I recently recommended to a customer to turn their air pressure down on their system as low as their process would allow. Meaning regulate the pressure so you have enough to complete the operations needed but find that happy medium where your compressor isn’t working as hard to build those high pressures for no reason!
Compressed air is an amazing tool to have, and when used properly it can be more efficient that other non compressed air tools that run off electricity. How ever its pretty common to see compressed air systems running at their max just because.
Lowering the air system pressure reduces the compressor power consumption by about 1% for every two psi of lower pressure. Lowering the pressure also makes any unregulated operations reduce consumption by almost 1% for every one psi of pressure reduction. Not to mention the extra savings if your compressor system can turn down the compressor power because of the reduced flow and possibly shut off compressors that are no longer needed!
The best pressure at which to set your system is the level where your production can operate efficiently and effectively without waste: There is no right pressure—it depends on your operations and tools. You may have 90 to 100 psig at the compressor, but at the production machine, where the actual work is being done, you could have only 65 to 70 psig. In some cases, it may be even lower due to pressure drops in undersized piping, filters, regulators. The goal is to lower compressor discharge pressure without affecting the the operations at the end of the line.
Having artificially high plant-pressure can help you deal with surges in compressed air demand that might occasionally cause low-pressure and affect production. The higher pressure acts to store reserve air in the various volumes made up of receivers, pipes and such in your system. However, the higher pressure costs more to produce and makes unregulated end uses consume more air, which is an expensive trade-off. Another option is to make sure you have line pressure regulators at each point of use. This will allow you to regulate the operation to the pressure needed being sure to save compressed air and keep the over all system running more efficient.
The big thing that sets engineered products like EXAIR Intelligent Compressed Air Products apart from other devices is the engineering that goes into their design. Several principles of fluidics are key to those designs:
Bernoulli’s Principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in static pressure or a decrease in the fluid’s potential energy. It’s explained further here, along with details on how EXAIR products use it.
The one I wanted to discuss today, though, is the Coanda Effect, what it means for our engineered compressed air products, and what they can do for you:
The Coanda effect is named after Henri Coandă, who was the first to use the phenomenon in a practical application…in his case, aircraft design. He described it as “the tendency of a jet of fluid emerging from an orifice to follow an adjacent flat or curved surface and to entrain fluid from the surroundings so that a region of lower pressure develops.” Put simply, if fluid flows past a solid object, it keeps flowing along that surface (even through curves or bends) and pulls surrounding fluid into its flow. Here’s a demonstration, using an EXAIR Super Air Amplifier and a plastic ball:
What’s interesting here is that the Super Air Amplifier is not only DEMONSTRATING the Coanda effect, it’s also USING it:
EXAIR Standard and Full Flow Air Knives also have Coanda profiles that the primary (compressed air) flow follows, and uses, to entrain “free” air from the surrounding environment:
EXAIR Air Wipes can be thought of as “circular Air Knives” – instead of a Coanda profile along the length of an Air Knife, an Air Wipe’s Coanda profile is on the ring of the Air Wipe, which entrains surrounding air into a 360° ring of converging air flow:
So that’s the science incorporated in the design of our products. But what does it mean to the user?
Efficiency. Pulling in a tremendous amount of “free” air from the surrounding environment means minimal consumption of compressed air, while still getting a hard hitting, high velocity air flow.
EXAIR Corporation is committed to helping you get the most out of your compressed air system, and thanks to Mr. Coandă, that includes reducing your compressed air consumption and noise levels. If you’d like to find out more, give me a call.
Russ Bowman, CCASS
Application Engineer EXAIR Corporation Visit us on the Web Follow me on Twitter Like us on Facebook
EXAIR manufactures a variety of intelligent compressed air products that can cool, clean, coat, convey, and conserve. They’re designed specifically with enhanced efficiencies, OSHA safety, and high quality in mind. What could make our products even better? Making them movable, with the ability to aim them exactly where you need them! EXAIR offers Magnetic Bases and Stay Set Hoses to achieve this. In this blog, I will cover the features and benefits of both products.
