Showing posts with label variable area flowmeter. Show all posts
Showing posts with label variable area flowmeter. Show all posts

What Are Rotameters?

Rotameter (ABB)
Rotameters are a type of variable area flow meter used for measuring the volumetric flow rate of a fluid. A tapered tube, usually glass, has a float that gets pushed by the drag force of the flow being measured and is pulled down by gravity. The simple operating principle and design makes rotameters a popular choice, and they are able to measure high flow rates as well as very low flow rates.

The rotameter has a number of advantages for use in a process. No external power or fuel is required, only the corresponding flow and gravity. They are simple devices that can be produced from low-cost materials, which is a main reason for the rotameter’s widespread use across many applications. Additionally, the area of the flow passage increases when the float moves, resulting in a linear relationship. The clear glass used also allows for a low risk of thermal shock and resulting issues from measuring chemicals. Rotameters also typically do not experience large drops in pressure, are simple to install, and are repeatable for long periods of time as long as they are operating under the same process conditions.

A few limitations exist in rotameters, the first of which relates to the fact the rotameter relies on displacement to function. A rotameter made to measure a certain substance at a particular temperature is only going to be accurate when measuring the substance and process qualities originally intended. While a rotameter can be scaled to measure different densities and viscosities, a limitation exists when the fluid characteristics being measured change in complexity. Secondly, while floats are often designed to function independent of viscosity, it can be difficult to ensure their effectiveness. Additionally, measurements being evaluated via rotameters can be uncertain when the float oscillates or near the bottom of the scale being used by the rotameter.

Certain fluids may also obscure the reading on the rotameter since the reading must be read through the flowing medium. This limitation can be countered by coupling he rotameter with a transducer in certain process applications. Another option for readability involves using a magnetic float that can be accompanied by a follower outside the tube, allowing the operator to easily read the measurement.

For more information about rotameters, visit

ABB Rotameters Quality and Performance a Legacy of Fischer and Porter Roots

The Fischer & Porter Company, founded in 1937, was a well-known and respected manufacturer of
process instrumentation. The Fischer and Porter brand has long been associated with an industry-leading range of flow measurement products. The legacy is strong though, and despite the F&P brand being shelved, their rotameter (variable area flowmeter) line is still referred to by some old-timers as "Fischer and Porter Rotameters" or "F&P Rotameters".

In 1994, Fischer & Porter was acquired by Elsag Bailey Process Automation as a strategic union to blend Elsag Bailey's expertise in distributed systems with Fischer & Porter's expertise in process instrumentation. In 1999 ABB acquired Elsag Bailey and moved the F&P products in to a larger portfolio of ABB process instrumentation and the Fischer and Porter line of rotameters became known as ABB rotameters.

Today, Fischer & Porter products are fully integrated into the ABB portfolio of process instrumentation products which include variable area flowmeters (rotameters), magnetic flow meters, vortex shedding meters, and mass flow meters.

In 1947 Thompson Equipment (TECO) was the first firm ever appointed to represent and sell the Fischer & Porter Rotameter line.  TECO proudly continues that relationship today and specifies, services, and sells ABB Rotameters nationwide.  TECO also maintains a large inventory ready for same-day shipment. For more information, visit or call 800-528-8997 for immediate service.

TECO: A Stocking ABB Rotameter National Distributor

TECO's relationship with ABB rotameters dates back to 1947 as the first firm to represent and sell the Fischer & Porter Rotameters (as they were known back then). TECO is your best source for rotameters, with many models in stock, and decades of application assistance. ABB rotameters are simple, low cost, and maintenance free. TECO's specialty is helping customers choose the right instrument for their application. TECO offers standard flow ranges as well as custom flow ranges sized to our customer’s unique flow environment.

Download the latest ABB Rotameter brochure here, or view the embedded version below.

Variable Area Flowmeters Basics: Fundamentals and Descriptions

Want to learn more about variable area flowmeters (rotameters)? Here is a great resource compliments of ABB.

You can download your own copy of the Variable Area Flowmeter Basics: Fundamentals and Descriptions here. Or, view the document below.

Contact Thompson Equipment for any ABB Rotameter requirement. TECO is an ABB Nationally Authorized Distributor for variable flow meters.

Basics of Variable Area Flowmeters

Variable Area Flowmeter (Rotameter)
Rotameter (ABB)
Flowmeters are a class of devices or instruments used to measure rate of fluid flow. Flow measurement stands as a vital input to many process operations across almost every industry. Applications can range from precise measurement of very small gas flows to oil or water flows through large diameter piping systems. There are a number of technologies employed for measuring fluid flow, each with attributes of design, performance, or cost that can make them an advantageous choice for a particular application.

Variable-area flowmeters are designed to measure flow using a precisely fabricated obstruction in the flow path that is repositioned in a tapered flow tube by changes in fluid flow.

Variable Area Flowmeter (Rotameter)
Rotameter (ABB
A rotameter is a flow indicator consisting of a tapered tube containing a plummet. The plummet is generally a solid object and sometimes referred to as a float. Rotameters rely on gravity as part of their operating principle, so the instrument must be installed such that the inlet is at the bottom and fluid flows directly upward through the tapered tube. As fluid flows through the tube, a pressure differential develops across the plummet. This creates an upward force on the plummet, moving the plummet in the direction of the flow. The flow area around the plummet increases as it moves from the narrow portion of the flow tube to a wider portion up the measurement scale. As the available flow space around the plummet increases, the upward force on it decreases. Eventually, the equalization between the pressure force and the weight of the plummet occurs and the float stops moving. The flow rate is indicated by the plummet's position relative to a pre-calibrated scale printed along the length of the tube. The same type of system can be used to measure liquid or gas flow, with the rotameter being specifically calibrated for the fluid to be measured. It is common to employ a rotameter with an integral needle valve as a metering device for delivering a precise fixed flow of a fluid into a process.

