Spring Energized PTFE Seal
by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Polymer Seals in Food and Dairy Applications: Challenges for Engineers

There are numerous challenges associated with polymer seals for the food and dairy industries, and the complications are numerous. From hygiene by design and zero tolerance for contamination to the unbelievably high cost of recalls, to temperature swings and moisture issues, engineers put in a significant amount of work to ensure that polymer seals are designed and specified correctly. 

This blog post will explore the challenges and discuss solutions to each one.

Challenge 1: Surviving sanitation cycles (CIP/SIP)

CIP (Clean In Place) and SIP (Sanitize In Place) are harsh on seals and can involve repeated exposure to hot caustics, oxidizers, steam, and sometimes UV radiation. Additionally, the thermal spikes that often accompany CIP/SIP can lead to dimensional issues due to expansion and contraction. Issues with moisture absorption during the sanitation cycles are also a major problem.

Engineers need to consider the chemical intertness of the polymer chosen, as well as dimensional stability through temperature changes and low moisture absorption. Materials such as PTFE and UHMW-PE are an ideal choice for addressing these issues. They can retain key properties across cryogenic to steam conditions and withstand the most common CIP/SIP chemicals. Finally, PTFE is stable under exposure to UV used for sanitation.

Challenge 2: Chemical compatibility with cleaners and barrier fluid

Some of the common chemicals that are used to clean food and dairy equipment include . . .

  • Alkaline cleaners (such as sodium hydroxide-based)
  • Acidic cleaners (such as phosphoric or nitric acid) 
  • Oxidizing agents like sodium hypochlorite (bleach) or peracetic acid 
  • Quaternary ammonium compounds (quats)

These chemicals can lead to various issues, depending on the material used for the seal, including softening, hardening, and cracking. However, PTFE and UHMW-PE are minimally reactive to such chemicals.

Challenge 3: Contamination control and lubricant management

In the food and dairy industry, any external lubricant can become a contaminant; even “food-grade” oils complicate HACCP plans. This severely limits the type of polymers that can be used for seals; however, PTFE and UHMW-PE are both self-lubricating and can handle dry running.

Challenge 4: Moisture, swelling, and dimensional drift

Hot washdowns and steam can drive steam into hygroscopic materials, which leads to swelling and dimensional drift that can, in turn, cause compression and changes in clearances. PTFE and UHMW-PE exhibit negligible moisture absorption, which enhances fit and facilitates improved leak control after washdown. 

Challenge 5: Abrasion and scratch avoidance on product-contact surfaces

Product-contact surfaces must stay as free as possible of abrasions and scratches because such surface imperfections can trap microbes and residues. For this reason, surfaces must be durable, smooth, and easy to clean. UHMW-PE offers exceptional abrasion resistance while remaining gentle to mating surfaces, and PTFE has a very low surface energy that effectively sheds debris.

Challenge 6: Wear life and unplanned downtime

When seals fail, there is a much higher risk of contamination and increased downtime. Both are expensive to deal with. PTFE and UHMW-PE both exhibit excellent wear resistance, which can extend service life and reduce the frequency of unplanned downtime. 

Challenge 7: Taste, odor, and extractables

Some polymers leach flavors or odors into sensitive products, which is unacceptable in the food and dairy industry. However, both PTFE and UHMW-PE do not impart any taste or odor, and are non-toxic, making them an ideal solution to this challenge.

Challenge 8: Compliance and hygienic standards

Finally, engineers must navigate the FDA, 3-A Dairy, and customer audits while balancing performance and cost. Fortunately, PTFE and UHMW are available in FDA-compliant grades and are used in 3-A Dairy-compliant designs.

PTFE vs. UHMW-PE Seals in Food and Dairy Applications

Here is a table to help you choose between PTFE and UHMW-PE for polymer seals in the food and dairy industry.

If Your Primary Concern Is…Choose:Reason
Aggressive chemicals, oxidizers, or caustic CIP/SIP agentsPTFEUnmatched chemical inertness and high-temperature stability
Steam sterilization or UV sanitationPTFEHandles heat and radiation without degradation
Abrasion, impact, or misalignmentUHMW-PEExcellent toughness and wear resistance
Cost-effective wear surfaces in moderate cleaning regimesUHMW-PEEconomical and durable for non-critical seals
Low friction, precision dynamic sealingPTFEVery low coefficient of friction and dry-running capability
Hygienic, FDA / 3-A compliant designEitherBoth are available in food-grade, non-contaminating formulations

Solutions for Polymer Seals in Food and Dairy Applications

There are several challenges engineers face when designing for food and dairy designs. However, the right choice of material can address many of these issues, and both PTFE and UHMW-PE are popular choices.  

