FEATURE Materials Handling & Conveying
The benefi ts of transparency in fl uid handling
Loris Medart, founder of feed systems manufacturer SR-Tek, explains how introducing transparency into the production process can prevent product faults, support planned interventions and ensure consistency
F
luid handling can be one of the stickiest points of a production process. Changes in viscosity, quality and pressure can all have a detrimental impact on the fi nished product, resulting in having to destroy batches and machine downtime as production lines are reset. Temperature, humidity, pressure and viscosity are just some of the variables that can aff ect the performance of fl uids in the manufacturing process. With a small amount of eff ort, however, control and automation can be used to tame even the trickiest liquids.
The type of dispenser used and how it is set is often the main focus of engineers. This is important, but to truly control a fl uid you need to consider the environment within the pressure tank. There are several added features and sensors that can be fi tted to a vessel to fi x the variables. Temperature control jackets, for instance, maintain the temperature inside the tank to keep material viscosity consistent throughout shifts and from batch to batch. This is particularly useful when it comes to handling and dispensing thread locks which are highly sensitive to temperature variation. A couple of degrees higher or lower is enough to aff ect viscosity and deposit sizes. Then, there are thixotropic fl uids, which see their viscosity drop as the result of movement. A good example of this would be wallpaper glue. At the start, the glue is often diffi cult to stir but the more it is stirred, the easier it becomes to mix. What is happening here is that the viscosity of the material is changing as a result of the mixing movement applied to it. This can lead to dramatic inconsistencies, resulting in too much or not enough material added to parts which may have to be reworked, cleaned or in some cases even scrapped. The answer lies in viscosity control which in this case might be through agitation. This can be either set as a fi xed parameter for a full production day, or coupled with sensors to adjust to changes within the fl uid.
22 December/January 2021 | Automation Clear tank system setup
Monitoring and adjustment Fluids, more so than many other substances in the production process, are heavily aff ected by the environment. Temperature changes can be just a few degrees to disrupt the production process. In a traditional setting this will often lead to a lengthy reset as parameters are reviewed and adjusted to achieve optimum performance. Yet, several major manufacturers have found a shortcut to this process – transparent tanks. While most areas of production lines
are visible to the naked eye, fl uids have remained hidden from view. Large industrial-sized steel tanks, no more sophisticated than oversized paint pots, have remained the norm. Yet, production has moved on. Fluids have become more complex and expensive; shorter production runs and more diverse product lines mean huge simplistic containers are now a liability rather than an asset. For ABB, BMW and Johnson & Johnson the answer has been to switch to transparent
Various sizes of clear tanks
tanks, where fl uid levels, consistency and quality can be monitored not just by sensors but also by eye – being able to see when a fl uid needs topping up or adjusting from virtually anywhere on the line is invaluable. Added to this, common signs of issues within the fl uid, which would previously lead to product faults, such as crystallisation, thickening of the fl uid due to solvent evaporation, skinning or colour changes due to deterioration, can be spotted early and resolved with less product wastage. It also enables engineers to spot faults further up the line, such as air entering the tank and causing bubbles, or a faulty compressed air line leading to oil, and detritus entering through the pressure pod. A great example of this was a project
we recently completed for an automotive part manufacturer. The company had been using the same fl uid provider for many years; there hadn’t been any changes to the composition or even transportation of the liquid, yet, all of a sudden, it couldn’t achieve the necessary viscosity and production was brought to a halt. Having adjusted and tested all of the parameters and observed the reaction in real-time, we identifi ed a solution by controlling the viscosity through agitation. Agitation dropped this material’s viscosity to its set point, allowing consistency from batch to batch, which was not possible with static fl uid. What could have been weeks and months of lost production time as a new fl uid was developed or sourced from an alternative supplier was solved through the simple application of agitation in the pressure vessel. With all other parameters confi ned, the engineers are now able to eliminate batch to batch variation. Through careful management there is no reason why even the most temperamental of fl uids can’t be adapted to ensure consistent results.
CONTACT:
SR-Tek
www.smartreservoirs.com
automationmagazine.co.uk
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