Giovanni Battista Venturi: A Real Renaissance Man

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
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About EXAIR’s Reversible Drum Vac™

Looking back at my plastic injection molding days we would occasionally experience a hydraulic hose failing. Anyone who has witnessed this knows it can create quite a mess. If only I knew about EXAIR and their Reversible Drum Vac™ (RDV) back then as it would have made the cleanup process so much easier.

The RDV is a purpose built, compressed air driven, high powered vacuum used to empty and fill coolant sumps and clean up spills. It can fill a 55 gallon drum in less than 2 minutes and can attach to closed head 30, 55 or 110 gallon drum. Once the drum is full this same stainless steel pump can be emptied by a simple turn of of a knob. The RDV does not use electric and has no moving parts, assuring maintenance free operation. An automatic safety shutoff valve prevents spills or overfilling.

The RDV is, hands-down, a workhorse of a product. It has been relied upon for 30+ years to empty and fill coolant sumps on metal working machines. They function time and time again in machine shop environments with very little to zero maintenance required. If they should diminish in performance, they can be returned back to new condition in the field – most of the time. You can rely on these rugged and effective vacuums for decades.

EXAIR has a Mini (5 gallon) RDV System that delivers the same two-way action for small jobs. It comes complete with a 5 gallon drum and all the tools.

5 Gallon RDV System

EXAIR has other Industrial Housekeeping products that can be found at www.EXAIR.com. If you need help with attachments or replacement parts please contact any of our Application Engineers.

Eric Kuhnash
Application Engineer
E-mail: EricKuhnash@exair.com
Twitter: Twitter: @EXAIR_EK

Intelligent Compressed Air: What You Need To Know About Deliquescent Dryers

Moisture free air is a “must” for industrial use, for a number of reasons:

  • An awful lot of distribution systems incorporate iron pipe. It’s inexpensive, readily available, easy to work with, rated for pressure, and has a long history of successful installations. Iron pipe will also oxidize (make rust) in the presence of water:
Here’s what we find a lot of the time inside a Reversible Drum Vac that’s been sent in for refurbishment because it’s not drawing effective vacuum anymore.
  • Regardless of what your distribution lines and components are made of, water droplets can erode them. Compressed air itself is a gas; it follows the curves in elbows, and flows around valve discs & regulator diaphragms. Water droplets, on the other hand, run full speed INTO those things, often at high velocity. This eventually causes pitting, which is bad enough…those pits, though, are little pockets for salts, acids, or alkalines to effect their destructive little chemical reactions.
  • When used for blow off applications, anything in your compressed air will get on anything you’re blowing off. If the intent is to remove moisture from a surface, moisture in your compressed air supply decidedly works against your goal.
  • Water can freeze as it is carried along with air flow through orifices. This can quickly block the flow of air. The US Navy lost a submarine, USS Thresher (SSN-593) and all hands in 1963. A number of factors contributed to the sinking, but a significant one was that compressed air being blown into the ballast tanks (to create negative buoyancy) had higher than permissible moisture content, and froze in orifice plates in the lines. The ballast tanks stayed full of water, and 129 sailors & shipyard personnel died as the boat passed crush depth.

There are a number of types of air dryers that are commonly fitted to industrial air compressors to take care of moisture problems. The least expensive one of these is the Single Tower Deliquescent Dryer. Here’s how they work:

Deliquescent dryer: how it works (1)
  • Incoming compressed air enters near the base, where a form of mechanical separation occurs…the air flows back & forth, around trays of desiccant.  The simple act of changing direction causes some of the water to just fall out and collect in the bottom.
  • The air then flows upwards through the desiccant bed. The desiccant in a deliquescent dryer absorbs moisture (as opposed to the adsorption that occurs in a regenerative desiccant dryer) until they get so wet, they dissolve.
  • After the desiccant does its job, moisture free air flows out the top, and gets on with it’s work.

