OP-ED

Moving Beyond Combustion Safety — Designing a Crystal Ball

/ AUTOMOTIVE HEAT TREAT, BURNERS & COMBUSTION SYSTEMS TECHNICAL CONTENT, FEATURED NEWS, OP-ED

In June, we spent a good deal of time discussing a simple pressure switch to emphasize the many considerations that are necessary for proper installation. Now we will expand the discussion to how the switch works and what steps we can take to detect a failure that is likely to occur sometime in the future.

This column appeared in Heat Treat Today’s 2021 Automotive August print edition. John Clarke is the technical director at  Helios Electric Corporation and is writing about combustion related topics throughout 2021 for Heat Treat Today.

John B. Clarke
Technical Director
Helios Electric Corporation
Source: Helios Electric Corporation

A pressure switch is a Boolean device — it is either on or off — so how can we evaluate its performance in a manner where a potential failure can be detected before it occurs? The simple answer is time — how long does it take for the switch to respond to the condition it is intended to sense? What is the period between starting an air blower and the pressure switch closing? Has this time changed? Is a change in this time period to be expected, or does it portend a future failure?

A simple approach to evaluating this pressure switch’s time is to create predetermined limits — if the switch responds either too rapidly or too slowly — an alarm is set and the operator is alerted. Graph 1 illustrates this approach.

In Graph 1, the black band represents the time between the action (the start of the air blower) and the pressure switch closing. There is a warning band (yellow) — both high and low — that provides the early warning of a system performance problem. There is also a critical band (red) — both high and low — that provides the point at which the feedback for the pressure switch is determined to be unreliable. If the switch is part of a safety critical interlock, the system should be forced to a safe condition (in the case of a combustion system, with the burner off and a post purge being executed) if required.

Graph 1

Graph 2 depicts when a switch closing time exceeds the warning level. It could be the result of a problem with the blower and/or the pressure switch, but the deviation is not sufficiently large as to undermine confidence in the switch’s ultimate function.

Programmatically, if the time exceeds the warning band, and an alarm is registered, the responsible maintenance person is notified. If that is in the warning band, it can be addressed as time allows.

Graph 2

The warning bands give us the crystal ball to potentially see a problem before it causes a shutdown. As it is continuously monitored by the programmable logic controller (PLC), it may provide an increased level of safety, but that is dependent on a number of factors that are beyond the scope of this article.

The switch can be not only too slow to respond: an unusually fast response is a reason to be concerned as well. It could be that the pressure switch setpoint has been set too low — so low that it no longer provides useful feedback. Graph 3 is an example with an unusually fast response.

If the time is less than the “Critical Low” preset value, the switch’s feedback is determined to be unreliable. In this case, the setpoint may have been changed during a maintenance interval or even worse — the switch may be jumpered (this assumes we have an interlock string wired in series). The critical values are NOT intended to provide forward looking estimates of required maintenance — they are simply an enhanced safety measure.

This scenario assumes that the response of a component is consistent. In our example of a pressure switch monitoring an air blower, we can assume the time the blower required to reach full speed, the time for a pressure rise time in the air piping, and the responsiveness of the switch is consistent. These time intervals may not be consistent. The air supplied to the blower could be sourced from outside the building (temperate climate), which could cause air density changes between a cool, dry day and a hot, moist day. In this instance, what can be done to detect a failure?

An approach where we see fluctuations in the timing even in instances where all the components are operating properly would be to run a moving average of the time based on the last n operations. Then we compare the moving average to the last time and confirm that any change falls within a specific range.

Step 1 would be to average the last n values for the time required for the switch to trip. Then compare this value (ta) to the last time and see if the deviation exceeds the preset values. Let us assume if the time varies by more than 20% a warning should be issued to the maintenance staff.

Now this method will accommodate rapid fluctuations – but if the performance of the component degrades in a near linear fashion, this formula will not detect a premature failure.

An alternate approach would be to execute this routine on the first n cycles, as opposed to continuously updating the average. Using this method, the performance of the specific component is captured. Or this averaging can be executed on demand or based on the calendar or Hobbs timer.

These concepts are far from new, and it has only been because of the recent expansion in PLC memory storage capacity and processing power that it has been reasonable to perform this analysis on dozens of components on a furnace or oven. Remember, it is a shame to waste PLC processing time and memory!

One or more of these approaches, or similar approaches analyzing time, can indeed be a crystal ball that gives us warning of any of a number of potential failures — warning before a system shutdown is required.

About the Author:

John Clarke, with over 30 years in the heat processing area, is currently the technical director of Helios Electric Corporation. John’s work includes system efficiency analysis, burner design as well as burner management systems. John was a former president of the Industrial Heating Equipment Association and vice president at Maxon Corporation.

technical Tuesday

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Message from the Editor: How to Use This Guide

/ EDITOR, FEATURED NEWS, HEAT TREAT NEWS INDUSTRIES, OP-ED

OCAre you someone who is satisfied with the same services and equipment that you've used for years, regardless of how mediocre the results are? Would you like to use a new guide to find better heat treat solutions?  

