PTFE seals are widely used in the food and beverage industries. One reason is that they won’t contaminate foodstuffs. A second is that PTFE resists attack by acidic products like fruit juices. And third, they stand up well to the intensive cleaning and sterilization processes used in those industries.
Here’s a closer look at how those processes influence gasket selection.
Gasket Cleaning Protocols: CIP
Food and beverage (F&B) manufacturers are acutely aware of the risks of product contamination. That’s why regular cleaning and sterilization is a way of life. Facilities producing liquid products often employ Clean-in-Place (CIP) protocols.
CIP is where cleaning fluids are pumped through the pipes, tanks, mixers, kettles and filling equipment. A combination of aggressive chemicals, turbulence, and rinsing remove contamination from surfaces that contact the food and could otherwise harbor pathogens.
The alternative, Clean-out-of Place (COP) entails stripping down plumbing systems to remove components like valves for cleaning. For many F&B companies, it’s slower and less effective than CIP.
Gasket Cleaning: The CIP environment
CIP usually starts with a hot water pre-rinse. This is followed by running caustic soda through the system at 80°C (176°F). Caustic soda, chemical formula NaOH, (sodium hydroxide,) is highly corrosive. It kills and removes practically everything it comes into contact with. The caustic is then followed by thorough rinsing to get the surfaces food-ready.
Some plants and processes use acid in place of caustic soda. Nitric or peracetic acids are common choices. Steam and ozone are other alternatives sometimes used.
Gasket Cleaning Impact on Gasket Material Selection
Materials like NBR, EPDM, and neoprene have no problem handling CIP temperatures. Where they struggle is with resistance to acids, alkalies and often also water, steam, and ozone.
PTFE seals and gaskets function at temperatures up to 260°C (500°F). More importantly, they won’t react with any chemicals, whether acidic or alkaline. In addition, most grades of PTFE don’t impart any taint to product and are FDA-approved.
If you’d like to learn more about the advantages of PTFE seals in processes that need cleaning and sterilization, contact a material specialist at Hennig Gasket.