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A walk in the machine park or quality inspections?

Detailed inspections require the right type of person with the right mind-set, attitude and training. Most mills/mines/plants have some type of inspection program but, unfortunately, the inspections are often ineffective.

There may be many reasons why inspections often aren’t effective. But, one reason is that inspections are not done detailed enough to find problems. Many inspectors simply walk by equipment, making sure it wasn’t stolen last night, and if they are in a good mood, they may make sure it hums.

Let’s look at a few examples.

Example 1: A typical pump and motor coupling configuration in a paper mill

This plant has an inspection system in place, which means Mr. or Mrs. X should have checked it. I watched this piece of equipment intermittently for a whole week and it looked pretty much the same. Some questions would immediately come up when an experienced inspector looks at this equipment.

An experienced inspector would note:

• I can’t see cables well, so the condition can’t be checked.
• I can’t take a stroboscope to the coupling because the inspection ports are covered.
• The motor is running hotter than necessary because it is covered with dirt.
• I can’t see the oil level on the pump.
• The breather on the pump is most likely clogged.
• The breather is just a “goose neck” breather allowing dirty air into the oil.
• I wonder if the motor has jack bolts to allow precision alignment.
• There are no flow meter or inlet or outlet pressure gauges on the pump. How would I know if it operates on the right B.E.P.?
• There are no spots or hookups for taking vibration and temperature readings. I wonder where the last guy took the readings so I can compare readings.

Example 2: A jacking bolt (push bolt) on a motor in a refinery

This is a close-up of a jacking bolt on a motor base. What would an experienced inspector see? This photo was taken in the southern U.S. in March.

 An experienced inspector would note:

• The bolt is touching the base. As it gets warmer, the bolt will lengthen due to thermal expansion and push the motor out of alignment. I need to back the bolt off.
• Great, there is a jacking bolt there, so we can align it well. But I wonder why they don’t buy them with jacking bolts in the first place, since it would be a lot cheaper than putting them in after installation.

 Example 3: Inspecting a solenoid valve in a food plant

In the picture, you see a typical solenoid valve on a hydraulic system. An inexperienced inspector may just look at it and confirm the valve is mounted and that the electrical cable is undamaged.

An experienced inspector would:

• take the temperature on the coil, knowing that if the valve sticks internally, the coil often gets hot because it is trying to move the sticking valve;
• would listen to the solenoid for a buzzing sound, which is created when the solenoid is trying to move the valve multiple times; and,
• make sure there are no leaks, realizing leaks can cause performance problems and create additional heat.

 Example 4: Pneumatic regulator in a surface mine

The picture illustrates a pneumatic regulator that has been in the game for a while. Most inspectors would not look at the instrument at all since mechanics feel it belongs to instrumentation, while instrumentation techs seldom do physical checks of devices.

An experienced mechanic would put his or her hand in front of the weep hole and check if air is leaking out of the weep hole. If he or she feels air, that person would know the membrane inside the unit is broken.

Leadership and inspections

These four simple examples illustrate that there is a difference between walking by equipment and actually understanding how to inspect it. As leaders in operations and maintenance, we shouldn’t just give people a list of 40 equipment numbers and assume they know and are willing to inspect equipment correctly.

We should:

1. Make sure we have a documented system for how to inspect equipment and why we are doing these inspections. IDCON has more than 100 standards that we use in our projects and training. Feel free to download a few of our condition monitoring standards (http://www.idcon.com/condition-monitoring-books.htm ); click on “Sample 1″ and “Sample 2″.
2. Train people in how to do inspections. Even if many operators and craftspeople would know the simple techniques above, training and coaching the execution of the inspections are important to change attitudes and explain the level of detail that is needed.

Have you witnessed plant issues similar to the ones outlined above? Have you created detailed inspection and detection strategies? Tell your stories by responding to this blog post.

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Filed Under: Maintenance Excellence    |  Tags: condition monitoring, equipment checklists, maintenance, maintenance procedures, motors, predictive maintenance, preventive maintenance, pumps, reliability, routes, standard work, TPM, training, vibration analysis

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