This original content article was written by Karen Gantzer, editor of Heat Treat Today, for Heat Treat Today's June 2021 Heat Treat Buyers Guide print edition. Feel free to contact Karen Gantzer at karen@heattreattoday.com if you have a question, comment, or any editorial contribution you’d like to submit.

80%-90% of you tell us that you prefer to have a print, hard-copy magazine – and the Heat Treat Buyers Guide is no exception. While it is the “hip,” “cool,” or “in” thing to “go digital,” the facts say otherwise. So, slap this hard-copy, bad boy down on your desk or table and let it sit around until you’re ready to buy something in the North American heat treat market. Then pick it up and enjoy all of the resources it has to offer.

Here’s how you can get the most out of this resource:

The Buyers Guide is divided into three major sections.

1. The first section, from pages 17-27, contains an alphabetic listing of all the suppliers of heat treating equipment and related services in the North American heat treat marketplace. You’ll notice that some of the companies listed in this section have a red star before their name. These are the advertisers who make this print version possible. Please lend your support to these industry-leading companies when it comes to purchasing.

Other companies have a boldface listing along with their company logo, but no red star. These are our Gold level suppliers who have paid extra to be in the online version. These companies are also worthy of your serious consideration.

There are still other companies who have not yet completed their online listing and therefore have relatively little information in this print edition. You’ll be able to recognize these companies because they have a blue asterisk (*) next to their name. More and more of these companies are signing up daily, so our suggestion is to check our website (www.heattreatbuyersguide.com) for the latest information about these companies OR go directly to these companies’ websites, which are listed along with their company names in this first section.

Those companies without a red star, no logo, and no blue asterisk are what we call our Basic Level companies. They’ve also contributed a nominal yearly amount to be listed in the online and print versions of this Buyers Guide. These companies are also very much worthy of your consideration.

2. The second major section of this Buyers Guide is an exhaustive listing of heat treat equipment and related services. There is a comprehensive index of these services listed between pages 28 and 32. This is a good place to start your search.

Immediately after the Index of Equipment & Related Services are six sub-categories with hundreds of products and companies who provide them. The six sub-categories are: 1) Heat Treat Furnaces, Ovens & Induction Equipment, 2) Heat Treat Components, Supplies & Materials, 3) Heat Treat Controls, Instrumentation & Sensors, 4) Heat Treat Auxiliary, Subs-System, Ancillary Equipment & Services, 5) Heat Treat Lab, Testing, & Materials Characterization Equipment, and 6) Heat Treat Gases & Atmosphere Generation Equipment. There are too many products and services to reproduce here, but you can see them all on pages 34-78.

3. The third and final section of this Buyers Guide runs from pages 79 to 83 and is a state-by-state listing of commercial heat treaters. If you’re looking for a company to perform heat treating on a product your company makes, this is a good place to start. There wasn’t room in this print edition to list the processes that these commercial heat treating companies perform, but if you go to the website, www.heattreatbuyersguide.com, you’ll be able to search for a commercial heat treater by the processes they perform AND their proximity to you.

A final thought. If you are a supplier of heat treating equipment or related services OR if you are a commercial heat treater and you are NOT listed in this directory, there is a quick and easy remedy. All you have to do is go to www.heattreatbuyersguide.com and search for your company’s name. If you are there, all you need to do is “claim” your listing. If you are not there, you can easily create a listing for your company in less than 15 minutes. If you have any trouble, please feel free to contact us at buyers_guide@heattreattoday.com with any questions. We’ll respond as quickly as possible.

Happy shopping!

Message from the Editor: How to Use This Guide Read More »

HEAT TREAT 2021: Meet Me in St. Louis!

/ FEATURED NEWS, HEAT TREAT NEWS INDUSTRIES, OP-ED

op-edThe 31st Heat Treating Society Conference and Exposition (Heat Treat 2021) is scheduled for September 14-16 in St. Louis. This bi-annual, can’t-miss event provides an excellent opportunity for the heat treating community to meet, exchange information, and conduct business.

Eric Hutton
President,
ASM Heat Treating Society
Vice President Operations
Aerospace, Defense and, Energy
Bodycote

In addition to our standing colocation with AGMA’s Motion & Power Technology Expo (MPTE), we are excited to also be co-locating with ASM’s NEW Annual Meeting, “International Materials, Applications, and Technologies (IMAT)” Conference and Expo. Heat Treat conference registration includes full access to IMAT 2021. Co-locating with IMAT 2021 will provide access to additional exhibitors and more than 400 technical presentations on a wide variety of materials-related topics.

This year’s Heat Treat organizing committee did an excellent job of ensuring that the latest research and development is included for a high level of technical content on a wide variety of important topics, including Atmosphere Technology, Additive Manufacturing, Internet of Things, Nitriding, Vacuum Technology, Applied Technology, Quenching and Cooling, etc.

