Machinery Lubrication / Vibration Analysis

Pass-along knowledge for the next generation of engineers and operators

In this Big Picture Interview, Robert Perez explores the role of the machinery reliability engineer.

Robert X. Perez is a machinery reliability engineer with more than 30 years of experience in the petrochemical industry. He earned a BSME degree from Texas A&M University, College Station, and an MSME degree from the University of Texas at Austin, and he’s a licensed professional engineer in the state of Texas. He has written extensively about machinery reliability and served on the Turbomachinery Symposium Advisory Committee for 10 years.

PS: What does a machinery reliability engineer do?

lead robert perezRP: A machinery reliability engineer, or MRE, is a subject matter expert in the field of process machinery, such as centrifugal compressors, centrifugal pumps, reciprocating compressors, reciprocating pumps, and steam turbines. As an MRE my job duties include selecting new process machinery, overviewing major machine repairs, troubleshooting, leading root cause failure analyses, participating in reliability centered maintenance reviews, implementing machinery-related RCM recommendations, or answering all questions related to process machinery.

I was told many years ago that a maintenance person’s job is to pull carts out of the ditch, but a reliability engineer’s job is to keep the cart from falling into the ditch. So as an MRE, my primary role is to ensure machinery does not failure prematurely. Every premature failure is an opportunity to figure out what happened and an opportunity to prevent a recurrence of a similar failure in the future.

PS: How has machinery reliability engineering changed over the past 30 years?

RP: Over the past 30 years or so we have gone from a focus on maintenance to a focus on reliability. When I began in this field, management was more concerned about repair processes, that is, repair cost and the time to repair. Sites wanted to minimize machinery repair costs. However, in the ’80s there was more of a push to look at the total cost of ownership. Instead of just looking at repair cost, we started looking at the cost of process downtime and the risk of machine failures. A methodology called reliability-centered maintenance, or RCM, became a valuable tool to optimize the maintenance resources in process facilities.

Another change was the development of many powerful analysis tools aimed at improving machinery reliability. To name a few new tools, software for analyzing rotor-dynamic, pressure pulsation, and computational fluid dynamics (CFD) were developed and refined. Additionally, many new bearing and seal designs were invented to solve chronic problems. Another great force shaping machinery reliability were forums aimed at encouraging technical exchanges between users and manufacturers, such as the Texas A&M Turbomachinery Symposium. Numerous complex problems were solved as a result of the discussion of many important reliability issues.

PS: What would you tell a young engineer just entering the field of machinery reliability engineering?

RP: Keep your technical tools sharp, and continue learning about the latest developments in machinery reliability. They should learn all they can about lubrication, vibration analysis, reliability theory, RCM methods, root cause failures analysis, and troubleshooting. You never know what knowledge set you are going to need when called on to solve a problem or answer a question. Every day on the job is different. Some days you’ll be called on to answer a question on rotor dynamics, and the next day you’ll be asked review a pump start-up procedure. Master all the site software tools to gather data for analyzing machinery problems — CMMS, DCS, vibration gather software, or any other software that collects and analyzes data. Data is the fuel that drives discovery and improvements.

Finally, look at machines holistically. In another words, look at the machine and process as a whole. Many times a machine problem is simply a reflection of a process problem.

PS: What are your main concerns when reviewing the status of machinery reliability at one of your sites?

RP: My overall goal is to ensure that we are applying the right resources to the right machines in order to optimize reliability. To achieve this goal, I need to apply an RCM approach to our machinery. This means we need to continually ask the following questions. What is the criticality level of a given machine? What are most common machinery failures modes? What are the failure rates of these failure modes? Is the current risk level acceptable?     What are the current safeguards in place aimed at detecting potential failure and mitigating machine failures? Are additional safeguards, such as oil analysis, vibration monitoring, or periodic resting, required to reduce risk to an acceptable level?

We know every site has a finite amount of resources in the form of maintenance budget and maintenance personnel. My job is to ensure these resources are utilized properly. At the end of the day, our goal is to optimize the overall level of plant reliability and safeguard the site from experiencing dangerous machinery failure events.

PS: What motivated you to start writing books about machinery reliability?

RP: About eight years ago, a chemical plant where I was working suffered a number of major centrifugal pump failures directly due to improper start-up procedures. These failure events motivated me to write my first book titled Operator’s Guide to Centrifugal Pumps. The book is meant to cover the basic body of knowledge that I think all operators should possess.

A few years later, I met Julien LeBleu. We soon discovered that we had similar views on operator training. We both believe that there needed to be more basic operator training available. In the production environment, management is struggling just to keep up with the growing number of regulations imposed on them, which tends to push basic operator training and refresher training to the back burner. This year, Mr. LeBleu and I teamed up to write a more general book titled, Operator’s Guide to Rotating Equipment.

Next year, I hope to release the third book in this series, Operator’s Guide to General Purpose Steam Turbines, written with the help of David Lawhon. All of these books are written in straightforward, easy-to-understand language. My hope is that these books will be used by operators, entry level engineers, and managers for self-study, in-house company training, or in formal seminars.

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