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Webinar: Improving Heat Exchanger Inspection Analysis

Webinar Transcription

Hello and welcome to Zetec’s webinar on Improving Heat Exchanger Inspection Analysis. My name is Wayne Waxman, I’m the director of marketing at Zetec.

I’d like to thank everyone for joining us today. I have a couple of logistical items before we get started – everyone is in listen only mode and we are recording today’s session so you can review and listen to it or share with your colleagues in your organization.  Everyone who registered for this webinar will receive an email later this week with a link to the recording.

Finally, there will be a Q&A session at the end of this webinar. You don’t need to wait until the end of the webinar to send in a question. At any time, simply type your inquiry in the questions section on your GoToWebinar panel.

Before we begin the webinar, I would like to give a quick overview of Zetec.

Zetec: The Inspection Advantage

Zetec is a global NDT leader. For 50 years, we’ve advanced the science and standards in both Ultrasonic and Eddy Current technologies — setting new heights in inspection performance, productivity and predictability. Zetec’s proven expertise and complete product portfolio serve the inspection needs of our customers worldwide in transportation, power generation, manufacturing and oil & gas. Zetec is a subsidiary of Roper Technologies.

Let’s get to today’s session which will be presented by Tom Bipes and Jerry Park.

Tom Bipes is a Project Manager in the RevospECT and Eddynet software business at Zetec.

Tom has been involved in NDE for the past four decades.  Tom has held roles in vendor field services, education and NDE research.  Tom’s current role is Project Manager of RevospECT and Eddynet applications and field operations for Zetec.

Jerry Park is a Sales and Applications Engineer at Zetec. He has been with Zetec for over 14 years, where he has worked as a field operator in acquisition and analysis, as well as working with the engineering team in designing and testing hardware and software products

With that, let’s start today’s webinar.…

Why we are here today

Thanks Wayne. 

I want to thank you all for attending today’s webinar,  I’m really excited about the technology I am about to share.

I have prepared the agenda you see in front of you, to give you an idea of how this presentation will unfold.

First I will briefly talk about the challenges we have seen in the way inspections are typically performed today …

Then we will talk about some of the enabling technologies within the system that make it perform

From there I will cue up a video with Jerry Park to demonstrate the system in action where you will be able to truly see the value this system can provide.

From there, I will explain some of the background of RevospECT HX Pro, information about the use of Historic Data Compare, plus a bit about Signal InjECT, Zetec’s signal injection tool.

Finally we will wrap with a summary, then we will take your questions.

There are various factors in the current Heat Exchanger inspection process that detract from the ability to improve component reliability.

Often, only a sample of the component tube population is examined with eddy current testing.  This is often due to inspection cost and scheduling during a busy refuel or turnaround outage.

During the inspection, the planned scope may also be reduced due to other dynamics of the outage.

Because of component unreliability, inspection requirements may need to change.  Oversight engineers are often reacting to component operability issues.  To better diagnose tube integrity of the component, there may be a need for increased inspection frequency and the use of more complex inspection techniques such as array probes.

Poor performance from service vendors elevates quickly within the view of utilities and asset owners. With higher expectations on asset performance due to competitive energy pricing and operational goals, asset owners are demanding fast and competitive delivery of inspection services to get the assets quickly back on line. Vendors striving to meet the challenge and provide fast and competitive inspections are at risk of performance issues when humans are placed in stressful service.

All of these factors cumulate in plant management questioning the effectiveness of Eddy Current Testing. Trending of inspection results may be difficult with traditional tracking techniques and inspection scope.  The RevospECT HX solution allows for various enhancements to inspection results tracking for better performance predictions.

Automate and refine the process

Zetec is excited to offer an integrated solution that automates and refines the process from acquisition through analysis of the inspection data.

The use of this automated process will increase the inspection productivity dramatically to address inspection issues such as scheduling demands, available manpower and the aging workforce.  Automation of the process will also help provide shorter inspection turnaround, and standardize techniques for varying inspector experience levels.

