As a child of the 1970s, my friends and I played with a LOT of toys that were die-cast. Most of us didn’t know what that meant; we just knew that we had to try REALLY hard to break them. Turns out, the ruggedness of those toys – and their widespread availability to the first crop of Gen-X kids – is directly related to the casting process. Metal casting produces stronger products than welding pieces together, and it’s WAY more cost-effective than machining parts that don’t necessarily need to hold tolerances measured in thousandths of inches.
One of the more popular methods for parts & products like this is called green sand casting. Basically, they add a specific amount of water to the sand so that it’ll hold its shape – that’s why the best sand castles on the beach are made closer to the surf – and make a mold. Then they pour in molten metal, let it cool, remove the cast part, and repeat for as many parts as they need to make. Fun fact: they call it “green sand” because of the moisture content – like “green wood” gets its name because of the sap content – not because of the color (it’s NOT green colored).
Anyway, the mixing process for the sand & water blend is kind of an exact science. Too much water, and the mold won’t hold its shape, and too little will make it brittle. It’s also easier and quicker to mix if the water is sprayed, as opposed to dumping or pouring it in.
The reason I know all this is that I had the pleasure of talking with a caller who runs a specialty casting foundry. They make parts that weigh a couple of ounces, a couple of hundred pounds, and anything in between. They, of course, keep the molds they’ve made for repeat customers, so they’re ready to go when a new order is placed, but they’re also making new molds all the time, and wanted to improve the sand/water mixing process. They didn’t need the extremely fine droplet size of an Air Atomizing Spray Nozzle, nor did they want something whose flow was measured in gallons per hour. They were actually looking for about one gallon per minute from a compact device that could spray a wide round pattern into a rotary drum that looked an awful lot like a small concrete mixer. They chose Model FL1010SS OmniStream Cone Nozzle.
Since 1 gallon per minute is right in the middle of the FL1010SS’ flow performance range, it was the obvious choice for this application.
As the sand in the mixer turns, the conical spray is evenly, and quickly, is soaked into the sand. This reduced the time it took to get a consistent mixture, and eliminated clumps they’d occasionally get when the water was poured in, which they’d have to break up by hand after stopping the mixer, which saved even more time…and operator frustration!
If you need to spray liquid in a consistent, repeatable manner, EXAIR has an enormous range of flow rates & spray patterns. If you’d like to find out more, give me a call.
Russ Bowman, CCASS
Application Engineer Visit us on the Web Follow me on Twitter Like us on Facebook
If you’re a registered user on our website, you likely got word of this already through our August 15, 2023 Press Release. If not – or even if you did and want some more details – read on, and I’ll tell you all about it.
Like all of our previous catalogs, Catalog #35 provides specification, dimensional, and performance data on all of our stock products. Many of them include detailed descriptions of “textbook” applications for those products. You’ll also find:
Efficiency Lab (page 6): If you want a full performance report on a compressed air device you’re using right now, this is a free service we offer. Contact an Application Engineer and arrange to have it sent in. We’ll test it for compressed air consumption, force applied, and sound level, and send you a report on it. It’ll include, of course, the EXAIR engineered product(s) that we’ll recommend, along with performance data on them, as a comparison.
Our Six Steps (page 7): The first page of our Optimization section details the Six Steps To Optimizing Your Compressed Air System. It’s not necessary to follow them in order, and not all of them are applicable to every single compressed air system. But if you’re serious about reducing your compressed air costs, this is a comprehensive plan on how to do it for sure.
OSHA Maximum Allowable Noise Exposure table & typical Air Consumption values of common “homemade” blow offs (page 53): We put this here so you can turn the next few pages and see what a difference engineered products like EXAIR Super Air Nozzles can make.
Droplet Size data (page 98): Use this to determine the suitability of our Atomizing Spray Nozzles for liquid spraying applications.