The Heat Treat Expo, co-located with IMAT and MPTE, is the place to be, featuring more than 500 companies. Activities on the show floor include a VIP guided industry tour on Tuesday, Solutions Center presentations, welcome reception with exhibitors, the Fluxtrol Student Research Competition, and the HTS Strong Bar Competition.

We hope attendees will join us during our premiere networking event, “The Heat is On,” at the Anheuser Busch Biergarten, scheduled for Wednesday, September 15. This special evening will feature live music, a tempting array of locally inspired food, craft beer, and a few “hot surprises.” Attendees will have the opportunity to network with Heat Treat, IMAT, and MPTE attendees.

We know that things might look a little different this year, but, rest assured that your health and safety are always our top priorities, and the ASM team continues to closely monitor all federal, state, and local guidelines. We are confident that we can safely come together and are taking all appropriate measures to ensure a healthy and successful in-person conference and expo.

Let’s get back to business! I hope you will join me at Heat Treat 2021, a great location to reconnect, make new contacts, share information, and collaborate with attendees and exhibitors from around the world in the global heat treating industry. We look forward to seeing you in St. Louis in September.

HEAT TREAT 2021: Meet Me in St. Louis! Read More »

Moving Beyond Combustion Safety — Plan the Fix

/ BURNERS & COMBUSTION SYSTEMS TECHNICAL CONTENT, FEATURED NEWS, MANUFACTURING HEAT TREAT, OP-ED

Last month we began the discussion about the relationship between combustion safety and uptime, highlighting how combustion safety, reliability, emissions, and efficiency are inseparable. This month, we will explore the subject in greater detail and outline a path that can both reduce the risk of an incident and protect the bottom line.

This article written by John Clarke, technical director at Helios Electric Corporation, appears in the annual Heat Treat Today 2021 Buyer's Guide June print edition. Return to our digital editions archive on Monday June 21, 2021 to access the entire print edition online!

John B. Clarke
Technical Director
Helios Electrical Corporation
Source: Helios Electrical Corporation

How many times have we heard the tale about the man with the leaky roof? He cannot fix his roof when it is raining, and the roof doesn’t need repaired when it is not. This story is also applicable to heating system maintenance, perhaps more so than other plant maintenance activities because it so seldom “rains.” Ovens and boilers tend to be very reliable. (This statement is true for equipment operating at low or moderate temperatures, less so for equipment operating above 1832°F (1000°C).) It is exactly when the machine is properly producing parts that the planning for combustion safety, availability, and performance must occur.

The first critical step we must take is to understand that combustion safety, routine maintenance, tuning, and calibration are parts of a larger work strategy. To focus solely on the annual inspection of safety components while ignoring system tuning will not only compromise tuning and efficiency, but also the safety. We have seen how managerial reactions to high profile incidents have caused some firms to dispatch teams to annually examine valves and pressure switches. This effort is highly compromised if it does not include all aspects of system maintenance as well as capturing what is learned each time to improve future inspections and equipment designs. There is data beyond pass and fail that is valuable if we wish to optimize the performance of our equipment

Let us assume it is a clear sunny day, and we are ready to invest some time in preparing to improve our combustion system starting with a deep dive examination of two pressure switches: the low fuel gas pressure switch (LFGPS) and high fuel gas pressure switch (HFGPS). These ubiquitous components are present on nearly every fuel train and are vital for safe operation. As their names imply, they monitor the fuel pressure and shut the safety valves if the fuel gas pressure is either too high or too low.

These switches must be listed for the service they provide by an agency independent of the manufacturer – UL, TUV, FM, etc. Simply looking for a stamp may not be enough; take the time to read the file or standard being applied by the agency and determine if it describes the application. Next, ask if the pressure switch carries the basic ratings expected, like the enclosure rating (Nema or IP). Is a Nema 1 switch operating in a Nema 12 area? Temperature ratings must be confirmed. All too often a component rated for 32°F (0°C) is applied in an outdoor environment in cold climates, or one with a maximum rating of 120°F (50°C) is applied next to the hot wall of a furnace. The component may operate out of specified environmental ranges for some time, but to apply a component in this manner is betting against the house – sooner are later we are going to lose. Ask the people of Texas if the bet against sustained cold temperatures in early 2021 was worth it.

"John Clarke, Technical Director, Helios Electrical The first critical step we must take is to understand that combustion safety, routine maintenance, tuning, and calibration are parts of a larger work strategy"

Next, let us look at the contact(s) rating of the switch and how it is applied to the burner management circuit. More often than not, these switches are in control circuits fused for more current than the contact rating. If the switch rating is too low, the electrical designer has an option to use an interposing relay to increase the current carrying capacity to this device. This relay is an added component, and as such, adds yet another possible point of failure. If the relay is interposed, is it dedicated to this one switch? Multiple devices being interposed by a single relay is prohibited by NFPA 86, for good reason. Is the relay designed to fail safely? That is, will a relay coil burn out or wiring fault close the critical safety valves? Is the wire gauge suitable for the current carried and protection device used?

