A clean freeze
A large scale cheese producer in California utilizes a custom freezer for its shredded cheese product. The process of shredding and freezing its cheese is contained within a 22’ W x 22’ H x 47’ L freezer to maximize the throughput rate for a final frozen product. The freezer stores at processing capacities up to 20 tons per hour and operates at temperatures of -20F or below. All internal freezer surfaces need to be cleaned at the end of each operating day and include cooling units, fans, ducts, air handlers, conveying systems and the freezer walls. Adding to the complexity of this project, large quantities of cheese fines accumulate in and around all the freezer equipment as well as on the chamber roof and walls. Any improved cleaning operation not only had to consider equipment cleaning for sanitary purposes, but sufficient water had to be distributed throughout the freezer during an initial rinse phase to mobilize and flush the large quantity of cheese fines to drain before final cleaning could proceed. Only recycled hot water is then used for the subsequent washes and rinses. The overall cleaning effectiveness depends heavily on the pre-rinse since only hot water is used in the cleaning process.
Prior designs utilizing rotating spray heads from other manufacturers did not function properly or malfunctioned completely due to the temperature cycles and other equipment characteristics. They also required a large number of cleaning “zones” to keep the supply system size to a reasonable amount (<350 GPM). Initial designs used 9 zones and 105 devices. To meet the goal of improved cleaning and shortened turnaround time, the existing devices were replaced with the Alfa Laval Toftejorg TJ20G, SaniMidget and Midget MiniFlow devices depending on their position in the freezer.
Once installed, the Alfa Laval Toftejorg equipment reduced the total number of cleaning zones from 9 to 8 or by 10% and also reduced cleaning time complexity and controls. The 360° high impact, pattern-based cleaning action of the TJ20G rotary jet head met the challenge of removing cheese fines during the pre-rinse phase for a large portion of the 44’ long chamber roof. The cleaning time of these areas and around the suspended equipment was reduced by 50% while improving the repeatability of the freezer’s cleanliness and the cleaning cycle time.
Results
The newly installed Alfa Laval Toftejorg equipment and cleaning design was considered a success on many levels. Overall, the design reduced the number of devices by 28.5% (from 105 to 75), eliminated one cleaning zone, reduced the individual zone flow rates between 11.5% to 56.5%, and dramatically reduced the overall cleaning time. These changes addressed about 90% of the cleaning areas inside the freezer and improved the cleaning efficacy in these areas over the previous design. Furthermore, this new design is now operating successfully and has been accepted as the standard for this and future freezer units.
