When it comes to spray technology, food processors are spoilt for choice. We talk to Spraying Systems Co’s Kerry McPhail about what types of spray solutions work best for various applications and what is new on the market.
Spray technology is an essential part of food and beverage manufacturing operations. It is used for everything from cleaning tanks to glazing cakes, and from sanitising bottles to portioning vitamins.
As Kerry McPhail, Senior Sales Engineer at Spraying Systems Co told Food & Beverage Industry News, spray technology is not a one-size-fits-all proposition.
“We actually make in excess of 100,000 spray nozzles for use in a wide range of industries including food and beverage,” he explained. “We’re continuously working with clients in designing new nozzles, because as clients improve and expand their processes they often require variations or improvements to their spray solutions.”
McPhail explained that bakeries are big users of spray technology. These operations use air knives to clean baking trays, air atomising electric guns to apply oil to trays as a release agent, and fast electric guns to apply glazes to cakes, doughnuts, buns and and other bakery products.
Within the meat processing industry, spray technology applications include carcass washing, screen cleaning, boot cleaning, spray chilling, and sanitising evisceration tables, while dairy processors use spray technology for applications like apportioning preservatives to cheeses. Beverage processors use spray technology to sanitise bottles, clean tanks with caustic solutions and so forth.
Each application is unique so each is best performed by a specialised product. As McPhail pointed out, there are a number of factors to consider when using spray technology.
Repeatability and accuracy are two of these. For example, food processors often use spray nozzles to apply vitamins to their products. “These have to be sprayed in the required dosage,” said McPhail.
Using spray technology ensures even and accurate coverage of the target or product.
When attempting to clean a tank, you need force and power to remove food build-up. A mist with a very small drop size would not work for this task.
Precision Spray Control
Asked if there are any new technologies making a difference in the market, McPhail spoke about Precision Spray Control (PSC) which is often used in conjunction with Spraying Systems Co’s PulsaJet spray nozzles.
“I’ve been in the company for over twenty years. I’ve seen a lot of things come into the industry but this sort of technology has always been missing,” he said.
Similar to fuel injectors in motor vehicles, PSC is a technique for controlling a device by turning it on and off – or “pulsing” it – very quickly. It allows users to significantly change flow rate automatically without varying the drop size or changing spray angle and coverage.
“It was very hard in the past to change the flow rate through a tip and still get the same result on the product,” McPhail said. “We used to do it in what I would now call very agricultural ways. If you wanted to change the flow rate, the best nozzle was an air atomising nozzle.”
This wasn’t an adequate solution because it produced unwanted additional mist.
In contrast to this old technique, PSC makes it possible to control the duty cycle of the spray gun nozzle via a control panel. (It can be turned on and off as often as 30,000 times a minute with the latest technology). While to the naked eye there may appear to be a continuous spray, the spray gun nozzle may actually only be operating five percent of the time.
The absence of misting, along with the fact that spray nozzles do not operate continuously, mean that wastage is minimised. On top of that, the lack of misting means overspray onto surrounding machinery is also minimised. This reduces the need for cleaning and the associated costs and downtime.
As McPhail pointed out, oil mist can even affect the electrical operation of surrounding machinery. Guarding against this is another clear benefit of using spray technology.
PulsaJet spray nozzles work best with fast, complex, variable or constantly changing applications using less viscous liquids. For example, they are recommended for spraying natural antimicrobial agents onto meat to ensure safety; applying surface colouring with protein, egg or caramel; spraying oil to improve mould release; and moistening bread rolls with water to add sesame seeds or other toppings.
Although PSC has been used in spray technology for about ten years, according to McPhail it is just now coming into its own. “We are now fully trained and equipped to use this technology in manufacturing. And as we understand we’re able to pass that understanding to our customers,” he said.