Next, is the switch mounted in a safe location free from possible vibration or the foot of an eager  furnace operator? If the switch must be changed, are clearances provided to perform this maintenance? What is the mean time to replace (MTTR) the component? Is the way the device is wired providing a path for combustible gas to enter the control enclosure and cause an explosion? Flexible conduit, without a means to seal the connection, is a very common error. Use a properly specified cord and consider using some type of connector to terminate the wiring at the switch. A simple 7/8-16 or DIN connector not only provides additional protection from combustion gas getting into the electrical conduit but is also a great benefit when changing the component in a rush and helps to isolate the component’s control circuit during testing and calibration.

Is the pressure switch suitably protected from bad “actors” in the fuel gas? Perhaps soot is present that could foul narrow passages or H2S that could result in corrosion. These are rare conditions, but coke oven gas may not be as clean as purchased natural gas. Do we need to specify stainless steel components? Would a filter make sense to protect the switch and increase the intervals between maintenance?

Finally, let’s discuss pressure ratings. Unfortunately, nomenclature varies by manufacturer. What is the maximum pressure the device can sustain and not fail, i.e., leak fuel gas into the environment? Many switches can experience a pressure surge without risk of leakage, but the high-pressure event will damage the switch internally. It is important when determining if this rating is adequate to consider possible failure modes that might expose the pressure switch to excessive pressure. As a rule of thumb, a pressure switch must be able to sustain a surge pressure delivered to the inlet of the pressure reducing regulator immediately upstream of the device. Think of it this way, if the upstream regulator experiences a failure, the full pressure delivered to this regulator will pass to the pressure switch in question.

Other obvious pressure ratings are the maximum and minimum set points. The pressure switch should be set to trip as close to the middle of the range as possible and should never be set close to either the minimum or maximum setpoint. Is the pressure switch manually or automatically reset after a trip? In general, it is best practice that the LFGPS resets automatically, and the HFGPS requires a reset by the operator. This recommendation is because LFGPS trips each time pressure is removed from the system, and it is generally understood that the system needs fuel to operate. On the other hand, a high-pressure event is exceedingly rare, and the operator should be made aware of this unusual event.

This article has discussed a lot about the simple pressure switch. It appears to be a heavy lift to perform this analysis on every pressure switch in a facility, but take comfort, once the exercise has been completed on the first system, it is much easier to replicate what has been learned to properly assess other systems. We should most definitely insist that our OEM provides this data, in detail, when new equipment is supplied. Why did we review all these specifications? Because I have been around for a while and have seen nearly every one of these errors in the application of pressure switches on operating combustion equipment.

Next month, we will expand on the pressure switch discussion to describe the tune/calibration and testing processes. I hope this deep and specific dive has been of value. If you have any questions or comments, please let me know.

About the Author:

John Clarke, with over 30 years in the heat processing area, is currently the technical director of Helios Corporation. John’s work includes system efficiency analysis, burner design as well as burner management systems. John was a former president of the Industrial Heating Equipment Association and vice president at Maxon Corporation.

Moving Beyond Combustion Safety — Plan the Fix Read More »

Regionalization: How it’s Transforming Mexico’s Manufacturing Industry

/ OP-ED

Explore how the shift from globalization to regionalization is making a positive impact for businesses in the manufacturing industry, not only in Europe and the U.S., but also in Mexico, especially in the aerospace and automotive sectors.

This article, written by Humberto Ramos Fernández, founder and CEO of HT-MX, first appeared in Heat Treat Today’s May 2021 Induction print edition. Find the digital upload and other past editions here.

Humberto Ramos Fernández
Founder and CEO
HT-MX

It’s an interesting time in the Mexican industrial ecosystem, to say the least. It has, of course, been a very abnormal couple of years for obvious reasons such as the pandemic, the oil and gas crisis, and even the aerospace industry problems with the Boeing 737 MAX. However, these events have triggered a shift in the global manufacturing industry away from globalization and into regionalization. US and European OEM companies are realizing that having their suppliers in the same region as opposed to halfway around the world is becoming more and more important as it lowers risks, allows for faster technology transfer, and reduces project implementation times and costs.

All of this helps move the T-MEC* zone, especially Mexico, into a strategic position to take advantage of these opportunities. A heavily industrialized country with over 30 years of complex manufacturing experience, Mexico has the infrastructure to attract and develop its industries during these global manufacturing shifts. A strong workforce including engineers and trained technical population, an industrial culture, and an actively developing supply chain are important components that contribute to Mexico’s strengths.

Regional manufacturing clusters have been developing in Mexico for several decades now, but more recently, there has been a strong push for a fuller, more complete high tech supply chain.

Mexico has several manufacturing hubs with a wide range of industries served, including the aerospace manufacturing hub located in Chihuahua (200 miles south of the Texas border) and the automotive manufacturing hub located in the El Bajío region, both of which have been continuously strengthening their supply chains with certified suppliers.

We must be ready, but we also must be able to communicate that we are ready to help these international companies successfully launch their Mexican initiatives, even in the shape of a joint venture between Mexican and international companies.

