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Discovering Valuable Trends in Machinery Reliability

Discovering Valuable Trends in Machinery Reliability

Discovering Valuable Trends in Machinery Reliability

by Heinz Bloch

Much can be said about trends that relate to equipment reliability in one way or another. Like everything else, they come and go randomly. Just like carbonated water, trends that are reduced to the flavor of the month can fizzle out and disappear rapidly. Trends probably always existed in all fields of endeavor and have been observed for years in the field of machinery reliability improvement. This article focuses on some recent ones that are on relatively solid ground and should be of interest to you.

The basis of certain trends is of interest. Misleading trends often originate in nostalgia for the past (i.e., “the good old days”). These trends can be quite costly because inaccurately remembering the past often causes people to repeat errors and get locked in a never-ending cycle of repeat repairs. Not learning from past mistakes can steer a profession or even an entire industry in a multitude of unforeseen directions, with dead ends among them. By its very nature, nostalgia for a past that is not remembered correctly overlooks or suppresses facts, thereby assigning undue importance to unsupported opinions. Whenever managers act with nothing but unsupported opinions to guide them, the laws of unintended consequences leave many job functions without a realistic coping mechanism.

Numbers Versus Quality of People Trend: Stable Quality, Just Not Enough of Them

Observers have expressed amazement when they see how some engineers and managers spend precious resources compiling meaningless statistics and benchmarks. As but one example reaching back a few decades, reliability engineers attempted to quantify manpower requirements in terms of manpower per horsepower (hp). As the thinking went, a good refinery should employ one machinery expert per “X” hp of installed compression equipment, or that it’s best to have a backlog of “Y” working days in the facility’s repair shop. Today, reliability engineers now know there is little gain in making comparisons based on these metrics alone. While certain benchmark studies are still incorporating these and similar statistics, there is little or no correlation with best of class (BoC) performance. It’s decidedly not the number of people, but rather the quality of people that matters.

Today, the reliability engineering profession includes staffers who are resourceful thinkers and others with a bureaucratic streak, to say the very least. Figure 1, which depicts an oil ring partially immersed in a pool of lubricant, is a recent example of shallow thinking. The intended function is to fling a certain amount of oil into one or more nearby bearings. However, oil ring performance is immersion sensitive. Here’s where a bureaucratic streak can cause problems. In late 2016, an overseas reliability engineer had found a discrepancy between a number given in a book and an article written later. The book recommended an oil ring immersion depth of 5/16th of an inch, while the article mentioned oil rings should be immersed to a depth of 8 mm. For the record, 5/16th of an inch times 25.4 mm/inch equals 7.9 mm.

Figure 1Figure 1: Typical oil ring

The problem is this engineer was serious, an indication of the lack of common sense often seen today. If this 8 mm versus 7.9 mm individual reported to a concerned manager, this person would be asked to become more familiar with how oil rings function and what makes them malfunction. Hopefully, the manager would question whether the employee is using his and the employer’s time wisely. Notice that what is being described is an unhealthy trend that people are becoming less inquisitive and more inclined to offer opinions instead of facts. You should anticipate problems when there is no management function in place that questions or readjusts shallow thinkers. Shallow thinkers are grown, not born. Training, tutoring and mentoring are management supported activities that foster professional growth. Take, for example, a 21-year-old who in 1955 was taught how to dismantle a Willys Jeep engine, regrind the eight valve seats, perform appropriate measurements, replace worn parts and reassemble the engine. As awareness of the actual and related collateral value of such hands-on work continues to decline, the machinery reliability industry will be the eventual loser. Putting it more bluntly, the application of common sense is also declining and that, quite obviously, is a worrisome trend.

Does Company Size Matter? Trend: Erroneous Assumptions on What Matters

Managers who are impressed by the sheer size of a supplier or the low bid price of products is an unhealthy backward trend. In the absence of detailed specifications, supply chain managers favor low bid price over everything else and participate in a trend that rarely makes sense. Nevertheless, big name providers and the buyers’ quest for low as bid cost are receiving more emphasis today than three decades ago. This issue merits being examined next.

