Food-focused freezing with in-line steaming and self-stack conveying
The Frigoscandia GYRoCOMPACT S6 steamer from JBT FoodTech was the first technology to offer both affordability coupled with the hygiene, reliability and performance advantages of a self-stacking conveyor. The self-stacking freezers replaced the refrigeration system with a steam injection system and a modified enclosure that can withstand high temperatures. Engineering from a freezer design instead of a more complex oven system has given a solution that is significantly less expensive than conventional “oven-concept” steamers on the market.
The development history
Frigoscandia GYRoCOMPACT spiral freezers set new standards for performance and cleanability when they were introduced in 1978 by JBT FoodTech of Helsingborg, Sweden. The incorporation of a unique, patented self-stacking belt – the FRIGoBELT conveyor – eliminated the need for a bulky, difficult-to-clean support structure. The result was a more compact machine with more efficient air flow control, which reduced freezing time and achieved higher food quality and less weight loss through the formation of smaller ice crystals.
Because of its breadth of expertise across the food processing spectrum, JBT FoodTech has been able to respond to customer needs. The GYRoCOMPACT S6 was initially developed in response to a request from a fresh pasta manufacturer that sought a replacement for an old spiral steamer. By combining the cooking knowledge of the Stein product line and the vast experience producing spiral systems and managing airflow of the Frigoscandia product line, a solution was designed that met the customer’s need for a higher-performing yet affordable in-line steamer.
The GYRoCOMPACT series was a major milestone for JBT FoodTech. However, as various enhancements and new belt sizes were added to the range, the GYRoCOMPACT family became somewhat differentiated. Spare parts for a newer model were not always compatible with an older machine. Aware that GYRoCOMPACT spiral freezer customers were seeking common features and parts across the whole freezer series, JBT FoodTech returned to the drawing board to create a new, unified range of spiral freezers based on the proven GYRoCOMPACT system. The result was the new M-series of GYRoCOMPACT spiral freezers, chillers and proofers with enhancements in all areas.
Unlike regular spiral steamers, which have trouble controlling steam flow and reaching ideal operation temperatures, the GYRoCOMPACT S6 has a controlled steam environment that provides even product steaming across the belt width. A patented “two-zone cooking” approach offers a mixture of saturated and dry steam that achieves better cooking results than traditional steamers. As the product enters the bottom of the spiral, it encounters saturated steam, which condenses on the product to cook it. The steam enters the belt stack from the top, where it hits a hood, or “top hat,” that covers the top tiers of the spiral, creating a zone of dry steam. The product has already been cooked by the saturated steam when it reaches the dry zone, where excess surface water is removed for a higher-quality final product.
Ideal for gently cooked food
The GYRoCOMPACT S6 steamer is ideal for pasta products and for other foods that are steamed or gently cooked, such as corn on the cob, sausages and poultry fillets. It is also a good option for pasteurization of a wide range of packed products. Unlike products pasteurized using common steaming or water bath methods, foods pasteurized using the GYRoCOMPACT S6 do not require an additional time-consuming drying step in the production line, since the steamer itself dries the product when it passes through the dry steam at the spiral’s top.
By offering an all-stainless-steel hydraulic design that operates using food-grade oils that can tolerate elevated temperatures, the steamer enhances uptime. There are no electrical parts inside the machine, making it ideal for steaming applications. The control cabinet is located away from the machinery, and the lights for the steamer are on lever arms that can be swung near the machine and turned on only for cleaning and maintenance.
Freezing applications in Asia
In Asia, the GYRoCOMPACT spiral freeze range has seen successful applications in many food segments. Prawn processors were among the first users of the spiral freezer. By reducing freeze burn, product damage and weight loss, the adoption of spiral freezers played a crucial role in achieving the product quality and safety standards required by Asian exporters.