Vortex Tube Specification and Performance tables (pages 201-202): If you know how much cold air flow you need, and at what temperature you need it, you can use these tables to determine which EXAIR Vortex Tube (or other Spot Cooling Product) to use.
Cabinet Cooler System Sizing Guide (page 220): Just fill in the blanks & send this in, and we’ll quickly & accurately calculate the heat load of your electrical/electronic enclosure, and specify the right Cabinet Cooler System for you.
Now, if you’ve ever had any of our previous catalogs, you might have noticed that those were already in there, and that’s all pretty great. What’s REALLY great about Catalog #35, though, is some of the new features:
Line Vac Conveyance Data (pages 176-177): While there’s WAY too many variables in bulk conveyance applications to accurately calculate conveyance rates. We’ve done some controlled, in-house testing with several different materials, several different Line Vacs, at several different lengths & heights, though, and we’re proud to publish that in the new catalog. This shouldn’t be considered a guarantee of performance, but if you’re wondering how much of a particular bulk material you can convey, this table will certainly get you in the right ballpark.
Best Practice for Using EXAIR Intelligent Compressed Air Products (pages 239-240): This information has always been in the Air Data files on our website, along with an ABUNDANCE of data that’ll help you get the most out of your compressed air system. Now, it’s at your fingers.
Of course, I’d be remiss if I wrote a whole blog on the new catalog without mentioning the new products:
Model 9207 Ultrasonic Leak Detector (pages 18-19): This serves the same function as the now-obsolete Model 9061, but with some handy upgrades like a LED display, a sleek new body, and high quality ear buds.
Use the Model 9207 Ultrasonic Leak Detector’s parabola to find the vicinity of the leak, and the tubular extension to identify its exact location.
1/2 NPT HollowStream Cone Atomizing Nozzles (page 105): With five new distinct models at the high-flow end of our already comprehensive line of Liquid Atomizing Spray Nozzles, these provide up to 53 gallons per minute of liquid flow, and are capable of passing particulate up to 0.344″ in diameter.
The Hollow Cone spray pattern is ideal for cooling, cleaning, foam breaking, rinsing, and dust suppression. It also uses considerably less liquid than the OmniStream models, when higher flow rate isn’t necessary.
EXAIR’s ATEX Cabinet Cooler Systems provide heat protection for electrical enclosures in potentially explosive atmospheres, like those found on offshore drilling platforms, petrochemical plants, mines, flour mills, etc.
Like our previous catalogs, Catalog 35 is now available for download (in product line sections due to file size) from the PDF Library at EXAIR.com. You can also request a copy to be mailed to you, or you can contact an Application Engineer to have individual product line sections (again, because of file size) email to you right away.
As always, if you’d like to talk about how to get the most out of your compressed air system, our team of Application Engineers are here Monday to Friday, 7am to 4pm Eastern, to help with that. Give me a call.
Russ Bowman, CCASS
Application Engineer Visit us on the Web Follow me on Twitter Like us on Facebook
This may seem biased, but my answer is, “EVERYTHING!” Now, that may SEEM biased, but consider the fact that, as an Application Engineer, I have a front row seat for the “Innovation Show” that is EXAIR. The attention to detail that gets paid to the design, testing, verification, and manufacturing of new products constantly reminds me that it’s a level of excellence that EXAIR’s founder, Roy Sweeney, instilled and promoted in our culture from when he started this business in 1983, until his passing in 2016. It’s a testament to his legacy that, not only does it continue; it shows no signs of slowing down. It’s that level of excellence that’s always made it easy for me to speak with confidence about the quality, performance, durability, and effectiveness of all of EXAIR’s engineered compressed air products.
