Spiral Immersion System

“It's a surprisingly simple invention. Why no one ever thought to combine brine freezing and spiral technology before, I don't really know.”

That’s Steve Kelley, referring to an innovative new freezing technology from Food Process Solutions (FPS) called the Spiral Immersion System. Kelley is the Director of Spiral Immersion Systems at FPS, as well as the product’s inventor. The idea came about while he owned Charlottetown Metal Products (CMP), a food processing OEM that’s now part of FPS.

Based in Vancouver, BC, FPS has been designing technology for freezing and cooling equipment since 2010. “FPS is the largest freezer manufacturer in North America and the second largest freezer manufacturer in the world,” Kelley says. “They've achieved that remarkable growth by focusing primarily on new technologies that enhance the hygienic design of food processing equipment, specifically in the chilling and freezing sector.”

The Spiral Immersion System’s simple solution

The inspiration for the Spiral Immersion System (SIS) was the cooling technology behind straight-line brine freezers. Using liquid transfer, brine freezers are able to cool 25 times faster than air, at temperatures as low as -70℉. “It’s basically a long tank with a conveyor,” Kelley says. “The conveyor takes the product that you’re trying to freeze under the surface of the brine, down through the tank, and up the other end. The technology has been around for years in particularly difficult freezing applications like lobster, crab, turkey, and other very large objects.”

The issue though, as Kelley realized while at CMP, is how much space brine freezers take up. “Some of these things are ridiculously long, hundreds of feet long, in fact, and very inconvenient. They take up a lot of plant space, and plant space is expensive.” So when customers began asking for a smaller footprint, it occurred to Kelley to combine brine freezing with spiral technology.  Spiral cooling systems traditionally use an air cooling method that involves “spiraling a belt around a drum in order to fit a lot of belt space, and therefore product dwell time, in a smaller footprint.”

The result of combining the two is hundreds to thousands of feet worth of product dwell time, without taking up nearly as much floor space. In fact, Kelley says the footprint is half the size of traditional equipment.

The advantages of faster cooling

Despite the simplicity of the SIS concept, it has numerous benefits over traditional cooling equipment, beyond saving floor space. “We think it's going to revolutionize the way people freeze foods,” Kelley says.

Faster cooldown time

“The heat transfer coefficient of water is 25 times faster than the heat transfer coefficient of air,” Kelley explains. Adding salt (in the form of calcium chloride, sodium chloride, etc.) helps bring the water to the coldest temperature possible. Usually, this temperature is -35℉, but it can be as low as -70℉. Once it reaches the right temperature, the product goes onto the spiral belt, which maximizes its dwell time.

“The surface of the food cools down 2,500% faster in the brine than it does in air,” Kelley says. “The interior of the product will cool down 20% to 70% faster. The reason for the wide range is that the heat transfer coefficient of the food product comes into play as well.”

Better product quality

The faster the freezing, the better the product’s quality will be. “That's because of the ice crystals that form in the cellular structure of the product,” Kelley says. “If you freeze slowly, those ice crystals are big and they destroy or disrupt the cellular membrane. When the food thaws out, the moisture in the cellular membrane drains away.” This causes diminished texture, color, and nutrient retention, whereas faster freezing keeps ice crystals smaller and minimizes product damage. This way, when the product is eventually thawed, it will retain more of the same quality it had before it was frozen.

Safer food

The other benefit to fast freezing is bacteria reduction. “The danger zone of food processing is between 40-100℉,” Kelley says. “That’s where bacteria grows exponentially faster.” So when food comes out of the oven or cooker at high temperatures, cooling it down to below 40℉ as quickly as possible minimizes the level of bacteria. “Less bacteria on the product translates to longer shelf life, less spoilage, and safer food.”

Lower energy use

The SIS is also an environmentally-friendly design that requires “less refrigeration, less Freon, less ammonia, and less electricity” compared to air cooling. Specifically, it uses 30% less refrigeration tonnage and 80% less electricity.

“If you think of a spiral freezer with air, you've got anywhere from three to six fans, 20 to 30 horsepower each, blowing a lot of air around. Those fans create a lot of heat that has to be cooled down.” Because of its more efficient heat transfer, the Spiral Immersion System only requires a 10-horsepower pump to move the same number of BTUs.

Less maintenance

To top it off, the SIS also saves on maintenance cost and time. “The belt, the drum, everything is buoyant in the water,” Kelley says. “So there's very little friction, very little weight on the drives.” And it never needs to be shut down for defrosting like air cooling systems do, either.

Beyond chilling and freezing

“You can cook, you can pasteurize, you can chill, you can freeze — all in one machine.”

Despite SIS’s origin in cooling, Kelley says about 40% of the inquiries FPS receives relate to cooking, mostly for sous vide products. The Spiral Immersion System makes these processes more convenient. “If you're cooking in hot water, this is a continuous operation,” Kelley says, “as opposed to packing and loading baskets in batch-style operations.”

The SIS can handle a variety of processes, as long as the temperature range stays between -70 to 220℉ and the product is skin-sealed or plastic-sealed so it doesn't absorb the salt. Products that are ideal for the SIS include vacuum-sealed meat, poultry, and seafood; bagged soups and sauces; and things like lobster, crab, and shrimp that can be immersed in brine.

Making its industry debut

FPS introduced the Spiral Immersion System back in January and expects to evolve the technology as it makes its way into the food industry. They are currently working on raising the height clearance between the self-stacking belts from 3 ½ inches to 5 ½ inches to accommodate larger products.

Regarding PROCESS EXPO, Kelley says it’s the size and attendance level that keeps FPS coming back, especially now that they’ve launched the SIS. “If you've got a new product and you want everyone in the world to find out about it, PROCESS EXPO is the place to be,” Kelley says.

To learn more about the Spiral Immersion System, stop by Booth #3912 at PROCESS EXPO.