Fermilab: Can cheap flowmeters be good?

CONTROL Editor in Chief Walt Boyes takes a look at how an anti-matter factory works at one of the largest high energy physics labs in the world, and why flowmeters are critical to the operation of the plant.

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 By Walt Boyes, Editor in Chief

F

ermilab (Batavia, Ill.), a Department of Energy research facility in the western suburbs of Chicago, is one of the largest high energy physics labs in the world. It is also the largest manufacturer of the world&rsquos single most expensive product. In a hybrid continuous and batch process, Fermilab produces and stores anti-matter particles called anti-protons.Fermilab is home to the Tevatron, the world&rsquos highest energy particle accelerator.

The Tevatron occupies a four-mile circular tunnel under the Fermilab grounds. It takes 150 GeV particles and accelerates them to an approximate energy of one TeV. The Tevatron is a colliding accelerator. It receives its beam, either protons or anti-protons, from the Main Injector. A normal shot setup consists of injecting bunches of protons followed by anti-protons into the TeV. These two "trains" of particles, protons and antiprotons, are accelerated in opposite directions and then forced to collide at certain points around the ring. The Tevatron can send beam, protons or anti-protons, back to the Main Injector. The Main Injector accelerator is housed in an elongated circle with approximately two miles of tunnel. It can accelerate particles with energies of 8 GeV up to 150 GeV.

The anti-matter beam is used for research, and for practical applications, including nuclear medicine. Fermilab&rsquos real-time process control system displays current values on its website, as well as in its control room.

            AN AERIAL VIEW OF FERMILAB
             

Because of the highly specialized nature of its manufacturing process, originally the Fermilab instrumentation engineers built their own controllers. As you walk through the corridors, however, you can see a nearly "geological" progression from custom hardware and custom software to customized Allen-Bradley PLCs and PanelView displays, and finally to COTS (commercial, off-the-shelf) equipment from AutomationDirect.com.

The two critical control parameters are electric feed into the system, and water flow to cool the enormous set of magnets that cause the anti-protons to go where they are supposed to go. Fermilab is installing a large number of Universal Flow Monitors&rsquo inexpensive Coolpoint vortex shedding cooling water flowmeters to measure this critical parameter.

Why would Fermilab&rsquos engineers use a "cheap flowmeter" to measure a parameter absolutely critical to their cutting edge, and very expensive, manufacturing process? David Peterson, Senior Engineer, said, "It isn&rsquot the cost of the device but the durability that we&rsquore looking for. It doesn&rsquot have to be accurate, either, as long as it is very repeatable. If we lose cooling water, the process is shot, we have to dump the particles and start all over again. These flowmeters, because they have no moving parts, are very attractive from a durability point of view." Peterson added, "We&rsquove been through a lot of expensive flowmeters here, so ask us in a year how well these worked."

Universal Flow Monitors developed the Coolpoint vortex flowmeter to fill a need for inexpensive flowmeters with no moving parts. "We saw that people had an aversion to buying mechanical flowmeters, such as we also manufacture," said UFM vice president Erik Rosaen. "And we also saw that for many applications like cooling water flow, flowmeters like vortex shedders were too expensive. So we deliberately set out to create a vortex shedding flowmeter that was only as accurate as it really needed to be."

             
Custom to COTS, from custom hardware to AutomationDirect PLCs.
 
           
While many manufacturers trumpet very high accuracy claims, and, in fact many applications require them, there also are many flow applications where repeatability, not absolute accuracy, is of paramount importance. Using this fact as a design criterion, "producing a device at 1% Full Scale accuracy cut our costs and made the device simpler and less expensive," Rosaen concludes.

The typical 1" Coolpoint flowmeter is priced at approximately $500, and with optional temperature sensor and transmitter, under $900. Typical vortex shedding flowmeters from more traditional manufacturers have accuracies of 1% of Reading, and sell for significantly more money.

Every time a vendor reduces the price of a process instrument, or introduces a lower overhead control system, it increases, sometimes tremendously, the number of processes that become "worth measuring." As this happens, new opportunities are created for cost avoidance, increased productivity, and even profit. This level of increased competition benefits the end user and the integrator greatly.

"The trend toward manufacturing less expensive flow sensors often includes a component of increased performance relative to the old sensor that is replaced ," said David W. Spitzer, consultant with Spitzer and Boyes LLC, "or sometimes increased durability. This is important for permitting more measurement points in the average process facility."

Sometimes, it is durability and repeatability that wins out, as David Peterson of Fermilab pointed out. But lower cost doesn&rsquot hurt.


Click the Download Now button below for a screen shot of the Fermilab website, showing realtime Tevatron status.
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