About Rotary Shaft Seals in Food Processing
Rotary shaft seals in food processing play a vital role in ensuring the integrity and hygiene of processing equipment. They help maintain a clean, pollution-free environment, comply with food safety regulations, and contribute to the overall quality and safety of food.
While there are several options when it comes to approved polymeric or elastomeric seals for food processing applications, PTFE is one of the more popular choices–and that includes rotary shaft seals, as well.
Why are PTFE rotary shaft seals good in food processing applications? Rotary shaft seals in food processing equipment have to do more than an ordinary seal: they also need to withstand aggressive cleaning and sanitation regimens that may involve corrosive chemicals, be approved for contact with food, and offer effective, reliable performance.
Special Features
Due to the specific requirements of the food industry, Rotary shaft seals in food processing have some unique features and considerations. Here are some of their salient features:
■ Food-grade materials: Rotary shaft seals in food processing are made of food-grade materials that comply with food safety regulations. These materials are non-toxic, non-reactive and resistant to food-related chemicals, ensuring they will not contaminate food.
■ Hygienic design: The design of rotating shaft seals in the food industry emphasizes hygiene and cleanability. They are usually smooth and have no cracks or pockets where food particles, bacteria, or cleaning agents can collect. This design facilitates easier cleaning and sterilization, ensuring the equipment maintains a high level of cleanliness.
■ Comply with regulations: Food processing facilities must comply with strict food safety and sanitation regulations and standards. Rotary shaft seals in these applications are designed to meet these regulations, including those set by organizations such as the Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA).
■ Lubricant compatibility: In food processing equipment, lubricants are often used to ensure smooth operation and reduce friction. Rotary shaft seals in food processing are designed to be compatible with food-grade lubricants and prevent their contamination or leakage, thereby maintaining the integrity of the lubrication system.
■ Temperature and chemical resistance: Food processing involves a range of temperatures and exposure to a variety of chemicals used for cleaning and disinfection. Rotary shaft seals are designed to withstand these conditions, including high temperatures during equipment operation and chemical exposure during cleaning processes.
■ Easy to maintain and replace: Rotating shaft seals require regular inspection, maintenance and replacement to ensure their effectiveness and prevent any potential risk of contamination. Food grade seals are typically designed to be easy to install and replace, minimizing downtime and promoting efficient maintenance procedures.
■ Performance in challenging environments: Food processing environments can be very demanding, including factors such as high-pressure washdowns, abrasive particles and rapid temperature changes. Rotary shaft seals in food processing are engineered to withstand these challenging conditions and maintain their sealing performance over time.
How PTFE Rotary Shaft Seals Are Used In Food Processing Applications
Food processing machinery that uses shaft seals includes mixers, food dispensing equipment, dry product filling systems, ice cream dispensers, milk dispensers, high-pressure homogenizers, water purification equipment and distilled water pumps. They can be used with binders, flavorings, water, powders, preservatives, sauces, condiments, steam and a variety of liquids.
Operating conditions
Rotary shaft seals in food processing industry must be able to handle the standard operating conditions involved, such as speed, temperature and pressure. However, their operating environment may be more than just this: the type of media they will come into contact with (e.g. powders, extremely viscous liquids) must be considered.
PTFE is a polymer with a proven track record in rotating shaft seals that must perform over a wide range of temperatures, pressures and speeds, and is available in a variety of grades to provide more customized performance.
CIP/SIP
Rotary shaft seals must withstand the sterilization or cleaning procedures involved. CIP (Clean in Place), SIP (Sterilize in Place), and COP (Clean Out of Place) methods often require aggressive cleaning agents and/or superheated steam, powerful disinfectants, and potentially corrosive acids.
PTFE is highly resistant to a wide range of aggressive chemicals, can handle repeated exposure to hot water and superheated steam, and will not react chemically to the powerful disinfectants and sanitizers that food processing equipment is exposed to.
Safe for food contact
Any part of the rotating shaft seal that comes into contact with food must comply with applicable regulations, such as FDA 21 CFR 177.1680, (EC) No. 1935/2004, and/or USP Class VI. This approval isn’t easy to achieve: It takes into account whether the material releases any chemicals, readily absorbs moisture, undergoes physical changes when exposed to high temperatures, reacts chemically with acidic ingredients, outgasses, and more.
PTFE grades are fully compliant with regulations regarding food contact and are FDA-approved, making them a safe choice for rotating shaft seals on food processing equipment. Additionally, it is the most chemically reactive polymer on the market today.
Conclusions
Finally, PTFE rotary shaft seals have proven themselves to be highly reliable, which is why you will see them used in dangerous, mission-critical applications where safety and ruggedness are vital, such as those found in the oil and gas or aerospace industries. If you are looking for an FDA-approved rotary shaft seals in food processing applications, PTFE seals should be at the top of your list.
