Types Of Fluid Flow Meters Used Industrially And Their Applications

The importance of fluid flow meters in everyday industrial processes is understood by all manufacturers across practically all industries, such as the food and beverage, HVAC, petroleum, utility services, chemical, automotive, and many other industries. The fluid flow meters are important to accurately monitor liquid flow in refineries, power generation, and water treatment plants. The industrial fluid flow meters are used to maintain efficiency and help understand profit gains and losses. A flow meter is a device used to measure the mass or volume of a gas or liquid. Depending on the particular industry, the flow meters are referred to by many names such as flow indicator, flow gauge, flow rate sensor, liquid meter, etc. To keep the entire system to operate efficiently, precise monitoring of liquid flow is necessary. Most of the flow meters work by forcing flow through a known confined space and measuring different properties to determine the flow rate of a fluid.  There are many types of flow meters, each performing optimally under different conditions. Having a clear understanding of the particular application requirements is the most important part of choosing a flow meter. How would you decide which type of fluid flow meters are needed for a particular application? Well, a few good questions may help you.

  • What's the expected temperature of the fluid?
  • What type of fluid is being measured?
  • How accurate must the meter be?
  • What's the maximum pressure expected at the location?
  • What array of flows will the system be under?
  • Will the fluid be sporadic or continuous?
  • What's the size of the pipe the meter will be installed on?

In this article, the commonly used types of flow meters are listed and explained briefly. The different industrial fluid flow meters are -

  • Differential Pressure Flow Meters
  • Positive Displacement Flow Meters
  • Velocity Flow Meters
  • Mass Flow Meters
  • Open Channel Meters

A) Differential Pressure Flow Meters

The oil and gas industries and refinery are largely dependent on differential pressure flow meters for their liquid flow measurement applications. The differential pressure flow meters operate by restricting the cross-sectional area of a flowing fluid. A pressure drop is caused across the constriction when the flow area is restricted and this drop in pressure is caused by a change in the velocity of the fluid. A differential pressure flow meter is the best choice at times when no moving parts are required or when prompt response time is needed. These fluid flow meters are found in industrial applications to calculate the fuel output, plain water measurement testing or in specialty chemical manufacturing. They are also used in laboratories for calculation and controlling the flow of gases while separating or mixing them with the help of chromatography. After analyzing the pipe's size, nature of liquids and flow conditions, the users must select the right type. Several types of differential pressure meters are available. These include -

  • Flow Tubes
  • Orifices
  • Venturi Tubes
  • Target Meters
  • Flow Nozzles
  • Elbow-Tap Meters
  • Variable-Area Meters
  • Rotameters

B) Positive Displacement Flow Meters

Also known as PD flow meters, the positive displacement flow meters are the only type of flow meters that directly measure the fluid volume passing through a pipe. These flow meters are ideal to measure the flow of adhesives, petrochemicals, and paints. They are also largely utilized for precision flow meter applications in power, food processing industries, chemical, and pharmaceutical. Some of the advantages associated with this unit include - low-pressure drop, low operating costs, high accuracy, self-contained operation, and long service life. Regardless of the fluids density, velocity, viscosity, or temperature, the positive displacement flow meters are very accurate.  They are also commonly used for domestic water measurement because of its ease of use and accuracy. Several types of displacement flow meters are available for industry-specific applications. These include -

  • Oval Gear
  • Rotary Vane Meters
  • Reciprocating Piston
  • Nutating Disk Flow Meters

C) Velocity Flow Meters

To operate linearly concerning the flow rate, the velocity flow meters can be directly connected to pipelines. The units attached to pipelines are supplied with flanges or fittings. A few advantages of these units include - outstanding accuracy when used with low-viscous fluids, fixed pressure loss at all flow rates, and reliable operation over a wide range of pressures and temperatures. These types of flow meters are largely used for applications in wastewater treatment, chemical and refinery industries, and power generation. The velocity meters are available in several types. These include -

  • Electromagnetic
  • Ultrasonic
  • Turbine and Paddle Wheel
  • Doppler Ultra-Sonic Flow Meters
  • Vortex-Shedding
  • Calorimetric Flow Meters
  • Pitot Tube Flow Meters

D) Mass Flow Meters

The mass flow meters, also known as true mass flow meters, are an ideal solution when precise measurement of the mass rate of a liquid is your requirement. In short, they are used for the direct measurement of mass flow. They are largely used for measuring liquids whose viscosities vary with velocity. Extremely high accuracy, reliable operation over a wide range of pressures and temperatures are some of the advantages of these systems. The common mass flow meter types include -

  • Mass Gas Flow Meters (Coriolis Flow Meters)
  • Thermal Mass Flow Meters.

The Coriolis meters are commonly utilized in wastewater treatment facilities, natural gas measurement, nuclear facilities, and pharmaceutical manufacturing.

E) Open Channel Meters

As the name suggests, these fluid flow meters used in industries, are ideal for measuring liquid flow in open channels. The open channel flow occurs when part of the flowing fluid is open to the free surface. Because of this, the cross-section of the flow is determined by the depth of the pipe or channel and shape, that the fluid is flowing through. This irregularity in the area makes it tough to determine the flow compared to fixed area flows such as pressurized pipe flow. However, these units enable precise and continuous flow rate monitoring in partially filled pipes, tunnels, streams, canals, and rivers. Unparalleled accuracy, versatile modular system, and easy-to-install design are some of the advantages associated with these units. The most common types of open channel flow meters are -

  • Flumes
  • Weir
  • Sluice Gate

Flow Meter Manufacturers

It may be difficult to determine which meters are best for a particular application, with so many various flow meter types and configurations. As per industry experience and expertise, we have compiled a list of flow meter manufacturers and suppliers.

  • Sierra Instruments
  • Kobold Instruments
  • GPImeters
  • HydraCheck
  • John C.Ernst Co. Inc.
  • Hoffer Flow Controls, Inc.