Our Marketing folks proudly passed out copies of the new EXAIR Catalog #35 the other day, and I immediately started immersing myself in that pride as I thumbed through. I thought of 12 years (for me) worth of success stories in helping customers get the most out of their compressed air systems through the use of our products, and our expertise in not only those products’ implementation, but how they can best fit into those customers’ air systems, overall. I wasn’t too far in to my thumbing through, when the “new stuff” really started making an impression on me:
Ultrasonic Leak Detector: Model 9207 is the first new product you’ll see if you start at the beginning. It has the same functionality and tools (parabolic disc for finding out you have leaks in a particular area, and a tubular extension so you can track the leak to its exact location), and some nice upgrades: it’s powered by four AA batteries (instead of a 9V) and comes with a set of earbuds (which I personally prefer over the previous model’s earphones, which I always considered a compromise between headphone & earbuds, with the benefits of neither). It’s never been easier to find those costly leaks in your air system, and fix them.
1/2 NPT HollowStream Liquid Atomizing Spray Nozzles: We’ve had these in 1/4 and 3/8 NPT sizes for a while now, with the ability to spray up to 7.28 gallons per minute. The 1/2 NPT models almost double that capacity to a flow rate of 14 gallons per minute. These spray a ring of liquid, so their flow rates are lower than a comparably sized Full Stream Liquid Atomizing Spray Nozzle, which spray a full, filled-in circle.
Line Vac Conveyance Chart: Remember what I said above about the ability to speak confidently about our products? This new chart compiles decades of controlled in-house testing and details that some customers have shared with us on the performance of different Line Vac models with different materials they’ve been used to convey. While we can’t guarantee EXACT conveyance performance for any specific application, this is a VERY handy tool to get us “in the ballpark” and further increases our great ability to specify the right Air Operated Conveyor for your application.
ATEX Cabinet Cooler Systems: It was a pretty big deal when we introduced our HazLoc Cabinet Cooler Systems that are UL Classified for Class I Div 1, Class II Div 1, and Class III environments. And it WAS a big deal, in the United States & Canada. Now, we can offer the certification of hazardous location requirements, globally, for ATEX Zones 2 & 22. That’s ANOTHER big deal.
Speaking of big deals, come October, EXAIR will have been providing quiet, safe, and efficient compressed air products to industry for 40 years. Catalog 35 has all the products that we’ve been making since then, and everything we’ve added over the years. Click here to get one mailed out to you right away. If you’ve got questions about anything in our catalog, or how EXAIR can help you get the most out of your compressed air system, give me a call.
Russ Bowman, CCASS
Application Engineer Visit us on the Web Follow me on Twitter Like us on Facebook
I had an application where a customer needed to have a room at 75% relative humidity (RH). They produced a nylon backing for carpet, and they needed the high RH to reduce the “stickiness” in the gluing process. Currently they were at 40% RH in a room that was measured at 40ft long by 20ft wide by 20ft high (12.2m long X 6.1m wide X 6.1m high). They wondered if our Atomizing Nozzles could help him to increase the relative humidity in the room. I decided to put on my engineering hat to calculate the amount of water that he would need to increase the humidity.
Relative humidity (RH) is the percentage of water vapor as compared to the saturation level at the same temperature. So, at 100% RH, the ambient air is saturated and cannot hold any more water vapor. You can feel the difference in the Amazon versus Arizona at the same temperature. With dryer conditions, water can be added to increase the relative humidity; like a humidifier. With the EXAIR Atomizing Nozzles, we can break liquid water into very small droplets to help increase the humidification rate. For the customer above, I will have to determine what size and how many Atomizing Nozzles are required.
Equation 1
H = V * ACH * (Wf – Wi) / (v * 7000)
Where:
H – mass flow rate of water, Lbs/hr
V – Volume of room, ft3
ACH – Air changes per hour
Wf – Final Water Content, Grains/lb of dry air
Wi – Initial Water Content, Grains/lb of dry air
v – Specific Volume of Air, ft3/lb
Conversion Constant – 7000 Grains/lb
The customer stated that the room was set to 68oF (20oC), and they used an air handling unit (AHU) that produced 1,600 cfm (44.5 M3/min) of air into the room. From these factors, we can determine some of the variables above. For the Air Changes per Hour (ACH), we can use Equation 2.
