It’s a great day today, you think as you get out of bed at 8:00am on a Saturday. You’re happy because for the first time in about 8 months, you’re going golfing. Somehow you have this weird knot in your stomach because you know a pump at work has been making a high pitched noise lately and you know what can go wrong. It’s now 9:15 and you pack the car your buddy Mike calls and says he’s ready to go but you have to go and get him. You open the car door, then hit the garage opener and your phone goes off. It’s the office and so your mind goes into panic mode wondering if you should even answer the call…if you don’t answer the call…this call…it will be something bad…if you do answer it it’s probably going to be someone looking for a tool that magically only you know the location of. You answer it, it’s the Plant Manager. “John, I need you here quick!! The pump just quit and we cannot go down today!”
Has this already happened to you?
If not, consider yourself lucky.
The chances of a weekend ruining critical equipment failure is more likely than you can imagine. Know why? Less than 20% of all manufacturing facilities in the US and even less outside the US have implemented a real life lubrication management program that meets best practices.
This example, which is probably pretty normal, doesn’t have to happen. Contamination could be the culprit in as many as 80% of critical failures in any given scenario. Once contamination is in your oil, it must be filtered out, even new oil must be filtered. Contamination degrades viscosity, degrades surface area, and in the story above, degrades weekend fun.
Whenever performing an equipment audit, poor breathers such as J-Tubes are consistently installed in equipment. I have encountered these open breathers in all sorts of equipment from units operating in moist conditions such as steel mills, paper mills, even systems operating outdoors. Seems to me it makes more sense than ever to ensure the most critical of equipment is functioning correctly. Practices which will help to eliminate breakdowns as much as possible in order to continue making products or servicing clients. The lesson here is that it is less expensive to keep contamination out of machine systems than removing them after they get in and already cause damage, if not machine failure.
Contamination comes in three types:
- Particulate Contamination
- Water/Moisture Contamination
- Heat Contamination
Built in particle contamination describes both the contaminants which are in new fluid and contaminants which are in new (or rebuilt) systems from either the manufacture or improper care for the storage of machine components. Typically lubricants are pre-contaminated due to storage and handling practices which allow infiltration of moisture and particulate. Improper storage and handling can occur at various places such as the transportation, blending facility, and distribution chain. From one end to another, the lubricant is pumped into tanks, barrels, trucks, through pipes, pumps, and back again. If any of these areas are not flushed and cleaned properly the fluid could be cross contaminated or worse, for instance, what if the transporting tanker was just carrying used gear oil out of one plant just before transporting your new hydraulic fluid to your plant? Elemental Analysis such as spectroscopy or FTIR (Fourier Transform Infra-Red), Viscosity, Particle Count and TAN can determine the quality of the “new” lubricant, and provide a baseline for what you need to do to condition it for use.
Built-in contamination in new machines and maintenance generated contamination can be in many forms. These issues have simple solutions. All new equipment before it is put in to service should be cleaned if possible then thoroughly flushed with a lighter oil in the same family as what it is going to be used. For maintenance generated contaminants, after a rebuild and before storage on the spares rack, the equipment should be flushed out much the same way and then all open ports and area should be sealed using clean material such as a compatible plastic film. The storage area itself can be the problem; most often these areas are dusty, dirty, maybe even humid and wet. If a clean room is not possible then sealing the equipment as much as possible and flushing the component before use would be recommended.
While in-service machines can bring contaminants into the system in various ways. The most common way that contaminants enter machine systems are through breathers which can be J-tubes, screens, or even just small holes. Gearboxes, pumps and reservoirs will ‘breathe’ some way or another when the air expands and contracts, as well as, when incoming fluid displaces air or air is drawn in when internal parts move around. Each time the unit breathes in; it brings with it everything in the environment. In order to eliminate contaminants entering the system, you must know the enemy. Understanding what might be in the ambient environment will tell you what can possibly get into your equipment. Spin on filters make great breathers because they are made to trap particles, the type and size can differ greatly. Steel mills, paper plants, oil production facilities have three different operating environments. You must know and understand what’s out there, in the air. Spin on filters are not the best option when eliminating water and as the pores get blocked by built up debris the machine can build up pressure and seals can fail. If water is your primary contaminant, then a desiccant breather may be used which has the same issue; possible pressure build up. Closing the system and adding expansion chambers is probably a better option in these cases, no-pressure build up and closed to ambient conditions kills two birds with one stone.
Gaining popularity for smaller to medium sized pumps and gearboxes is sealing the systems with the use of expansion chamber(s) and a closed system oiler. The expansion chamber is a bladder type pressure balancer that contracts and expands which allows the system to breathe, but entirely eliminates all contaminants from entering. Closed system oilers have a pressure balancing line allowing the fluid level to change by venting to the closed system, as opposed to, the atmosphere.
Another way contaminants can enter machine systems is through poor seals. Taking a critical asset down to replace a non-leaking seal is probably never going to happen. It would be nice if hydraulic and lubricant circulating system reservoirs were located in a clean controlled environment, reality is they are not. In most plants, opening the cover would probably expose the system to more contaminants than a faulty gasket could. Reservoir gaskets should be inspected during fluid changes and replaced as necessary. Hydraulic cylinder seals are another great way for contaminants to enter; the cylinder extends, gets covered with debris and when it retracts it brings the debris in with it. This type of debris can be limited with the use of protective boots designed for cleaning the ram.
Keeping contamination out of your machines is the goal for your lubrication contamination control program. Particulate, water, and heat combine to accelerate the degradation of the lubricant. Removing these factors, as much as we practically can, will extend the life of the lubricant, and increase the reliability many fold. Once we understand our enemies, we can win the war!