Selecting the right seals for food and beverage processing

Sealing in food and beverage applications is extremely challenging. Not only must seals stand up to extreme temperatures, steam and wear in dynamic situations, but they must also meet regulatory requirements and be compatible with different food types and ingredients, such as fats, oils and acids. In addition, hygienic design, resistance to aggressive cleaning regimes and avoidance of flavor carryover are top priorities.

This article discusses seal materials used in food and beverage processing applications, the use cases for each, and common factors that can affect seal performance, equipment uptime and food and beverage product performance, as well as the benefits of partnering with an experienced seal manufacturer to ensure the sealing solution best meets the requirements of the application.

Seal materials used in food and beverage applications
One of the keys to prolonging the life of seals used in food and beverage applications is matching the material to its processing system or the processing system it is used in. The seals must be resistant to the foods and beverages processed, as well as the chemicals used in cleaning regimes, often at elevated temperatures.

One of the most commonly used materials for O-rings and gaskets in food and beverage processing is ethylene propylene diene rubber (EPDM), a fully saturated, non-polar hydrocarbon-based elastomer. Its polymer geometry gives it superior compatibility with polar fluids even at elevated temperatures. EPDM demonstrates high chemical resistance, is suited for use with alkaline and acidic cleaners, and is an excellent choice in most dairy applications, except for products with high fat content. Its typical applications are filling, dispensing, pumps, pipe and flange gaskets, valves and quick connectors.

For applications using animal and vegetable fats and oils, acrylonitrile-butadiene rubber (NBR) is a good choice when the O-rings will not be exposed to harsh cleaning regimes, ozone or superheated steam. NBR is a copolymer of butadiene and acrylonitrile, and the percentage of these in the NBR formulation determines the performance characteristics of the material.

Fluoroelastomer (FKM) materials are optimized for steam environments in the food and beverage industry. They demonstrate good suitability for use in contact with vegetable oil and fat, animal fat and high-fat dairy products. They also have good resistance to ozone and aging.

The gold standard for elastomer sealing, perfluoroelastomer (FFKM) is more expensive than other sealing materials but is compatible with virtually all media. It is ideal for extremely aggressive processing and cleaning regimes in which seals can deteriorate very quickly. Though more expensive, FFKM seals can extend planned maintenance and, therefore, lower the total cost of ownership substantially.