Bring on the heat!
Cost, quality and safety concerns of food processors drive improvements in heat transfer systems.
By Mike Pehanich, Contributing Editor | 10/09/2004
Its application to a mix of ingredients creates a critical control point, a vital stage where issues of quality, safety and, ultimately, cost come to a head.
This heat juncture is often the focal point in the product stream, the defining point where raw ingredient becomes processed product. How carefully and hygienically you move heat from one medium into another may determine the quality and safety of your product.
Heat exchangers enable heat to pass from one medium to another without allowing them to mix. The evolution in heat exchanger technology has been a quest for the perfect tailoring of equipment design and materials to specific processed foods and beverages. Today, that quest encompasses process efficiency as well, namely lower cost and energy consumption and, equally important, running more product through the system.
|Note to R&D
Low-carb foods are driving changes in heat exchanger selection. The reasons illustrate the importance of versatility in today's processing equipment.
"Processors are substituting fiber for carbohydrates and fats in the new formulations," says Alfa Laval's Neil Swift. "This leads to more viscous-type products that require a scraped surface heat exchanger."
"When you're designing a system, each process has certain requirements, such as throughput and rate of heat exchange," explains Carlos del Sol, vice president of global engineering systems for Campbell Soup Co., Camden, N.J. "Any equipment you buy for that system must meet those requirements.
"A lot of questions come into play with your selection," he continues. "Will the system be able to do what it's intended to do? What are the energy costs of running it? And then there are issues of maintainability: How long will it run before we have to change a part? How quickly can you clean it? What is the equipment's projected life?"
Cost has long been of paramount concern in the product development lab where pennies saved on ingredients convert to dollars on the profit ledger. For a few years now, food processors have been taking equal issue with the cost components on the processing side of the business. The goal may seem simple: produce more and more product at lower and lower cost. But in the real world, notes del Sol, decisions on systems and equipment must strike a balance between product, equipment life, maintainability and overall cost.
Yet cost considerations are never far from a food processor's mind.
"Every manufacturer is trying to get more throughput," says del Sol. "Virtually every manufacturer has a program of cost improvement. Yes, that entails consideration of line speed, but it is also influenced by the uptime of your system. It's not always a matter of how fast your equipment can run. Downtime can take that away. It's what you end up with at the end of the day. Throughput is the name of the game."
Throughput, indeed, factors seriously into the selection of heat transfer equipment these days. It is one of several key factors in the cost/quality equation.Bigger is better
Manufacturers of heat exchangers are facing a good news/bad news scenario. The bad news is food processors still have a stranglehold on their moneybags. The good news is some heat transfer equipment, particularly in the dairy industry, is old enough to draw attention from antique collectors.
|Above: Heat exchanger plates from API Schmidt-Bretten.
But another basic need is driving processors into the heat exchanger market. They need "bigger and better" to get the most out of their manufacturing network, bigger heat exchangers, bigger ports, larger surface areas to heat product.
"Processors need to accomplish bigger duties than in the past," says Jeff Ceier of API's Schmidt-Bretten division (www.apiheattransfer.com/
), Buffalo, N.Y. "Some food equipment is simply not big enough. That's certainly been the case in much of the dairy industry. The duties of evaporators are getting bigger all the time. The food industry is not in the habit of investing now for results later. But the purse strings are opening."
Melissa Fryer, senior applications engineer for Invensys APV (www.apv.com/
), Tonawanda, N.Y., reiterates the theme: "Higher flow rates. Longer run times."
Processors hunting for new equipment are finding more versatile heat transfer systems in their crosshairs.
"Processors want equipment to work with a large variety of products," says Fryer, whose company finds plate and frame heat exchangers its biggest sellers. "Sales of corrugated tubular heat exchangers are on the rise. They tend to be a bit more versatile (than plate and frame heat exchangers)."
"Our Votator II (scraped surface heat exchanger) was designed to be efficient with several process options so that it could be adapted to most heating and cooling applications," says Ray Klusman of SPX Process Equipment/Waukesha Cherry-Burrell (www.gowcb.com
), Delavan, Wis. He links the introduction of new food products and ongoing plant consolidation to the expansion of scraped surface heat exchanger use.
"It also had to be easy to maintain," Klusman continues. "For example, the product heads are held in place by a bayonet ring, which does not require bolts. An integral gear motor drive eliminates the traditional drive shaft and motor coupling, and it reduces the overall length or height of the unit by almost two feet."