HeatTek Discusses 5 Red Flags with Aging Can Washers

Not many pieces of equipment take more abuse than a washer. Depending on the circumstances and original components, canmakers are seeing as little as a three-year life on areas of their washers. Considering the expense required to replace them, many canmakers are looking for options.

What can a canmaker do when they see critical components of their washer start to fail? Many are starting to take advantage of fully prefabricated replacement parts.

These in-field replacement options are giving canmakers worldwide a huge advantage over the alternative - expensive, new equipment:

• Extending washer life at a fraction of the cost
• Avoiding 1-2 month outages
• Increasing plant efficiency and versatility with newer technology
• Reducing footprint with more sustainable components

The Red Flag:

When bearing box seals fail, you’ll notice water leaking external to the washer. And as soon as the chemicals are outside the system, it will corrode the stainless steel sidewalls and areas directly below it. Over time, pocket walls, shaft seals and bearings lose effectiveness. This leads to catastrophic failure and an unplanned shutdown.

Solution:

You can have replacement hold down bearing box kits fully fabricated and then shipped directly to your plant. Canmakers can plan for a shutdown of only one to three days while they are replaced.

The Red Flag:

When air knives start to lose effectiveness, canmakers will start to see an increase in carryover of chemicals between stages.

Solution:

Air knives can be easily replaced onsite with prefabricated replacements. When ordering a new air knife system, canmakers should consider the velocity of their older model. Newer designs allow for better and more efficient systems.

Also, when ordering new prefabricated air knives, canmakers have the option of replacing them with a newer, more sustainable technology that uses recirculated airflow. These systems utilize only one blower and use the air contained within the system (vs. air from outside the washer). This minimizes the exhaust fan airflow required to keep the washer balanced.

The Red Flag:

When canmakers are challenged to be more versatile by performing change overs for multiple types of cans, they may need a quick solution to replace their single can size risers.

Due to lack of available personnel, canmakers may also require a design that makes maintenance easier.

Solution:

Traditional riser systems can be traded out in the field for quick release risers. 

Risers should be analyzed for a few different features:

• Weight – Lighter weight risers are now available for easier transitions for production schedule with multiple can diameters and for simplified cleaning and maintenance. 
• Nozzle density - The most efficient risers will have high density nozzle spacing. While traditional risers may have 27-35 nozzles, a more advanced system will have as many as 47. More nozzles result in more contact points on the can.
• Centers – Less efficient risers will have 12-inch centers. New, more efficient systems will have 8-inch centers. This increases production capacity and efficiency.

The Red Flag:

This is another factor in canmaker flexibility. Traditional can guides (value-guides) aren’t optimized for can size changeovers. If a plant needs to produce different diameter cans, the can guide will be one of the components to examine.

Solution:

Upgrading the can guide to a tight pack allows for flexibility to optimize the washer for different diameter cans. A versatile tight pack system can be prefabricated and designed for installation on site.

The Red Flag:

Washers utilize shafts and sprockets as part of a conveyor to transport cans through the system.  Without a well-maintained conveyor, no cans can be made. Often, sprocket teeth and shafts wear out over time due to friction and corrosion.

Solution:

With a simple drawing, your trusted supplier should be able to provide customized sprockets for replacement right in the plant. And when installing new sprockets, your washer’s shafts should always be replaced. These components have a similar life expectancy, and, after years of wear, old shafts often don’t fit with new sprockets.

The stainless steel components of a washer take the brunt of the corrosive chemicals that are constantly running through the equipment. The process of passivation is the key factor of a component success story (or failure). It provides the barrier to harsh chemicals and protects the integrity of critical welds that prevent leaking.

But not all passivation processes produce the same results. A hot dip, nitric acid passivation will result in the longest life for stainless steel while a brush-on, citric acid process will only mildly protect the stainless steel. For anything related to washer components, a discussion about passivation could ensure that you aren’t planning the same project again in a few years.