These hubs started as maquiladoras, or plants doing simple, but labor-intensive jobs and have slowly evolved into full-blown high-tech operations where aerospace assemblies (landing gears, engines, interiors, bodies, etc.) or fully assembled cars, roll out of the lines on a daily basis. Such evolution, where OEM and Tier 1 operations became more complex, forced the supply chain to start upgrading. This is still happening at the moment, but major gaps in the operation, such as heat treat and surface finish, are now fulfilled. Today you can have a part machined, heat treated, HIPed, surface finished, painted, and assembled without leaving Chihuahua.

A more complete regional manufacturing chain allows our customers to transfer more production lines or develop more products, thus benefiting the entire manufacturing industry. And we, along with many others, are here to help fill historically empty gaps in the manufacturing chain.

So, as a Tier 1 and Tier 2 supplier, secondary process companies in Mexico must be ready to help transition to regional manufacturing; and this transition must be as painless as possible. We must be ready, but we also must be able to communicate that we are ready to help these international companies successfully launch their Mexican initiatives, even in the shape of a joint venture between Mexican and international companies.

The ability to accompany the customer through the development of the manufacturing process, from machining, to heat treating, HIPing, surface finishing, assemblies and to even helping locate local suppliers for complementary processes, is key for Mexican market success.

It is indeed an interesting time here in Mexico. Come and take a look.

*Editor’s note: T-MEC is also known as the United States-Mexico-Canada Agreement or USMCA in the U.S. and in Canada as CUSMA.

About the Author: Humberto Ramos Fernández is a mechanical engineer with a master’s degree in Science and Technology Commercialization. He has over 14 years of industrial experience and is the founder and current CEO of HT-MX, which specializes in NADCAP-certified controlled atmosphere heat treatments for the aerospace, automotive and oil and gas industries. As of 2020, HT-MX became Latin America’s only hot isostatic pressing (HIPing) supplier. With customers ranging from OEMs to Tier 3, Mr. Ramos has ample experience in developing specific, high complexity secondary processes to the highest requirements.

Contact Humberto at humberto@ht-mx.com.

Regionalization: How it’s Transforming Mexico’s Manufacturing Industry Read More »

Happy Memorial Day!

/ FEATURED NEWS, HEAT TREAT NEWS INDUSTRIES, OP-ED

Heat Treat Today would like to wish everyone a Happy Memorial Day as you spend time with loved ones and reflect on the sacrifice that men and women gave to protect this nation in the hopes of it becoming a more perfect union. From the Civil War origins to the World War I symbolic adoption of poppies to Congressional affirmation of the permeant holiday as "Memorial Day," we are grateful for this moment to take a rest and give humble thanks to those now past.

Have a blessed and safe holiday!

- The team at Heat Treat Today

Happy Memorial Day! Read More »

Moving Beyond Combustion Safety

/ FEATURED NEWS, INDUCTION HEATING EQUIPMENT TECHNICAL CONTENT, MANUFACTURING HEAT TREAT, OP-ED

op-edIn this month’s column, John Clarke will expand his discussion beyond combustion safety to include the economic issues that are concerns to all equipment owners and operators.

This column appeared in Heat Treat Today’s 2021 Induction May print edition.

 John Clarke is the technical director at Helios Electric Corporation and is writing about combustion related topics throughout 2021 for Heat Treat Today.

John B. Clarke
Technical Director
Helios Electric Corporation
Source: Helios Electric Corporation

The furnace's or oven’s burner management system (BMS) and its associated components are all that stand between us and an incident. The severity of these incidents ranges from the very expensive — a damaged furnace or oven — to the tragic — loss of a human life. It is a testament to the good work of hundreds of people that combustion system explosions are so rare. That said, the risk to life and property mandates that we revisit this subject frequently, and the risk to profitability dictates we expand our consideration beyond safety to include uptime and quality, as well.

National Fire Protection Association Standard 86 (NFPA 86), or “Standard for Ovens and Furnaces,” provides a standard that is the most common guide to the application of combustion components used in the US. This excellent prescriptive standard reflects the common thinking of people with hundreds of years of combined experience; but it still requires expertise to properly interpret and apply its requirements. It is important to not only understand what component must be provided, but also why.

NFPA 86 is used as a guide for the design of your BMS which includes the various control components to properly monitor the startup and operation of the burner. NFPA 86 also applies to the fuel train, constructed of components that regulate the flow of fuel and air and includes blowers, regulators, valves, filters, and sensors. What BMS and fuel train safety system issues should most concern an end user? An end user must know what it really means when your system is stamped “NFPA 86 Compliant.” To paraphrase Clint Eastwood: The end user needs to know their system’s limitations.

The NFPA 86 standard has been developed to protect life and property, but not production and profits. It is also a prescriptive standard, providing specific guidance to what components need to be applied and in what order. The shortcoming of a prescriptive code is that it must be mostly generic, that is, it applies to types or classes of equipment as opposed to specific applications. Given the variety of burner applications used in industry, it would be impractical to specify every component, order, and wiring for every conceivable process heating application.

