The Super Air Knife?
EXAIR’s Super Air knife is an advanced generation tool used to blow off liquid or debris from products as they travel on conveyors. The knife consists of a high intensity, uniform sheet of laminar airflow sometimes known as streamline flow across the entire length with hard hitting force. An industrial Super Air knife is a pressurized air plenum containing a series of holes or continuous slots through which pressurized air exits in a laminar flow pattern. The exit air velocity then creates an impact air velocity onto the surface of whatever object the air is directed.
Super Air Knives are aerodynamically engineered and tested to produce an efficient, uniform and high velocity stream of air. Air Knives are designed for 24/7 use, have smooth edges and seams for easier cleaning, can be precisely adjusted without tools for faster change-over’s and are custom sized for your application. Super Air knife dramatically reduce compressed air and noise levels as compared to other blow-off products. The sound level is surprisingly quite at 69 dBA even at high pressure of 80 PSIG (5.5 BAR). It produces air amplification ratios (entrained air to compressed air) of 40:1.Meets OSHA maximum dead-ended pressure & noise requirements. .
Friday, 24 June 2016
Super Air Wipe
EXAIR’s Air Wipe produces a “laminar” flow of air along its 360° angle using the “Coanda” effect which “entrains” a large volume of air from the surrounding area along with the small amount of compressed air. It is easy to mount and the split design provide easy Super Aire Wipe Split Designclamping around the surface of the material ,eliminating the need for threading .EXAIR Air wipe reduces both compressed air consumption and noise levels.
It produces an output flow up to 30 times. All Super Air Wipe models include stainless steel screws & shims. For added corrosion & heat resistance braided hose is also included on sizes up to 4” (102mm).For Aluminum models the temperature rating is up to 400°F (204°C) & stainless steel models for temperature up to 800°F(427°C).
The process of making cocoa powder and chocolate products is fascinating to say the least. The video above shows the process at the Hershey factory in a throwback “How Its Made” video from the 70’s. (We think; based on the hairstyles. Also based on the video description, but mostly based on the hairstyles.) It’s interesting to see the process and the mechanical aptitude it took to create the machines, especially with the weights and measures. The level of complexity and number of steps involved can make you wonder how we ever figured it all out, but thankfully we did!
Current cocoa production follows the same basic process through harvesting, roasting, extracting cocoa butter, and grinding of cocoa cakes into powder. And, like any manufacturing process, there are sure to be applications which demand unique solutions. This is where a recent application took place for an EXAIR end user.
The cooling carriage for the cocoa powder
Not shown in the video above is a cooling process for the cocoa powder. During the cooling process the powder is transferred through a carriage system resembling a radiator without the fins. Inside the carriage system cocoa powder can accumulate in the 180° bends, and the build-up over time can stop material flow. So, these bends are serviced as part of a regular preventative maintenance program.
Cocoa build-up in the curves of the carriage
The end user was looking for a way to extend the service interval length, hoping to find a solution to target the build-up areas in the 180° bends. The current setup requires manual cleaning every 15 days of operation. Modification of the existing setup is possible, provided it increases the time between maintenance procedures.
The service procedure
The solution Exair's Person devised is a series of 316 stainless steel Super Air Nozzles, fed into the curves of the cooling carriage to prevent accumulation of the cocoa powder. The solution agitates any accumulating cocoa, removing the build-up and greatly extending the time between service intervals.
This solution can be implemented in one of two ways; either through periodic entry of the nozzles into the cooling carriage (a somewhat difficult solution to implement), or through permanent installation with guarding in place to protect the nozzles (even powders can deteriorate a material with direct contact over time). A (very) crude representation of the permanent installation is shown below.
A quick sketch of the possible permanent solution
To install the nozzles into the curves of the cooling carriage, holes must be drilled into the curves. Sealed bulkhead fittings can be installed into the holes, and the necessary compressed air lines can be fed through the sealed bulkhead fittings. This will allow installation of the air nozzles in the needed locations.
The final detail left to be sorted in this application was the exact model Super Air Nozzle to be used. The force requirement to dislodge the cocoa is highly specific and ultimately unknown, so we focused on a solution with what we deemed adequate force at an 80 PSIG operating pressure. We chose a series of 1101SS Super Air Nozzles, remembering we can always reduce force and compressed air consumption through pressure regulation if needed.
Exair received an inquiry from a customer to test their current air guns through Their Efficiency Lab service. According to the operators, the handheld blow gun they were purchasing from a commercial retailer was too loud and complaints were rolling in. They were also hoping to save some compressed air in the process as they were performing an energy audit at the same time.
Commercial Air Gun w/ Cross Cut Hole
Cross Cut Hole Nozzle
The gun they sent in looked fairly similar to Exair Precision Safety Air Gun but it did not have an engineered nozzle on the tip of it. Instead, it was simply a cross cut hole in a piece of material. The air inlet to the gun was a 1/4″ NPT just like our Precision Safety Air Gun, the extension on the gun was slightly longer, the only significant variance I saw was the tip.
