Canned food has been around since the early 1800s, when the French government offered 12,000 francs (I don’t know how much that is in today’s currency, but it sounds like a LOT) to the first person to come up with a way to effectively and affordably preserve food, so the French army could take it with them during Napoleon’s planned conquest of Europe. Nicolas Appert, a candy maker and chef to the rich and famous, had been experimenting with cooking food inside sealed containers and noticed that it didn’t spoil if the seals didn’t leak. So he demonstrated his technique to the powers that be, and walked away with the 12,000 franc prize. It didn’t really pan out for the army because the process was slow & expensive, but canned food became something of a novelty among the aforementioned rich & famous of the day. This WAS the heyday of the Industrial Revolution, though, and food companies quickly advanced the technology for mass production. Today, there are very few food products that you won’t find a canned or jarred version of. In the early days, you had to use a can opener, but today you can find pull tabs on many cans, especially beverages.
Ever since Jimmy Buffett cut his heel on the one on the left in “Margaritaville”, we’ve been drinking from cans with ‘pop tops’ like the one on the right.
A more recent innovation is a peel-off foil seal on the lid that seals the product for freshness, immediately after packaging. It’s then removed by the consumer after purchase, and the container is commonly supplied with a plastic lid that snaps onto the rim.
A container manufacturer uses Model 3925 Adjustable Spot Cooler Systems with Dual Outlet Cold Air Hoses to rapidly cool the freshly heated sealed foil onto metal lids like those that are used for coffee cans. This allows them to move the lids from the heat sealing station to the next process faster.
From left to right: EXAIR Mini Coolers, Cold Guns, and Adjustable Spot Coolers come with Magnetic Bases for instant installation.
Because they generate cold air flow on demand, this is a very common application for EXAIR Vortex Tube Spot Cooler products. With no moving parts to wear or electrical components to burn out, they’re reliable & durable. If you’d like to find out more, give me a call.
Russ Bowman, CCASS
Application Engineer Visit us on the Web Follow me on Twitter Like us on Facebook
If you’re just looking to spray water or just about any water-like liquid, you’ve got plenty of options…among them, any EXAIR Atomizing Spray Nozzle. We’d just need to find the one with the flow rate and pattern size & shape you’re looking for. That’s something we can handle in a short phone call, or if you’re a control freak, do-it-yourself-er like me, you can use the spec sheets in our Atomizing Spray Nozzles catalog section.
For applications involving liquids with higher viscosity or suspended solids, we’re going to look at our External Mix Air Atomizing Spray Nozzles. Internal Mix models are limited to liquid viscosity of 300cP or less, and you can’t use Siphon Feds for liquids with higher than 200cP viscosity. While we don’t publish a maximum viscosity for the External Mix models, we have customers who successfully use them with 800cP viscosity liquids. They also have larger internal passages for superior performance with suspended solids.
Two of my favorite examples of applications involving these elements come from the food industry — the snack food sector, specifically. The first one is from a company that makes thin, light crackers called ‘crisps’ that come in different flavors, achieved by coating them with a variety of seasonings. To make the seasonings stick, they needed to spray a light coating of oil onto the surface of the crisps, immediately prior to sprinkling the seasoning onto them, and then baking it in. And they called EXAIR for help in selecting the right Spray Nozzle.
We started our selection of the External Mix line, not only because of the viscosity of the oil (it WAS close to 300cP, which ruled out Siphon Feds, and was close to the upper limit of the Internal Mix models) but also because, with an External Mix, the liquid supply pressure ONLY affects the liquid flow rate, and the air supply pressure ONLY affects the pattern size. So, since they had a VERY specific volume of oil to apply to each crisp, they could set the liquid supply pressure accordingly, and use the air supply pressure to spread it evenly & consistently onto each piece. We know it worked because they sent us a video of it:
Model EF9040SS 14.42 GPH 1/8 NPT No Drip External Mix Narrow Angle Flat Fan Atomizing Spray Nozzle
The other one came from a food production facility as well — this time, from a bakery that wanted to spray oil with a suspension of cheese powder onto dough before baking it. And the reason that the External Mix models are best for high viscosity liquids is the same reason they’re best for liquids with suspended solids. Namely, the liquid doesn’t have to go through a cavity between the Liquid & Air Caps where resistance to flow, either from viscosity or particulate, could cause problems. Since the dough was on a 12″ wide chain conveyor, we specified a Model EB1030SS 14 GPH 1/4 NPT External Mix Wide Angle Flat Fan Pattern Atomizing Spray Nozzle. It’s a fairly continuous run, so they didn’t need (or want) the No-Drip feature to turn the spray on & off. They simply shut the pump and the compressed air off when they’re done making the cheesy dough.
