Whether a social gathering or sporting event, there is a soft drink for every occasion. Crafted by blending water with syrup, carbon dioxide and various coloring and flavoring agents, soda production also entails a series of meticulous filtration procedures. Noteworthy among these are activated carbon filters designed to eliminate both odor and coloration from the syrup, the principal ingredient, as well as low calcium filtration to avoid issues of instability.

The caliber of the final product is profoundly influenced by the excellence of this syrup, which in turn hinges upon a multitude of factors encompassing origin, production protocols and transportation and storage conditions. Consequently, the formulation of soda syrup emerges as one of the most pivotal phases within the overall manufacturing continuum of soft drinks.

In order to maintain consistency throughout its production process, starting from the initial ingredients through to the end product, a European producer of popular carbonated beverages partnered with Eaton. Its goal was to create a more proficient filtration system. The outcome was an automated filtration line that employs backflushable stacked disc cartridges. This advanced setup enabled the manufacturer to effectively eliminate microbiological impurities and suspended particles from the raw syrup, while also enhancing process efficiency and prolonging the service life of the filter media through correct backflushing.

A Sticky Challenge

The inherent nature of soda syrup renders it susceptible to particulate and microbiological impurities, including yeast, mold and bacteria. The presence of suspended solids profoundly impacts the visual characteristics of the final product, while contamination holds the potential to induce deterioration, thereby giving rise to unfavorable attributes encompassing appearance, taste and off-flavor manifestations.

Notable is that the supply chain dynamics of raw sugar have undergone significant transformations in recent years, resulting in a shift in product quality at the desired price point and introducing novel challenges. Traditionally, raw syrup, regardless of its inherent quality, exhibits microbial stability at 70 degrees Brix, a measurement unit used to quantify the sugar content in a liquid solution. At this concentration, where 70% of the solution's mass consists of dissolved sugars and other soluble solids, the sugar content is sufficiently high to hinder the growth of microorganisms due to the unavailability of water for their proliferation. However, when the syrup's Brix levels dip lower, its stability is compromised, necessitating the application of microbial reduction filtration or alternative sterilization methods.

In the case of the soft drink producer, a 45-degree Brix syrup was employed at a temperature of 113°F (45°C), leading to a turbidity issue that manifested as cloudiness in the final product. Microbiological concerns were traced back to the raw sugar itself. While meticulous monitoring of these quality challenges was already in place throughout the manufacturing process, the mitigation strategies employed fell short of achieving optimal results in terms of both productivity and cost efficiency.

The manufacturer's objective was to attain comprehensive control over the production process, thereby ensuring consistent syrup quality irrespective of whether refined, unrefined or dissolved raw sugar was utilized. The pursuit was centered around the identification of an automated, in-line filtration solution capable of eradicating microbiological organisms and suspended solid particles from the sugar syrup matrix.

Eaton’s backflushable BECODISC R+ stacked disc cartridges meet national and international quality standards set by the LFGB (German Food and Feed Code), the FDA (U.S. Food and Drug Administration) and EU regulations (10/2011). Image courtesy of Eaton.

Syrup Filtration

Drawing from prior filtration line implementations at soda production plants across Europe, a proposal emerged from Eaton to replicate a similar solution using BECODISC R+ stacked disc cartridges. The BECODISC R+ range comprises eight backflushable and extra-robust variants that can be used for coarse, clarifying and fine filtration, as well as for microbial reduction and microbial removal filtration of various liquids.

“Stacked disc cartridges are often employed for soda syrup filtration due to their exceptional efficiency and versatility,” says Elke Brandscheid, team leader, technical service at Eaton Technologies, Germany. “These consist of numerous closely packed filter cells. Their piled arrangement also maximizes the filtration surface area, which enhances throughput while maintaining a compact footprint. Soft drink makers will note that the market offers many adaptable configuration options that permit tailored filtration based on syrup quality and processing requirements.”

The essential mechanics of the cartridges encompass the utilization of BECOPAD premium depth filter sheets, crafted from high-purity cellulose renowned for its exceptional wet burst strength and dependable backflushing capabilities. Particularly within the realm of food and beverage production, cellulose, a naturally derived material, stands acclaimed for its proficient capacity to purify liquids.

Producing the backflushable stacked disc cartridges is an intricate process where high assembly pressure is applied to join the cells with an intermediate layer of multilayer polyester fabric, which results in a very robust and compact unit. The honeycombed polyester fabric fills the space between the individual filter cells, forming a cushion. This allows for optimum inflow into each filter cell and optimum use of the entire filter surface area of the stacked disc cartridge. During the regeneration process, which restores the functionality of clogged or fouled filter media, it provides the stacked disc cartridges with the necessary robustness for a minimum of 20 cycles and helps to protect the depth filter sheets against damage, such as tearing or bursting caused by water pressure.

Further, the stacked disc cartridges can be flushed with cold and then hot water, 50-185°F (10-85°C), at a maximum differential pressure of 7.25 psi (0.5 bar) in the direction opposite to the filtration flow, meaning no additional backflushing kit is required. This also helps to assure sustained operational resilience.

Sweet Success

Collaborative efforts between Eaton and the soda producer’s production and laboratory teams soon yielded the development of a fully automated filtration line equipped with eight BECODISC R+ 16-inch stacked disc cartridges. This solution has been instrumental in achieving the requisite standards for microbiological and particle retention levels. A noteworthy accomplishment has been the ability to regenerate the filters iteratively, all while upholding the integrity of the filtration process, an achievement that has the further potential to significantly prolong the operational service life of the filters.

For the soda manufacturer, the outcome has translated into a reduction in the number of required filters and a substantial decrease in maintenance and service-related activities. Consequently, there has been a substantial alleviation of associated costs.

“In order to rationalize the capital outlay for the implementation of the fully automated filtration line, while meticulously accounting for both energy expenditures and filter procurement costs, the manufacturer established a goal of processing 50 tons of raw syrup per cycle utilizing a complete assembly of stacked disc cartridges,” said Brandscheid. “The outcome, however, surpassed projections significantly, as the filtration system adeptly processed a remarkable 300 tons of raw syrup, exceeding initial estimations by a factor of six.”

As a result of this collaboration with Eaton, the soft drink maker has taken command of its production processes. Moreover, it has effectively mitigated dependence on any specific supplier to ensure just-in-time delivery and the quality of the raw sugar.

Process parameters of Eaton’s fully automated filtration line solution that improved productivity, microbiology, and filter media service life for the soda manufacturer.

Utilization of backflushable stacked disc cartridges has emerged as a transformative solution in the realm of soda syrup filtration. Through their innovative design, these filters enable efficient particle removal of varying sizes, resulting in enhanced syrup purity and quality. The increased surface area offered by the stacked configuration both elevates filtration efficiency and optimizes production without compromising spatial considerations. Furthermore, backflushable filters can greatly extend filter media life, resulting in simplified maintenance, cost savings, and even environmental benefits by reducing the amount of filter material that ends up as waste.

For soda manufacturers seeking to fine-tune their syrup filtration processes, backflushable stacked disc cartridges can play a key role in ensuring consistent soft drink quality.