EXAIR Corporation’s Research & Development team often finds themselves at odds with our Marketing department, who thinks R&D, through their constant introduction of new ideas & products, is trying to turn our catalog into something resembling a phone book.
I do not believe that is their aim or intention, though (and to be fair, Marketing doesn’t either.) Honestly, we just want to help folks in a wide range of industries solve problems. And a diverse range of engineered compressed air products is our tried-and-true, successful method for doing so.
There are a great many applications that require a spray (as opposed to a stream) of liquid. Certain droplet sizes, and flow rates, are beneficial for certain applications. For example, if you’re fighting a fire, you want as high of a flow rate as possible – the more water you douse the fire with, the quicker it goes out. You also want a fairly large droplet size, since a mist would tend to evaporate instead of extinguishing the flames.
Pressure washers also benefit from higher (though not near as high as fire hose) flow rates, and droplet sizes. You want an appreciable flow rate, because that means high velocity, and good sized droplets combine that velocity with their relative mass to “blast” away dirt and detritus from the surface.
Medicine delivery devices, like asthma inhalers, are designed to produce mid-sized droplets, but pretty low (and controlled) flows. The droplets need to be small enough to efficiently spread the medicine through the breathing passages, but large enough to where they won’t evaporate before they ‘plant’ on the nasal & bronchial membranes to get absorbed.
These are examples of “liquid-only” nozzles…no other media or means of force are used to effect the spraying action. Most of the time, the droplet sizes in these applications are measured in hundreds of microns, which “liquid-only” nozzles are ideally suited to generate. Other applications, however, call for much smaller droplet sizes…such as those only attainable through atomization.
Small droplet size is key to cost effectiveness in many applications:
Think about expensive coatings…the smaller the droplet size, the better and more even the coverage, and the less you have to spray (and pay) out.
Or humidification…smaller droplet size means more stays airborne, for longer, and in a larger space.
Petroleum based lubricants, by their nature, only require a thin layer for best results. Smaller droplets make as even and thin of a layer as possible.
Dust control is much more effective with smaller droplet sizes, since the longer the mist lingers in the air, the more dust particles the individual droplets will adhere to…and then drop with them to the surface. This also prevents getting the surface of the material any wetter than it has to be.
If you’d like to discuss a liquid spraying application, I’d love to hear from you. Call me.
Russ Bowman Application Engineer EXAIR Corporation Visit us on the Web Follow me on Twitter Like us on Facebook
Many times, when discussing product selection with a customer, we commonly reference supplying as clean and dry air as possible to promote peak performance. In iron piping systems for example, when moisture is present, rust can develop which can reduce the performance of end use compressed air operated devices like air tools or cause issues on the exhaust side as you could exhaust unwanted mist onto a surface, like in a painting operation.
Typically, an efficient and properly installed industrial compressed air system will include some type of dryer to remove any moisture that may be present in the supply.
Let’s take a look at the various types of dryers available.
Refrigerant and desiccant dryers are two of the more commonly used types of dryers.
Refrigerant based systems have several stages. The compressed air first passes through an air to air heat exchanger which initially cools the air. The air is then delivered to an air to refrigerant exchanger where an external source of liquid refrigerant further cools the air and sends it to a separator, where the water vapors condensate and are removed through a drain trap. Now that the air is dry, it is then cycled back to the air to air exchanger where it is heated back to ambient temperature and exits the system.
Desiccant dryers typically incorporate 2 tanks containing a porous desiccant which causes the moisture to sort of “cling” to the surface. In these systems, compressed air flows through one tank, while, using it’s own regeneration cycle, heated or unheated air is blown through the desiccant in the other tank to remove the moisture and dry the air.
Membrane Dryers are typically used at the end use product. These types of systems utilize membranes to dissipate water vapor as it passes through the material, while allowing a small amount of the dry air to travel the length of the membrane to sort of “wipe” the condensate and remove it from the system.
Deliquescent Dryers use a drying agent which absorbs any moisture in the air. As the vapors react with the desiccant, like salt, the desiccant liquefies and is able to be drained at the bottom of a tank. These are the least expensive dryers to purchase and maintain because they have no moving parts and require no power to run.
When a dryer is being considered for a particular setup, there are 3 common reference points used when determining the dryers rating – an inlet air temperature of 100°F, supply pressure of 100 PSIG and an ambient air temperature of 100°F. Changes in supply pressure or temperature could change the performance of a particular dryer. You want to follow the manufacturer’s recommendations when dealing with variances as they will typically provide some type of conversion.
For help with this or any other topics relating to the efficient use of compressed air, please give us a call, we’d be happy to help.
One of the most difficult aspects of handling and working with dusty materials is suppression of airborne contaminants. Small particles can easily become a dust cloud, minimizing visibility and decreasing the quality of working conditions. This then leads to lower productivity, low morale, and a missed opportunity to maximize the potential of personnel and equipment.
Our distributor in New Zealand recently assisted one of their customers facing this set of problems when working with cement and microsilica as it was poured into a mixer. An exhaust fan was in place, but failed to extract the dust sufficiently, so a new approach was needed to minimize the dust.
The solution was to use an EXAIR AN2010SSNo Drip Internal Mix Atomizing Nozzle, shown above in the red box, to produce an atomized water mist. The dust produced during pouring is captured by the small droplets of atomized water produced with this nozzle, reducing the dust and allowing proper use of the mixer.
In order to position the nozzle exactly where it needs to be, an 18” Stay Set Hose, shown above with the red arrow, was used to position the nozzle. This hose is built specifically to have “memory” of the desired position, allowing for quick, easy, and repeatable position of the nozzle attached to the hose.
This simple setup is controlled through a timer to ensure water and compressed air use realize maximum efficiency. It’s an easy solution to a painful problem for this customer.
If you’d like to explore how an EXAIR solution can solve problems in your facility or application, please contact an EXAIR Application Engineer.
Have you ever dropped one of your nice dinner plates on a tiled kitchen floor? And noticed how they seem to go in slow motion as they hurtle to their doom? I never cease to be impressed at how far some of the smaller pieces can go. I recently had to replace our oven, and I found broken dishware shards (and an impressive amount of trash scraps, pet toys, and ‘dust bunnies’) all the way against the back wall.
Curiously, as small as the pieces can be when a dinner plate meets its end, it started its life in even smaller pieces…as a fine ceramic powder, pressed into a mold and heated to a temperature that is WAY hotter than when the server at your favorite restaurant warns you that plate “might be hot.”
I’m writing about this because recently, I had the pleasure of assisting a maker of ceramic dishware with a messy little problem…this fine ceramic powder is moved from where it’s produced, to the various mold stations (dinner plates, salad plates, saucers, etc.) on a vibratory belt conveyor. The vibration keeps the powder loose and homogenous, both of which are extremely important to the molding & firing process. It also causes a cloud of dust to rise along the entire length of travel, and they wanted to minimize this. Their chemists had told the engineer who called me that they could live with a small amount of moisture, as long as it wasn’t enough to make the powder clump up – this would evaporate out at a point closer to the molds anyway.
This was an ideal application for the EXAIR Atomizing Spray Nozzles…they produce a fine mist of liquid that is precisely controllable…one Model AW1010SS Internal Mix, Wide Angle Round Pattern Nozzlewas installed near the beginning of the line, and once they find out how long it takes the dust-suppression supplied by the misted water to evaporate away, they will install more nozzles accordingly.
EXAIR Atomizing Spray Nozzles are ideal for situations where you need a fine liquid mist and fine adjustment of the flow & pattern. With ninety models to choose from, we’ve got the one you’re looking for. Call me if you want to find out more.