In addition to the low price tag, other things to like about them are:

  • Low pressure drop.
  • No moving parts or electrical components.
  • Can be used outdoors, and in hazardous, mobile, dirty, or corrosive environments.

Of course, there are things to NOT like about them as well:

  • Limited suppression of dew point – because they are drying the air to a specific relative humidity, as opposed to a specific dew point, the attainable dew point is dependent on the incoming air temperature, the chemical composition of the desiccant salt, and the ambient temperature where it’s installed. Unless you use some sort of specialty salt desiccant, the typical dew point is only 20-25ºF lower than the air inlet temperature.
  • Desiccant carryover – speaking of those specialty salts, they’re even more corrosive than the basic sodium chloride that’s often used. Any carryover will wreak havoc on your distribution system and air operated devices.

Deliquescent dryers’ particular set of “pros and cons” presents challenges for their use in industrial settings, for sure. But if the primary concern is preventing pipes from freezing up, then their low cost, low maintenance, and simplicity make them a great choice.

At EXAIR Corporation, we’re keen on compressed air efficiency. The attention to detail we pay to our products – from design, to manufacturing & assembly, to availability, and right on through to technical support – bears out our commitment to helping you get the most out of your compressed air system. If you’ve got questions, we can talk about this all day long…and most of the time, we do. Give me a call.

Russ Bowman, CCASS

Application Engineer
EXAIR Corporation
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Image courtesy of Brian S. Elliott, Wikimedia Commons Creative Commons Attribution-Share Alike 4.0 International License

The Case For The High Lift Reversible Drum Vac

If you need to fill -and empty – a drum with water, or water-like liquid quickly and easily, there’s really no quicker – or easier – way to do it than the EXAIR Reversible Drum Vac.  They’ve been around for decades, and are successfully used in a wide variety of applications.  The Reversible Drum Vac pulls a -96″H2O suction head on a 5, 30, 55, or 110 gallon drum, which makes it ideal for a number of typical Industrial Housekeeping or fluid handling applications.

EXAIR Reversible Drum Vac Systems come in a variety of sizes and configurations to meet the needs of most any application.

In cases where the liquid has a higher viscosity, or is below grade, the High Lift Reversible Drum Vac was developed with those exact situations in mind.  It generates a -180″H2O suction head, and comes with a 20ft vacuum hose.  Since its introduction, the High Lift Reversible Drum Vac has been successfully implemented in numerous uses where the extra suction head has been key:

  • A maker of bottled condiments (think barbecue sauce- or ketchup-like consistency) uses them to clean up accidents when bottles are overfilled, or a conveyor malfunction results in dispensing a bottle’s worth of condiment when there’s not a bottle under the nozzle.  The 20ft hose gives them the reach to service several production lines from one centrally located drum, and the two way pumping action allows them to easily pump the drum into their waste collection system.
  • A precast concrete company uses one for various cleanup applications.  The High Lift RDV‘s suction head is needed, in particular for their hydraulic oil leaks & spills.
  • A ferry operator uses one to clean out the engine room bilge.  They put the High Lift RDV on a deck above the engine room…the 20ft hose extends down to the bilge to pump it out, and when the drum is full, it reaches to the main deck so the drum can be emptied into their waste recycling company’s receptacle.
  • A construction company uses one to clean up the slurry created during concrete cutting operations.  The High Lift RDV is able to keep up with the slurry from even their largest saws, and the 20ft hose allows them to keep the drum conveniently out of the cutting area.

EXAIR High Lift Reversible Drum Vac Systems come in different configurations for 30, 55, or 110 gallon drums.

EXAIR Corporation has a variety of Industrial Vacuums to meet most any cleanup need.  They’re all compressed air operated, which means they have no electric motors to burn out, or moving parts to wear out.  If you’d like to find out more, give me a call.

***Order before 5/31/2021 and get a FREE Vac-u-Gun with any qualifying Industrial Vacuum System purchase***

Russ Bowman, CCASS

 

 

 

Application Engineer
EXAIR Corporation
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