Maintenance

replacing chemical filters for ahu

replacing chemical filters for ahu

Machines run. Machines breakdown. It is so common. Machine parts wear down. Many factors cause breakdowns. The challenge for the management of plant facilities is to avoid unplanned breakdowns. The key to avoiding unplanned breakdowns is maintenance.

 

Preventive Maintenance

sludge centrifuge separator bearing change

sludge centrifuge separator bearing change

As the name suggests, Preventive Maintenance helps to prevent breakdowns. Preventive maintenance, commonly called PM, focuses on cleaning, lubrication of moving parts, tightening loose parts, replacing parts, and other similar activities at certain intervals of time. It is done even before the machine show any sign of deterioration.

A PM program essentially consists of the following:

  • A list of all the equipment to be maintained
  • A list of the activities to be done as maintenance.
  • A schedule of the activities to be done
  • A record of the activities being done
  • Follow up supervision work
changing ion exchange resins

changing ion exchange resins

Computerized PM programs can be designed as simply or as complicated as desired. Some programs include store inventory, costs, labor hours. Some have features for on-line tracking, history, purchasing, and so on.

In PM, machines are serviced based on time schedule. It does not matter whether the machine is running fine or not. Sometimes, it is better not to maintain machines this way. It could be more expensive, or disruptive. In these times it is better to do Predictive Maintenance.

 

Predictive Maintenance

infra red hot spot checking

infra red hot spot checking

Predictive Maintenance is based on condition monitoring. Machines are monitored for abnormalities in vibration, lubrication oil, hot spots, sound, insulation resistance and others. These methods are based on the idea that the deterioration of the machines can be detected through monitoring. By following a trend of monitored values, any impending breakdown can be detected early. In a way, it can predict that a machine will break down within a certain period of time if no action is taken to do preventive maintenance on it.

replacing ultra violet lamp

replacing ultra violet lamp

Usually, predictive maintenance is feasible for critical equipment, or those equipment that are very expensive to do normal PM. In the latter case, it may be more cost effective to prolong the frequency of the PM.

Some of the common predictive maintenance methods in use are:

  • Vibration Monitoring
  • Thermal Imaging
  • Lubricating oil analysis
  • Insulation resistance monitoring
  • Ultrasonic leak detection

A predictive maintenance program consists of the following:

  • A list of all the equipment to be monitored
  • A schedule of the activities to be done
  • A record of monitored values
  • Trend charts for the equipment
  • Follow up supervision work

 

Corrective Maintenance

air compressor capacity valve dismantled

air compressor capacity valve dismantled

Very often during preventive maintenance or predictive maintenance, we can detect serious faults in the machines. It may be a broken or worn out part. It may be an installation fault. Or an environment that can cause problems to the machines. Sometimes, we will be called upon to troubleshoot and rectify any fault in the systems. Sometimes breakdowns do occur even with preventive maintenance.

Correcting these faults is distinct from preventive maintenance. The latter is about cleaning, lubricating, checking, adjusting and replacing. Corrective maintenance is about repair and modification. Sometimes, these repairs are unscheduled.

dismantling magnetic drive chemical pump

dismantling magnetic drive chemical pump

Special training has to be given to persons doing corrective maintenance. Unskilled persons installing bearings, aligning shafts, gland packing, belting, and so on, can contribute to more breakdowns in the future. Skills in fitting are useful for fabrication and dismantling of machine parts.

Knowledge of lubricants, materials, and seals are useful. So is familiarity with common faults of machines.

You will find much information to help you with the required skills in this website.

A good maintenance program will lessen the incidence of corrective maintenance through preventive actions and early detection.