Controlling product temperature is critical for creating consistent mixes and for controlling bacteria counts. For thicker, more viscous, flowable product a scraped surface heat exchanger – like Wilevco’s Cryolator — is vastly more effective – and accurate – than a shell and tube heat exchanger.
While shell and tube (or shell in tube) systems are often more economical, without paddles, scrapers, or moving parts inside the chamber the product can stick to the sides, burning or freezing on the walls, resulting in product inconsistencies or creating pressure buildup that can cause low-flow or product blockages. Even worse, product “sitting” on the walls acts as an insulator, reducing the effectiveness of the heating and cooling medium.
Scraped surface systems, sometimes called swept surface, are far more effective for sticky or viscous products or formulas, especially with particulate. The scrapers, or paddles, mix and pull the product off the walls, preventing sticking or freezing and continually shifting warmer and cooler product pockets, resulting in a more consistent overall product temperature.
Scraped surface heat exchangers are used to heat or cool many types of food products including a variety of batters (batter-bread, pancakes, waffles, etc), tomato sauce or paste, icings, pasta sauces, soups, broths, juices, and more. The Cryolator in the video below is being used to heat nacho cheese.
While there are copies on the market today, Wilevco introduced the original swept surface heat exchanger in 1968. The upright mount is perfect for facilities with limited space, and the sanitary design makes it easy to clean and maintain and simplifies changeover between products.
While a shell and tube heat exchanger may be less of an investment, it is often an example of “penny wise pound foolish” situation where the equipment savings result in greater losses in product processing. Food processing plants needing to accurately control product temperatures of flowable products with high viscosities or formulas with particulates find that a swept surface heat exchanger is a superior solution for better thermal efficiency and improved product consistency.
Food Processing Resource: www.foodprocessing.com
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