Benefits of data logging in manufacturing operations
When I began my career with an automotive supplier in Zeeland, Mich., in 2003, there were three reverse osmosis (RO) systems and four deionized (DI) systems in place. Today, seven RO systems with 17 DI systems are used. As the company grew, I found the need to data log the operations. Data logging has allowed us to go from being reactive to our manufacturing needs—waiting for a problem to occur—to proactively monitoring conductivity, resistivity, water temperature, flow rates or any other parameters we program in, with a touch of a button.
I believe the need for data logging will become greater in manufacturing, as it has for this company, and in other industrial, commercial and residential water treatment industries.
Pure water is necessary in the manufacture of self-dimming automotive and airplane windows, as well as circuit boards and microchips.
Tool For Success
In manufacturing, water quality is a high priority. In the manufacture of self-dimming automotive and airplane windows, two pieces of glass are put together. These glass elements need to be cleaned and rinsed to eliminate any possibility of contamination. In addition, the automotive company creates its own circuit boards and microchips. Pure water is a must in creating these items.
Continuous data logging of more than 800 data inputs allows us to benchmark and view the total dissolved solids (TDS), resistivity, water pressure, flow rates and other parameters. The information is used to protect water quality, sensitive equipment and processes at every level of the manufacturing process.
Because production seldom is shut down, it has become increasingly difficult to complete maintenance and troubleshoot problems. By letting the data run the show, data logging lets us know when quality specs are changing. It can pinpoint equipment malfunctions and unexpected process changes.
The continuous output of data is also set to alarms. For example, a simple open/close switch is mounted to a hanger within a brine tank. If more than the required brine goes into the tank from the brine silo located outside the building, a text warning will be issued, allowing us to respond before salt water spills out to the overflow catch basin.
Additionally, equipment faults and power interruptions are apt to occur at any time. It is quicker and more efficient to be notified by the data logging system than to wait for a phone call from production. Since the inception of this system, response times have increased and production has never seen an issue with any water purification equipment faults. In the event of a power interruption, some of the water processing equipment needs to be manually reset. When the power is restored, the system sends out a notice and operators can respond immediately.
Data logging is successfully used in the DI systems. When resistivity reaches 15 megohm, the system will send a message saying it is outside of specs, indicating the system requires a new regenerated tank.
Data logging is successfully used to uncover hidden quality issues and create new processes to ensure continued quality. After installing the data logging system, it was found that water quality dipped in resistivity every Sunday after production halted. When production began again on Monday, the high resistivity would return. As a result, a small recirculation pump was added into the system, thus ensuring high-quality water throughout the production week.
Where the Action Is
For the automotive supplier, being able to monitor and track the specs of the water from raw water, soft water, permeate, DI, concentrate, distribution and reuse makes it easy to respond to unexpected changes in quality and usage.
Raw water probes first measure city water pressure, chlorine continent, TDS, temperature, pH and flow rate. This is followed by water softening with hardness, pressure and flow rate monitoring. Carbon filtration probes monitor for excess chlorine leakage, temperature and pressure. Data logging is used to make sure the water to the RO system is of good quality.
DI water is used in microchip and circuit board manufacturing. DI water monitoring includes resistivity, pressure, flow rates, pH, ORP and water temperature. Microchips are cut from wafers that are scored to separate where the individual chips are placed. Ideal water temperature for cutting wafers is 74°F. If the DI water temperature varies significantly, the wafer will shrink, ruining most of the microchips. In Michigan, it can be difficult to maintain ideal water temperatures. The installation of heat exchangers is the answer, and being able to monitor, trend and respond to unexpected changes in the temperature helps consumers save money.
Concentrate is collected from normal RO run cycles, and instead of letting this run to the drain, it is reused as cooling water for the compressed air systems. Probes continuously monitor the concentrate to ensure fast response times to unexpected issues. Reuse water is water that is collected from production. Because many manufacturers buy water from municipalities, being able to collect, reclaim, and purify (if necessary) the used water for a secondary process is not only ecologically beneficial, it is a cost savings for the company. The ability to trend, monitor and alert for contaminants is key to ensure quality water for this secondary system as well. Water from production is collected by gravity to a storage tank underground. The tank is used to hold then re-pressurize the water as it is sent through additional sensors for quality analysis and separate sanitization system for reuse throughout the facility.
RO Delivery Systems
Storage tanks are not only important in the reuse system, they also are essential for delivering all processed water to the manufacturing floor. After proper processing for purification, the water is repressurized and is disinfected with ultraviolet (UV) radiation. By constantly data logging the UV radiation, burnt out lamps or loss of system effectiveness can easily be diagnosed.
In the storage tanks, float alarms similar to those used in the brine tanks are in use. Water is sent to production from storage tanks via circulation pumps. The data logging system will alert operators if water goes out faster than RO units can process replacement; DI or secondary RO units will be triggered to ensure continued supply to the production floor. An investigation to look into the root cause for the shortage will begin. Typically, this scenario occurs when a manual valve is left open by production, but it also has been caused by broken distribution lines or a primary RO unit fault.
A return loop is part of the delivery system and also needs constant monitoring. The return loop is redundant to the main distribution system, but this redundancy can isolate an abnormality and more quickly rectify the situation as probes are located on both sides of the loop. All main systems are built in a loop to keep water moving 24/7 to minimize the chance for dead leg bacterial growth.
Deionized water data logging includes resistivity benchmarking and temperature monitoring.
Data Reports for Management
While producing quality water is the main goal, an added benefit is the ability to generate reports using the data collected. These visual representations of how the system is working can be helpful when speaking with management and others who are not familiar with water processing.
Final product quality issues do arise from time to time. Because many production managers or personnel are not familiar with these systems, they often request documentation regarding the water quality in their efforts to troubleshoot a manufacturing issue. Having the ability to quickly generate on-the-spot reports is helpful in easing their worries that the issue is not caused by changes in water quality.
Manufacturing process changes also can also impact water usage and the bottom line. Production line managers often will change processes in an effort to clean the lines. In one case, it was decided to open all the control valves and flush the production equipment once a week. By using data logging charts, it became apparent that this flushing of equipment was not necessary and was costing the company money.
In another example, despite being told to use less than 0.25 cup of bleach in weekly sanitization processes, production employees were using 1 gal of bleach for each washer tank on each line. This caused high spikes of TDS in the reuse systems that occurred only on the day of sanitization. When managers saw the data report, processes changed and the TDS spikes disappeared.
Finally, when plans to expand production, add additional manufacturing lines or build new plants are discussed, data logging and the reports the data generates play an integral part. Data reports can include the number of gallons each production line requires, total number of gallons each water system creates, when current water systems will be at capacity, justification for additional water systems, type of water systems required based on end product the line will manufacture, and any other parameters that can be added by the consumer.
Data can be any type of information that is recorded for immediate or future use. Whether it is in an industrial setting or at a customer’s home, benchmarking and trend data can turn an operator’s work from reactive repairs, to proactive maintenance, saving money, time and resources. Choose the best place for the probe and let the data run the show.