## Carburetors and Venturi Tubes: Thank You Giovanni Battista Venturi

I know it has been a little while since I blogged about something with a motor so it should be no surprise that this one ties to something with a combustion chamber. This all starts with an Italian physicist, Giovanni Battista Venturi. His career was as a historian of science and a professor at the University of Modena. He gave Leonardo da Vinci’s creations a different perspective by crediting da Vinci to be a scientist with many of his creations rather than just an amazing artist. He then began to study fluid flow through tubes. This study became known as the Venturi Tube. The first patents in 1888 came to fruition long after Giovanni passed away. So what was this Venturi effect and how does it tie in to carburetors let alone compressed air?

The illustration below showcases the Venturi effect of a fluid within a pipe that has a constriction. The principle states that a fluid’s velocity must increase as it passes through a constricted pipe. As this occurs, the velocity increases while the static pressure decreases. The pressure drop that accompanies the increase in velocity is fundamental to the laws of physics. This is another principle we like to discuss known as Bernoulli’s principle.

Some of the first patents using Venturi’s began to appear in 1888. One of the key inventors for this was Karl Benz who founded Mercedes. This is how the Venturi principle ties into combustion engines for those that do not know the history. This patent is one of many that came out referencing the Venturi principle and carburetors. The carburetors can vary considerably in the complexity of their design. Many of the units all have a pipe that narrows in the center and expands back out, thus causing the pressure to fall and the velocity to increase. Yes, I just described a Venturi, this effect is what causes the fuel to be drawn into the carburetor. The higher velocity on the input (due to this narrowing restriction) results in higher volumes of fuel which results in higher engine rpms. The image below showcases Benz’s first patent using the Venturi.

While carburetors slowly disappear and now can mainly be found in small engines such as weed eaters, lawn mowers, and leaf blowers, the Venturi principle continues to be found in industry and other items. Needless to say, I think Giovanni Battista Venturi would be proud of his findings and understanding how monumental they have been for technological advancements. For this, we will recognize the upcoming day of his passing 199 years ago on April 24, 1822.

Brian Farno
Application Engineer
BrianFarno@exair.com
@EXAIR_BF

1 – Thierry Dugnolle, CC0, Venturi.gif, retrieved via Wikimedia Commons https://upload.wikimedia.org/wikipedia/commons/1/16/Venturi.gif

## Internal Mix Atomizing Spray Nozzle Used In Feed Additive Process

Last week I took a call from an agricultural customer looking to replace the spray nozzle used in their feed additive process. The soy oil/beeswax solution they are applying to the feed, is slightly viscous (close to 100 cP) which seems to be clogging the tight clearances inside the current nozzle, resulting in varying flow rates and an erratic spray pattern. They had tried to contact the current manufacturer several times for a solution but were unhappy with the lack of assistance they were receiving, not to mention the long lead times of 6-8 weeks for a replacement.

After further discussion, they confirmed they weren’t as concerned with the flow rate or spray pattern, as they were with the nozzle potentially getting clogged.  They were able to obtain some internal dimensions of the existing nozzle and after further review, I recommended they use our Model # AF1030SS Internal Mix Flat Pattern Atomizing Nozzle as a replacement. This nozzle has larger inside diameters which would reduce the potential for clogging. Our Internal Mix Atomizing Nozzles mix the liquid and air inside the air cap and produce the finest atomization. The flow rate can be changed by adjusting the control valve on the nozzle and/or by adjusting the liquid pressure. Internal Mix nozzles are capable of handling fluids up to 300 Centipoise. All of our Atomizing Nozzles are In STOCK, so delivery is never an issue.

When considering an Atomizing Nozzle for an application, there are some general parameters that can be helpful in making the best selection.

1. Do you have a pressurized liquid source?
2. What is the fluid viscosity?
3. What spray pattern best fits the process?
4. How much flow (GPH/LPH) do I need?

If you have an application requiring a fine mist of atomized liquid spray, please contact an application engineer for assistance.

Justin Nicholl
Application Engineer
justinnicholl@exair.com
@EXAIR_JN

## EXAIR No-Drip Atomizing Spray Nozzles Recognized By Plant Engineering

If you follow our blog, Twitter, or Facebook pages, you may have seen us mentioning recent nominations for Plant Engineering Product of the Year Awards.  2015 will mark the 28th anniversary for this award, in which Plant Engineering readers select the most outstanding new products that help them do their jobs smarter, safer, more efficiently, and more productively.

Considering the pre-qualifiers for such an award, it makes sense that EXAIR products would show up, and show up repeatedly.  This year our No-Drip Atomizing Spray Nozzles have been nominated as a finalist in the Fluid Handling category.

Products in this field are recognized to present improvement potential, allowing users to create a more innovative process.  EXAIR No-Drip Atomizing Spray Nozzles do so by providing effortless integration of controlled liquid spraying.

Compressed air and pressurized (or non-pressurized) liquid are plumbed to the nozzle.  When compressed air is flowing, liquid will flow as well.  When compressed air flow stops, liquid flow stops.  Immediately.

For an end user of this product, this means that a precise volume of a specific liquid can be sprayed in a given time (duty cycle), with complete control before, during, and after nozzle activation.

The key to adding this innovation rests in the proprietary, patented (#9,156,045) design  of EXAIR’s No-Drip Atomizing Spray Nozzles.  Our engineers have worked tirelessly to create a stand-alone nozzle capable of controlling liquid flow without requiring a liquid control solenoid.

The viability of these nozzles has been recognized by Plant Engineering as an innovative new product in 2015.  If you agree and would like to cast a vote for EXAIR, please click here.

We thank you for your readership and, hopefully, for your support in this competition.

Lee Evans
Application Engineer
LeeEvans@EXAIR.com
@EXAIR_LE