Equation 2
ACH = 60 * Q / V
Where:
ACH – Air changes per hour
Q – Volumetric flow rate, CFM
V – Volume of room, ft3
The volume of the room is V = 40ft X 20ft X 20ft = 16,000 ft3. The volumetric flow rate by the AHU is 1,600 ft3/min. From Equation 2,
ACH = 60 * (1600 ft3/min) / 16,000 ft3
ACH = 6/hr.
In determining the water content values, you can find a chart online to determine the amount of water vapor that is contained in the air at a specific temperature and RH. At 68oF (20oC), I was able to find the following information:
Wi = 40.58 Grains/lb of dry air at 40% RH
Wf = 76.71 Grains/lb of dry air at 75% RH
v = 14.286 ft3/lb @ 68 deg. F, 1 atm
V = 16,000 ft3
If we plug in the numbers that we have into Equation 1, we can determine how much water that we will need to spray into the air to increase the RH from 40% to 75%.
With my prior line of work in room humidification, we know that there is a lead/lag time between measuring and humidifying. This may seem complicated, but it is important to get a steady state condition for the Relative Humidity. To help this customer, I recommend a cycle time of 15 second to turn on and wait 105 seconds to re-measure the RH. This will help to not over-saturate the room. As for the location of the Atomizing Nozzles, we want to be near the ceiling to get the most “air” time to vaporize. We also have to be careful to not allow the water spray to hit any objects or each other as this will cause the water to condense.
To start, I suggested our model AT2010SS No Drip Internal Mix 360o Hollow Circular Pattern. This type of nozzle helps to extend the settling time of the water droplets; the amount of time that the droplets are suspended in the air. The orientation of the spray is outward in all direction to increase coverage. With the No Drip option, it is controlled by the air pressure to open and close the liquid side for spraying. When the compressed air is turned off, a valve will seal the liquid side to not allow any drips. It also helps to eliminate the need for any liquid valves next to the Atomizing Nozzles. When it comes to cycle spraying, the No Drip option works wonderful.
In taking into consideration the flow rate required during operation time, we can calculate the amount of liquid flow required for the Atomizing Nozzle in Equation 3.
Equation 3:
Flow rate: Q = H / (D * T * f)
Where:
Q – Liquid flow rate (gal/hr or GPH)
H – Mass Flow Rate (lbs/hr)
D – Density of Water (8.34 lbs/gal)
T – Span division (no scale)
f – Intermittent Factor (no scale)
To determine the number of Atomizing Nozzles, we want to look at the time determination with the controller and the intermittence of operation. With the ACH = 6/hour, the air in the room will change over every 10 minutes. We want to have a balance between the new air and the existing air. So, with the time measurement of 15 seconds on and 105 seconds off (2 minutes), we will have 5 humidity checks over the 10 minutes. We can divide the amount of water to be injected into the room by the span division, T, to cover the time span for check and atomization. Thus, T = 5. We will also have to adjust the amount for only running 15 second intervals. So, the intermittent factor, f, will be 0.0042 (the 15 seconds portion of the hour).
With these values, we get:
Q = (34.68 lbs/hr) / (8.34 lbs/gal * 5 * 0.0042)
Q = 198 gal/hr (GPH)
In the catalog, the model AT2010SS will flow 14.7 GPH (55.7 LPH) of water at 60 PSIG (4.1 Bar) liquid pressure. If we divide these out, it will tell us how many atomizing nozzles that is needed to humidify the room.
Number of Nozzles: 198 GPH/14.7 GPH = 13.5 or 14 Atomizing Nozzles.
With the above Atomizing Nozzles, the company was able to control the RH at a high level for his manufacturing process. In turn, he was able to increase productivity and reduce downtime. If you need to increase the level of humidity in your area, you can contact an Application Engineer at EXAIR for help. We can make it feel like the Amazon.
