Fluid Dynamics – Laminar Flow – Turbulent Flow – Transitional Flow & Particle Reduction

Fluid Dynamics – Laminar Flow – Turbulent Flow – Transitional Flow & Particle Reduction

In physics and engineering, fluid dynamics is used to describe the flow of fluids – liquids and gases. For the sake of this discussion, it includes the subset of aerodynamics, which is the study of air and other gases in motion. Many clean room consultants chagrin at the idea of using compressed air movement inside of a clean room that was developed using Laminar Flow techniques. Laminar air flow by design is intended to be slow, smooth regular paths of an air pattern traveling from entrance to exit. The air then travels back through the pre-filters, to the laminar flow filters and back into the room as part of the air change rate per hour. Laminar air low patterns are important to keeping particulate moving out of the clean room, but what if products being process inside of the clean room are already contaminated with particles that could come from people, other items that were brought into the space or that were created by the process itself.

In order to clean particulate from a device, component or packaging material, compressed air devices are necessary. The air devices are typically in the form of ionizing air guns, blowers, nozzles or air knives. These air tools cause turbulent flow, which is fluid motion that agitates the parts and creates eddies, which are violent swirling motions caused by the position and direction of turbulent flow. Eddies can transport mass, momentum and energy across different regions of the flow, with a result being clean, static-free parts. Heat transfer also happens in turbulent flow. So why is heat important? With heat, the flow resistance decreases, making it easier to clean parts. The process of laminar flow becoming turbulent is known as laminar-turbulent transition. It is also known as transitional flow.

Is there a happy medium between using compressed air and maintain an acceptable level of laminar flow? Can we agree that compressed air is a requirement and that compressed air is turbulent? Static Clean believes in the idea of “Controlled Turbulence”. The placement of Static Clean Particle Trap® Systems, in conjunction with compressed ionizing air devices means that the turbulence is localized, particles are captured and removed from the process and the products and parts are clean. By using an ionizing air gun or similar device in front of a Particle Trap®, the debris is directed into the flow of these source capture systems and delivered into the filter media and not back into the clean room to re-contaminate cleaned parts.

It’s That Shocking Time of the Year

It’s That Shocking Time of the Year

Ethanol; Intoxicating or Explosive?

This week, especially because it’s December and so close to the Christmas holiday, I worked on an alarming application that involved a static hazard. 100% ethanol was poured from a plastic container, which held approximately 5 gallons of the liquid, into smaller or larger containers that were also made of plastic.  Ethanol is a colorless, volatile liquid.  Most people recognize it as the ingredient in liquor, which has an intoxicating effect on most people.  However, it is also used as a solvent which can ignite under certain conditions.  Static electricity is one of the three components necessary to create an event, which is a soft way of saying an arc-over, a fire or an explosion.  The other two ingredients are oxygen and a volatile vapor.

There are well established protocols for handling and working with ingredients that can go “boom in the night”.  The front line of defense in protecting oneself from mishaps is grounding everything that is capable of being grounded. If we take a simplistic approach and look at the world as being made of only two materials, insulators and conductors, you can get a better sense of safety procedures that will keep to us out of harm’s way.  Metal is a conductor and easily grounded by clamping onto a known building ground or electrical ground or even by driving a rod deep into the earth.  Hence, we call it an earth ground. A water pipe inside of a facility can also act as a good ground source.  By grounding the metal, electrons can flow through the metal to ground itself. Conversely plastic cannot be grounded. This is why my static application hit a bump in the road. Static is generated on plastic materials through friction which we call Tribocharging.  There are a myriad of types of plastic, but for the most part, assume that all plastics are huge static generators.  Plastics are insulators and not conductive so the energy generated by simply handling plastic stays on the surface and can be a source of ignition.

Static Hazard

In my static hazard application, an ungrounded person holding the ethanol picks up an ungrounded plastic container and pours it into another ungrounded container.  This is not a good situation.  During the pouring process, a potentially explosive, volatile vapor cloud forms around the pouring action in both the dumping container and the receiving container.  There are three possible opportunities that can cause ignition in this scenario: a discharge from the ungrounded tech who is pouring the flammable ethanol; a discharge from static on the container which is high enough in proximity to the vapor cloud which forms in the discharging plastic container; a discharge from static to the same cloud that can form in the receiving plastic container.  If a static charge is present, with enough energy behind it, there is a strong chance that any of these actions can create a safety hazard.   

A Grounding Solution

Finding a solution to this problem can be a bit tricky.  The basic approach is to ground everything that can be grounded or switch to materials that can be grounded.  Simply switching from plastic containers to metal is a huge step in the right direction.  There will be times when grounding is not possible and materials cannot be changed.   In that case, ionization is the only choice.  There are approved ionizing static bars and blowers that remove or greatly reduce static electricity on plastic materials.  Static Clean and Fraser AntiStatic Techniques of England have formed a strategic alliance / partnership to address these dangerous scenarios.  When you have concerns about your facility and the safety of workers who may be in harm’s way, please reach out to Static Clean for help.   At this special time of year as with any time of year, it is important to always think “safety first”.

