Fasteners: SAE, Metric, Titanium, Stainless. Yes, We Can Accommodate.

In a previous life I worked in the metal cutting industry on machines that were all imported to the USA. Every machine we brought in had to have the air inlets changed out to match the NPT ports that most of our domestic customers had within their facilities. This simply made sense, why force someone to change an air fitting or something as simple as that to match the rest of their facility. The option we did not offer was to change all the hardware on the machine to match the rest of the SAE sized hardware and limit the number of tools their staff needed. That didn’t make sense. Well, here at EXAIR we like to do things differently.

There are several companies that I deal with here who always prefer their air inlets be different, whether it be a metric BSP thread or a larger NPT thread, maybe a global thread, or even a special fitting like a taper lock fitting. No matter the needs, as long as it will physically fit on the product, chances are we can offer the fitting that will simplify installation. Even past the installation we like to look forward to the complete ownership of our products. Once a machine is located in a facility, what other types of fasteners are used, what is the rest of the machine tooled with. When working on a machine as a maintenance person or adjusting the operation, not having to struggle with determining which Allen wrench or hex size a bolt is and risk damaging the bolt can be extremely helpful.

Most EXAIR products come from stock with standard fractional hardware. We do offer a number of products with a BSPT air inlet and they are often available with the same expediency as our other stock products, same day on orders received by 2 PM ET that are shipping within the U.S. As mentioned above, we can customize a product with the fasteners of your choice, as long as they pass our design criteria. Some of the most common fastener changes I have seen are converting a Super Air Knife to an M6-1.0 threaded bolt rather than the stock 1/4-20 fastener. There are a multitude of other requests that I recall throughout the years. Some of the most intricate are listed and explained below.


Specialty Hardware

From left to right: M6-1.0 stainless steel bolt, a titanium hex-head bolt, a Hastelloy hex-head bolt, brass hex-head bolt, Kolsterized hex-head bolt, special acorn head fastener, Allen key flat-head bolt. Each of these fasteners has been used within a custom configuration to meet a specific need, whether it be simply to match the metric or SAE hardware in the rest of the machine or to meet the demands of the environment they are going into. The bottom row are, integral star washer nut, serrated safety washer, and spring washer. Each of these has, again, been requested by a customer to meet the design and safety standards they have a requirement for. These are just a sampling of the custom hardware we have used over the years to support our customer base and fill their need with product that meets their standards.

If you would like to discuss custom hardware in a stock product or even a full on custom point of use compressed air product, the Application Engineer team here is ready to help. Contact us and we will do our best to understand what your need requires and offer a solution to fit.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

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.

1 – Venturi

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.

2 – Venturi Patent

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

2 – United States Patent and Trademark Office – Benz, Karl, Carburetor – Retrieved from https://pdfpiw.uspto.gov/.piw?Docid=00382585&homeurl=http%3A%2F%2Fpatft.uspto.gov%2Fnetacgi%2Fnph-Parser%3FSect1%3DPTO1%2526Sect2%3DHITOFF%2526d%3DPALL%2526p%3D1%2526u%3D%25252Fnetahtml%25252FPTO%25252Fsrchnum.htm%2526r%3D1%2526f%3DG%2526l%3D50%2526s1%3D0382,585.PN.%2526OS%3DPN%2F0382,585%2526RS%3DPN%2F0382,585&PageNum=&Rtype=&SectionNum=&idkey=NONE&Input=View+first+page

Centrifugal Air Compressors: How Do They Work?

Centrifugal air compressors are one example of dynamic style air compressors. The dynamic type of compressors have a continuous flow of air that has its velocity increased in an impeller that is rotating at a higher speed. The kinetic energy of the air is increased due to the increase in velocity and then becomes transformed into pressure energy through the use of a volute chamber, or a diffuser. The volute chamber is a curved funnel that increases in surface are as it approaches the discharge port. This converts the kinetic energy into pressure by allowing the velocity to reduce while the pressure increases. Approximately 1/2 of the energy is developed in the impeller and the other half is developed in the volute chamber or diffuser.

