SPECIAL SECTION | Flow & Filtration
Handling Thick Fluids: Pumping Challenges in Food & Beverage Processing
Learn to choose the ideal pump for a specific application.
Pete Scantlebury | Finish Thompson
| IMAGE 1: Corn syrup is a high-viscosity fluid that demands special pumps for transfer. (Images courtesy of Finish Thompson)
In the food and beverage industry, moving fluids efficiently is central to nearly every stage of production—from blending and processing to filling and packaging.
While some products flow easily, many of the most popular items on store shelves—in particular syrups, savory sauces and thick pastes—present a very different challenge. These high-viscosity fluids resist flow, behave unpredictably under pressure and demand careful handling to maintain product integrity, consistency and quality.
That is where specialized pumping systems come into play. Designed to handle thicker materials without compromising texture or composition, these pumps allow for smooth, sanitary and reliable movement throughout the production process.
Regulation & Compliance Considerations
Handling challenging products requires more than simply moving fluid from point A to point B. It demands equipment designed around their specific properties.
For food and beverage manufacturers, this means not only evaluating pumping technologies and system design to ensure product integrity, efficiency and compliance, but also evaluating food-approved equipment to make sure it is deemed safe for use in food production by a number of organizations, such as the Food and Drug Administration (FDA), the American National Standards Institute (ANSI), the National Sanitation Foundation (NSF) and the European Union (EU).
Each of these organizations has its own regulations and compliance standards that food and beverage manufacturers must adhere to. In the U.S., these include:
- Good Manufacturing Practices (GMPs): This set of federal regulations (Title 21 Code of Federal Regulations [CFR] Part 110) form the foundation of FDA compliance, providing guidelines to maintain consistency, quality and safety in manufacturing processes.
- Food Safety Modernization Act (FSMA): The FSMA focuses primarily on preventing contamination by implementing hazard analysis and preventive controls.
- Current Good Manufacturing Practices (CGMPs): Established in 21 CFR Part 117, CGMPs address the design and construction of a food plant and maintenance of plant grounds, plant equipment, sanitary operations, facility sanitation and production and process controls during the production of foods
Specifically, these standards focus on the safety of materials that come into direct contact with food products. Equipment must be designed to prevent any harmful chemicals or substances from leaching into the product, while also being durable and easy to clean to minimize the risk of contamination and support sanitary operations. To meet these requirements, manufacturers rely on approved materials for both the equipment and all product-contact surfaces. Common choices include stainless steel, elastomers, polytetrafluoroethylene (PTFE), polypropylene, polyvinyl chloride (PVC), ceramics and titanium, each selected for their compatibility with food processing environments and their ability to maintain safety, cleanliness and performance.
| IMAGE 2: AODD pumps with FDA-compliant materials can handle a wide range of high-viscosity foods and beverages.
High-Viscosity Pump Considerations & Challenges
Once industry standards and regulatory requirements are accounted for, manufacturers can shift their focus to the characteristics and needs of high-viscosity foods and beverages. These substances are defined by their resistance to flow, requiring greater force and more precise control to move than low-viscosity liquids like water or juice.
Common high-viscosity food and beverage products include honey, chocolate, peanut butter, tomato paste, syrups, molasses, yogurt and cream, as well as bakery batters, fillings and concentrated beverage bases. These sticky sweeteners, dense pastes and dairy products require equipment specifically designed to preserve product quality throughout production.
Not only are these foods often sensitive to shear, temperature variation and contamination, they also present a number of operational challenges. Air entrainment and cavitation can interrupt flow and strain equipment, while changes in temperature can significantly impact how easily a product moves through the system. Some materials may also thicken further, clog or crystallize if not handled under the right conditions.
Overcoming these issues often involves turning to pump technologies engineered for steady, controlled flow and minimal internal disruption while also accounting for factors like flow consistency, product stability and sanitary conditions to ensure reliable processing. To meet these demands, pumps must provide the control needed to move high-viscosity fluids efficiently while maintaining product integrity and adhering to strict food safety requirements. Two pump designs that are suited to this task are air-operated double-diaphragm (AODD) pumps and drum pumps.
FEA & Physical Testing: Complementary Tools
FEA is not a substitute for physical testing, but a complement to it. It allows engineers to explore design behavior under realistic conditions without building a prototype for every iteration. This accelerates development and reduces cost, but it does not eliminate the need for testing of the f inal product. Physical validation remains essential for confirming assumptions and capturing phenomena that models cannot fully predict.
The FEA simulation can be used to make testing smarter: narrowing its scope, focusing on critical areas and avoiding trial-and-error design cycles. Instead of discovering problems late through repeated prototypes, simulation helps identify and mitigate risks early so physical tests become a final confirmation rather than a troubleshooting exercise
| IMAGE 1: FDA-compliant drum pumps engineered for high-viscosity fluids offer low-shear handling and ease of use.
| IMAGE 2: High-viscosity foods such as pastry fillings require pumps specifically designed to handle the viscosity as well as preserve product quality throughout production.
AODD Pumps & Drum Pumps for Viscous Transfer
AODD pumps are often used in the handling of high-viscosity foods and beverages, particularly in applications where flexibility and gentle handling are key. Powered by compressed air, AODD pumps use two diaphragms that move back and forth to create suction and discharge, allowing them to easily transfer thick, sticky and even particulate-laden products.
One of the primary advantages of AODD pumps is their ability to handle a wide range of viscosities without requiring complex controls or electrical components. They are inherently self-priming and can run dry without damage, making them well-suited for batch processing, drum unloading and transfer applications. Their low-shear operation helps preserve product structure, which is especially important for items like sauces, fruit preparations and fillings.
From a sanitation standpoint, AODD pumps are available in designs and materials of construction that meet strict hygiene standards and offer clean-in-place (CIP) capabilities. Because the product is contained within the fluid path and isolated from moving mechanical parts, the risk of contamination is minimized.
However, AODD pumps do come with some considerations. Their pulsating flow may require dampeners for applications needing a smoother output, and they are generally less precise than other positive displacement pumps for metering or continuous, high-accuracy dosing. Even so, their durability, ease of maintenance and ability to handle challenging fluids make them a practical option in high-viscosity food and beverage processing.
For applications that need a second choice, drum pumps may fit the bill. Drum and barrel pumps are used in facilities across the globe to transfer viscous food and beverage products from bulk containers, barrels or intermediate storage tanks to production lines safely and efficiently. They are specifically designed to handle thick, sticky and sometimes particulate-laden fluids such as syrups, chocolate, peanut butter, sauces, molasses and fruit concentrates that cannot be easily poured or siphoned.
For high-viscosity applications, the ideal drum pump features a progressive cavity, positive displacement design to ensure consistent flow regardless of fluid thickness. This design has a number of benefits, including:
- Gentle, low-shear handling to preserve product quality and texture
- Sanitary construction with food-grade materials like stainless steel and FDA-compliant elastomers
- Versatility to transfer a wide range of viscosities without product damage
- Ease of use and maintenance, supporting fast changeovers and cleaning
When the right pump type is combined with proper material selection, both AODD and drum pumps can provide a reliable solution for safely transferring thick foods and beverages while maintaining hygiene, flow consistency and efficiency. By carefully selecting pumps based on product characteristics and operational needs, manufacturers can maintain quality, reduce waste and streamline processes across the food and beverage industry.
Pete Scantlebury is vice president of development for Finish Thompson, Inc. He has more than 45 years of experience in several technical positions with the company and is the go-to resource on the nuances and applications of industry pump systems. For more information, visit finishthompson.com.
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