The experts at Advanced EMC are here to help you find the right sealing solution, from the type of seal you need to the best material for your food and dairy applications. Contact us today to learn more!

by Denise Sullivan Denise Sullivan 1 Comment

Navigating Sealing Challenges in Food and Dairy Equipment: A Comprehensive Guide

Maintaining stringent hygiene standards and ensuring product safety are paramount in the food and dairy industries. One critical aspect that plays a vital role in achieving these goals is equipment sealing. Effective sealing solutions prevent contamination, ensure operational efficiency, and comply with regulatory standards. However, the unique challenges posed by these industries require specialized solutions. This blog post will explore the common sealing challenges faced in food and dairy equipment and discuss strategies to overcome them.

food and dairy equipment

The Importance of Proper Sealing in Food and Dairy Equipment

Seals are essential in food and dairy equipment, preventing leaks, contamination, and equipment failure. Given the sensitive nature of these industries, seals must adhere to strict regulations set forth by bodies such as the FDA and the EU. Proper sealing not only ensures the quality and safety of food products but also extends the lifespan of the equipment and reduces maintenance costs.

Common Sealing Challenges in Food and Dairy Equipment

1. Temperature Extremes

Food and dairy processing often involves exposure to extreme temperatures, from the high heat used in pasteurization to the low temperatures required for storage. Seals must withstand these temperature fluctuations without degrading or losing their effectiveness.

Solution: Use materials like PTFE (Polytetrafluoroethylene) and silicone, which are highly thermal stable and can maintain their sealing properties across a wide temperature range.

2. Chemical Exposure

Cleaning and sanitization processes in the food and dairy industries use harsh chemicals. Seals must resist degradation caused by frequent exposure to cleaning agents, acids, and other chemicals.

Solution: Opt for chemically resistant materials such as EPDM (Ethylene Propylene Diene Monomer), FKM (Fluoroelastomer), or PTFE, which offer excellent resistance to various chemicals.

3. Wear and Tear

Food and dairy equipment seals are subject to constant motion and friction, leading to wear and tear over time. This can compromise the seal’s integrity and result in leaks or contamination.

Solution: Utilize high-performance materials like UHMW-PE (Ultra-High Molecular Weight Polyethylene) or PTFE, known for their low friction and high wear resistance, ensuring longer seal life and reliability.

4. Hygiene and Cleanability

Maintaining hygienic conditions is crucial in food and dairy processing. Seals must be easy to clean and not harbor bacteria or other contaminants.

Solution: Choose non-porous, easy-to-clean materials like PTFE and silicone. Additionally, seals should be designed to minimize crevices where bacteria can accumulate.

5. Regulatory Compliance

Seals must comply with stringent regulatory standards to ensure food safety. This includes FDA, EU, and other international standards that dictate material composition and performance.

Solution: Ensure all sealing materials are certified and compliant with relevant industry standards. Regularly review and update materials and designs to meet evolving regulations.

Innovative Sealing Solutions for Food and Dairy Equipment

  1. Encapsulated O-rings: Encapsulated O-rings combine a PTFE jacket’s chemical resistance with the rubber core’s elasticity, providing an effective seal in challenging environments.
  2. Sanitary Gaskets: Designed to meet strict hygiene standards, sanitary gaskets made from materials like silicone or PTFE offer excellent sealing performance while being easy to clean and maintain.
  3. Spring-Energized Seals: These seals are ideal for dynamic applications requiring high wear resistance. The spring component ensures consistent sealing pressure even under varying conditions.

Sealing challenges in the food and dairy industries require specialized solutions that address temperature extremes, chemical exposure, wear and tear, hygiene, and regulatory compliance. Manufacturers can ensure their equipment’s safety, efficiency, and longevity by selecting suitable materials and designs. As the industry evolves, staying abreast of the latest sealing technologies and standards will be crucial for maintaining high-quality production and protecting consumer health.

For more information on advanced sealing solutions for food and dairy equipment, contact our experts at Advanced EMC Technologies. We are committed to providing innovative and reliable sealing solutions tailored to your needs.