The time to complete analysis & final reporting is on critical path for the asset owners to disposition the component and return it to service. The service vendor is typically working with a manual process and tools and has a lot of pressure to produce the final results and little ability to improve the time. Often the final report is delivered later than the asset owner would expect.

Zetec automated acquisition and analysis solutions will increase the number of tube inspections performed in the allotted timeframe.  These processes will also ease the transition to advanced inspection technologies such as array probe inspection data.  Automation addresses redundant acquisition and analysis tasks that can lead to human performance issues.

The first step of this enhanced process is to automate the acquisition workflow.  Automation controls the probe movement from insertion of the probe into the tube through retraction and recording of the tube data.  This enhancement of these manual tasks leads to less quantity of tasks for the operator providing more focus on the critical aspects of the inspection

Automated analysis with RevospECT HX provides the needed consistency and reliability for detection and classification of tube flaws.  The process is also very repeatable and reduces overall human error that can results from tedious manual analysis.

Automation enhances the abilities of the analyst and therefore brings the inspection resources to the same level of capability.

Analysis test results are now available earlier in the inspection process. Let’s watch a short video presentation by Jerry Park, demonstrating the automated acquisition and analysis RevospECT HX solution in action.

Common inspection model

In today’s inspections, we commonly see a team of three people with individual responsibilities to perform the vessel inspection. This is common for heat exchangers ranging from hundreds to thousands of tubes. 

In the top illustration the first person, starting on the left is what we will call the “Acquisition Probe Handler”. His responsibility is to either hold a conduit to direct the probe into the desired tube if a probe pushing device is used or push the probe manually into the tube to be inspected and withdraw it at a constant speed while the date file is recorded. 

Moving to the right, the second person is the “acquisition operator” and his primary function is to run the acquisition software. He is in tight communication with the Acquisition Probe Holder to coordinate the recording of the data when the acquisition operator moves the probe and synchronize the tube location being acquired.

The third person in the team is the “Data Analyst”. His obvious role is to analyze the data coming from acquisition.  Depending on the job, there may be several teams like this deployed to inspect multiple vessels in parallel.

The Data Analyst is commonly in a trailer or building where the data from acquisition team is passed to via a USB drive that is hand delivered. The frequency of data delivery varies but in many cases it is around 4 hours or a complete shift. As you can see, this sets up a batch cycle for the analysis activity, causing a built in delay after the completion of acquisition.

This leads to around an 8 hour delay to wrap up the analysis and complete the preliminary report.

The final report is often done off-site for convenience and in some cases can take up to one week to submit.

In this example, we are looking at more than one week to produce the final results for the inspection.

Improving inspection cycles for cases similar to this example can provide great value to the asset owner. 

Automated inspection analysis model

Let’s revisit our model of the inspection in the lower graphic.  This time we are going to explain it with the RevoHX solution

We’ll start off with just a single operator and illustrate how this system can perform the entire process of what had previously been done with 3 people.

We will equip this one man team with an eddy current instrument, probe pusher, bobbin probe, and RevoHX.  Again remember that RevoHX is the integrated software the performs acquisition and analysis. As RevoHX is going to both acquire and analysis the data, we don’t have to deliver data periodically to the analysis team in the trailer. 

The acquisition features are going to manage the probe movement in an efficient and controlled manor and the analysis features are going to process the acquired data automatically.

This lets the operator focus on probing the tubes

With this model we expect a nearly 100% improvement in efficiency so the acquisition of the data can be accomplished in around 8 hours compared to the previous model of the manual system and 3 people that consumed about 16 hours or 2 days to acquire all of the tubes.

In reality, the analysis of the data is nearly instantaneous with acquisition, analyzing at around 15 seconds per tube.

How do we know this?

We deployed systems in Oil & Gas and powerplant facilities and benchmarked the performance of both the manual and the RevoHX models.

