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Making Your Job Easier ......	September 21, 2005
Posted by Joe Lewis at 04:12 PM | Comments (0)

Your Choices

The Problem

The Solution

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How Blogs, Feeders and Feedback Loops Make Processes More Effective	September 11, 2005
Posted by Don Dunnington at 09:53 PM | Comments (0)

Hurricane Katrina forced my friend Steve O’Keefe to evacuate New Orleans, but thanks to local blogs he has been able to keep up with what’s happening in New Orleans right down to the neighborhood level. He also made his own urgent calls here on how to help those left behind. In both cases, we see individuals using blogs to create ad hoc communication channels that provide vital information and perhaps help save lives.

This is an example of how Blogs and other Internet technologies, such as websites and email, are facilitating the growth and speed of networked social feedback loops. Such feedback loops are not new, but their numbers and power have been multiplied and amplified by the Internet and other electronic media.

To appreciate the power of feedback loops, it’s useful to look at its application to feeding technology. Accurate feeder control depends on the microprocessor and its ability to process timely data from a feedback loop on what’s happening as the feeder discharges.

A Brief Explanation of Feeders and Feedback Loops
You can think of feeders as automation’s alternative to a scoop or shovel. A feeder delivers bulk material (usually dry, though liquids are also fed) into a process. It’s a feeder, not a scoop, that puts the two scoops of raisons into your breakfast cereal.

Volumetric feeders are the simplest type of industrial feeder. As the name implies, they measure material by volume. Most use a screw or auger to deliver the material into the process. An open loop control on a volumetric feeder provides no feedback as to how the feeder is performing. You're feeding blind and have no way of knowing (short of watching it) whether the feeder is running at all. A closed loop control tells us only whether the feeder motor is running at the speed we expected. It does not tell us if material is actually being delivered into the process, nor does it tell if the amount of material delivered is exactly what we wanted.

Gravimetric feeders, such as loss in weight or weigh belt feeders, tell us how much material was actually delivered by weight. Since weight is a more accurate measure than volume, the feedback information is more reliable than what can be expected from a volumetric feeder. Since the weight feedback is fast, as well as accurate, it is also possible for the controller to adjust the feed rate on the fly to makeup for variations in bulk density. This ability to monitor and adjust continuously is essential to producing many modern materials, ranging from high-tech plastics to life-saving pharmaceuticals.

Social Feedback Loops
Consider now, the feedback loops found in the business, economic and political arenas--the social feedback that keeps an organization or a society on track. In business, price and profits are the main signals that keep companies in business. In economics, we’ve seen that--despite its apparent chaos--a free market works better in the long run than a command economy because the market has more information and more accurate feedback mechanisms. In government--for all its apparent inefficiency and noise--democracy governs best because it is structured to seek and respond to the flow of information from a diverse public.

Feedback Is Important to Industry and Society
In industry, we see that feedback keeps a process on track so it achieves its targeted outcome. For those tasked with designing industrial control technology, the microprocessor was a liberating force that allowed a precision in machine and process control that simply wasn't possible with mechanical controls.

Today, it's remarkable to see how closely computer-aided human interactions have begun to parallel earlier developments in computer-aided machine interactions. That is, the networked computer has greatly expanded and enhanced the ability and ease with which we can give, receive and process feedback of a social nature. One of the more promising aspects of the blog is its power as a feedback loop.

Don Dunnington

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Explosion disasters can strike .........	September 07, 2005
Posted by Joe Lewis at 09:36 AM | Comments (0)

Disaster can strike at almost any facility that processes bulk materials.  Did you know that almost 70% of all powders are explosive?  I read that somewhere and it makes sense when you think of what it takes to create an explosion.

I recently found an interesting research article published as a set of web pages entitled "An Introduction To Dust Explosions".  It's published by the School of Engineering and Science in Edinburgh, Scottland in the United Kingdom.  So what does it take for a dust explosion?  According to this research article it takes the following:

What's needed for a dust explosion to occur?

• Combustible dust
• Airborne dust
• Dust distribution and size capable of flame propagation
• Dust concentration within explosible range
• Ignition source present
• An atmosphere that supports combustion, i.e. sufficient oxygen

This might describe many environments within your plant, right?  The subject of this article deals with only one of these elements, the ignition source.  In addition, I recommend you take a close look at the information presented by the School of Engineering and Science in Edinburgh, Scottland (click logo).

Ignition sources

There are many possible sources of ignition for a dust explosion.  These include the following:

• Open flames (welding, cutting, matches, etc)
• Hot surfaces (dryers, bearings, heaters, etc)
• Heat from mechanical impacts
• Electrical discharges
• Electrostatic discharges
• Smouldering or burning dust

Electrical equipment can create "electrical discharges" and possibly "electrostatic discharges".  With proper classification, manufacturing and installation of electrical equipment we can minimize problems created by electrical equipment during normal operation and during faults.  In the United States the National Electric Code (NEC) dictates requirements and their are several organizations and standards that can be utlized to help with the design of equipment that can be used in what is termed "hazardous areas".

One type of electrical equipment that may be found in hazardous areas is electronic instrumentation.  This includes, but is not limited to, point level indicators, continuous level measuring equipment, weighing sensors, as well as other instruments.

Free Whitepaper

When applying elecrtical instrumentation in a wide variety of industrial environments we must be aware of the type of area the instruments are being installed within.  Making sense of these classified areas can sometimes be difficult.  Download the free white paper for information and guidance regarding area classifications and required approvals for instrumentation.

In addition, whatever your "area classification" requirements may be, Monitor Technologies has a full line of level measuring and solids flow detecting instruments approved for use within most hazardous areas.  Take a look and let us put our creative solutions to work for you.

Credits:  the photo used in this blog is provided courtesy of Flamex, Inc. of Greensboro, NC.  An article with this photo can be found at their website.  Click here

Joe Lewis
Vice President - Marketing & Sales
Monitor Technologies LLC
Phone: 800-766-6486 or +1-630-365-9403
Email: jlewis@monitortech.com

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