Tuesday, December 7, 2010

PREDICTIVE MAINTENANCE ON CHEMICAL TANKERS -- CAPT AJIT VADAKAYIL

                                 PREDICTIVE MAINTENANCE

WHEN YOU DO PREDICTIVE MAINTENANCE OR CONDITION BASED MAINTENANCE ,YOU CARE FOR THE MACHINERY AS YOU CARE FOR YOUR OWN BODY.  

PROCATIVE USE IS MADE OF ALL 5 SENSES OF THE HUMAN BODY PLUS AN INTELLIGENT SURVEILLANCE SYSTEM WHICH USES INSTRUMENTS LIKE FLIR CAMERA, ULTRASONIC DETECTORS, STROBE LIGHTS, VIBRATION  PENS ETC TO MULTIPLY ABOVE SENSES AND TO WARN OF IMPENDING FAILURE.

IT IS A PHILOSOPHY AND AN ATTITUDE BASED ON PRO-ACTIVE RISK ASSESSMENT.

MOST OF THE PEA BRAINED PMS SHIPBOARD PROGRAMS ( MADE BY PRETENDERS WHO HAVE NO IDEA WHAT GOES ON ON A CHEMICAL TANKER ) FAIL TO REALISE THAT THERE ARE ONLY 24 HOURS IN A DAY-- OUT OF WHICH SOME TIME IS MANDATED FOR REST AND SOME FOR MERE RUNNING OF SHIP , LOADING/ CARRIAGE AND DISCHARGE 
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It is  all about early detection and elimination of equipment defects that could lead to unplanned downtime or unnecessary expenditures , The bonus is that the equipment is in normal in-service operation, with little to no process interruption an the tesing is non-destructive.

This is in contrast to time- and/or operation count-based maintenance, where a piece of equipment gets maintained whether it needs it or not. Whether you like it on not, you have to lump it. The "predictive" component of predictive maintenance stems from the goal of predicting the future trend of the equipment's condition.

 Zero oriented concepts such as zero tolerance for waste, defects, break down and zero accidents are becoming a pre-requisites in the current age. . Normal mechanical failure modes degrade at a speed directly proportional to their severity.

You will NOT allow a time based , predetermined medical schedule , which does NOT care for the actual condition of your body , to be inflicted on your own body. Before you submit yourself to heart surgery, you will get your whole body tested and analysed. 


Checks done are temperature ( thermal analysis ), blood pressure ( pressure analysis ), blood test ( Lub oil analysis, the oldest method ), heart beat sounds by stethoscope ( acoustic vibration analysis ), urine analysis ( emission analysis ), insulation testing, infrared/ ultrasound , motor current signature etc.





Purging Framo cofferdam on a chemical tanker, is PREDICTIVE maintenance. You will not change the cargo seal or mechanical  hydraulic seal, just because it is time to do so as per some pea-brained , time based , pre-conceived ulterior motived schedule.  

Predictive maintenance differs from preventive maintenance by basing maintenance needs on the actual condition of the equipment, rather than on some predetermined schedule. A well-orchestrated predictive maintenance program will all but eliminate catastrophic equipment failures.

On limited crew  chemical tankers where we do multitasking , intelligent time management and prioritizing ,predictive maintenance is most important.  Condition monitoring is done while the equipment is in normal operation, with little to no process interruption.


Preventive maintenance is time-based. Activities such as changing lubricant are based on time, like calendar time or equipment run time.

For example, most people change the oil in their vehicles every 6,000  kms traveled. This is effectively basing the oil change needs on equipment run time. No concern is given to the actual condition and performance capability of the oil. It is changed because it is time to change it, a bit silly 



This methodology would be analogous to a preventive maintenance task. If, on the other hand, the operator of the car discounted the vehicle run time and had the oil analyzed at some periodicity to determine its actual condition and lubrication properties, he may be able to extend the oil change until the vehicle had traveled 15000 kms.

This is the fundamental difference between predictive maintenance and preventive maintenance, whereby predictive maintenance is used to define needed maintenance tasks based on quantified material and equipment condition.


A predictive maintenance approach strives to detect the onset of equipment degradation and to address the problems as they are identified. This allows casual stressors to be eliminated or controlled, prior to any significant deterioration in the physical state of the component or equipment. This leads to both current and future functional capabilities.




Advantages of predictive maintenance:--
·         Provides increased component operational life and availability
·         Allows for preemptive corrective actions
·         Results in decrease in equipment and/or process downtime
·         Lowers costs for parts and labor
·         Provides better product quality
·         Improves worker and environmental safety
·         Raises worker morale
·         Better energy conservation
·         Results in an estimated 30% cost savings
·         Creates a pro-active culture
·         Prevents crew burn out
·         Elimination of breakdown 80%

Ship staff will be able to schedule maintenance activities to minimize or eliminate overtime costs. And, inventory can be minimized, as parts or equipment will not need to be ordered ahead of time to support anticipated maintenance needs. Equipment will be operated at an optimal level, which will also save energy costs and increase plant reliability.

A  properly functioning predictive maintenance program can provide a savings of 30%  over a program utilizing preventive maintenance strategies alone. inventory can be minimized, as parts or equipment will not need to be ordered ahead of time to support anticipated maintenance needs..

Predictive maintenance manages trend values, by measuring and analyzing data about deterioration and employs a surveillance system, designed to monitor conditions through an on-line system on a UMS ship. A predictive maintenance approach can detect the onset of equipment degradation and to address the problems as they are identified.

It is essential to have a firm commitment, by management and all facility staff and organizations, to make it work. The goal of any predictive maintenance program should be to invest in predictive tools that give you the best information to make an informed decision on the condition of your plant’s production machinery

Breakdown maintenance:
In this type of maintenance, no care is taken for the machine, until equipment fails. Repair is then undertaken. This type of maintenance could be used when the equipment failure does not significantly affect the operation or production or generate any significant loss other than repair cost. However, an important aspect is that the failure of a component from a big machine may be injurious to the operator. Breakdown maintenance at sea should be avoided, as it can be very de-motivating and expensive.


Preventive maintenance :
It is a daily maintenance (cleaning, inspection, oiling and re-tightening), design to retain the healthy condition of equipment and prevent failure through the prevention of deterioration, periodic inspection or equipment condition diagnosis, to measure deterioration. It is further divided into periodic maintenance and predictive maintenance. Just like human life is extended by preventive medicine, the equipment service life can be prolonged by doing preventive maintenance.

Disadvantages
• Catastrophic failures still likely to occur.
• Labor intensive.
• Includes performance of unneeded maintenance.
• Potential for incidental damage to components in conducting unneeded maintenance.

All preventive maintenance management programs assume that machines will degrade within a time frame typical of their particular classification and the requirement to use ORIGINAL spare parts ONLY is more of a business move.


Periodic maintenance or Planned Maintenace (Time based maintenance - TBM):
Time based maintenance consists of periodically inspecting, servicing and cleaning equipment and replacing parts to prevent sudden failure and process problems. This is expensive and labour intensive.







CAPT AJIT VADAKAYIL ( 28 YEARS IN COMMAND )
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3 comments:

  1. This is very good information.i think it's useful advice. really nice blog. keep it up!!!
    Predictive Maintenance

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  2. The reason why I liked this article is because it shared about major features about mechanical engineers and what attributes they should possess in order to give their best in the job. Thank you so much for writing this wonderful article.

    Regards
    Henry Jordan

    Hydraulic Seal Kits

    ReplyDelete
  3. I appreciate all of the information that you have shared. Thank you for the hard work!

    - The Predictive Maintenance

    ReplyDelete