With the analysis progressing near the rate of acquisition, preliminary reports can be produced within an hour of completion

For the final report, the operator can review the analysis results and provide some oversight to then produce the final report in about 8 hours

RevospECT HX Pro Solution Background

We’d like to share some background on the RevospECT HX solution development

Zetec has a long standing goal of supplying inspection hardware and technology for the NDE inspection industry.  Zetec recognized a convergence of events indicating a need for applying advanced technology to the analysis of inspection data.

Various items led to this decision, including an aging analysis workforce and shrinking availability fo experienced data analysts.  It has also been shown that analyst experience levels with the wide variety of HX components and degradation mechanisms can limit the inspection capabilities.

With aging plants and HX components, the reliability is becoming reduced, which causes an increase in down power events and unplanned component replacement.

The industry as a whole has been somewhat stagnant in the development of new technologies, assuming the asset owner is comfortable with current inspection capabilities.

RevospECT HX uses proven RevospECT technology that has been used for many years in the steam generator inspection industry.

RevospECT HX harnesses this proven technology to automate the acquisition and analysis process for almost any plant heat exchanger.

These technologies provide a solid solution to address inconsistencies in analysis results due to the previously described human manual analysis component.

Automation of the acquisition and analysis process provides for the inspection of components at a higher data acquisition rate with improved reliability and consistency.  The overall process becomes transparent but provides for the flexibility to address near term and future inspection needs.

Speaking of the analysis, I will give a brief description of how analysis occurs with the RevospECT technology we have integrated into RevoHX.

The Zetec approach to automated analysis

Zetec has approached auto analysis in a very methodical way. We developed a modular analysis structure were in signal processing space, we define the mathematical equation used to find, qualify, and report a specific flaw type.  We call this equation an “Analyzer”.

In fact, considering that data can be influenced by other conditions such as noise, deposits, etcetera it is a good practice to have various Analyzers for a given flaw type to ensure good performance

It is very handy to have these multiple Analyzers grouped together so they can be easily assigned to targeted regions of the tube. We call this grouping, an analysis capsule.

With our analysis capsule methodology, you put together a “Analysis Configuration” that contains all of the capsules you need for the particular inspection.  Pretty neat and tidy.

Zetec is building an extensive library of capsules for customer use. When a customer implements a capsule from Zetec, there is a simple interface where the user can make adjustments to the capsule performance to meet their needs.

In this graphic, a typical bobbin probe inspection technique is being utilized.  Capsules are built to address all of the active and potential damage mechanisms for the component to be inspected.  The computer processes the data and it is analyzed by each of the specific analysis capsules.

If multiple capsules classify a signal to more than one potential flaw mechanism, a logic path we call “Final Acceptance” is used to rationalize the results.  For example, the examination results may provide a differential channel flaw signal and an absolute channel flaw signal at the same location.  Final acceptance will utilize logic steps that you select to determine which signal response has priority, and is therefore reported. Likewise, a Configuration may be produced that uses multiple techniques, such as a bobbin/array combination probe. Two configurations, one for each technique, can be applied with separate RevospECT HX capsule sets.  Final acceptance can rationalize the results of signals produced from both bobbin and array techniques.

You may be thinking, what assets are needed to provide the necessary data for RevospECT HX to function at it’s highest level?

Some of these assets include the historic data and results from previous inspections.  Of course the inspection techniques and practices developed for the specific component will be utilized to develop the RevospECT HX techniques.

Once a Configuration is developed, it is tested by utilizing the previous inspection data, and comparing results to that of the inspection “truth” or previously reported results.  Zetec Signal InjECT may also be used to enhance this process of validation by producing real and artificial flaw signals to prove the capabilities of the system.

More about Signal InjECT later in this presenation.

Zetec has also made enhancements to tube support structure landmarking as structure locating is imperative to successful automated analysis, to ensure the proper capsules and techniques are applied to each specific Region of Interest (ROI).  This process ensures the proper degradation reporting is maintained.

Zetec RevospECT HX can be deployed at your facility in a variety of ways.  Utilizing Zetec acquisition test equipment and probe handling hardware integrated with RevospECT HX can allow for automated acquisition and analysis with minimal staffing.  A preliminary report of the inspection results can be provided soon after the acquisition of inspection data is completed.