EXAIR Model 1410SS-CS
The Model 1110SS Nao Super Air Nozzle and Chip Shield
To try and get as much information as possible Exair's Application Engineer measured the O.D. and I.D. of the extension, the hole size was approximately .140″. He measured the extension on our Precision Safety Air Gun just to see what is different, it came in at the same size. So, he flows tested the competitive blow gun with their tip on it and came up with air consumption of 12.69 SCFM, noise level of 92 dBA at 3′ away, and a blowing force of 11.5 oz at 80 psig. He then measured the same attributes of EXAIR’s model 1410SS-CS Precision Safety Air Gun at 80 psig inlet pressure. The model 1410SS-CS measured 8.3 SCFM, gave 8.1 ozs of working force, and only produced a 75 dBA sound level from 3′ away.
The sound level reduction was a total of 17 dBA which is below the OSHA standard for allowable noise level exposure, as well as reduced their air consumption by 4.39 SCFM. That is almost a 35% reduction in their compressed air usage per gun replaced. After seeing these levels of reduction the customer had more than enough information to provide management with in order to replace the blow guns not just for noise level reduction but also because it will reduce air use and save money. A clear supportive role in their energy audit.
I am always happy to see the sun rise each morning. But, electrical panels that are exposed to the sun are not. Solar heat adds significant BTU’s to the overall heat load in an electrical panel.
A customer had a VFD to control a 300HP blower motor for a dust collection system. The VFD was getting an over-temp error and shutting down the system. He contacted EXAIR to get a Cabinet Cooler to keep the VFD cool. We went through our normal questions to determine the heat load, i.e. the size of the cabinet, the temperature inside, the temperature outside, the maximum external temperature and the desired temperature. As we went through the questions, he stated that the cabinet was located outside. This is not an issue for our Cabinet Coolers as EXAIR has NEMA 4 and 4X (IP66) Cabinet Coolers. It did stem another question; was it under cover? He mentioned that it was not.
NEMA 4 Cabinet Cooler
Generally in calculating cooling capacities with our Cabinet Coolers, we size the units by adding the ambient heat load and the electrical heat load. With the panel exposed to the sun, this adds another component to the total heat load. To get an estimation on the amount of solar heat, color becomes a big factor as the darker colors will draw more heat. Here is a good approximation to follow:
Solar heating by color
In this application, the customer had a gray panel, a common color. With an exposed surface area of 16 ft^2 (1.47 M^2), Exair would have to increase the heat load by 16 ft^2 * 7 Watts/ft^2 = 112 Watts. This equates to 112 Watts * 3.41 BTU/hr/Watt = 382 BTU/hr of added heat. (Or 112 Watts * 0.86 Kcal/hr/Watts = 96 Kcal/hr).
If an electrical panel is outside and cannot be shaded from the sun, we can still protect the sensitive components inside. With the proper sized Cabinet Cooler, your equipment will remain running cool.
At EXAIR, They get asked a lot of interesting questions about what Their products can do. One of them that occurs with some frequency is, “Can your Line Vac convey slugs from a stamping operation?” The answer is usually yes as “slugs” (the material punched out of a sheet of stock to create a hole) are well suited in size, shape and weight to be conveyed effectively with the Line Vac product. They are used to this question from folks who are processing various types of metal sheet. The slugs tend to build up within their tooling and basically get in the way, if not even jam up the tooling from time to time. So getting rid of them from the process becomes a necessity that is, many times, not addressed during the tool making process.
Recently, They had another customer with this same kind of problem with foam. They were processing a foam sheet by punching a many holes in it which generated the waste stream you see above. Little pieces of foam about 8 – 10 mm in diameter and about 40 mm long. As you probably have guessed by now, the area that was set up to receive these renderings quickly became loaded full with the foam slugs. The customer needed to find a way to remove the slugs to a remote area so the receiving container could be switched out easily without stopping production. The original container was small, plastic bin about the size of a kitchen garbage can. The new receiving container was a large cardboard box that typically goes by the term Gaylord. The customer needed to set the Gaylord about 3 – 4 meters away from the die punching area. This is where the EXAIR model 130300 (3” Light Duty Line Vac) comes into play. The customer fabricated a chute that was positioned under the area to catch the slugs. The chute transitions to accept the 3” Light Duty Line Vac for connection at the bottom. Then, a 3” hose is connected to the output side of the Light Duty Line Vac so it could blow the slugs over to the Gaylord.
Foam Slugs From Die Stamping Process
The customer chose the Light Duty Line Vac because it uses less air than a comparable size of our Standard Duty units. They didn’t need a tremendous amount of suction power due to the light-weight nature of the slugs. They also wanted a 3” unit to make sure none of the product would get caught anywhere within the conveying stream.
With the new Light Duty Line Vac installed, the operators do not have to spend as much time tending to the emptying of the previous, small containers that had to be used due to their size for fitting into the catch area. For an application where thousands of these slugs are produced in an hour, the productivity gain was significant. The customer didn’t place an exact value on the gain, but are considering this method for other, similar processes they have in the plant.
