Small innovations can have big impacts An editorial and also an article in the April 2006 issue of PLANT ENGINEERING got me thinking about readily available innovations and why the rate at which some plants adopt innovation is too slow for comfort. Certain innovations are not totally new; they have been extremely well proven elsewhere.
Small innovations can have big impacts
An editorial and also an article in the April 2006 issue of PLANT ENGINEERING got me thinking about readily available innovations and why the rate at which some plants adopt innovation is too slow for comfort. Certain innovations are not totally new; they have been extremely well proven elsewhere. Although small by themselves, it has been my experience that adopting some of these seemingly small innovations can quickly add up to huge savings.
There are common issues at work, and at least four facts or considerations keep surfacing in maintenance effectiveness audits:
The assumption that equipment performance (and therefore, maintenance intervals) is forever linked to the initial design is fundamentally flawed. Such assumptions deny the findings that upgrading a single component (the weak link) is often possible with little or no incremental investment, and that such upgrading will often pay back more than a hundred-fold over the life of a machine.
Benchmarking is necessary to understand where one stands compared to one’s best-of-class competition, but concrete action steps and component upgrades must be implemented to reduce maintenance frequencies and downtime. There can be huge gaps between benchmarking and the conscientious pursuit of tangible remedial steps.
The root causes of unavailability must be found and explained in precise hardware, work process or procedural steps. Unless root causes are identified, organizations find themselves locked in a cycle of avoidable maintenance and/or repeat repairs.
There is consensus among knowledgeable reliability professionals that the basics are less and less well understood. Realization that machinery and components obey the basic laws of physics is declining; the costly results are rather evident in elevated maintenance expenditures, asset unavailability, safety violations and ever-increasing frequency of costly litigation.
So as to make the issues clear by example, this very brief article highlights three of many widely available -- yet sadly neglected -- opportunities to increase the availability and reliability of lubricated machinery in the United States. Many plants could, in the aggregate, save hundreds of millions of dollars each year by paying attention to the underlying facts and principles shown in just a few simple illustrations.
In millions of pump bearing housings, certainly comprising the preponderance of total applications, we still find the pressure-unbalanced constant level lubricators. These tend to limit bearing life because:
The oil level in the lubricator base (“surge chamber”) is contacted by the ambient environment. In an industrial environment this ambient air contains dirt and water vapor.
The caulking that seals the bottle against the surge chamber has a finite life. After years of thermal cycling in an industrial outdoor environment, the caulking develops cracks and allows rainwater to enter.
According to Bernoulli’s Law, an increase in bearing housing pressure above ambient pressure will cause the oil level in the surge chamber to differ from the oil level in the bearing housing. While large housing vents might ensure bearing housings to be at ambient pressure, such vents would only allow more contaminants to enter.
A far more appropriate pressure-balanced constant level lubricator is available from the same manufacturers. At an incremental cost of often less than $30 compared to same-size pressure-unbalanced lubricators, the pressure-balanced models assure true level indication and reduced bearing failure risk.
Oil ring (“slinger rings”) may have been around since the heydays of the industrial revolution, but they often expose users to the potential risk of
Running “downhill” unless the entire shaft assembly is truly horizontal
Making contact with the bearing housing interior, thus slowing down
Lubricant contamination from wear debris (abrasion of these slinger rings)
Operation at excessive shaft surface velocities, i.e. velocities that have been observed to cause slinger ring instability (“skipping around”)
Slinger rings not being manufactured to within the needed concentricity tolerance
Slinger rings having unacceptable (excessive) bore roughness
Decades ago, leading equipment manufacturers recognized these risks and avoided them by using flinger disks in rolling element bearing housings. While flinger disks may cost a few dollars more than cheap slinger rings, they are an important and readily available upgrade “innovation” which often pays for itself in days!
Some innovations can be very readily implemented and their value has been amply documented in the literature. Chasing after the elusive big dollar item may be far less productive than becoming familiar with the many available small innovations. Maintenance avoidance through upgrading makes much economic sense.
Heinz P. Bloch, P.E.
Process Machinery Consulting
West Des Moines, IA
Spanning the globe at Plant Engineering
I recently just stumbled on your April publication of PLANT ENGINEERING , and I was fascinated by the content. I work for an engineering contracting firm for a Chevron cooperative here in Nigeria as a maintenance employee. Recently there has been more emphasis on proper asset management and operational excellence and the write-ups in your publication were of such great value to me, that I would wish to subscribe to your publication.
Accordingly, can your guide me on how I can subscribe to be able to get this magazine on a regular basis and if possible past editions from January till April 2006.
Dr. Edward S. Popko
Solid feedback on solid state article
I found Wendell Rice’s short article on “Solid-state circuits still create a buzz” in PLANT ENGINEERING just great. It is hard to find clear writing on technical subjects and Rice did a great job on a subject that still mystifies many people.
I hope you continue these short pieces. They are very helpful.