Daily check are extremely important to ensure safe and stable operation of equipment at chemical plants.
This area is a field that Japanese people are good at.
In today’s busy world, we tend to cut corners, but we must not cut corners when it comes to daily inspections.
The future where DX can perform inspections instead of humans is not far off, but humans still have an advantage.
In particular, people who promote DX try to install equipment without knowing much about equipment and not knowing what to check.
What do we see during daily inspections ? This means that only those who handle the equipment can understand, so the value of mechanical and electrical engineers can be demonstrated here as well.
Understand the equipment correctly and do daily patrols!
Daily check is the key to stable operation
Daily inspections are very important in chemical plants that operate 24 hours a day, 365 days a year.
In general, the percentage of abnormalities discovered during daily inspections, during operation, and periodic inspections is
It is said that daily inspection, during operation, and periodic inspection = 3:5:2 .
Let’s clarify the definitions of daily inspection, during operation, and periodic inspection.
- Daily inspections are inspections carried out by manufacturing department managers and staff during daily patrols.
- During operation , when starting or stopping equipment or operating surrounding valves, etc.
- Periodic inspection is an inspection in which the equipment is completely stopped and the equipment is disassembled and checked.
According to this definition, in reality, daily inspection and during operation can be regarded as having almost the same meaning.
If daily inspections include those during operation, the ratio of daily inspections: periodic inspections = 8:2 .
That’s probably not an exaggeration.
After all, the people who are using the product on site are the most important.
Abnormalities are most easily discovered when the pump or agitator is in operation.Operators who check the site when moving are in a position to get the most information..
- different from usual!
- Something is wrong!
Just noticing at that level is enough as an operator. It is important to have this sensitivity.
Rather than saying nothing, it’s more important to raise what you’ve noticed.
By discovering abnormalities here and preparing for regular maintenance , stable facility operation is possible.
Five senses for daily checks
I’m afraid that I might fall for the tone of the field-oriented camp, but daily inspections at the field are all about the five senses .
The five senses are eyes, ears, nose, taste, and touch .
In the field, it is necessary to make maximum use of these.
The basis of daily inspections is to check the equipment in operation to the extent possible .
Let’s take a look at how much you can realistically do.
Visually check for gauges and leaks
The eyes are the most important of the five senses .
What kind of information can you obtain using your eyes in the field?
The easiest to understand is the instrument information .
But if you import the necessary information into the DCS, you don’t have to be on site.
There is probably a need to see the instruments with the naked eye, even if they are of relatively low importance.
Example of installation of field instruments
- Pressure gauge/negative pressure gauge
- Continuously running flowmeter
- heat exchanger outlet thermometer
- stirrer ammeter
None of them are of high importance, so they are information that is often overlooked even during on-site patrols.
In addition to instruments, there are omissions of information that should be checked on site .
Especially in chemical plants, early detection of leaks is very important for stable operation.
Here are some examples of what to check for leaks.
Places that are prone to leaks
- Leakage from flange gasket
- Leakage from sampling port
- Powder leakage from the powder inlet
- Lubricant leakage
That’s a very conservative thing. This is probably the basics of patrol.
Check for abnormal noises with your ears
Ears are surprisingly important in daily inspections .
Because the human ear is pretty good.
Does it sound different than usual?
Just be careful here.
If there is an abnormal noise in front of or behind a rotating device or valve , something is wrong.
If you know what is normal, you can judge that what is not normal is abnormal.
For specialized maintenance, a stethoscope is used, but for routine inspection, a valve handle or ballpoint pen can be used instead.
I feel the odor in my nose
The nose is also very important in daily inspections.
The probability of being able to detect with your nose when gas leaks is high.
There are times when we receive complaints from people living near our factories that they smell strange.
Smell is more intuitive than sound.
Some of the chemicals handled at chemical plants have a strong offensive odor, making it easy to determine.
Although it is important to use gas detectors, etc., the measurement range is limited, so the human nose is still useful.
Taste → None
It is impossible to use the sense of taste to preserve food in a factory.
It seems that researchers in the past tried to lick unknown chemical solutions with their tongues, but in today’s factories this is immediately denied.
Examine vibration and temperature by hand → Opposite
It is often said that you can touch the motor with your hand to check its vibration and temperature.
However, I disagree with this.
At least it’s not something you do on a daily basis.
- If you touch the rotating part with your hands, the idea of getting caught in something will not be fostered.
- Touching equipment or piping with your hands may cause burns .
If you touch it with your hands, you may get injured.
In the past, even minor injuries were tolerated, but times have changed.
Five senses that can be substituted with DX
The five human senses will continue to be important in daily inspections, but the number of areas that can be replaced by DX will continue to increase.
There are some fields that are targeting the automation of maintenance with DX, but the basic idea is to automate the five senses.
Let me give you an example.
eyes are cameras
Among the five senses, the eyes are extremely important.
When you go to a job site, don’t you naturally say, “I won’t know until I see the site”?
There is an awareness that the information of the “eye” that we see is important.
There is a lot of information that can be seen with the naked eye, but a lot of it can actually be covered by surveillance cameras .
We use surveillance cameras for many places in chemical plants.
Applications for using surveillance cameras in chemical
- Work to observe the values of on-site instruments and measuring devices
- On-site work such as sampling, preparation, and filling
- Situation inside the reactor
- Condition of liquid in glass tube during separation work
- Check valve opening/closing
- Monitoring for theft, etc.
- Fire monitoring
So-called ordinary explosion-proof cameras can check a large part, but there are also devices that use special sensing such as infrared rays to monitor more efficiently than the human eye.
Ears are difficult to replace
You could use a microphone to replace your ears with DX.
However, analyzing sound is extremely difficult.