Static Innovates for High Reliability

Shocking Technology!

Static Clean International has developed a new breed of transformer-based high-voltage line-frequency AC power supplies (e.g. TSN75A and TNS75E 7500Vac PSs) relying upon patent-pending technology for application in ionizing equipment. This new technology has been so far applied within SCI static-neutralizing equipment systems and within SCI ionizing blowers.

The longstanding conventional technology within the industry relies upon the use of sound-muffling and corona-resistant materials to pot over the underlying iron-core transformer. The high-voltage secondary winding of the iron-core transformer generates partial discharge of encapsulated air bubbles at normal operating voltages. This limits MTBF of such equipment due to eventual chemical breakdown of the organic polymers subjected to the continuous slow and insidious damage from corona.

The user HV connections (if applicable, as in some static-neutralizing systems with HV-cable user-mounted components) in the conventional power supplies also require proprietary methods and tooling to fabricate the secondary section of the transformer that are only used within the ionizing equipment industry for the most part.

Warning! High Voltage..

SCI’s new technology is a form of resistive coupling between transformer secondary winding and ionizing electrodes circuitry. It enables the use of more common transformer fabrication methods and raises the partial-discharge inception voltage (aka PDIV) to levels above normal operating voltage for the equipment. It provides some regulation (i.e. high-voltage stability) for non-ferroresonant HV transformer topologies, and it enables the quick-connect/disconnect de facto standard (threaded spring-contact) for ionizing equipment systems that contain a user-mounted HV-wire component as well as similar equipment-internal spring-contact HV connections that are desirable for assembly and reliability.

We at SCI believe that a superior cost-performance-quality trade-off can be achieved with the new transformer/resistive-coupling methods for some products, and are continuing with ongoing new product development based upon this proprietary technology and provides a high reliability solution.  New products in the field have demonstrated excellent robustness with respect to the common failure mode of HV-secondary dielectric breakdown.

When Is It Time To Hang It Up?

That’s All folks!

I was chatting with a friend/customer the other day and asking him if he was still playing hockey in a men’s no-check league. His response was that it was “time to hang it up”. It got me to thinking about all the things we do in life where we can use or connect that phrase.

The obvious meaning of hang it up is to stop doing something that you’ve done for a long time. How about hang it up as in hat, coat, phone, pictures, and decorations.   The gloomier side of the phrase can mean break-up, bring to a close-like a chapter in one’s life- and cease, which has very strong connotations, but the one that I like the most is “bag it”.   Many of us have used the phrase, “why don’t you bag it” on people we know. From watching detective TV shows involving criminal investigations and forensics, “bag it” refers to putting evidence in a sealed bag or container.

Plastic, All Wrapped Up?

There are many kinds of bags and containers that are produced every day in factories throughout the world.   They can be either converted film, blow molded containers, injection molded boxes or cast materials, but can you imagine not having a plastic storage bag or container to keep food in the refrigerator?   While we all try to be “green”, the plastics converters are working to make improvements with bio-degradable, engineered materials, but the reality is that plastic bags and containers are creature comforts that make our lives easier and will be around for a long time.

Most plastics come from petroleum based resin, that by the time it becomes a finished product on the various machines, it has been subjected to high amounts of static electricity. These unwanted static charges can cause defect in the materials, lost production because of having to run the equipment slower than possible, particle attraction which reduces quality and jamming in the process, which causes down-time and lost profits. Static Clean provides many types of ionizing air products that reduce the ill effects of static electricity. They are available in the form of static bars, blowers, nozzles, air knives and cleaning systems.

In time, the choice of materials will lean more towards environmentally friendly resins that may not cause static levels that are harmful, but until then Static Clean can help improve the process, because most of us would have to agree that it is not quite time yet to “Hang It Up” when it comes to creature comforts like plastic bags.

Where Have All the Good Times Gone?

Questions, Answers and  a Tidbit about Life and Business:

Where have all the golfers gone?

About 10 years ago the golf industry hit its peak. Golf balls, golf clubs, and related clothing products flew off the shelves. That has all changed now, with fewer players entering the sport. The decline is not really attributed to a lack of interest, but the time it takes away from family and the skyrocketing costs of a round of golf, its equipment and appropriate attire. The World Golf Foundation claims that in 2005 over 30 million participants played over 550 million rounds of golf. In 2014, the number of players shrunk to 25 million participants playing 465 million rounds. The fallout will have a financial impact on many suppliers to the game.

