Magnetic Flow Meter – When Is It the Right Selection for Your Project?

Industrial Magnetic Flow Meter

Courtesy Yokogawa Corp.

Flow measurement is a ubiquitous function in the industrial process control field. Anywhere there are pipes, somebody wants to know what, and how much, is passing through them. Fortunately for us engineers, there is a wide array of industrial flow meters capable of measuring some physical characteristic of fluid moving within a pipe that can be translated into a useful measurement of flow rate.

In industry, there are a number of different technologies used to measure a physical property related to fluid motion, referred to as magnetic, ultrasonic, vortex, Coriolis, differential pressure, and several others. Each methodology exists in the market because it may perform better or cost less when meeting certain performance requirements. This article is focused on magnetic flow meters and when they may be a good candidate for your project.

Here is a list of some of the positive attributes of magnetic flow meters.

• Magnetic flow meters have no moving parts, always a plus.
• General construction arrangement allows for use of an interior liner for corrosion resistance.
• With no sensor insertions into the fluid flow, the impact of the instrument on the flow is minimized.
• Accuracy, when compared to other technologies, is high.
• Application to laminar, turbulent, and transitional flow profiles is permissible.
• General insensitivity to fluid viscosity, specific gravity, temperature and pressure.
• Magnetic flow meter technology can be applied to a very wide range of pipe sizes.
• Device responds rapidly to changes in fluid flow.
• Can be successfully applied to liquids containing heavy particulates.
• Generally long service life with little maintenance.

There are, though, some points about magnetic flow meters which may make them unsuitable for your application.

• Magnetic flow meters only work on liquids with conductivity above a certain threshold. They may be unsuitable for use with hydrocarbons and high purity water for this reason.
• Cannot be used to measure gas flow.
• Pipe must be grounded.
• Typically, the pipe cross section must be filled by the fluid being measured.

This listing of positives and negatives is intended to be very general in nature. Some manufacturers may have product application solutions that overcome some of the negatives, while others may not be able to deliver all of the positives.

Your best course of action:

Use this general overview to start shaping you understanding of where magnetic flow meters may be a good option, and contact a product application specialist to discuss what you want to accomplish. Combining your process knowledge with their product knowledge should move you toward a good solution.

Industrial Flowmeter Handbook From Yokogawa

Magnetic Flowmeter
Courtesy Yokogawa Corp.

Measuring the volume, mass, density, and temperature of flowing fluids is a common and necessary function of industrial process control. Industrial flowmeters employ various measuring technologies to deliver accurate measurements, which are utilized to make safety, operational, and financial decisions.

Each measurement technology; magnetic, Coriolis, vortex, differential pressure, rotameter, ultrasonic, or another, has specific attributes of meter design and measurement principle making it more suitable to differing application classes. Yokogawa Corporation has summarized the suitability of the different flowmeter types for a range of process and operational conditions in a table that provides the user a consolidated comparative view of flow meter technology for almost every application. It is a useful tool that allows the engineer to quickly focus in on one or two technologies that will best suit project requirements.

Preview the handbook below, and obtain a copy of the handbook from a Yokogawa product expert, from whom you can also get expert level application assistance.

Flowmeter Handbook by Yokogawa from Miller Energy, Inc.

Data Acquisition - A Step in the Direction of Process Improvement

Data acquisition, like an equipment acquisition, is the procurement of an asset. Data is an asset. It helps an operator evaluate process or business conditions and make decisions that impact the success of the organization. Let’s define data acquisition as the sampling of signals that represent a measurement of physical conditions and the conversion of those signals into a numeric form that can be processed by a computer. A data acquisition system will generally consist of sensors, transmitters, converters, processors, and other devices which perform specialized functions in gathering measurements and transforming them into a usable form.

DAQ incorporating data acquisition, process
control, recording, display and networking
in a single compact unit
Courtesy Yokogawa Corp.

Industrial process operators and stakeholders benefit from the collection and analysis of data by enhancing performance of valuable facets of the process or activity. Data acquisition, commonly known as DAQ, is widely employed in high stakes and sophisticated processes where there is a true need to know current conditions. A desire for increased profit drives the need for increased process output and efficiency. A desire to reduce risk of loss drives the need for reduced downtime and improved safety. Today, there are likely many useful applications for data acquisition that are not being tapped to their fullest potential. The modest cost and simplicity of putting a data acquisition system in place, compared to the benefits that can be derived from a useful analysis of the data for your operation or process, makes the installation of a data acquisition system a positive move for even small and unsophisticated operators in today’s market.

What we call DAQ today started in the 1960’s when computers became available to businesses of large scale and deep pockets. By the 1980’s, personal computers employed in the business environment could be outfitted with input cards that enabled the PC to read sensor data. Today, there is an immense array of measurement and data collection devices available, spanning the extremes of price points and technical capability. For a reasonable cost, you can measure and collect performance data on just about anything. You can get an impression of the simplicity, modularity, and compactness of a modern system with a quick review of this product.

Data acquisition has an application anywhere an operator or stakeholder can benefit from knowing what is occurring within the bounds of their process or operation. Here is a partial list of the many physical conditions that can be measured in industrial settings:

Other examples of industrial data acquisition equipment
Courtesy Yokogawa Corp.

• Temperature
• Pressure
• Flow
• Force
• Switch Open or Closed
• Rotational or Linear Position
• Light Intensity
• Voltage
• Current
• Images
• Rotational Speed

Consider your industrial process or operation. Are there things you would like to know about it that you do not? Would you like to increase your insight into the workings of the process, how changes in one condition may impact another? Do you know what operating condition of each component of your process will produce the best outcomes? Is reducing maintenance, or heading off a failure condition before it occurs something you would like to have in your operation? Applying your creativity, ingenuity and technical knowledge, along with the help of a product expert, will help you get the information you need to improve the outcomes from your industrial process or operation.

Process Measurement and Control Essentials – Industrial Pressure Transmitters

Industrial Liquid Level
Transmitter
Courtesy Yokogawa Corp.

The measurement and control of fluid pressure is ubiquitous throughout many industrial processes. Measurements of pressure, directly and indirectly, provide real time information about what is happening in places that cannot be seen, such as inside a pipe, tank, or machine. The very nature of “process” suggests movement and change, the control of which is necessary to produce a consistent desirable outcome. Industrial pressure transmitters employ specific technologies and physical principals to derive a measurement of process pressure, then deliver or transmit, the measured value to a controller or recording device.

Fluid pressure tells a process operator much about what is currently happening. The pressure variable can be used to determine, among many industrial process elements:

• Degree to which the process is conforming to a recipe or specification
• Whether machinery is performing within its specified operation range
• If conditions of the process remain within the bounds established for safety
• A quantity measurement of flow, mass, or volume

Differential Pressure
Transmitter
Courtesy Yokogawa Corp.

Global industrial processes have widely varying physical arrangements, operating environments, and measurement requirements. Manufacturers of industrial pressure transmitters have responded with an immense array of transmitter technologies, arrangements, and configurations. When selecting the best suited pressure transmitter for your application, consult a sales engineer and consider some of the following:

• Signal requirements – Type, distance, possible sources of interference
• Device environment – Hazards, extreme conditions of temperature or corrosion
• Accuracy and stability of measurement
• Response time to changes in the process condition
• Ratings and certifications required for the device
• Configuration, arrangement, and mounting aspects of the transmitter device

Explore the differing technologies and how they can be best applied to implement or improve your process. Experienced sales engineers can be a useful sounding board for discussing your needs. Take advantage of their extensive experience with a wide array of process applications.