At the very least, it will take some time before it becomes cost-effective.
It’s not impossible to detect only specific sounds from specific equipment, but what frequency sound should be picked up from many equipment? The best we can do is proceed from this perspective.
Specialized personnel are required to install, operate, and maintain the measuring equipment.
People with this kind of technology will become one of the paths that maintenance workers should take in the future, but it will not become mainstream.
The nose is difficult to replace
It is difficult to replace information about nasal odor with DX.
This is because the detection range of the measuring device is narrow.
Gas detectors such as gas detectors and oximeters can be used as a substitute for the nose, but the narrow measurement range is an issue.
The human nose will remain mainstream in that sense.
Detectors are used to monitor in place of humans even when patrolling is not in progress.
I think the future is still a long way off when DX will allow machines to do most of the work done by humans.
Taste → None
Taste is the only one of the five senses that humans do not use in chemical plants.
This is a part that even DX doesn’t touch on.
touch → basically none
The need for detecting equipment by touching it with measuring equipment will also be slow to advance.
I can think of using primitive equipment such as a vibration meter, but like sound, it is difficult to analyze.
It is necessary to pull out only a specific frequency, but it is difficult to determine the range.
A number of pieces of information are added, such as the operating conditions of individual equipment, process capacity, and building strength.
It is unlikely that it will replace humans, as it will only be attached to truly important equipment.
maintenance-free
There are some machines that are virtually maintenance-free with daily inspections.
It is a machine that only requires a full-time maintenance worker to visit once a month.
Let me give you an example.
induction motor
Induction motors are almost maintenance-free.
- There are few opportunities to use it under 100% load conditions.
- Ambient environment is less harsh than inside the process
This is because such conditions are expected to prevail.
Rarely run at 100% load
Particularly in batch-type chemical plants, operating under 100% conditions is limited to equipment in commercial operation, and limited to pumps and blowers.
Stirrers and other equipment are equipped with inverters, so they are rarely operated at 100% speed.
There are fewer opportunities to use it under maximum load conditions.
The environment in which motors are used is not much different from that of air.
Electric motors inside the plant are not affected by rain and wind, but if they are made “outdoor type,” they have considerable protection.
The contents of pumps and rotating machines are highly corrosive and easily affected by temperature and pressure, but since the motor is exposed to the outside air, the effects are minimal.
The negative effects of the external environment include organic solvent gas and powder.
This is a much milder condition than the internal effects of the process.
If the electric motor is established as a general machine, the conditions will not change significantly even if it is an electric motor for a chemical plant.
It can be said that it is almost maintenance free .
Bearings are also nearly maintenance-free.
Bearings, especially plain bearings, can be used almost semi-permanently.
In the case of rolling bearings, if they are filled with grease, there is almost no need for daily inspection.
It is better to decide on a cycle and have it repaired regularly.
Decelerator
Just like the motor, the reducer is nearly maintenance-free during daily inspections.
This is because the environment is filled with oil.
Regular maintenance is required because the structure is relatively complex and easily damaged during startup and stoppage.
However, it is difficult to check it during daily inspections.
When patrol inspections are carried out once a month, there are many patterns in which the equipment is not operating at that time.
hydraulic equipment
Hydraulic equipment can also be used without maintenance during daily inspections.
This is because it is an oil-filled structure similar to a reducer.
Because equipment that uses hydraulic cylinders and hydraulic motors is solid equipment, the importance of daily inspections is relatively low.
Position of instruction manual
The instruction manual that comes with the purchase of the manufacturer’s equipment.
How many companies are trying to utilize this in their daily inspections?
At the very least, there has been no progress in mechanical equipment in chemical plants for over 30 years , so I don’t think anyone would be grateful for it.
It’s actually a useful instruction manual.
inspection list
The instruction manual includes something like an inspection list.
This is very difficult to see.
The following mode should be listed for each equipment part name.
- damage
- pollution
- Looseness
- motion
As the name suggests, a daily inspection list is intended for daily use.
Daily life means “every day.”
No one goes on patrol while looking at the instruction manual every day, and even if you include a checklist, the amount of material would be enormous.
It is useful in the sense that you can extract only the essence from the contents written in the instruction manual and create a conservation calendar.
Extracting only the parts that are realistically possible will be related to the skills of a maintenance engineer.
In-house training
It is possible to use the instruction manual for in-house training.
From an educator’s point of view, it is a state of “eye-opening”.
This is because you can inflate the materials and have a track record of providing information to the students, which at first glance appears to be the case.
However, even if the student looks at the manual, it is unlikely that they will be able to understand it immediately.
just the shape.
how to drive
The instruction manual contains operating instructions .
This is a surprising pitfall.
The equipment was deteriorating rapidly, so when I looked into it, I found that the equipment configuration was different from the instruction manual .
Such cases are rare.
This is a question of the designer’s ability.
The more equipment you use on a daily basis, the more likely you are to fall into pitfalls.
Maintenance personnel can comprehensively grasp the repair history of equipment, so if you review the instruction manual for items that are frequently repaired, you may discover something new.
I watched it so much that I have already memorized it as a veteran! Some people may think so, but I am learning every day.
reference
There is a strong tendency to learn equipment maintenance on-site.
However, now that there are fewer teachers who can teach you, you can also use the books below to study efficiently.
lastly
We have explained the daily inspection efforts that mechanical and electrical engineers at chemical plants should know.
On-site inspections involve all five senses. Especially important are the eyes, ears, and nose.
Eyes have been replaced by cameras, but ears and noses are still areas where humans are active.
Please feel free to post your worries, questions, and questions about the design, maintenance, and operation of chemical plants in the comments section. (The comment section is at the bottom of this article.)
*We will read all comments received and respond seriously.