A second solution is to produce analysis results, and have a data analyst review the Revo HX produced analysis results, to make a final decision on results from challenging components.

Other solutions include the ability to perform off-line trending of historical vs current inspection results.  One example of this is to perform automated structure mapping of secondary structure such as tube stakes.  Stakes may be added to components such as main condensers to improve tube rigidity and help avoid tube structure fretting wear.  RevospECT HX can be configured to map the added structures and record their positions to provide further enhanced flaw algorithms specifically for those structures.

Quite recently Palo Verde, using Zetec RevospECT HX Pro, received an NEI (Nuclear Energy Institute) TIP (Top Innovative Practice) award. 

Palo Verde operations have been significantly challenged with 3 recent down power events caused by tube leaks in their Low Pressure Feedwater Heaters (LPFWH).  In an effort to improve their component reliability and availability, Palo Verde performed a comparison of automation vs manual analysis methods on historical data.  The study revealed that, by applying automation to the data analysis process, a significant improvement to detecting pluggable indications was realized.  It was also observed that the speed and efficiency in which the analysis results were produced were equally as significant.  It has been estimated that automation could reduce outage costs by almost $100K per inspection and upwards of $2M in plant down power avoidance.

In this innovative approach to applying automation to the HX data analysis process, Palo Verde will be well positioned to realize these benefits for many years to come.  

Historical data comparison (HDC) capability

RevospECT HX includes other technologies developed and proven over recent years, including Historic Data Compare or HDC.  Let’s review how HDC works, and how it can be applied to enhance your component inspection and reliability.

Through the years of eddy current inspection of components, it has been proven that eddy current inspection data is highly repeatable.  Signals from the signature of the tube can be seen through inspections from many years of history.

Comparison of data from the current inspection to historic inspections can prove to highlight changes in the tubing resulting from degradation over time.

This comparative approach was first prototyped in the 1980’s.  More recent advancements in thinking and processing power has led to the current HDC solution.

HDC improves the ability to perform historic data comparisons dramatically.  In this way, it is much easier to see changes in degradation growth over time.

HDC has been field proven and qualified at various customer sites across the US and internationally.

HDC Process

Let’s first discuss how the process works.

In this illustration, we are showing the current inspection data segment as the green strip chart, and the historic data as the orange. The data is aligned through a proprietary process, to allow for variations in the data collection speed, pull direction and even probe type variation. The interpolated data from history is then “subtracted” from the current data, similar to a support structure mix. The resulting “delta channel” shows only the areas where the signals have changed from the previous inspection.

In this graphic presentation, we see HDC applied to two sets of historic data.  Again, the green signal is the current data, the orange data is historic data from a previous inspection, and the blue data stream is from the component baseline inspection.

On the left two panes, you see the overlapped baseline and current Lissajous signal.  Next to it, is the baseline delta signal, which is the subtraction of the baseline data to the current data.  The resulting signal shows a large “change” signal.

On the right, we are doing a similar HDC comparison, using the recent inspection results subtracted from the current results.  The change here is more subtle, and to the naked eye of the manual analyst, it is difficult to notice change.  The delta change channel however, illustrates the signal change, even though it is a much smaller amount of change.

RevospECT HX Signal detection can be setup to detect very small amounts of change with good reliability.

HDC Video Demonstation

Here’s a short video of the HDC process to better illustrate it’s functionality.

We start by running the HDC process.

Now we see the baseline (blue) historic (orange) and current (green) Lissajous at a given location

We can zoom in on the data segment of interest

We can now show all three data sets overlaid on one display

We can separate the displays for better clarity

In the center display, we change it to show current and baseline, and in the right display we will show the baseline delta, the difference between those two channels.  The strip chart can also be changed to show the same delta channel

We can scroll through the data segment to show changes in each channel including the delta channel

The same process can be done to display the history delta channel

Why consider HDC?

