Mechanical Applications for Industrial Infrared

InfraMation 2018 Application Paper Submission

Frederick Gallardo, CMRP IVC
Technologies

ABSTRACT
In the 1950’s Infrared was basically limited to Military or Government use, as the cost of these systems was extremely high, and the sizes of the cameras were huge. By the 70s and 80s, more and more industries started using Infrared as part of their inspections, but the number of users was still small based on cost. Today, you can buy a good Infrared camera for under $500 and a great camera for under $8000. More and more companies are buying these cameras and deploying them within their facilities. Infrared is a powerful, noninvasive tool, but understanding its limitations is critical. You will quickly see infrared thermal imaging equipment is not difficult to learn or use. Unfortunately, it is also not difficult to make very serious mistakes interpreting what you see. The most common mistake that people make is forgetting to think. Thermal imaging equipment is simply a tool. You must also think about how that information can best be used to solve problems. To do that you need to remember to think! The following case studies will illustrate the proper use of Infrared Imaging for Mechanical Inspections.

INTRODUCTION
An unfortunate result of the lower cost of Infrared Cameras and their increased availability has been a flood of inexperienced inspectors performing infrared inspections. This coupled with unrealistic or uninformed expectations from clients has created a general state of confusion concerning the real capabilities of infrared technology. Here are some Infrared facts: Thermal Imaging cameras CANNOT see inside walls and ceilings. They are not X-ray machines nor are they related to Superman. Their operating wavelengths limit them specifically to the infrared bandwidths.

Figure 1. Electromagnetic Spectrum

Finding a difference in temperature with an Infrared Camera does not insure an accurate diagnosis of the cause of the differential; nor the true value of the temperature. An infrared picture can be a valuable tool in analyzing some commercial issues that might surface during a standard inspection. Other analysis is almost always needed to determine the source of a problem and the appropriate solution. In all plants there is a diverse collection of equipment that can be successfully inspected using infrared thermography. For most mechanical equipment the knowledge necessary and the techniques used toinspect them are straightforward. You will also need to know something about the equipment you are inspecting, including, at a minimum,the following:

• Understand the basic operation of the machinery
• Understand the heat flow characteristics of the machinery
• Understand the machinery's heat-related failure mechanisms
• Have a procedure to safely inspect machinery while it is in operation
• Observe the machinery during startup and cool down as well as during normal operations

The problems you will be looking for in machines are typically related to several common factors:

• Excessive friction: Bearings and gears
• Non-uniform heat flow: Casting operations
• Non-uniform temperature distribution: Ovens
• Inadequate cooling or heating: Heat exchangers
• Inadequate fluid flow: Blockages
• Differences in capacitance: Levels
• Differences in conductive heat flow: Refractory
• Abnormal electrical resistance: Robot welder
• Air leakage: Condensers

When looking at mechanical equipment, it is important to have a full array of inspection techniques at hand, as well as to have a thorough understanding of both the technology and the equipment you are inspecting.

INDUSTRIAL MECHANICAL INFRARED EXAMPLES

Insulation/Seal Breakdown:

A basic technique used for all types of inspections of mechanical systems is called thermal mapping. Thermal mapping creates a series of comparative thermal images of a mechanical system that detail the changes in the system during operation or over time or compared to similar machines.

Figure 2. Example of Thermal Mapping – Insulation or seal deterioration

Recommendation: The bottom area of the Superheater (AR2) continues to show elevated temperatures. Insulation or door seal may be degraded. The top area (AR1) has been showing a gradual increase in temperature.

Analysis: Inspect insulation and door seal and repair as necessary. Continue to monitor on a periodic basis.

Boiler Skin Leak:

Figure 3. Boiler Skin Leak

While performing an electrical scan for a client, the down-time waiting for the proper support to open the electrical components; this leak was found on their boiler shell by simply scanning around the area. At first the visual discoloration suggested that this thermal image was a reflection of some sort. By changing the angle of view, it was determined that it was in fact NOT a reflection, but rather an area of the boiler skin that was losing precious heat.

Operation Checks:

When looking at reliability and efficiently, checking intercoolers becomes quick and simple. Here is an example comparing the incoming fluid temperature versus that of the outgoing temperature; where the unit is operating as expected.

Figure 4. Intercooler operation check

Time Constraints:
Vibration analysis is one of the most common used non-invasive inspection techniques when it comes to determining the condition of rotating equipment. But what happens when you have well over 1000 bearing block locations to inspect on a conveyor system. Well, mechanical Infrared inspections work great for these applications. Let’s assume it takes 10 seconds to measure the vibration signature from each of these bearings, that would be about 2 ¾ hours of collecting the data. With an Infrared Camera and the proper understanding of the use and limitations, the same bearing locations can be scanned and recorded within 30 minutes or so. As we all know, time is money.

Figure 5. Inspecting bearings with thermography saves time

Hydraulic Solenoid Checks:

Figure 6. Solenoid ran hotter than all other units with the same rating and load.

Safety or Access Issues:
When steel is formed, it must be super-heated to become malleable so it can be shaped. It passes through many shaping spindles (roll stands) to form its shape. After passing through these roll stands, it must be placed on a cooling bed to cool down and harden so it will not lose its shape. The cooling bed is a large, complex mechanism with many moving components. One such component is the Auto-Stacker, which stacks the steel when it has finished cooling. A motor/ gearbox driving setup is at each end of the cooling bed. These are attached to drive shafts with two Ujoints. As the drive system turns, the stacker moves in a North-South direction, lifting the steel and placing it on the stack a few feet away. In this way, the drive system only operates in short bursts, just long enough to stack the steel at a timed rate. Due to the nature of the mechanism, the many moving components, and its location, human access is highly restricted. Safety is always of first priority.

