Condition Monitoring
 
   
   
Condition Monitoring

 Where is Condition Monitoring Today?

Condition Based Maintenance (CBM) systems have proven to be a valuable tool in improving and optimising both asset management functions and productivity factors associated with large mechanical systems. Historically, condition analysis was performed by highly experienced maintenance personnel who applied lessons learned through years of practice in their trade rather than utilizing formal standardized and structured methodologiesImage




Image However, the increasing complexity of industrial mechanical systems, coupled with the need to minimize human resources has made this approach ineffective. Further, the time needed to acquire sufficient experience through on-the-job training places an effective limit on the number of people who are qualified to act in such functions. These challenges have been addressed to some extent through the use of analytical methods and standardized technologies that form the basis for maintenance decisions. While there have been many advances in this area, the current state-of-the-art in condition based maintenance still remains fragmented to a large degree.




Macom Technologies has developed a solutions-based approach to condition monitoring that brings together varied sensor technologies, network architectures, and software applications into an integrated system. This system not only enhances machine performance, but overall asset management through improved information management.

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Lubricant Quality The Foundation of Machine Condition
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Analytical laboratory testing has become an accepted tool in condition based maintenance programs to quantify both lubricant quality and machine condition, and an entire industry has grown to provide oil sampling, analysis, and reporting services to the market. Some of the parameters that are quantified in such programs are:
Wear Debris
Water Content / Infiltration
TAN
TBN
Particle Count
Viscosity


Such analytical testing provides generally reliable results using accepted methodologies. However, while on-line oil analysis does not completely replace such testing at present, it does solve many of the problems associated with analytical methods. One of the most significant drawbacks of sample testing, aside from the risk of sample contamination, is that the vast majority of samples sent for analysis report no indication of problems. Since this cannot be predicted, a large portion of the investment in a sample-testing program is actually wasted effort.

Manual Oil Sampling/ Lab-based Oil Analysis
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Sample Collection Manual sample collection requires allocation of manpower resources, and thus financial assets. Further, since oil samples are only collected at intervals (typically monthly), they can only reflect trends that have a relatively slow onset and development, therefore potentially missing acute events.

Sample Testing Contract testing services require samples to be mailed to laboratories for analysis. This process requires time and thus delays the ability to take action based on the results of the analysis performed. In-house testing programs remove this delay but incur significant costs in terms of capital equipment and personnel resources.

Reporting Generating and transmitting the results of analytical testing also requires time in writing the report, transmitting the report, and its eventual evaluation by the reader. Also, although databases exist for tracking analytical results over time, they still require a significant investment in both manpower and software, and are not uniformly implemented.

Report Analysis Although most reports include recommendations, they still require an individual who is intimately familiar with the machine they were collected from to be effectively interpreted. Further, this individual must also be trained in understanding the significance of the values included in the report if he is to take appropriate action based on them.

Implement Action Assuming that a correct interpretation of analytical results has been made, any action to be taken based on these data must be done so in a timely manner. However, the entire nature of the entire oil analysis process has inherent time delays that limit this ability.

Vibration Analysis The Gold Standard:
Vibration analysis has become the gold standard and perhaps the most widely used method of determining machine condition. In this case, data is acquired either on-line or manually using portable data loggers. The interpretation of such data requires not only an investment in computer hardware and software, but also an experienced user to interpret results. Further, vibration analysis only registers a problem when it is already in a relatively advanced stage (e.g., bearings have worn enough to cause vibration).
Therefore, joint Vibration / Wear Debris Monitoring system provides greater value added offering in terms of CM systems offering, more so when integration is refined and streamlined, especially with regard to the net effect on cost; the bottom line to machine users/ owners,

Other Parameters:
Other machine quality parameters (as opposed to process control parameters) such as temperature, pressure, and others are typically collected through transmission of analogue signals to central control boards and automatic alarm systems. This approach is effective but complicates the interpretation of secondary relations between variations of different types of parameters. For example, changes in a single parameter may not be sufficient to trigger a primary alarm, however, changes in two or more parameters within their individual acceptable range may be indicative of a problem, and need to be correlated.

The Net Results Less Than Optimum!
Who is ultimately responsible for tracking available data, making decisions from that data, formulating action plans, implementing them, and evaluating their results? How much time and money are wasted in this process? How is performance benchmarked and tracked? While individual tools are available to address these issues, they have not generally be utilized to their fullest by being integrated into a single unified system.

The Macom Solution


Macom believes that significant improvement in condition based monitoring can be achieved through implementation of advanced networking, sensor and software technologies. Schematically, such a system is shown below.


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Machine Level One of the fundamental factors in extending machine lifetimes and performance is lubricant quality, which can be degraded both through use in the machine and infiltration of water and particulate matter from external sources. Thus a total program of oil quality control must be instituted that addresses oil handling and filling, fitting of breathers and desiccators, and filtration.

In particular, while in-line filters provide a reasonable level of cleanliness, Macom believes that, high efficiency off-line filtration (e.g., at the sump) should also be applied. There are two reasons for this. First, state-of-the-art off-line filtration removes virtually all particulate matter from the lubricant so that the machine is always using clean oil, thus creating less sources of wear. Secondly, while on-line oil analysis works reliably on a wide range of oil quality levels, ultra filtration of the oil provides a stable background from which to make measurements, thus improving and simplifying data collection and analysis. At this level, Macom is in cooperation with a world leader in off-line filtration products and can offer tailored solutions to a wide spectrum of application.

Sensor Level In general, Macom believes that the implementation of a tailored suite of on-line sensor technologies is the ideal method of data collection. This solution not only automates the data collection process, minimizing human resources, but also provides for continuous parameter monitoring so that both acute and long-term changes can be efficiently detected and monitored.

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