Why is this a concern for end users? A specific application may have unforeseen risks or are out of the scope of NFPA 86 . Critical failure modes may be indirectly associated with a burner failure. For example, loss of a process air flow may allow a heat exchanger to overheat before a high temperature limit instrument detects the temperature rise. In this case, the process air flow must be monitored, and the flow or pressure switch monitoring the air flow must be added to the interlock string. This way, the burner will shut off as soon as the air flow failure is detected and not wait for the heat exchanger’s temperature to rise to an unsafe temperature. Another reason to “exceed” the code is that often ovens or furnaces are one element in a much larger manufacturing system. An example would be a continuous paint line, where a failure of the curing oven might shut down an entire facility.

What should an end user do? Ensure the system provided meets the standards and codes, NFPA 86, the Fuel Gas Code (NFPA 54), NEC, etc. This level of compliance is the minimum – and is often not the optimal. Additionally, invite the OEM who built the system to apply their experience and exceed the standards if it provides a more robust system. It may cost a few dollars up front, but it will be pennies when compared to the cost of an incident or, in many cases, an outage.

Encourage your supplier to apply a recognized process to the system review, perhaps a failure mode effects analysis (FMEA) and factor in not only the cost of an incident, but the cost of lost production or quality rejects as well. Consider an independent third-party review – it never hurts to get a second opinion. Review the cost of redundancy, be it online or near online . What is the cost of a second flame rod and flame safeguard when compared to the value of four hours of production?

Next, review the steps to service the system. Look at the mean time to replace (MTTR) a failed component. Has the system been designed to be easily serviced? Are there pipe unions on either side of all critical valves? Where are the spare parts located? What skill trades are required to make the repair? Is post replacement calibration or testing required? And if so, has it been documented?

Ask if the BMS provides a clear indication of the reason for a shutdown. The interlock string, a logical series wiring of critical components where any one component indicating a fault will disable the combustion system, should be monitored in a way where the “first out” or component that will shut down the system, is clearly identified.

Lastly, it is the end user’s responsibility for periodic inspections and equipment maintenance. NFPA 86 prescribes that the BMS and fuel train components are inspected per the manufacturer’s recommendation, but at least once a year.

The annual inspection is a critical step for safe operation but is viewed by many end users as simply a cost. Add to this the relative reliability of most components and we are presented with the ironic risk that maintenance personnel may take short cuts during the periodic inspection. One such person may say, “I always check the low gas pressure switches and they always pass, so I thought, what would it hurt if I skipped the test this year?”

For a more robust inspection, consider adding more value to the process. Combine the safety inspection with an extensive equipment calibration and service: Replace the filters, change the thermocouples, calibrate the control instruments, tune the burner, check the fuel-to-air ratio of the burner, and inspect the BMS components. This adds value to the process and makes it more palatable for the maintenance department.

When the cost of downtime of a key piece of equipment is high, practice the repair, at least on paper. However, if a failed burner shuts down an automotive assembly line, isn’t it worth the time to run actual drills?

In general, most burner trips are the result of a failed sensor, a UV scanner, dirty flame rod, an open thermocouple, or the vibration from an unbalanced fan tripping a pressure switch. In other words, when this type of trip occurs, the greatest cost is lost production, followed by the labor to diagnose the problem and then the cost to replace the component. Generally, the purchase price of the component is far less than the other costs associated with the system trip. Do not be penny wise and pound foolish. Spare parts are a pretty good investment.

If you need the heat from a burner to make your product, it makes sense to not only consider safety, but also plan reduced downtime as well. In the coming articles, we will examine these issues in greater detail, so stay tuned.

 

References:
[1] https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=86

 

About the Author:

John Clarke, with over 30 years in the heat processing area, is currently the technical director of Helios Corporation. John’s work includes system efficiency analysis, burner design as well as burner management systems. John was a former president of the Industrial Heating Equipment Association and vice president at Maxon Corporation.

Moving Beyond Combustion Safety Read More »

When Heat Treat and St. Patrick’s Day Collide…

/ FEATURED NEWS, MANUFACTURING HEAT TREAT, OP-ED

op-edWhen heat treat and St. Patrick’s Day collide, Heat Treat Today editors have a little fun. Today’s post is inspired by furnaces and Ireland. Happy St. Patrick’s Day, and enjoy the hot topics!

| The Irish Turf Fire |

Have you heard of this heat treating solution? The fuel for this furnace is turf. “Turf is dried-peat and was a primary fuel source for Irish people for thousands of years[…] In the past, Irish people used turf to heat their homes and cook their food. Turf was harvested from a bog. Cutting turf by hand is a laborious task.” Not sure your general manager will let this one by... (Mairead Geary, “Smell of an open fire in Ireland is intoxicating but what is Irish turf?” IrishCentral)


| Irish Terms |

Here are some Irish and Gaelic terms that a heat treater may want to use instead of the same ol’ same ol’. Just for today. Search more options for yourself here.