To answer questions on size and merit, ponder the example of a company many have dealt with decades ago, Bently Nevada Corporation. Don Bently was born in 1924 and lived until 2012; he started Bently Nevada in his garage in 1961. He designed and manufactured vibration monitoring sensors and whatever instrumentation is needed for data acquisition and data analysis. Bently Nevada was minuscule in size compared to GE, to whom Don Bently sold his company in 2002. Bently was an innovator and innovators create demand. That’s quite different from waiting for demand to develop or assuming that only out of an abundance of demand the mythical innovators will arise. Fluid machinery users who early on accepted and supported Bently Nevada reaped great benefits. Innovators create demand from the reliability-focused. In contrast, providers that emphasize low product price over high quality are favored by the more risk-prone buyers.

It’s something to keep firmly in mind as you consider linking up with a potential supplier or provider company. You might think of it as you visualize how the bearing protector seals in Figures 2 and 3 work. The configuration shown in Figure 2 allows its dynamic O-ring to contact the sharp edges of an O-ring groove, whereas the one shown in Figure 3 has its active O-ring move axially, without the risk of damaging the O-ring’s surface. Because Figure 2 is less expensive, it outsells the superior technology depicted in Figure 3. Reliable products tend to cost more than products marketed with cost as the primary objective. Almost always, reliable products reward you with surprisingly attractive payback.

Figure 2Figure 2: Bearing protector geometry where a dynamic O-ring could inadvertently make radial contact with sharp edges, i.e., a pinched O-ring (courtesy of ASSEAL, Inc.)

Figure 3Figure 3: There is zero risk of sharp edges being contacted by either of the two O-rings in this advanced bearing protector seal (courtesy of ASSEAL, Inc.)

Why Waiting for Demand Stifles Innovation

The preceding paragraph gives an indication of the tie-in between today’s emphasis on price and the relatively stagnant demand for innovative solutions. Waiting for demand stifles forward momentum and it is interesting how user indifference may have made users complicit in slowing down some recent reliability enhancing developments.

Looking back on decades of elusive failures traceable to the many inadequacies of oil rings, users could have helped themselves by diligently logging in relevant data. All they had to do was measure and record two important dimensions on a new oil ring and measure and record them again during a repair event, perhaps after one or two years of operation. Measuring the difference between the diameters before versus after dimensions gives users the out of concentricity; differences in width measurements are indicative of wear.

Although not eagerly broadcasting product deficiencies, fluid machinery manufacturers will (privately) agree that oil rings are not the best available technology components. Vendors and manufacturers have explained a lack of incentive to develop better lubricant application methods until there is a very high user demand. Meanwhile, observations continue on how complacent and complicit users spend time and money on oil rings that will almost certainly malfunction whenever (a) the shaft system is not perfectly horizontal; (b) the oil viscosity is not staying within narrow limits; (c) the depth of immersion fluctuates; and (d) the ring bore is no longer round, but has become slightly oval. 1 For oil ring bore dimensions to remain true to within 0.002 inches, an oil ring has to be stress relief annealed before finish machining.1 Cheap oil rings are not being produced in harmony with necessary thermal stabilization steps. Without heat stabilization, most oil rings will not be true running and concentric. Therefore, they will slip, oscillate, abrade and contaminate the oil. With an abrasive product inevitably causing bearings to fail prematurely, let’s construct an example and assume the bearings will survive for three years.

There is a good probability that a majority of non-BoC users think three years is a reasonable bearing life. Suppose, though, that better informed BoC users routinely achieve a bearing life of six years. If the six year expectation, or 2:1 ratio is correct, the average user spends twice as much for bearing replacements and maintenance than the informed user. As of 2017, the trend toward becoming more informed seems to have leveled off and the slope for acquiring maintenance knowledge is probably horizontal. And that’s the disappointing part; it didn’t have to be that way. A solid training program would bring these facts to the attention of plant engineers and maintenance technicians. How nice it would have been if only the U.S. emulated other industrialized nations that have implemented strong and consistent apprenticeship programs long ago. However, if history is our guide, an overwhelming urge to capture short-term rewards will again get in the way of progress. And that’s the sad outlook.

Upward Trend for How Well BoCs Work With Innovative Technology Providers

Fortunately, there is a favorable trend in how BoC companies interact with innovators. But first, note that for many years, the top five or 10 percent most profitable fluid machinery users have been arbitrarily labeled best of class. This subjective good versus bad judgment is based on published surveys and many informal conversations with BoC reliability professionals and their competitors at meetings, seminars and conferences. In addition, impressive or disappointing practices are observed during consulting visits to plants where incidents happened or at other plants where incident avoidance is deemed of much greater importance. In some plant visits, issues and deficiencies are obvious to the experienced observer. Against this background, many reliability engineers report noticing an upward trend in how BoCs and innovative vendors and service providers cooperate and make decisions that benefit both parties. Remember, again, that innovators create demand among the true reliability professionals. And if you make it a habit to link up with only the lowest cost provider, it sends innovators a signal to bypass your plant and focus instead on building a relationship with one of your more responsive competitors a few miles down the highway.