1 – Basic Centrifugal Air Compressor

The most common centrifugal air comppressor has between two and four stages in order to generate pressures up to 150 psig. A water cooled inter-cooler and separator is placed between each stage in order to remove condensation and cool the air down prior to being passed on to the next stage. These compressors still have advantages and some disadvantages. The list below showcases just a few.

Advantages:

  • Lubricant-free air is generated
  • Complete packages up to 1,500 hp
  • Initial costs decrease with increase in compressor size
  • No special foundations or reinforcements needed

Disadvantages:

  • Specialized maintenance requirements
  • Higher initial investment
  • Unloading/waste of air required to drop system pressures

To determine which type of compressor may be best suited for your facility, we suggest to locate and contact a compressor sales company in your geographic area. When it comes to determining the volume of air required to operate the EXAIR products and even some other point of use compressed air applications, EXAIR’s Application Engineers can help you determine the volume you will need to ensure the compressor is sized appropriately. If you would like to discuss any other point of use application, please contact us.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

1 – Dugan, Tim PE – Basic Centrifugal Air Compressor, Compressed Air Best Practices; retrieved from https://www.airbestpractices.com/technology/air-compressors/centrifugal-air-compressor-controls-and-sizing-basics

Additional Benefits To The Adjustable E-Vac Vacuum Generators

The EXAIR Adjustable E-Vacs are available in 4 different sizes to fit whatever your pick and place, vacuum holding, degassing, or vacuum evacuation process may call for. These units have been used in a multitude of applications and the Adjustable factor makes them versatile enough to fit a production line with changing needs.

These are all examples of how an E-Vac pick-and-place system is just a solenoid valve away from automation.

The Adjustable E-Vacs have a few benefits that may go unnoticed if one is not keen to exactly how they are constructed and function. This sets them apart from many vacuum generators. When dealing with vacuum generator applications such as pick and place, having a part that is always the same is easiest. This is not always the case. Sometimes it is not just the dimensions of the part that changes, sometimes the material changes or even the surface finish of the part. This is where the ability to change from a porous to non-porous vacuum generator is extremely helpful. Generally this means the material of the parts getting picked up will allow air flow through them (paper, cardboard, wood) or not (plastic, glass). A porous vacuum generator will pull more flow through the part material to hold the vacuum, a non-porous vacuum generator will pull less flow and achieve higher vacuum levels.

To better understand the difference between porous and non-porous, we’ve written about that. Check out Tyler Daniel’s blog on the difference between the two here. The beauty of the Adjustable E-Vac is that it can easily convert from porous to non-porous with a simple adjustment. This is a great feature for a job shop that may change materials they are cutting or engraving on their machines and need to adapt in a moments notice for the job at hand. This could also reduce the number of vacuum generator variances a store room may need to keep on hand for a series of production lines and help to reduce the chance an incorrect model is installed on a machine due to fewer variants.

Adjustable E-Vac

Another benefit which can be helpful in a production environment that has an E-Vac picking up dirty or debris ridden material is that the Adjustable E-Vacs can be disassembled and cleaned. Picking steel sheets off a laser cutter in order to remove the scrap that has a volume of spatter / dust can cause an accumulation of debris on the internals of any vacuum generator. By unscrewing the plug from the body the Adjustable E-Vac can be easily cleaned and all passageways maintained at a level to offer continual performance.

No matter what, the adjustability coupled with minimum components and fastener free disassembly of the unit are two great features that can help minimize machine downtime, lower number of parts kept on hand for machines, and ensure optimal performance no matter what the requirement is for the vacuum generator. If you would like to discuss further, please contact us.

Brian Farno
Application Engineer
@EXAIR_BF
BrianFarno@EXAIR.com