Stay Set Hoses:
The Stay Set Hose gives you that possibility of manually adjusting and re-adjusting smaller EXAIR products like Super Air Nozzles and Air Jets. The hose has a “memory” function, and it will not creep or droop until you physically move it. They work very well in directing the air flows at specific target areas. The Stay Set Hoses come in lengths from 6” (15cm) to 36” (91cm), and they have threaded connections with either ¼” NPT male on both ends or with a 1/8” NPT female X ¼” NPT male thread. The hoses are made from reinforced synthetic rubber and have a pressure rating of 250 PSIG (17 bar). They can add versatility to our Safety Air Guns and Blow-off Stations. If you need positioning for precise blowing or adjustments for different targets, the Stay Set Hoses would be a nice addition to include with your EXAIR products.
If you need a solid mount to steel surfaces or to move your blow-off system to different locations, the Magnetic Base will allow you to do these functions. It has a 100 lb. (45.5Kg) pulling force to keep the blowing device attached firmly until you want to move it. They can be mounted in a vertical or horizontal position. EXAIR offers a single outlet Magnetic Base or a dual outlet Magnetic Base (for multiple blowing products). The bases come with a ¼ turn shut-off valve to easily turn on and off the compressed air to the EXAIR products.
If you want to combine the Stay Set Hoses and Magnetic Bases with your EXAIR Air Nozzles and Air Jets, we can create this with the EXAIR Blowoff System. We can combine multiple parts into a single model number. At EXAIR, we pride ourselves with great customer service and an “easy to do business” philosophy. You can contact a friendly Application Engineer to build an efficient, safe, and movable system just for you.
Heat. One word can bring to mind so many different things from cooking to sun tanning. But what is heat and how does it move. Heat is essentially a form of energy that flows in the form of changing temperatures; this form of energy will flow from high to low. When you describe something as being hot, you are actually describing that the item in question has a higher temperature than your hand thus the thermal (heat) energy is flowing from that object to your hand. This phenomenon is what is referred to as heat transfer. Heat transfer can be observed all the way down to the atomic scale with the property known as specific heat. Every molecule and atom can carry a set amount of energy which is denoted by specific heat; this value is the ration of energy (usually in Joules) divided by the mass multiplied by the temperature (J/g°C).
But how does this heat move from object to object? On the atomic scale, the atoms are storing the energy which will cause electrons to enter into an excited state and rapidly switch between shells. When the electron returns back to a lower shell (closer to the nucleus) energy is released; the energy released is then absorbed by atoms at a lower energy state and will continue until the thermal energy is equal between the two objects. Heat has four fundamental modes of transferring energy from surface to surface and they are as follows:
Advection Advection is the physical transport of a fluid from point A to point B, which includes all internal thermal energy stored inside. Advection can be seen as one of the simpler ways of heat transfer.
Conduction Conduction can also be referred to as diffusion and is the transfer of energy between two objects that have made physical contact. When the two objects come into contact with each other thermal energy will flow from the object with the higher temp to the object with the lower temp. A good example of this is placing ice in a glass of water. The temperature is much lower than the room temperature therefore the thermal energy will flow from the water to the ice.
Convection Convection is the transfer of thermal energy between an object and a fluid in motion. The faster the fluid moves the faster heat is transferred. This relies on the specific heat property of a molecule in order to determine the rate at which heat will be transferred. The low the specific heat of a molecule the faster and more volume of the fluid will need to move in order to get full affect of convection. Convection is used in modern ovens in order to get a more even heat through out the food while cooking.
Radiation Radiation is the transfer of thermal energy through empty space and does require a material between the two objects. Going back to the how thermal energy is released from atoms; when the electron returns to a lower energy shell the energy is released in the form of light ranging from infrared light to UV light. Energy in the form of light can then be absorbed by an object in the form of heat. Everyone experiences radiation transfer every day when you walk outside; the light from the sun’s radiation is what keeps this planet habitable.
EXAIR’s engineered compressed air products are used every day to force air over hot surfaces to cool, as well as dry and/or blow off hot materials. Let us help you to understand and solve your heat transfer situations.
If you have any questions about compressed air systems or want more information on any of EXAIR’s products, give us a call, we have a team of Application Engineers ready to answer your questions and recommend a solution for your applications.
Cody Biehle Application Engineer EXAIR Corporation Visit us on the Web Follow me on Twitter Like us on Facebook