  • Cóir teasa: heat treatment
  • miotaleolaíocht: metallurgy
  • foirnéis: furnace
  • prásáil: brazing
  • gaibhnithe: forging
  • ainnéalta: annealing

| Heat Treatment in Ireland |

Content at Heat Treat Today is focused on the North American heat treat industry, however, we would be remiss if we didn’t highlight heat treatment going on in Ireland.

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For a featured in-house heat treater, “medtech” company Stryker has heat treat processes going on at their Ireland R&D base in Cork. After a commitment to invest in three facilities in Cork, Stryker’s Spencer Stiles said, “Our team in Ireland has built considerable research and development and new product development capabilities through the partnership of multiple divisions over the past 20 years in an effort to serve multiple market segments.”

Screen Capture of Stryker’s Landing Page

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BOC is a provider of industrial, medical and special gases in Ireland and has been producing atmospheric gases, including oxygen, nitrogen and argon in Ireland for over 70 years.

Source: About BOC, a member of Linde Group

While you may not have heard of these heat treater providers, they are a member of the international Linde Group.

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A heat treatment service provider, Hi-Life tools has been providing heat treatment service for a wide range of Irish based tool making, engineering and medical device companies for more than 20 years.

Source: PTG webpage

The company, part of Precision Tool Group, has built up a vast amount of experience of heat treating a wide range of metals from tool steels, stainless steels, and exotic metals. These can be treated using the standard processes or a custom made process can be developed to suit the customer requirements.

| Irish Voices: Winter, Fire, and Snow |

Thankfully, winter and snow are melting away, but fire remains! Listen to this beautiful ballad sung by Irish Tenor, Emmet Cahill. If you want to listen to a full playlist of Irish folk music, check out The High Kings.

 

 

 

 

That’s all for now, Happy St. Patrick’s Day!

— Heat Treat Today Team

 

 

 

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Excess Air: Its Role in Combustion and Heat Transfer

/ ENERGY HEAT TREAT, ENERGY HEAT TREAT TECHNICAL CONTENT, FEATURED NEWS, OP-ED

Excess air plays multiple roles in heat treating systems. Learn about its importance in combustion and heat transfer, and why being well-informed will help your system run at peak performance.

This original content article, written by John Clarke, technical director at Helios Electric Corporation, appeared in Heat Treat Today’s Aerospace March 2021 print magazine. See this issue and others here.

John B. Clarke
Technical Director
Helios Electric Corporation
Source: Helios Electric Corporation

Is your system running optimally? The following discussion will provide a better, albeit abbreviated, understanding of the role of air in combustion and heat transfer.

Excess air in heating systems plays many roles: it provides adequate oxygen to prevent the formation of CO or soot, can reduce formation of NOx, increases the mass flow in convective furnaces to improve temperature uniformity, and at times, wastes energy. Excess air is neither good nor bad, but it is frequently necessary.

To begin, we must first look at a basic formula. For our discussions, we will replace natural gas, which is a mix of hydrocarbons with methane (CH4). The oxygen (O2) is supplied by air.

The above simplified formula describes perfect or stoichiometric combustion. The inputs are methane and air (where only the O2 is used to oxidize the carbon and hydrogen in the methane), and the products of combustion (POC) consist of heated carbon dioxide (CO2), water vapor (H2O) and of course nitrogen (N2). (The actual reaction is far more complex and there are other elements present in air that we are ignoring for simplicity.) As we can see from the equation, the oxygen we need to burn the methane comes with a significant quantity of nitrogen.

In practice, it is very difficult to even approach this stoichiometric or perfect reaction because it would require perfect mixing, meaning that each molecule of methane is next to an oxygen molecule at just the right time. Without some excess air, we would expect some carbon monoxide and/or soot to be formed. Excess air is generally defined as the percent of total air supplied that is more than what is required for stoichiometric or perfect combustion. For natural gas, a good rule of thumb is to have about 10 cubic feet of air for every one cubic foot of fuel gas for perfect combustion. Higher air/fuel ratios, say 11:1, are another way of describing excess air.

In most heating applications, the creation of carbon monoxide and other unburnt hydrocarbons should be avoided, except in the rare cases where they serve to protect the material being processed. Employees must be protected from CO exposure; and soot can damage not only equipment, but the material being processed.

Source: Heat Treat Today

The amount of excess air that is required to find and combine with the methane is dependent not only on the burner, but also on the application and operating temperature as well. Some burners and systems can run with very little excess air (under 5%) and not form soot or CO. Others may require 15% or more to burn cleanly. Just because a burner performs well at 10% excess air in application A, does not necessarily mean the same level is adequate in application B.

Once the quantity of air exceeds what is needed to fully oxidize or burn the methane, combustion efficiency will fall because the added air contributes no useful O2 to the combustion process, and it must be heated. It is very much like someone putting a rock in your backpack before you set out for a 16-mile trek. Taking this analogy further, higher process temperatures equate to climbing a hill or mountain with that same rock — the higher the climb, or the higher the process temperature, the more energy you waste. Sometimes this added weight or mass can be useful.