Later, as the Chinese food industry embarked on a modernization drive, GYRoCOMPACT spiral freezers were commonly used to freeze dumplings and steamed buns. In Japan, frozen TV dinners, karage chicken and other prepared foods are popular applications. Space is at a premium in Japan, and Frigoscandia’s units are normally only half the size compared to other freezers. The freezer’s small size also allows them to be delivered as a single pre-fabricated unit for quick installation.
Redesigned for hygiene and cleanability
The current proliferation of quick-service food outlets in many countries has increased the risk of food-related illnesses. Inevitably, legislators have responded with more stringent hygiene standards, regulatory inspections, traceability requirements and tougher penalties for in-fractions. For those who supply frozen food to these consumer markets, the cost of producing unsafe food has never been higher. Consequently, sanitation concerns have been top priority for Frigoscandia’s GYRoCOMPACT spiral freezer, and the concept of cleanability has been taken beyond the freezing zone and applied to the entire freezer. One major required enhancement has been the cleaning of the evaporator coil. The evaporator coil that previously was located very close to the freezer walls has been made much easier to access by moving it further within the freezer so that it can be inspected and cleaned from all sides. The evaporator airflow also runs counter-current to flush water for optimal cleaning results.
A meticulous effort to eliminate bacteria traps, improve cleaning access and reduce cleaning time is evident in several other design features. Large, self-closing hatches that open to 80 degrees provide easy access to all parts of the freezer, making the product zone fully cleanable. The stainless steel infeed and outfeed are pre-assembled and seal-welded onto the freezer enclosure, eliminating areas where condensate can accumulate and form bacteria traps. Infeed legs are eliminated to improve cleaning access.
The freezer’s “open plan” stainless steel floor is fully welded, with elevated floor-to-wall joints (200 millimeters above floor) which slope to fully welded drains with beveled edges for faster and complete drainage. Side guides are made from stainless steel instead of plastic, and the open structure support ring is designed to minimize surface-to-surface contact between stainless steel and plastic parts. On the stand and drive system, horizontal surfaces have been reduced, with solid stainless steel rods replacing hollow horizontal beams.
The Frigoscandia GYRoCOMPACT S6 steamer self-stacking spiral conveyor enables processing of up to 50 percent more product than a conventional steamer with the same footprint, forming its own stack. There are no rails, no glide strips and no drum drive to complicate cleaning. Compared with a conventional spiral, it offers continuous stack support and minimal steam leakage. This gives uniform product outfeed temperature across the belt. The “belt squeeze” and “Christmas-treeing” that plagues traditional spiral conveyors is eliminated, thanks to the spiral’s tension-free self-stacking belt. Its unique TOPHAT drying zone gives exact control over surface texture and appearance, which gives a dryer finish on sealed product packaging. Positive steam feed and impeller fan ensure uniform distribution throughout the stack. Double-duty steam containment equalizes variations in steam flow and keeps the steam in place. It also eliminates leakage into the factory locale, ensuring a cleaner, more comfortable work environment. Full seal welding eliminates risk of condensation inside panels. Each panel forms a tightly sealed individual cassette, which is joined with other cassettes to build the enclosure. This also accommodates expansion and contraction, without leakage, during operation. High-quality insulation ensures that outside temperatures are not affected.
The FRIGoBELT conveyor delivers up to twice the capacity of a regular spiral steamer for a given height with a wide range of link heights, belt types and configurations to match current and future processing needs. Its self-stacking design eliminates the need for the stationary railwork in traditional spiral systems that can make cleaning difficult. The result is a more compact machine with more efficient air flow control, which reduced freezing time and achieved higher food quality and less weight loss through the formation of smaller ice crystals. The FRIGoBELT design has proven effective in GYRoCOMPACT freezers worldwide and operates even more efficiently in a steam environment.
Steamflow ensures balanced steam flow throughout the product zone. Each individual product portion gets identical treatment, which is desirable from a quality standpoint (color, texture, etc.). When pasteurizing food it is critical and absolutely essential that all products passing through the steamer has been steamed sufficiently to kill any bacteria.