Challenges of Rotary Shaft Seals in the Food Industry | Advanced EMC Technologies
by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Challenges Faced When Specifying Rotary Shaft Seals for the Food Industry

A good seal should be reliable, experience minimal wear, be easy to install, and enhance equipment performance–but the rotary shaft seals on equipment for food preparation and handling involves much more.

The wrong rotary shaft seal for a food industry application can lead to expensive downtime, costly material waste, damaged equipment, problematic production delays, and even lawsuits. That is why it is critical that the rotary shaft seals that are used in the food industry be carefully specified–which involves several challenges.

Where Are Rotary Shaft Seals Found?

Dynamic rotary shaft seals are a key component for equipment such as …

  • High pressure homogenizers
  • Water purification equipment
  • Meat blenders
  • Distilled water pumps
  • Milk dispensers
  • Ice cream dispensers
  • Food portioning systems
  • Mixers
  • Screw conveyors
  • Milling rice, wheat, and flower
  • Holding tanks
  • Hoppers
  • Crushers
  • Dry product filling systems

Reliable rotary shaft seals are critical for food preparation and handling that includes chocolate manufacturing, baking, beverage manufacturing, bulk material handling, material and poultry processing, feed and grain processing, and dairy processing.

Exposure to Media

Seals in the food industry can be exposed to various types of media, including water, oils, acids, adhesives, powders, semisolids, suspensions, slurrys, and more. Some forms of media, such as acids and slurries, can accelerate the rate of wear experienced by a rotary shaft seal and lead to premature failure if the wrong material is selected. The choice of a material that is compatible both chemically and with the form of media is critical.

Sterilization and Sanitation

Many times rotary shaft seals will be subjected to sterilization procedures for CIP (Clean in Place), SIP (Sterilize in Place) and COP (Clean Out of Place). These methods may require aggressive cleaning agents or disinfectants, superheated steam, and potentially corrosive acids. Finding a suitable rotary shaft seal material that can handle the sanitation and sterilization methods in place for the target equipment can be challenging but not impossible.  

Another potential issue with regard to cleaning involves potential need for seals that can be disassembled and cleaned daily. The ability to spend minimal time in disassembly/assembly can have a significant effect on the cleaning process in terms of time, effort, and the quality of sanitation or sterilization achieved.

Temperatures

As just alluded to, seals may be periodically exposed to extremely high temperatures for cleaning or may simply operate in a high-temperature environment. However, not all temperature concerns relate to high temperatures: some applications involve sub-zero temperatures. The seal and material behavior at the extreme operating temperatures must be considered when specifying seal geometry and material.

Contamination

The food industry can be quite demanding when it comes to rotary shaft seals. Because food is involved, there are a myriad of concerns regarding contamination, with potential sources including lubricants for the seals, contamination from seals that have begun to leak, and contamination from the seals themselves. 

Compliance with Applicable Standards

Any part of a rotary shaft seal that comes into contact with food must conform to regulations such as …

  • USP Class VI
  • FDA 21 CFR 177.1680, 177.1550, and CFR 177.2600
  • (EU) 1935/2004
  • 3-A sanitary standards 18-03 and 20-27
  • NSF/ANSI standard 61 for drinking water systems
  • WRAS BS 6920
  • 3-A Sanitary Standards
  • (EC) No. 1935/2004

And compliance involves more than just the contamination concerns just discussed. The standards and regulations also look at answers to questions such as …

  • Does the material release any chemicals?
  • Does it exhibit outgassing?
  • Does it tend to absorb moisture?
  • Does it react chemically to acidic food ingredients?
  • Can the material be detected or traced?

Conclusion

Issues such as media type, sterilization and sanitation procedures, temperatures, contamination, and regulatory compliance are all challenges faced in the food industry, and that includes dynamic seals for equipment such as mixers and dispensers. Failure to address these issues leads to the premature failure of seals, which in turn leads to material waste, downtime, and production delays as well as the loss of customer confidence and even lawsuits. 

At Advanced-EMC, we understand the challenges involved with specifying rotary shaft seals for the food industry. Our team has the knowledge and experience to assist you in finding the right rotary shaft seal for all your food industry applications. We will work with you to choose a sealing solution that will provide excellent reliability, easy maintenance, and outstanding performance, all while complying with all applicable standards.  

PET Thermoforms | Advanced EMC Technologies
by Jackie Johnson Jackie Johnson No Comments

The Problem with PET Thermoforms

PET thermoform packaging—such as those used for fruits, vegetables, muffins, eggs and more—is technically recyclable with PET bottles. In fact, many PET reclaimers accept thermoforms in bottle bales, as long as auto-sort systems and best practices are in place.

However, only 9 percent of them ever make it to recycling bins.

In this week’s blog post, we will go over the obstacles reclaimers face in recycling PET thermoforms and what the plastics industry has planned to work past them.

A New Law

On September 24th, 2020, Governor of California Gavin Newsom signed a bill made by California Assembly member Phil Tang, requiring manufacturers to include recycled materials when making plastic bottles, and, by extension, plastic thermoform parts.

AB 793 is designed to bolster the market for recycled polyethylene terephthalate in the state. Manufacturers must meet a number of deadlines for recycled content, achieving 15 percent by 2022, 25 percent by 2025 and 50 percent by 2030.

Clamshells play an important role in the ability of companies in California, the country’s largest agricultural producer, to safely ship products across the nation. Lawmakers hope that the bill will propel the whole supply chain toward more environmentally responsible packaging, making California a greener state.

However, opponents of the bill state that while recycled content mandates can be positive, there exists a significant gap between how much recycled content actually exists and the requirements of the bill. Shannon Crawford, director of state government affairs for the Plastics Industry Association, says of the bill:

“While this bill would develop end markets for plastic materials, there should be an equal emphasis on improving the collection and sortation of these materials.”

A New Report

A coalition of packaging and plastic industry groups, part of a project led by the Foodservice Packaging Institute, and includes the Association of Plastic Recyclers, the National Association for PET Container Resources and companies like Amcor Ltd., Driscoll’s Eastman Chemical Co. and Sonoco Plastics, released a report in December on pathways to try to increase PET thermoform recycling. The report estimated there to be around 1.6 million pounds of PET thermoforms used in packaging in the United States and Canada. That, also according to the report, is sufficient enough to sustain a recycling market.

The problem, it found, was that there were also sizable barriers. These include technical challenges that cap the amount of PET thermoforms that can be mixed in with bales of more valuable PET bottles. On top of that, the prices of virgin resin have lowered to the point of creating a competitive challenge. And while buyers of PET bottles are willing to pay a premium, that’s not the case with other PET markets such as thermoforms.

According to Resa Dimino, senior consultant at Resource Recovery Systems, which prepared the report for the industry coalition, the next phase after the report will be to develop a pilot project in a community and work with MRFs and others on technical challenges. It will also include developing a viable investment strategy for PET thermoform recycling.

In Conclusion

While it is clear that thermoforms can be recycled, we still have a long way to go before the process is viable for the industry as a whole. The good news is that the industry is increasingly moving towards more sustainable options.