Flow Meter Designed for Corrosive Slurries, Acids, Bases & Solvents

TECO Severe Applications Meter (SAM)

A patent pending magnetic flowmeter with abrasion resistant ceramic trim that exceeds the capabilities of Alumina or Yttria Zirconia. Capable of withstanding a variety of corrosive slurries, acids, bases, and solvents.


Severe Service Flow Meters by TECO

Stock Prep Solutions - Helping Paper Manufacturers Stay in Business

Stock Prep
The concept behind stock prep is to manage the raw materials being added to the process so the finished stock meets the requirements of the paper machine and the final quality of the finished product. Finished stock is a suspension of fibers, additives, and impurities matching a defined level of quality, which ultimately determines the operation of the machinery and the quality of the final product. Most of the machines used for individual processes provide not only the desired effect, but also may produce undesirable side-effects. Implementing process controls to reduce or eliminate these undesirables help paper producers gain considerable improvements in quality, consistency, and yield.

This video introduces, and presents a case for, specific process instrumentation designed for stock prep.


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 https://teco-inc.com/ABB.

Positive Displacement Flowmeters

Positive displacement flowmeter.
(Badger Meter Blancett)
Positive displacement flowmeters use fluid to mechanically move internal components such as pistons, gears and discs to measure flow.  These devices are both precise and simple to operate.

The positive displacement flowmeter, in contrast with other types of flowmeters, directly measure the volume of fluid passing through the meter instead of employing inferential flow measurement. The rotational velocity of the rotor in the flow meter is directly proportional to the rate of flow. Electronic versions of positive displacement meters rely on magnets to activate sensors in their fluid chambers, whereas their non-electrical counterparts rely on the rotation being driven by the fluid flow.

The operating principle of the positive displacement meter may be simple, yet the flowmeter type offers a few specific advantages for industrial application. A main benefit of this flowmeter is a high level of accuracy due to its internal components. The accuracy of the flowmeter is directly related to the size of the clearances, or the space between the sealing faces.

These flowmeters are also particularly useful for handling a high range of viscosities. As the fluid viscosity increases with the positive displacement meter, less slippage or bypass will occur, meaning more total fluid will pass through the positive displacement meters. In addition to these design-based advantages, the positive displacement meter typically allows for excellent repeatability and linearity.

The longstanding use of positive displacement flowmeters across various industries has been a source of stability in terms of design, with the most recent advancements in positive displacement technology focusing on maintaining precision at lower costs.

There are a few known limitations for the use of positive displacement meters. The meters are not the optimal choice for measuring fluids with large particles, and are also non-ideal for measuring fluids with large air pockets. Additionally, systems using positive displacement meters need to account for slight pressure drops in the positive displacement meter. While the meters are able to accurately measure non-lubricating fluids, using positive displacement flowmeters to measure these types of liquids will not be as efficient as using the flowmeter for lubricating fluids. Overall, these types of flowmeters are a cost effective, accurate and volumetrically based flow measurement solution.

For more information on positive displacement flowmeters, call Thompson Equipment Company (TECO) at 800-528-8997 or visit https://teco-inc.com.