Choosing the right fluid handling system for pumps in modern food processing facilities involves more than just technical specifications. Designers, operators, and managers must take on significant health-related responsibilities that go beyond standard industrial manufacturing. Since the end users of these products are the general public, maintaining product purity is critical. Contamination must be completely avoided, and corrosion is not acceptable. Any cracks or dead spots in pumps or piping that could trap fluids and promote bacterial growth are unacceptable.
In addition to selecting materials that are safe for direct food contact, the industry must also choose piping and tank equipment that can handle acidic and alkaline cleaning solutions used during maintenance. These systems must also be compatible with various environmentally compliant chemicals used in sewage treatment. Pumps used in food applications must be made from materials that do not chemically react with the product or affect its taste, color, or other characteristics.
Design considerations for non-food contact fluid systems include reducing maintenance and downtime, increasing throughput, lowering costs, and evaluating supplier expertise and service quality—factors that are often difficult to quantify but crucial for long-term success.
The use of plastic pumps has grown significantly over the past 50 years, starting with the development of a flexible linear screw-rotor pump by Vanton for use in heart/lung surgery. This early design had a simple structure, consisting only of a solid plastic body and a synthetic rubber liner. It addressed two key concerns: avoiding metal contamination and preventing damage to sensitive fluids like blood. Its simplicity also made it easy to clean and reassemble, making it ideal for medical and later industrial applications.
With the help of chemical manufacturers such as DuPont and Atofina, new thermoplastic materials were developed to handle corrosive substances like acids, bases, and solvents. These materials enabled the creation of more durable and cost-effective pump designs, meeting the growing needs of the food and pharmaceutical industries.
Today, there are approximately 150,000 flexible linear pumps in the U.S., with a total capacity of 40 GPM, and roughly double that number in Europe. These pumps are used for handling sensitive and corrosive fluids at low to medium flow rates. They are especially useful in industries requiring high delivery efficiency without the use of metallic components.
Thermoplastic centrifugal pumps are available in horizontal and vertical configurations, capable of handling up to 1,500 GPM, lifting fluid up to 400 feet, and operating continuously or intermittently at temperatures up to 275°F. They meet ANSI standards and come with sealless mechanisms and automatic starters. Vertical models can run dry and have segmented shafts that allow for lengths up to 50 feet. These features make them ideal for use in the food industry where no metal parts come into contact with the fluid.
One common application is in the handling of sticky mustard and vinegar. Flexible linear screw-rotor pumps can manage both clear and highly viscous fluids, including slurries and those with small particles. For example, vinegar is stored at ground level and pumped into an elevated tank, then flows into an ingredient tank via gravity. Mustard seeds and salt are added, and the mixture is transferred to a mixing tank before being filled into bottles.
At August Barer & Sons, a pump was installed to handle 10 GPM at 50 PSI with a viscosity of 5,000 SSU. Only two plastic parts come into contact with the fluid, ensuring no chemical reaction. The polypropylene cylinder has an unlimited lifespan, and the synthetic rubber liner requires minimal maintenance, with replacement needed only once every 20 years under normal operation.
In dairy processing, similar challenges exist, especially when using caustic chemicals for cleaning. Tuscan Dairies, for instance, uses strong base and acid solutions to neutralize waste streams before discharge. Flexible linear pumps are well-suited for delivering and draining these chemicals. Seven types of synthetic rubber liners and four pump body materials are available to meet different needs.
A Scottish dairy faced strict regulations regarding wastewater pH control due to sulfuric acid injection. To meet these requirements, they used a Sump-Gard Vanton vertical centrifugal pump made entirely of homogeneous polypropylene, which resists a wide range of pH levels. The pump’s components, including the impeller and housing, are molded from pure polypropylene, and ceramic and Teflon bearings ensure durability and performance.
Jiangsu Zijun International Trade Co., Ltd. , https://www.zijunplastic.com