Speaking of suppliers to the game, with the support of Monroe Electronics, one of our long-standing suppliers, we worked on an “Early Warning” lightning-detection system for golf courses that was based on an electrostatic field meters that are commonly used to measure static in industrial applications, especially the plastics industry. Golfers running around an open course with metal sticks in their hands during a lightning strike is not a wise decision. The decline in the number of golfers is not our fault!!

Where have all the Rich Folks gone?

Obviously, they are still playing golf, but physically they are starting to relocate. I was watching the Tonight Show about two years ago and his guest was Will Smith. They showed a clip of Will Smith from a French TV interview, where Will said that he was okay with paying higher taxes as they do in France. He was shocked when told that the President of France has advocated a 75% tax rate for those making more than one million euros. Has Will Smith changed his line of thinking? Wealthy people are no longer bound by country.

The billionaire founder of Facebook fled to Singapore and gave up his US citizenship, as did 1700 rich Americans last year who left the US, and the trend is growing.

At the same time, the new rich that are coming out of Russia and China want to come to America. There has been quite a bit in the news lately about Russia controlling an increasing amount of the world’s supply of plutonium (an element used in nuclear weaponry), but little is heard about Russia controlling Polonium-210. Polonium was discovered and isolated in 1898 by Marie and Pierre Curie in Poland, and was produced in the United States during World War II, as part of the Manhattan Project that developed the first nuclear bomb. It gets its name from the Latin word for Poland, which is Polonia. How about the fugitive Russian officer, Alexander Litvinenko, who didn’t agree with Putin. He died in the UK when someone dropped a couple of chips of P-210 into his drink and he died from radioactive poisoning. Today, common uses for safe versions of P-210 include anti-static devices, but when the US gave up production of Polonium, it left Russia as the main producer of the radioisotope. It is produced in nuclear reactors and it has the chemical symbol of Po.

 What was the Bonfire of the Vanities?

Not the book or the movie, but in real life, these were real bonfires. Throughout the 1400s some of the strict religious in Italy wanted to purge the world of sinful pursuits. They advocated for the destruction of clothing, jewelry, and priceless works of art. The largest of such fires took place in 1497 in Florence, Italy, the home of the Italian Renaissance and Leonardo Da Vinci. Citizens were required or forced to bring their valuables to the town square or piazza to be thrown into huge pile for burning. Talk about a sin!! On a related subject, static electricity discharges can cause fires and other devastation, but to intentionally destroy world class art is completely ridiculous.

Where have all the Static Companies Gone?

In an effort to tie this all together, I would say that business in many instances follows the ebb and flow of society. Businesses are born and die based on demographics, trends, movement to regions of lower labor costs, to be closer to raw materials and of course, operating in a mature market. About 25 years ago, there were close to twenty US-based manufacturers of anti-static devices. It doesn’t mean that globally there are fewer players, but in the USA you can count the number of ionizer device manufacturers on one hand. Mergers, acquisitions, consolidations, outright closures, and a migration towards the emerging markets, especially Asia, are the major reasons for the number of companies. Static Clean remains one of the last suppliers who rely on strong customer relationships for its continued survival and continued success. Please consider Static Clean for all of your static control needs, so that we don’t have to one day ask the question, “Where have all the good times gone”?

Swiss Made Movement Is Not a Dance, But a Quality Standard

Can a gadget get too small?

In the world of micro-electronics and the trend towards miniaturization, I don’t think we can put the Genie back in the bottle. We seem to be driven to pack the maximum amount of goodies into the smallest of spaces. When we use smart phones, and other digital devices we tend to hold them closer to our eyes than we would a book or magazine. The reality, according to a 2011 study by Dr. Mark Rosenfield of the New York School of Optometry, is that when we use these small devices we blink less, causing a natural decrease in tear production, thus we get eye fatigue. Now think of the employees who have to actually assemble these small but sophisticated products or worse yet, watches. They have to keep a keen eye to the task at hand.

What is Swiss Made?

We’ve all seen the special headband-style magnifying glasses that jewelers use. They need to be able look into the tight confines of the watches, with all of their gears and moving parts. High quality watches are synonymous with claiming to have a Swiss Made Movement, but what does that actually mean? There are four rules in being able to claim Swiss Made Movement.

  1. Must be 100% made in Switzerland.
  2. 60% of the overall value of the watch must be from Swiss Made Parts.
  3. The watch movement must be encased in the outer case in Switzerland.
  4. All quality control and inspections have to be done in Switzerland.

In an effort to maintain accurate movement of a Swiss Watch, it is important to make sure that it is free of particles or debris that can get into the wheels and gears. Static Clean offers the Piezonizer compact, lightweight, ANZ-SC3 Pencil Type Ionizer that delivers ionized air into the nooks and crannies to create a quality product while providing relief to the technicians who spend hours in assembly.