External Mix Atomizing Nozzles are ideal for higher viscosity liquids, and those with suspended solids.
And now…I’m hungry! But seriously, if you need to spray liquid of any kind, EXAIR probably has a Spray Nozzle on the shelf for that…give me a call.
Russ Bowman, CCASS
Application Engineer Visit us on the Web Follow me on Twitter Like us on Facebook
Right on schedule with the change in temperature as summer turns to fall, I woke up with a scratchy throat, runny nose, and a bit of fatigue this morning. I weighed my options for relief in the medicine cabinet: pain reliever/fever reducers, over-the-counter cold & flu medication that add cough suppressants, expectorants, and decongestants to the mix, homeopathic remedies with zinc, echinacea, all natural immune boosters, and a jar of honey for my tea or bourbon, depending on the time of day…and my mood. If my symptoms worsen, I can get tested for the flu or COVID, and may be prescribed antiviral medication. In any case, rest and hydration will likely be important factors in my recovery.
Much like my medicine cabinet, the Air Knives section of the EXAIR catalog has a selection of remedies for problems that can be addressed by a curtain of air. If the curtain of air needed is 36″ or less, we can consider any of the three styles of Air Knife we make: Super, Standard, or Full Flow. If it has to be more than that, the Full Flow Air Knives are out (36″ is their max length) but Standard Air Knives come in lengths up to 48″. Super Air Knives give us the most range here; they come in lengths up to 108″, and can actually be coupled together to provide uninterrupted curtains of flow in whatever length is needed.
Super Air Knives (left) come in lengths up to 108″, Standard Air Knives (middle) up to 48″, and Full Flow Air Knives (right) up to 36″.
Standard and Full Flow Air Knives come in aluminum or 303SS. Aluminum is lightweight and suitable for general purpose applications where high heat and corrosive elements are not a factor. Aluminum Air Knives are rated to 180°F. Type 303 Stainless Steel is suitable for mildly corrosive environments, and is rated to 800°F ambient temperatures.
Super Air Knives are available in aluminum and 303SS, as well as 316SS and PVDF. Type 316 Stainless Steel is stronger and more corrosion resistant than Type 303, and offers superior resistance to certain pitting, which makes it the best choice for food, pharmaceutical, and surgical product manufacturers. PVDF (polyvinylidene fluoride) Super Air Knives have Hastelloy C276 hardware and PTFE Shims. They provide superior corrosion resistance in more aggressive situations than Stainless Steel can like, like in electroplating, solar cell and lithium ion battery manufacturing, strong acid & caustic chemical handling, etc.
The first Air Knife developed by EXAIR was the Standard Air Knife (formerly known as the EXAIR Knife) and are still quiet and efficient alternatives to drilled pipes, manifolds with open-ended blowing nozzles, and blower-powered air knives. They use a Coanda profile (more on that in a minute) which causes the airflow to turn 90° from where it exits the linear nozzle formed by the shim between the cap & body. This primary air stream entrains surrounding air from the environment, resulting in a total developed airflow that’s 30 time greater than the compressed air consumption of the Air Knife. This entrainment creates a low velocity boundary layer, which reduces the sound level, but there still is some wind shear produced along the Coanda profile.
Because of the end ports in the relatively small profile of the body, there’s 1/2″ on each end where there’s no flow. Since we identify them by the length of the air curtain they generate, Standard Air Knives are physically 1″ longer than their published length (a Model 2012 12″ Aluminum Standard Air Knife has an overall length of 13″, a Model 2018SS 18″ 303SS Standard Air Knife is actually 19″ long, etc.) Full Flow Air Knives use a Coanda profile as well, but they have rear ports, so there’s full flow (as advertised) from end to end. Here’s more on how the Standard and Full Flow Air Knives work:
Compressed air flows through the inlet (1) to the Full Flow (left) or Standard (right) Air Knife, into the internal plenum. It then discharges through a thin gap (2), adhering to the Coanda profile (3) which directs it down the face of the Air Knife. The precision engineered & finished surfaces optimize entrainment of air (4) from the surrounding environment.