Figure 7: Drive System U-Jointed Drive Shaft

During a mechanical infrared survey on the cooling bed, an interesting anomaly was discovered on one of the drive systems. A drive shaft revealed an abnormal thermal signature that was documented as a problem.

Figure 8. Auto stacker magnetic drive axle

In the first thermal image, you see an area of the drive shaft that has been heated more than its surroundings. The drive shaft should have a uniform temperature if it is working properly. The anomaly seems to be in the location of the end of the splined shaft. The first thought that came to mind is a lubrication issue. When asked about the PM periodicity, maintenance personnel revealed that a PM had been performed on the shaft just two weeks prior to the survey, and that it had the proper type and amount of lubricant.

This posed an interesting question. What could cause the drive shaft to increase temperature in a specific area if it is properly lubricated? Infrared technology was used to find the anomaly, but other technologies were needed to diagnose the problem.

Dial indicators were used to detect the proper movement of the stacker. It was discovered that it was moving in an East-West direction at the same time it was moving North-South. The movement should be restricted to North-South only. This was a major discovery. The mechanism was then locked-out in order for an inspection of its components. Many loose components were found throughout the mechanism, which contributed to the excessive movement. This excessive movement put undue stress on the drive shaft, which caused extra friction and the thermal anomaly.

All components were then tightened to specifications. Unfortunately, damage to the internal splines of the drive shaft resulted in its replacement.

CRITICALITY REFERENCE INFORMATION

• For components that are lubricated, the maximum allowable temperature is that of the oil.
• Delta T criteria: hard to say because it is case by case. Criteria such as the one used for electrical inspection can be a first basis, but you'll have to determine your own set of thresholds.
• Maximum temperature criteria; below are some examples in degrees Celsius.

Power Transmission Components
V-belts 060
Chain drives: limited by maximum lube temperature.
Gear drives: limited by maximum lube temperature.

SUMMARY
Mechanical systems have hidden problems that can be identified quickly and safely utilizing an Infrared Survey. Today’s facilities and reliability engineers are saving a tremendous amount of money every year with infrared mechanical inspections. Infrared mechanical scans can significantly increase profitability and reduce your operating, testing and maintenance costs by:

• Reducing downtime and equipment damage
• Establishing repair priorities
• Quickly identifying problems
• Improving and expanding preventive maintenance efficiency and efforts
• Testing under load so as not to disrupt production

Excessive heat in mechanical systems is an indication of approaching trouble. High temperatures indicate excessive electrical resistance, worn components, lubrication failure, or other common problems that can lead to expensive or even catastrophic failures. Trying to find these incipient failures with visual and manual inspections is costly, inefficient, and at times extremely dangerous.

With the proper training, using your infrared camera can get you to quickly detect thermal anomalies that threaten the safety and reliability of your mechanical equipment.

Thousands of points can be inspected in a single day. In a matter of hours, infrared tests can develop a complete catalog of the hidden thermal issues in your facility's mechanical equipment.

With thermography being a non-contact and nondestructive test, there is no need to interrupt production or schedule costly shutdowns. Thermographers can inspect the equipment under normal loads and operating conditions, so the plant doesn’t have to disrupt their production schedules. By testing the operation of your systems in ‘real time’, a qualified inspector can assist facilities in understanding the impacts of potential component issues.

REFERENCES
Klaus-Peter Möllmann and Michael Vollmer
Infrared Thermal Imaging: Fundamentals, Research and Applications
ISBN: 978-3-527-41351-5

Hudson, Richard Jr.
Infrared System Engineering
ISBN: 978-0-470-09935-3

Nichols, Jeff Edifice
Inspections
http://www.edificeinspections.com/index.php/blog-articles/24-infrared-facts-and fiction.html

Machinery’s Handbook
22nd Edition
Industrial Press

Standard for Infrared Inspection of Electrical Systems & Rotating Equipment
2008 Edition
Infraspection Institute
http://www.motordoc.org/wp-content/uploads/2013/11/ElectricalIRStd.pdf

SKF General Catalogue 4000 US
1991
SKF

The Plane Bearing Handbook
1989
Bearings Inc

Steyr Bearings Technical Manual 281E
1981
Steyr

Parker O-Ring Handbook
Parker Seals

CR Handbook of Seals
CR Industries

ACKNOWLEDGEMENTS
Thanks goes out to all my Team members who provided many of the images within this manuscript. Special thank you goes out to Kenneth Starry and Robert Miller for their assistance and in providing additional data and information. The author wishes to thank IVC Technologies for providing the resources to make this work possible.

ABOUT THE AUTHOR
Fred holds an AS in Machine Design and BS in Mechanical Engineering. Fred’s industrial experience started back in 1989 when he worked as a detailer, then a design engineer for a large mill builder. In 1996 Fred shifted his passion from machine design to machine reliability. Certified as a Category III Vibration Analyst, a Level III Thermographer and CMRP, Fred joined IVC Technologies as a vibration technician in 2004 and over the years has gained significant technical expertise and practical knowledge in a variety of industries which include steel, pharmaceutical, paper, power, plastics, machine tool, aluminum and consumer goods. In 2009 Fred was promoted to Director of Operations, but continues to follow his passion by assisting with all aspects of testing and training within the team.

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