What can HDC do for me?  Why do I need to consider using it?

Zetec HDC can provide full-tube comparison of historical data.  In a few seconds, the entire tube can be scrolled to view any significant changes that occurred since the last or historic inspection.

Automatic calibration of historic data to the same settings as the current data provides a true “apples to apples” comparison of like data.

In the field, this process can be performed by a review analyst to manually compare a signal to history to look for change.  A small wear flaw that does not change may provide information for decision making on repair practices.  No need to repair (plug) a tube with wear if it is not growing.

The REvospECT HX configuration can also use HDC as an independent detection method to look for new indications that are present in the current data that were not there before, or showed significant growth.  This capability provides for defense in depth inspections of critical components for better reliability.

Comparing history data utilizing HDC eliminates the subjectivity of manual data comparisons.

Signal inject capability

Lastly, I’d like to inform you of another capability of Zetec software, Signal InjECT.  This tool provides the ability to capture or create flaws and insert them into component data in order to validate or “prove” the analysis process and provide for “what if” scenarios for flaws that may not be present but could be a potential damage mechanism.

Signal InjECT is Zetec’s tool for performing eddy current signal capture and injection.  With this tool, we can simulate degradation that could occur in a component at any location along the tube.

This process enhances the performance testing of the manual data analyst as well as the automated data analysis process.

It can also be used to provide flaw signal training for analysts, as well as performance testing.  Flaw sizes can be injected at various “sizes” to allow for determination of detection POD (Probability of Detection) for both manual and automated analysis processes.

What is signal Injection?

Simply put, signal injection is the ability to capture an existing signal, and injecting it into current data relative to the component being inspected.  The source signal could be from a flaw standard or machined flaw sample, or from actual flaws from the same or another component, even from a different plant.

Signal Injection Video Demonstration

Here is a short video clip demonstrating Signal InjECT.

Signal injection can be applied to bobbin, rotating probe and array data.  The signal can be merged into the current data host, or it can replace the data segment as needed.

This example is for Array data.

First we adjust a capture box around the data signal in both directions

We capture the flaw and save it to a data libray, naming it as desired.

We then open Eddnet or Velocity, and select the data and location where we want to inject the flaw.

We select our captured flaw from the library.

We may want to adjust the voltage scale or length of the signal, as well as other parameters.

Phase rotation can also be adjusted to make sure the flaw follows eddy current physics

The flaw is then pasted into the data stream, and adjustments in positon can be madfe.

Once satisfied, the data is modified.

Then, we create a new data file with the injected signal, leaving the original file intact

We can observe the flaw on any data channel we desire, including mix channels.

Signal InjECT can also be applied to bobbin and rotating probe data.  Combination probe data, bobbin and array, can be captured and injected simultaneously with both techniques.


Lets summarize our discussion today on heat exchanger inspection enhancements.

Today we learned how RevospECT HX can enhance and improve heat exchanger inspections in various ways.  We can reduce the amount of repetitive tasks and keep our focus on what is important, thus reducing human performance issues.

We can dramatically increase the number of inspections within our given schedule, to improve inspection performance and component reliability.

We elevate all of our inspection resources to the same level of capability by utilizing automated analysis, and allow the analyst to focus on the most important tasks.

With this enhanced technology and ease of use, we allow easier transition to utilize more advanced technology such as array and combination probes (bobbin and array).

Inspection results are obtained earlier allowing quicker decisions on component status and repair.

The RevospECT HX solution provides automated processes to improve production and repeatability of the inspection.  Auto Acquisition provides better productivity to complete more inspections within the allotted schedule.  Integration of RevospECT auto analysis reduces lag time between acquisition and analysis, and provides a high level of confidence in component flaw detection.

Utilizing additional tools such as Signal InjECT and HDC provides confidence that the inspection configuration meets all of the requirements to ensure degradation is detected and component tube integrity is maintained.

Compare the RevospECT HX solution to your current inspection program, and see how you can improve your component reliability and safe plant operation.