These devices are generally inexpensive and easy to apply. Key application considerations include a vertical installation orientation, matching the rotameter to the fluid, and providing physical access to read the indicated flow.

Industries use rotameters primarily as indicating devices. Rotameters enjoy a wide range of applications throughout research and manufacturing processes. Share your flow measurement challenges with instrumentation specialists, combining your own process knowledge and experience with their product application expertise to develop effective solutions.

Introduction to Industrial Flowmeters

Magnetic flowmeter
(courtesy of Badger Meter)
Flowmeters measure the rate or quantity of moving fluids, in most cases liquid or gas, in an open channel or closed conduit. There are two basic flow measuring systems: those which produce volumetric flow measurements and those delivering a weight or mass based measurement. These two systems, required in many industries such as power, chemical, and water, can be integrated into existing or new installations. For successful integration, the flow measurement systems can be installed in one of several methods, depending upon the technology employed by the instrument. For inline installation, fittings that create upstream and downstream connections that allow for flowmeter installation as an integral part of the piping system. Another configuration, direct insertion, will have a probe or assembly that extends into the piping cross section. There are also non-contact instruments that clamp on the exterior surface of the piping add gather measurements through the pipe wall without any contact with the flowing media.
Turbine flowmeter
Turbine flowmeter
(courtesy of Badger Meter)

Because they are needed for a variety of uses and industries, there are multiple types of flowmeters classified generally into four main groups: mechanical, inferential, electrical, and other.

Quantity meters, more commonly known as positive displacement meters, mass flowmeters, and fixed restriction variable head type flowmeters all fall beneath the mechanical category. Fixed restriction variable head type flowmeters use different sensors and tubes, such as orifice plates, flow nozzles, and venturi and pitot tubes.
Variable area flowmeter
(courtesy of ABB)

Inferential flowmeters include turbine and target flowmeters, as well as variable area flowmeters also known as rotameters.

Laser doppler anemometers, ultrasonic flowmeters, and electromagnetic flowmeters are all electrical-type flowmeters.

Basics and Practice of Applying ABB Rotameters (Variable Area Flowmeters)

ABB Variable Area flowmeters
Diagram of rotameter
(courtesy of ABB)
For decades variable Area flowmeters have become established in industrial measure- ment technology with an economical, mature measurement principle. The large variety of instrument designs, their repeatability and independence from supply power require- ments for local indication provide a suitable solution in almost every flow metering ap- plication for liquids, gases and steam.

The ABB-Program includes, a line of metal meter tube flowmeters particularly suited for high pressure and temperature applications, for aggressive and opaque fluids and for steam metering. Also offered is a line of glass meter tube flowmeters (the solution for extremely low pressure conditions) including float designs for viscous fluids or high flowrates in the smaller sizes. The purge flowmeters in both lines are available with a differential pressure regulator to maintain a constant flowrate even when there are pressure variations. The smallest flow ranges required in laboratory applications and high flowrates in industrial applications can be satisfied with ABB instruments.

This new “Handbook for Variable Area Flowmeters“ is a practical guide for the user with selection criteria for real applications (see Check List/Parameter Questionnaire), correction factors, Accuracy Classes, corrosion resistance tables and much more. A separate flyer with actual pictures demonstrate the application versatility.

Answers are provided to frequently asked questions about this measurement principle (see Page 20) and we have incorporated a preferential quick ship program for the most popular instrument versions.

We hope that this Handbook provides you with a practical selection guide; naturally our sales team is always ready to provide you with any personal assistance you may require.

For more information on any ABB variable area flow meter (rotameter), visit TECO at or call (504) 833-6381.

Variable Area Flowmeters (Rotameters)

ABB Rotameter
Variable area flowmeters (rotameters) are the most cost effective solution for almost all applications involving the measurement of industrial process liquids, gases or steam.

They meet the application requirements by featuring a wide range of design varieties and sizes. Technology proven, they offer a long life and high reproducibility. Variable area flowmeters are excellent mechanical back-up meters because no external power supply is needed.

TECO was the first firm to represent and sell the Fischer & Porter Rotameter Line, dating back to March, 1947.  With over 70 years of ABB Rotameter history, TECO is your best source to help with your rotameter applications. | 800-528-8997.

How a Rotameter (Variable Area Flowmeter) Works

Variable Area flowmeter
Components of a Variable Area flowmeter
A rotameter is a flow measuring device that belongs to a group of instruments called variable area flowmeters. For decades Variable Area flowmeters have become established in industrial measurement technology with an economical, mature measurement principle.

The Variable Area flowmeter is an instrument for metering the flowrate of liquids and gases in a pipeline. It includes a vertically oriented conical tube, whose diameter is larger at the top than at the bottom, through which the fluid flows upward and in which a vertically moving float is positioned.

The height of the float in the tube increases as the flowrate increases in such a manner that the resistance to the flow is always balanced by the weight of the float and remains constant regardless of the flowrate. The height of the float in the tube is a measure of the flowrate. The value of the flowrate can be read from a scale.

Variable area flowmeters are the most cost effective solution for almost all applications involving the measurement of industrial process liquids, gases or steam. They meet the application requirements by featuring a wide range of design varieties and sizes. They offer a long life and high reproducibility. Variable area flowmeters are excellent mechanical back-up meters because no external power supply is needed.

For more information on rotameters (variable area flowmeters) visit call TECO at  800-528-8997.