The higher the excess air, the greater the mass flow. In other words, the total weight of the products of combustion goes up, and the temperature of the CO2, H2O, N2, and O2 goes down. If we are trying to transfer the heat convectively, this added mass or weight will provide improved heat transfer and temperature uniformity. A simple way to think of temperature uniformity is that the lower the temperature drop between the products of combustion and the material being heated, the better the temperature uniformity. Many heating systems are specifically designed to take advantage of this condition – higher levels of air at lower temperatures. This is especially true when convective heat transfer is the dominant means of moving heat from the POC to the material being heated (when the process temperature is roughly 1000°F or lower).

Source: Heat Treat Today

Some heating systems are specifically designed to operate as close to perfect combustion as is possible as the material is heated then switch to higher levels of excess air to increase the temperature uniformity as the setpoint temperature is approached. In other words, it provides efficient combustion when temperature uniformity is less of an issue and a very uniform environment as the material being processed nears its final setpoint temperature.

Of course, a system can be supplied with too much air, which can waste energy, but also prevent the system from ever reaching its setpoint temperature. The energy is insufficient to heat all the air, the material being processed, and compensate for furnace or oven loses. In these instances, it is obvious that we must reduce the air supplied to the system.

In indirect heating systems – where the products of combustion do not come in contact with the material being processed, like radiant tubes, for example — air in excess of what is required for clean combustion provides limited benefit and should generally be avoided. In these systems, it is best to play a game of limbo, “How Low Can You Go,” so to speak. Test each burner to see how much excess air is required to burn clean and add a little bit for safety. Remember, if you source your combustion air from outside in an area with significant seasonal variations, the blower efficiency will change, and seasonal combustion tuning is required.

Lastly, some burners require a minimum level of excess air to operate properly. This additional air prevents critical parts of the burner from overheating – or the air may limit the formation of oxides of nitrogen (NOx). In this application, altering the burner air/fuel ratio could generate excessive pollutants or even destroy the burner.

Efficiency is important, but the process is king. There is no magical air-to-fuel ratio and no single optimum level of excess air in the products of combustion. Each application is unique and must be thoughtfully analyzed before we can confidently say we have optimized our level of excess air. But careful attention paid to the effect that excess air has on your fuel-fired systems will pay dividends in improved safety and efficiency.

About the Author:

John Clarke, technical director at Helios Electric Corporation, a combustion consultancy, will be sharing his expertise as he navigates us through all things energy as it relates to heat treating equipment.

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9 Industry 4.0 Terms You Should Know

/ MANUFACTURING HEAT TREAT, OP-ED

This brief reference guide is composed in response to insights on Industry 4.0 from Robert Szadkowski, VP of Aftermarket Sales at SECO/WARWICK. The list contains pertinent terminology to consider when speaking about Industry 4.0.

If this or any other article piques your interest and/or you would like to contribute to a Heat Treat Today article, please contact editor@heattreattoday.com.

  1. Additive Manufacturing – “a disruptive technology trend that is continuing to influence the future of the manufacturing industry and will continue to provide additional opportunities for heat treaters going forward.” (“Heat Treating, Additive Manufacturing, and Serialization” by Ron Beltz, Bluestreak)
  2. Augmented Reality – Digital enhancement of a real-world environment. For example, phone apps which can portray a digital overlay on a video feed, like Snapchat lenses. This can be used for the following (examples provided by Robert Szadkowski)
    • OEM internal training of new employees
    • remote training of the client’s employees
    • remote reviews
    • first line of support, direct from OEM for the customer
    • second line of support, OEM internal service support
    • “step by step” maintenance instructions
    • access to documentation directly on site
    • access to technical data directly at the device
    • access to technological data of the device operation bypassing the control cabinet
    • access to the knowledge base
    • possibility of multi-person interaction (furnace user, furnace OEM, manufacturer of the affected component)
  3. Autonomous Robots – Machines which have “decision-making” computers and can carry out precise actions from that computation (“What are Autonomous Robots?”)
  4. Big Data and Analytics / Big Data Analytics – The use of analytical software to comb through huge data sets in order to find trends and other useful insights that will enable a user to better understand a process in their control (“Datamation: Big Data Analytics”)
  5. The Cloud – a network of servers where a user can store information — versus their hard drive — and access it via the internet (“What is Cloud Computing”)
  6. Cybersecurity – Security of privacy and security of devices; “digital viruses threaten not only computers and phones, but together with industry cybernetics, all devices, including industrial furnaces, e.g. PLC, HMI, SCADA and even single intelligent sensors.” (Robert Szadkowski, SECO/WARWICK.
  7. Industrial Internet of Things (IIoT) – The physical networking of objects via internet-supported software is what is commonly known as the internet of things (IoT). Similarly, the “industrial internet of things” (IIoT) refers to these systems supporting industrial purposes, like synthesizing information from furnace sensors on a central app.
  8. Simulation – The technological imitation of a real-world process for the sake of education, experimentation, training, etc. (“Computer Simulation”)
  9. System Integration – Bringing user systems into a cohesive hardware, software, and communications package (“Gartner Glossary: System Simulation”)

(photo source: Stella Jacob at unsplash.com)

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