With the amount of applications capable of benefiting from a Super Air Knife we tend to field a lot of questions about the product. How much force does the Super Air Knife produce? (2.5 oz of force for every inch of knife length.) What is the noise level at various operating pressures? (57-69 dBA at operating pressures from 20-80 PSIG.) Is an Air Knife right for my application? (Possibly! Our Application Engineers can help answer that question definitively.)
Another common question we have from existing customers and prospective customers alike, is in regards to the proper mounting of an Air Knife solution in a conveyor blowoff application. As a standard practice we recommend to install the air knife/knives at a 45° angle of attack, opposite the direction of material travel. (We refer to this as counterflow.) And, if the knives are mounted vertically for a side-based blow off, we normally recommend to install the knives directly opposed to each other. This type of setup creates a nice chevron pattern in the blow off, removing water, dirt, or whatever other undesirables are at play.
Recently, though, I went through a troubleshooting exercise with an end user unable to achieve adequate blow off with our go-to type of setup. No matter the pressure or angle, we just couldn’t get the setup dialed in to remove the undesirable (in this case, water) while still allowing material flow. In this application the force from the two knives hitting simultaneously was too great to allow the lighter products through the blow off curtain. So I requested some sample product be sent in and ran some in-house tests.
What we found was identical to the results from the field, which were a bit puzzling. We could blow off the water from the product, but not to the degree of dryness necessary. This was because the weight of the product was too low to keep the product in place when in contact with the high force blow off from a set of two Super Air Knives. We could force the product through by hand, but that wasn’t a real or repeatable option.
But, after trying various configurations we found the solution! Two Super Air Knives mounted directly parallel produced too much force. BUT, two Super Air Knives mounted in a staggered pattern separated our blow off air flows just a bit. This setup allowed the product to pass through one air stream, then into the combined air stream of two knives, and then again through one air stream.
This solution, show above, brought the level of dryness to the needed level and allowed our customer to get back on track. Without a solution to this problem workflow slowed, production reduced, and defects increased. With the combination of an EXAIR product and our product support, we were able to increase workflow and production while eliminating defects due to excess water o the product.
If you have an application with a similar need, contact an EXAIR Application Engineer.