The latest, and greatest generation of engineered Air Knife in EXAIR’s arsenal is the Super Air Knife. As detailed above, they offer the most choices in length & materials. They’re also the most efficient, and quietest. Because the airflow exits straight from the linear nozzle formed by the shim gap between the body & cap, with no wind shear, the low velocity boundary layer produced by the entrainment of surrounding air means the sound level (with an 80psig inlet pressure) is a remarkably low 69dBA at a distance of three feet. Any style (Standard, Full Flow, or Super) Air Knife will perform just fine in just about any application that requires a curtain of airflow. If noise level, and/or operating cost, are on your mind, though, the Super Air Knife is certainly worth considering. With just a few details about the application, we can calculate the difference in operating cost for all three models of a given length, and provide you with the ROI (return on investment) for the Super Air Knife. If you’d like to find out more, give me a call.
Russ Bowman, CCASS
Application Engineer Visit us on the Web Follow me on Twitter Like us on Facebook
Leonardo Da Vinci (1452-1519) was the quintessential Renaissance Man: artist, philosopher, scientist, mathematician, and an inventor ahead of his time. From the 15th to 18th Centuries, though, he was primarily known for his paintings. Then, in 1797, Giovanni Battista Venturi published his “Essai sur les ouvrages physico-mathématiques de Léonard de Vinci”, which brought to light Da Vinci’s immense volume of work in the scientific fields of fluid dynamics and aerodynamics. Curiously, he was only able to do this because of the access he gained to notebooks that had been looted by Napoleon’s troops during their occupation of Milan, Italy, and brought back to France.
To conclude that Venturi was just a writer, though, would be as bad as regrettable as calling Da Vinci just a painter. Born into a rich family in northern Italy, he was a star pupil at the Jesuit seminary in his hometown of Bibbiano. He was such a good student that in 1756 – at the age of ten – he started attending the seminary in Reggio Emilia, studying logic, metaphysics, and mathematics.
As a teenager, he enrolled in the university there, studying physics and biology before returning to the seminary, where he was ordained as a priest in 1769. He taught logic at the seminary for five years, and then went on to “the big city” of Modena to teach philosophy and geometry at the university there. He was 28 when he started there, and by age 30 he was teaching physics as well.
In addition to his service in the priesthood and at the university, he also held the office of official state engineer, mathematician, and auditor, appointed by the Duke of Modena. This meant he was responsible for the construction of bridges, draining of marsh land, and implementing regulations for the building of dams. And, in his spare time, it seems he also completed the town of Modena’s historical memoirs, a task that had been started by the town historian, but had remained dormant since his passing, some 56 years earlier.
All of this would have earned Venturi local, probably regional, and perhaps even national fame…especially the part about making Leonardo Da Vinci famous for more than just his art. But what really sealed his place in the annals of history was his discovery of a particular fluidic effect: namely, that a reduction in fluid pressure results when a fluid flows from one section of a pipe into a narrower section.
The Venturi effect, named after the real Renaissance man who discovered it, Giovanni Battista Venturi who published a paper on it in 1794.
Despite its discovery in the late 18th Century, it was not actually practically applied for almost 100 years, when an American hydraulic engineer named Clemens Herschel patented a water flow meter, in 1889. He named it the Venturi Meter, and they became prolific in water works around the turn of the century. Coincidentally, Mr. Herschel had a background in bridge building too.
Today, there are numerous machines that use the Venturi effect: fluid moving educator pumps, gas inspirators in grills, stoves, & Bunsen burners, paint atomizers, wine aerators, locomotive engine steam injectors, sandblasting nozzles, scuba diving regulators…and vacuum generators.
That last one is where EXAIR gets involved. We incorporate Venturis into our E-Vac Vacuum Generators, which are capable of vacuum levels up to 27″Hg. They’re used for material handling, pick & place systems, bag/package opening, label placement, vacuum forming, and workholding, just to name a few.
The wide throat diameter of the Adjustable E-Vac makes it suitable for applications where small amounts of particulate and/or liquid may be drawn through.
They’re also used in our Reversible Drum Vac and EasySwitch Wet-Dry Vac Systems. These are just two selections from our extensive line of compressed air operated Industrial Housekeeping Products.
EXAIR Reversible Drum Vacs (left) can fill a 55 gallon drum with water in 90 seconds, using a powerful Venturi. Our Chip Trapper Systems (middle) incorporate a Reversible Drum Vac to vacuum coolant from machine tool sumps for filtration. The EasySwitch Wet-Dry Vac uses a Venturi as well for dry and liquid cleanup applications.
Giovanni Battista Venturi retired in 1813, but continued writing a number of scientific and literary works, including a collection of Galileo’s manuscripts & letters. He died in 1822, at the age of 75.
Russ Bowman, CCASS
Application Engineer Visit us on the Web Follow me on Twitter Like us on Facebook