Here is just one more example concerning the mechanical seal shown in Figure 4. 2 An innovative manufacturer developed this mechanical seal around 2007-2008. Note that it features a bidirectional, tapered pumping impeller. The manufacturer certainly can point out numerous installations or services where this invention has saved considerable money. The pumping impeller effectively pumps the flush liquid through a small heat exchanger. Do you know which of your hundreds of process pumps would qualify for and benefit from this enhanced fluid moving arrangement? Have you asked your seal supplier? Have you asked the innovator? Could you learn from your present supplier? Would it be helpful for you to communicate with and perhaps even learn from an experienced innovator? Would doing so be one of your roles?

Figure 4Figure 4: Mechanical seal cartridge with innovative bidirectional tapered pumping impeller (courtesy of ASSEAL, Inc.)

Strengthening the Role of the Reliability Professional

There are very significant differences in the work assigned to a reliability person at location “A” versus location “B.” In 1966, a BoC role statement for machinery engineers contained 20 or 25 items. It was not considered a proprietary document when published several decades back. The role statement clearly shows that subject matter experts (SMEs) at BoCs are proactive instead of reactive. Value-adding SMEs will have decided before arriving at their employer’s parking lot in the morning what it is they will be working on during that day. As the SMEs drive home in the afternoon, they will ask themselves if they have, in fact, done what they had hoped to accomplish on that day. The quality of their work product is the primary yardstick by which they do this self-assessment; the value of one’s work product will last when all else has been forgotten.

The value of one’s work product will last when all else has been forgotten.

There is much more on the subject of improving existing machinery. A true “uptime extender” pays attention to every maintenance intervention. She or he views maintenance events as worthy of attention; failures present an opportunity to implement an upgrade, if previously cost justified. Reliability professionals make this feasibility and cost justification determination long before a maintenance event happens. Determining feasibility and cost are the two most important roles of reliability professionals. With that in mind, BoCs make a clear distinction between a maintenance engineer and a reliability engineer. Maintenance engineers put their effort into maintaining a machine in the as designed condition. They get activated the moment the machine is available for maintenance or is taken out for repairs. Many may argue about definitions and their occasionally unpleasant connotations, but maintenance, broadly speaking, is a reactive activity. 2

The reliability engineer’s workday is almost entirely proactive. These professionals use all their available time to seek, obtain and develop answers to three very important questions:

  1. Is an upgrade possible?
  2. If yes, is an upgrade cost-effective?
  3. Which innovative technology provider should be selected to implement the combined repair and upgrade?

Needless to say, reliability professionals work with innovators; they make these innovators one of their primary technology resources. An innovator assists the reliability professional in determining and explaining payback. Together, reliability professionals and their upgrade provider review and document prior experiences. Both participate in finding or defining the field experiences at other client sites and, if possible, prepare a presentation to the reliability professional’s management. This shared activity is actually part of a structured machinery quality assessment (MQA) process. The cost of an MQA should be in the user’s or purchaser’s budget since MQA largely contributes to decades of future machinery reliability. Although that message was first broadcast in the late 1960s, MQA appears to be on the decline today; the trend is sloped in the wrong direction.

Unfavorable Trend Observed Regarding MQA

It is apparent that a rigorous MQA is on the decline. Again, consider an interesting example pointing to the time when MQA activities received the attention they deserved. In late 1965, a senior machinery engineer involved in an MQA was on what was then called a loan and training assignment from a company affiliate in the United Kingdom. He was the lead machinery engineer tasked with selecting electric power generator drives for one of the employer’s greenfield refineries in Southeast Asia. The customary bid process had narrowed the choice between slow speed, two-stroke marine diesels from Vendor A and higher speed, four-stroke diesel engines offered by Vendor B. But, maintenance costs and the crafts’ competence at the destination site had to be considered during the MQA, so the situation needed to be examined or assessed for the developing country where these diesels were to be installed.

To properly do this, the senior reliability engineer embarked on a two-week trip to West Africa, where such four-stroke diesels were operating and local conditions and crafts training most closely matched the conditions anticipated in Southeast Asia. The employer spent $60,000 (at that time close to two years’ salary) for the senior engineer’s overseas travel and associated outlays. It was later estimated that choosing the four-stroke diesels over the well reputed, two-stroke machines had saved the refinery $60,000 during its first four months of operation.

