MRO Today - Do your sorbents suck?

Do your sorbents suck?
Machine maintenance and the right sorbents
can make your plant cleaner and safer

by Paul V. Arnold

Are things looking up at your plant? To answer that question, look down.

Do you see little pools of oil on the concrete floor around the machines?

Is it easy to spot oil stains on the floors or boot prints made from liquids tracked around the plant?

Are absorbent compounds that someone spread on the floor to soak up the oil and discharge doing the job? Or, are the sorbents as big of a mess as the fluids?

Are there repairmen lying on the ground trying to repair machines that have become sluggish or simply have stopped working?

If you have answered yes to any or all of these questions, you are not alone.

“You still see a lot of that,” says John Sellars, president of Sellars Absorbent Materials, Milwaukee. “We were down at a bearing manufacturer in Chicago recently and he had a chipper area where there was a ton of oil and clay and mess lying around. They were using old T-shirts and clay to clean up the mess.”

Yes, many factories have problems related to chronic leaks and spills. In most cases, however, these types of problems are addressable, containable and reversible.

Taking the time to really get to know the plant — its machines, its messes, its materials — can go a long way toward remedying the situation.

Facing the facts
“As long as there are cars, there are going to be drip areas in garages,” says Bob Purdy, sales director at LeapFrog Technologies, an absorbent products company in Altoona, Pa. “As long as machinery has liquid that runs it or operates inside it, there are going to be leaks.”

The first step in finding a remedy is examining each machine and locating the source of the leaks.

“If our customers are not fixing the leaks in their equipment and looking at preventive and predictive maintenance on those machines, they are doing themselves a disservice,” says Purdy.

Get down, get dirty
Get several people who are familiar with the machine and check it out, top to bottom. See what makes it tick, and churn, and spit.

Use eyes and tools to find the source of the leak and examine where the extruded oil or fluids go. How large is each drop or spray? How far does it travel? Where is the point of impact?

Loctite Corp., Rocky Hill, Conn., has a program at its sealant plants called Operation Stop Leak where teams of employees do just such a check-up on their machines and identify leaks and other problems.

Darren Farrugia, marketing director at Loctite, says the program began five years ago. He says success rates vary from machine to machine and plant to plant.

Sometimes, the process ends there. In many cases, though, that is just the beginning.

“There are leaks that can be fixed and machine problems that can be addressed, but on the other hand, there are fluids on the floor caused by the process of the machine,” says Purdy. “Whether it’s milling or grinding or boring, the process causes overspray or drips that aren’t shielded. That’s not a leak. That’s a result of the process.”

In these cases, the types of absorbent products you use to contain, soak up and get rid of fluids can go a long way toward making the plant floor a clean, safe and productive environment.

Know your sorbents
“I would say that up to 96 percent of plants use some kind of absorbent product,” says Mark C. Johnson, vice president of sales and marketing for Sorbent Products Co. (SPC), Somerset, N.J. “The need is universal. The question is whether they are using the right products for their needs and are using them properly.”

Maintenance personnel should choose sorbents based on the kinds of fluids that leak and spill around a given machine. Is it strictly oil? Are there solvents, acids or chemicals involved? Different sorbents handle different types of liquid.

Here is a look at some commonly used sorbents:

Clays: These chemically-inert products absorb most liquids safely, are inexpensive and can be discarded in both sanitary and hazardous-waste landfills. However, they are much heavier than other products, are labor-intensive, only hold their weight or less in liquid and leave a gritty, dusty residue that can affect machine filters, gears, transmissions and other moving parts.

“Clays will always be used by some people, but when you really think about it, there are very few applications where it would be a good choice,” says Sellars.

Other organics: These products include ground corn cobs, rice hulls, peat and recycled newspaper. They are more expensive than clays but are still relatively inexpensive. They are light and hold about four times their weight in liquid. Since they are biodegradable, they can’t absorb acids and other aggressive fluids and can’t be disposed of at a hazardous landfill. They can be incinerated.

Organics create dust, but not as much as clay. They come in pillows and socks (polyester or polypropylene skins filled with the organic compound).

Polypropylenes: These plastic-based, chemically-inert products are divided into several sorbent groups. Oil-only polypropylenes are only used to pick up oil. Chemical polys are specially made to absorb acids. Universal polys pick up any type of liquid, from oil to acid.

Polypropylenes are more expensive than clays or organics, but are durable, lightweight and absorb around 20 times their weight in liquid. They’re produced as pads, rolls, socks and pillows.

Polys can be disposed of at a sanitary or hazardous landfill, depending on the liquid content. They can be incinerated and, in some cases, reused.

Color-coding polypropylene socks, pads and rolls helps identify what is being absorbed so hazardous materials can be handled safely.

Look at total cost
“A lot of people don’t put much thought into what type of sorbent products to purchase,” says Kent Oldenburg, national sales and marketing manager for Oil-Dri Corp., Alpharetta, Ga. “Some still treat sorbents as cleanup products and figure it’s pretty much like buying a ream of paper towels. They shouldn’t think of it that way. They need to think of it as a part of an overall floor and environmental safety plan.”

Oldenburg says many people focus on point of purchase price, but fail to do their math before buying.

“We try to have people buy products based on what we call ‘price per pound absorbed,’ ” he says.

A product that is twice as expensive but absorbs four times more than the cheaper product is a better overall deal.

For example, it takes seven pounds of corn cob to absorb one gallon of paint. To do the same job, it takes five pounds of newsprint or three pounds of peat. It takes two pounds of a plastic-based product.

Looking ahead
Clay used to be the absorbent of choice. Now, polypropylenes are winning over the market. But what is the future of sorbents?

Many companies guard against giving away their top-secret ideas, but several representatives offer a sneak peak.

Oil-Dri’s Oldenburg and LeapFrog’s Purdy both say that reusable polypropylene products will be the wave of the future.

With this special kind of poly, an oil- or chemical-laden sock or pad can be sent to the cleaners instead of the landfill.

Reusable polypropylenes have been around since the early 1990s but have improved greatly in the past few years and are now becoming an important part of the market.

SPC’s Johnson says chemistry could hold the key.

“When people start talking about revolutionary, they start talking about super-absorptive polymers,” he says. “Right now, they absorb water-related materials well, but they don’t work as well on oil.”

Sellars believes polypropylenes will continue to lead the way, even though newer compounds may be on the horizon.

“I would not be surprised if a new generation of absorbent comes along, but what it is, I don’t know,” he says. “We are working on a few things, but I think we can improve on the process of making polypropylene. I think our industry is constantly changing and improving.”

(Also view "Six steps to a clean machine.")

This article appeared in the August/September 1998 issue of MRO Today magazine. Copyright, 1998.