Dirt, gunk, crud, particulate contamination. Whatever you want to call it, the stuff can wreak havoc on machinery — more than 90% of hydraulic system failures are caused by contamination.
A recent John Deere survey discovered that contaminated hydraulic systems cost contractors more than any other machine maintenance problem. What's equally disturbing is that on machines with sophisticated, high-flow systems, the amount of dirt causing the problems wouldn't fill a bottle cap.
A proactive approach
A vigilant fluid-analysis program is very important to prevent problems from contamination. Obviously, changing fluids and filters at recommended intervals is critical, too. Unfortunately, even the most robust preventive maintenance program and fastidious fluid-handling procedures can come up short and allow catastrophic downtime. Rehabilitation of a hydraulic system after a component failure is a messy process that involves draining, disassembly, flushing, and days of downtime.
Deere has adopted a new technology called the Ultra Clean System, which removes contamination by using a pneumatic launcher to shoot a projectile through hose and tube assemblies. The projectile strips out internal contamination as it travels through couplings and around bends, forcing the contamination out in front of it. Thus, oil stays clean as it reaches expensive components, which extends system and filter life.
Flushing hydraulic lines with solvent and air can be tedious (and sometimes ineffective), but the Ultra Clean system makes decontaminating hydraulic systems fast and easy. It also avoids having to handle and dispose of harsh chemicals. It is as simple as disconnecting both ends of a line or hose and launching the projectile through it.
"The Ultra Clean system is more efficient than any other method we've tried," says Scott Dickey, service manager, Murphy Tractor, Lincoln, Nebr. "We no longer worry about the time and expense of hose replacement and tube disassembly for repair service. This is clearly superior than flushing with solvents and air blow-down."
Dickey says the system is also used to prepare fabricated hose assemblies for over-the-counter sales. He points out that it has increased the value of parts and service, by ensuring delivery of cleaned assemblies that are ready for service. Sealing tape covers the open assembly ends to assure the user that the assembly has been cleaned. It also serves as a reminder to keep contamination out of the system when the new assembly is put into place. Cleaning fabricated hoses right after they are constructed is another way in which dealers and distributors can take a proactive approach to reduce the risk of contamination in hydraulic systems.
Datatrending = less downtime
A little dirt can cost a lot of money if it gets into a hydraulic system. Dirt circulating in a hydraulic fluid grates like a belt sander on internal machine parts. Trending, along with a proactive approach to contamination control and elimination, can help prevent this scenario.
"A little bit of contamination can cause lots of wear and tear in just a short time," explains Mike Daly, fluid analysis program marketing manager for John Deere Construction & Forestry Co. "With this continuous abrasion, it only takes a small amount of foreign material to shut down a machine.
"Contamination in a hydraulic system typically shows up in the form of dirt and wear metals, water, or a chemical cocktail of mixed fluid types and viscosities," explains Daly. "All of these problems can be identified early and dealt with by using a properly applied fluid analysis program. A good program will give you a picture of how your hydraulic system is changing over time."
Trending is the key to under-standing what is happening inside a machine. It begins with sampling and analyzing a machine's fluid at its first service interval and every interval afterwards. Trending is the only way to properly document and measure the internal system changes.
Daly notes that trending is not an activity that shows a return on investment in the short term. It takes time to establish a data bank on a machine. Furthermore, the expense of taking fluid analysis samples can be as much as $150 per machine per year. The payoff is avoiding a major repair that costs more than 10 years of fluid analysis. "I've never heard of someone abandoning fluid sampling once they start a true trending program," says Daly. "Armed with a number of reports generated by your fluid analysis program, and an understanding of the machine's working environment (i.e. dust and heat), you can identify and eliminate potential problems before they cause a shutdown. For example, you will be able to replace an aging hydraulic pump that starts contributing contamination to the fluid before it fails — and failure can mean a costly mess.
"In some cases, contamination is just going to be a fact of life for a particular machine application. In those cases, you could improve the cooling system, shorten the filter change intervals, or use a filter cart to eliminate particulate material and water. If you can reduce the environmental variables that are causing the contamination to enter into the system, reliability and the bottom line will benefit."
Another method of keeping contamination from getting into equipment is to properly store and handle fluids, Daly notes. "Store them in a protected, enclosed area with a consistent, moderate temperature. Storage tanks or other packaging containers should be sealed and out of direct exposure to moisture. The outside of fluid service containers should be cleaned before opening. Dirt from containers can find its way very quickly into a fill opening. Tipping the dirt off the top of a five-gal pail into the system as you pour in oil is a sure bet to cause major machine damage."
If possible, a transfer pump with an integral filter should be used when filling or adding top-off oil. "Fifty-five to 80% of failures can be attributed to fluid contamination," states Daly. "That's why we need to allocate the necessary resources to monitoring contamination levels in fluids. Tools like our hose cleaning system, along with trending and fluid analysis, can increase the life and dependability of machines by either preventing contamination from getting into a system or quickly purging it, if it gets past the defenses."
A little monitoring and knowledge will pay big dividends in the life of your machine.