What to Do About the Declining MQA Trend

Because a declining trend was noted in how often companies engage in properly structured MQA activities, here are some noteworthy facts. Each of the four bulleted items suggests effort and reward.

Now, think about the world you live in and the exact role that evolved from the preceding MQA example. The late 1970s through the early 1990s saw an encouraging trend among best of class companies to reconfirm the roles of reliability professionals and to remind them of the expectations. Various elements that surely contributed to reliability professionals’ achieving their anticipated roles to the fullest were listed and revisited during periodic performance appraisals. As an example, a plant manager asked one of his reliability engineers about two reciprocating compressors that were scheduled for turnaround work a few months later. The reliability engineer was fully informed and answered with the plot designation of the two machines in hydrogen service at that plant. He knew the name of the manufacturer and the years the machines were made (1962) and put into operation (1963). When the plant manager asked about the difference between machines built in 1962 and the machines a successor company would supply if purchased today, the reliability engineer explained that today’s compressor frames are provided with internal bracing that allows approximately 12 percent higher frame loads and that the 1962 versions had piston rods with a nickel base hard surfacing alloy with chromium boride, whereas today these rods are supplied with a tungsten carbide coating. The reliability engineer also explained that the site was still using a certain style of compressor valve “A” and today’s compressor valves would invariably be style “B.”

This reliability engineer was an informed value adder. Working in cooperation with an innovative company, he proactively ascertained that upgrading to valve style “B” would be cost-justified, but no great gains would be derived from making changes to the present piston rod coating. He also began investigating whether operating cost savings would justify upgrading to electronically guided, infinitely variable cylinder clearance arrangements and, if so, would have his findings ready in time for order placement and delivery before starting the future turnaround. Needless to say, the reliability professionals at this particular plant worked with a compressor manufacturer whose engineering efforts and technology were leading edge.

Today, the trend among the few best of class user companies is to still do all of the aforementioned, and then some. The solid advantages of working with a supplier or provider with expertise in design, manufacturing and virtually all related phases of service are recognized by BoC companies. As noted previously, smart users enlist others as their technology resources. These users confirm that everybody benefits when there is close collaboration with midsize provider companies that make conversion, modernization and selective upgrading one of their core competencies.

So, pay attention to leading providers whose integration of engineering and service allows them to gain recognition on a very wide geographic basis. These worldwide technology leaders excel in safety and environmental performance, employee satisfaction and, perhaps, many other important attributes that ultimately reflect the value they can bring to a client’s enterprise. Such provider companies have a global presence and can be found in widely differing fields. They can be found in technology fields, such as mechanical seals, high performance couplings, centrifugal pumps, dynamic compressors, twin screw rotary compressors and positive displacement reciprocating and diaphragm compressors, to name but a few.

Working with these knowledgeable suppliers and providers gives modern, results-oriented users a competitive advantage. These collaborative efforts greatly accelerate the user’s or purchaser’s upward move on the profitability and reliability improvement scale. Collaboration and cooperation are training tools not matched by anything else. Be sure to recognize the imputed value of this training; it must be given weight in the user’s selection process.

Summary and Recap

After decades of active involvement in reliability engineering, some have come to realize that blindly joining in on a popular trend is worthless if the trendsetters were uninformed or have acted out of nostalgia from an inaccurately remembered past. Chances are you would not knowingly follow trendsetters who are responding to a wrong premise or are greatly misreading the future. A well-informed person will not be swayed by trends, but will reason on facts. Considering only the facts allows an individual to make informed decisions and he or she will do so in the assured expectation of future rewards.

Having read this article, consider how you can play a key role in the advancement of mutually rewarding manufacturer–purchaser relationships. Remember, there will never ever be a substitute for common sense, for being a person with motivation and, yes, a person who has developed a deep and lasting appreciation for the laws of science and basic physics. These laws are immutable; there are no substitutes for them. Like it or not, learning, applying and retaining the underlying principles of these laws are lifelong processes.

References

  1. Bloch, Heinz P. Pump Wisdom: Problem Solving for Operators and Specialists. Hoboken: Wiley, 2011.
  2. Bloch, Heinz P. Petrochemical Machinery Insights. Oxford: Butterworth-Heinemann, 2016.