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also includes data transmission and central computerization. This process automation is what allows us to move relatively seamlessly into a predictive maintenance system. Predictive maintenance relies on monitoring the actual operational condition of critical equipment and uses the data, and trends in the data, to detect upcoming failures. Failures are rarely instantaneous. There is usually some measurable change in local conditions that will predict an imminent failure. We can thus run equipment to its natural life cycle and provide maintenance and repair when it is actually needed. It allows planning of the repairs and procurement of parts and services, and it prevents catastrophic failures and collateral damage. This will also reduce process and production losses and eliminate the environmental non-compliances we face when our processes get knocked out mid-stream. This is an opportunity to stay out in front, while the existing developments and technological advancements keep us "behind the plow." Predictive maintenance, driven by the pharmaceuti- cal and petroleum industries, is becoming mainstream in other sectors. There are numerous companies that can assist in trans- forming a plant from its current paradigm into a predictive maintenance system. Condition-based monitoring and comput- erized control systems are already on the market. Many of the sensors currently being used can be easily integrated as condition monitors into a predictive maintenance system. For example, measuring flow from a pump will allow you to determine if the pump is operating properly. If you have to continually bump your variable-frequency drive (VFD) to maintain flow, or if the current draw starts to increase to maintain flow, or if flow or pressure start to drop, that information will be fed directly into the predictive maintenance software. The user interfaces can act as portals for maintenance staff to access the information they need. Predictive maintenance has a side effect — a good one. It will allow you to improve processes, both in quality and efficiency, through better equipment operations, less downtime, and a more complete monitoring of your process conditions. Feeding The System The more information you feed into your predictive maintenance system the better, to an extent. There is always the risk of informa- tion overload, and some information simply does not tell you any- thing about the condition of equipment in your plant. The same holds true with process automation. Occasionally someone sets up an oxidation-reduction potential (ORP) or a level switch that really does not give you information that is indicative of your process. An example is monitoring pH at one end of a tank and adding pH control at the other. Without proper and complete mixing, your control system will not be able to properly maintain a consistent pH. The same is true for condition monitoring in predictive main- tenance. All data must be real time, accurate, and pertinent. There are a few items that you will want to include that are not normally a part of process automation. Accelerometers (vibration sensors), for instance, can detect an upcoming bear- ing failure. Thermal scans will identify hot spots. Each plant is different. Every process is different. With modern wireless communication systems, incorpo- rating more and different condition-monitoring equipment becomes far less onerous and more economical. There are numerous protocols and systems available, and there are vol- umes of information available on each. Some condition monitoring can also be farmed out to vendors. Thermal imaging, ultrasonic thickness measurements, and oil analysis are examples of tests that are better handled by people who are properly equipped and do them for a living. Bringing in that level of technology and expertise on a full-time basis would be cost-prohibitive. Bringing in an inspector every month, or three months, or year to walk your plant and take the measure- ments for you is an economical and highly effective solution. In the water and wastewater industries, most of the tools neces- sary to implement an effective and efficient predictive maintenance system have been slowly introduced for process automation. We have most of what we need already on site. It's time for a paradigm change. Every time a new technology comes into use, it is the atti- tudes of the people involved that must be changed first. The easiest way to drive the change to predictive maintenance is to go slowly, one piece of equipment at a time. Start with the larg- est, costliest items and work your way through your process from there. Predictive maintenance is not just the future of maintenance; it is the present. We've had most of what we need for years. Now it is time to completely implement predictive maintenance into the water and wastewater industries. n 18 wateronline.com n Water Innovations MAINTENANCE Paul Brake is a mechanical engineer with nearly three decades of industrial and engineering experience. Brake specializes in the design and maintenance of water/wastewater and process equipment and is currently part of the strategic maintenance team at the North Atlantic Oil Refinery. Failures are rarely instantaneous. There is usually some measurable change in local conditions that will predict an imminent failure. About The Author