Heat! 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.
"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.
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." |
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.
"Energy costs are going up, and no one expects them to come down significantly in the near future," notes Chuck Sizer, former director of the National Center for Food Safety and Technology (www.iit.edu/), Argo, Ill. "So efficiency is important in heat transfer systems."That may explain the increase in new plate models. Among the primary categories of heat exchangers, plate systems are the most energy efficient. Tubular types rank next. Scraped surface heat exchangers provide no heat regeneration. Despite that fact, they remain popular and at the high end of the technology because they heat product very quickly and, due to constant scraping action, without fouling.
Heightened awareness to the threats of listeria and bioterrorism has made processors more open to alternative technologies. Advanced microwave pasteurization and sterilization systems could provide an alternative to irradiation to address bacterial threats, including anthrax."Microwave technology for in-package sterilization has taken off worldwide, but not here," says Sizer, who also sees opportunity for high pressure systems in the marketplace. Nevertheless, he anticipates advances in validating, controlling and monitoring microwave product that could pave the way for more use of the technology in the processing arena."Microwave will work," he says. "You just need to be able to control it. You also have a problem with absorption. Different compositions of food heat differently with microwave."And now there are special considerations for low-carb products and reformulations.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."Processors need very flexible heat transfer systems in today's competitive and safety-conscious world. Shorter runs with a clean-in-place cycle between are the order of the day."Another big development is the plate evaporator system for concentrating products," says Swift of a product introduced by Alfa Laval less than a year ago. "We used shell and tube evaporators in the past. They required a larger surface area to perform the same duty. They were less efficient and, with product spending more time in the evaporator, it was subject to greater heat degradation, which lowers the quality of the product."