotive, gas/petroleum, utility services, medical treatment and brewing. Read More…

Leading Manufacturers

Sierra Instruments

Monterey, CA | 800-866-0200


Sparta, NJ | 888-722-3569


West Valley City, UT | 800-316-5342

John C. Ernst Co., Inc.

Sparta, NJ | 888-463-7678

Hoffer Flow Controls, Inc.

Elizabeth City, NC | 800-628-4584

Siemens Process Instrumentation

Spring House, PA | 800-365-8766

Water flow meters are made to measure flow rates of water in various bodies, such as tubes, rivers, streams, channels, and partially filled pipes. Flow switches differ from other meters in that they have a fourth component that controls flow as a switching unit, and they may set off an audible or visual alarm if the flow is too low or too high. Observation windows, known in this context as flow indicators, help measure flow with visual indicators.

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Flow Meters – Sierra Instruments

Fuel flow meters, which may be positive displacement, ultrasonic, or turbine flow meters, take measurements of fuel usage rates from stationary pumps and transportation devices. In turn, positive displacement flow meters measure liquid flow by trapping it, rotating parts in it and measuring the created flow between the meter body and the seals; ultrasonic flow meters, like Doppler Effect meters and time-of-flight meters, measure flow rate through the use of sound, and turbine flow meters have rotors that measure fluid as it passes through its blades, based on blade speed.

Peak flow meters are made especially for use by asthma patients or others with breathing problems, so that doctors can measure their oxygen intake. Air flow meters simply measure the flow of air. Another type of meter, the vortex flow meter, measures flow rate by blocking the flow path with an obstruction called a bluff body, forcing liquids or gases to move around it. When it does this, two symmetrical vortices form on the opposite side, changing flow pressure. This pressure change is measured and by a sensor placed in between the vortices, which then transmits its data to an electronic signal conditioner separate from the meter.

Manufacturers make many decisions before, during and after flow meter design. For example, they must decide if they will make a meter that is incorporated into a larger system or if they will make a complete instrument, made of a combined primary device, transmitter, and transducer. They must also decide if the meter will utilize mass flow measurement, which produces results in kilograms or pounds, or volumetric flow measurement, which produces results in cubic inches or liters.

Generally, flow meters are installed to achieve one of three mounting styles: insertion, in-line, and non-invasive. To function properly and give you the most accurate reading, flow meters must be handled using specific guidelines. For example, gas flow, air flow, and liquid flow meters alike, must remain full of their respective element in order to stay accurate. In addition, meter operators must watch for and remove any foreign contaminants from fluid, like gas in liquid flow meters, and must maintain or take into account air, fluid or gas quality, as well as viscosity. A well maintained and carefully monitored flow meter will provide essential information and thereby improve efficiency of operations, application safety and application accuracy.

Flow Meters Informational Video