If you’re just looking to spray water or just about any water-like liquid, you’ve got plenty of options…among them, any EXAIR Atomizing Spray Nozzle. We’d just need to find the one with the flow rate and pattern size & shape you’re looking for. That’s something we can handle in a short phone call, or if you’re a control freak, do-it-yourself-er like me, you can use the spec sheets in our Atomizing Spray Nozzles catalog section.
For applications involving liquids with higher viscosity or suspended solids, we’re going to look at our External Mix Air Atomizing Spray Nozzles. Internal Mix models are limited to liquid viscosity of 300cP or less, and you can’t use Siphon Feds for liquids with higher than 200cP viscosity. While we don’t publish a maximum viscosity for the External Mix models, we have customers who successfully use them with 800cP viscosity liquids. They also have larger internal passages for superior performance with suspended solids.
Two of my favorite examples of applications involving these elements come from the food industry — the snack food sector, specifically. The first one is from a company that makes thin, light crackers called ‘crisps’ that come in different flavors, achieved by coating them with a variety of seasonings. To make the seasonings stick, they needed to spray a light coating of oil onto the surface of the crisps, immediately prior to sprinkling the seasoning onto them, and then baking it in. And they called EXAIR for help in selecting the right Spray Nozzle.
We started our selection of the External Mix line, not only because of the viscosity of the oil (it WAS close to 300cP, which ruled out Siphon Feds, and was close to the upper limit of the Internal Mix models) but also because, with an External Mix, the liquid supply pressure ONLY affects the liquid flow rate, and the air supply pressure ONLY affects the pattern size. So, since they had a VERY specific volume of oil to apply to each crisp, they could set the liquid supply pressure accordingly, and use the air supply pressure to spread it evenly & consistently onto each piece. We know it worked because they sent us a video of it:
The other one came from a food production facility as well — this time, from a bakery that wanted to spray oil with a suspension of cheese powder onto dough before baking it. And the reason that the External Mix models are best for high viscosity liquids is the same reason they’re best for liquids with suspended solids. Namely, the liquid doesn’t have to go through a cavity between the Liquid & Air Caps where resistance to flow, either from viscosity or particulate, could cause problems. Since the dough was on a 12″ wide chain conveyor, we specified a Model EB1030SS 14 GPH 1/4 NPT External Mix Wide Angle Flat Fan Pattern Atomizing Spray Nozzle. It’s a fairly continuous run, so they didn’t need (or want) the No-Drip feature to turn the spray on & off. They simply shut the pump and the compressed air off when they’re done making the cheesy dough.
And now…I’m hungry! But seriously, if you need to spray liquid of any kind, EXAIR probably has a Spray Nozzle on the shelf for that…give me a call.
Russ Bowman, CCASS
Application Engineer
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