Thinking About a Change?

A three-step approach can simplify pump bearing lubrication, reducing the number of oil sump-related lubrication changes --- and extending equipment life

Share Print Related RSS
Page 3 of 3 1 | 2 | 3 Next » View on one page

Prevention of improper quantity. Understanding and maintaining the proper quantity of lubricant comprise perhaps the easiest means of increasing lubrication life and effectiveness. Consult your equipment manufacturer for recommended oil levels, optimum lubricating equipment and preferred practices.

Prevention of excessive oil and starvation operating conditions can be easy and less time-consuming with the proper equipment and instruction. A general guideline is to maintain minimal contact with the lubricating element.

Step 2: detection

Lubricant sampling and testing. Evaluation of lubrication sampling and testing procedures is recommended. Routine oil sampling and changes can be costly and time-consuming. Every piece of equipment has its own unique set of circumstances, including age, operating environment, process fluid, speed, operating mode, temperature and history. A number of products and recommended practices are available to help increase the efficiency of oil sampling, testing and maintenance.

Visual indicators. Visual inspection is not the most reliable method of determining whether contamination is present or the oil has exceeded its useful life. However, visual indication can be used as an early warning to degrading conditions.

View ports mounted in the housing can be used for both quantity and quality checks. The "business card" analysis tool also can be an easy, low-cost method of checking oil quality. In this approach, a small amount of oil is placed on the back of a business card, or a similar type of paper. After a short period of time, the plant can evaluate the way the oil "wicks out" toward the edges of the card to determine the presence of contamination and degradation.

Monitoring devices. Newly introduced on-line monitoring devices measure water contamination by percentage, or saturated relative humidity (SRH). Continuous monitoring by this type of device prevents unnecessary sampling and oil changes. New technology "brings automatic understanding" to the safe operating levels of moisture in oil.

By maintaining water levels below the saturation point, hydrogen embrittlement of steel is prevented, minimizing or eliminating spalling and cracking on the steel ball bearing surfaces and increasing bearing life significantly. This level varies from oil to oil in terms of ppm, but is universal in terms of SRH. Only sensors specifically designed for this purpose can measure it.

Step 3: correction

Oil change and analysis. An evaluation of oil analysis lab results from routine sampling indicates that 25 percent of the samplings are performed unnecessarily. More than 60 percent are conducted after damage begins. This would indicate that more than 85 percent of oil changes/sampling are potentially performed at the wrong time.

It is important to learn what your problem is ," and when to look for it. For example, if you know your most common problem is water contamination, installation of moisture detection units will eliminate guesswork.

Storage and handling procedures. It is not uncommon for oil to be stored haphazardly in areas not specially designed for lubricant storage. This can lead to contamination of the oil and handling tools before the oil is even installed in the equipment.

It is important for plants to create a controlled atmosphere in which temperature and air quality can be controlled. Reduced inventory is recommended for cleaner, higher-quality oil. Evaluate how the oil is transported from the storage area to the equipment. Open storage containers and contaminated bottles, funnels and filling vessels increase the likelihood the equipment will be filled with contaminated oil. Specially designed containers are available commercially that will decrease the likelihood of introducing contaminated oil.

Maintenance procedures. Understanding how a constant-level oiler works is essential. Two leading causes of misuse are an improper level setting and the "second-shift syndrome." Review the instruction sheet provided with the oiler for a better understanding of how to adjust and set the device for proper use.

"Second-shift syndrome" results when maintenance personnel are instructed to keep the constant-level oiler reservoir of the oiler completely full. Tests have shown that frequent removal and replacement of the constant-level oiler reservoir result in an increased oil level in the equipment sump.

Another cause of improper quantity control is pump-filling methods. Frequently, the filler plug on the top of the housing is removed, and oil is introduced until the proper level is indicated in the view port. This leads to over-filling because much of the oil still is draining from the shaft in-line between the filler port and the sump.

Housing configuration. Close it up. Through proper configuration of nonvented oilers, housing seals, expansion chambers, vent replacements, desiccant dryers and monitoring devices, the pump housing environment can be maintained nearly effortlessly. For example, by installing a "closed system" consisting of a nonvented oiler and a desiccant oil dryer, plants can reduce oil changes from every six weeks to every three months. At an estimated cost of $30 per oil change, the payback on an installation cost of $72 can be realized in less than eight months (with two desiccant cartridge replacements).

Additional cost savings can be realized through increased mean time between maintenance (MTBM) and reduced oil disposal costs. Improper configurations of bearing housings are common and can contribute to high oil contamination levels. For example, tests have revealed that when a vent is used with certain types of labyrinth seals, the ingression rate of the air surrounding the pump increases ," as many as 10 times more than without a vent.

Contacting shaft seals such as lip seals and magnetic seals can minimize ingression significantly. However, pressure might increase without proper expansion chamber configuration. Technical support from the suppliers of these products is essential to ensure optimum performance and safe operation.

 

An automatic moisture removal unit can help reduce oil contamination significantly.

Conclusion

By timing oil changes correctly and selecting and installing oil sump lubrication systems properly, plants can reduce the frequency of oil changes significantly. In addition, associative costs, including those related to labor, used oil disposal, laboratory tests and equipment downtime frequently can be reduced.

Lubrication methods and maintenance often are overlooked or misunderstood as tools to increase equipment reliability and decrease maintenance costs. Don't just change your oil ," change the way you use it. CP

Rake has more than 21 years of experience in the research and development of industrial equipment. He holds a patent in lubrication technology and has four patents pending. He most recently held a position with Trico Manufacturing Corp., an industrial lubrication equipment engineering and manufacturing firm based in Pewaukee, Wis. Contact Trico at (800) 558-7008 or via e-mail at custserv@tricomfg.com.

 

Page 3 of 3 1 | 2 | 3 Next » View on one page
Share Print Reprints Permissions

What are your comments?

Join the discussion today. Login Here.

Comments

No one has commented on this page yet.

RSS feed for comments on this page | RSS feed for all comments