What do you do when you realize that a vacuum cleaner does not work because the filter is completely clogged? It’s probably not a happy face.
After all, the result is a vacuum cleaner that is overheating, having very low performance and electrical efficiency, increasing noise and so on. Now, imagine multiplying those unwanted outcomes by 100, which is the average number of fans in a medium-sized industrial site. It then becomes clear why the periodic hanging of filters, especially in a large facility, is a large maintenance undertaking.
When filter replacement is done properly and everything is working as it should, the outside air will be well filtered and the cooling system will be able to do its job. Consequently, the electrical and electronic equipment inside a building or enclosure will be at the right temperature, typically less than 30º C.
On the other hand, what is the effect of not replacing filters on time? Eventually a completely dirty and clogged filter and a spiral of serious consequences.
A filter that is completely clogged, one that is 100 percent dirty, means that the fan works in very unfavorable conditions. It will have a flow performance that can be 20% or less, meaning that it moves less than a fifth of the air that it should.
But, the equipment installed inside an electrical cabinet will continue to generate heat, which, when combined with reduced airflow, will dramatically raise the temperature inside the enclosure. If the temperature exceeds 50º C, the equipment enters a risk zone that may cause electronic malfunctions or even a technical stoppage. Either of these situations, but especially a stoppage, can have very grave consequences in continuous production processes.
With a clogged filter you will encounter a sudden rise in temperature inside the cabinet. This will cause malfunctions, hot spots or even a technical stoppage.
But, there can be other issues caused by a clogged filter. These include:
- Problems due to conductive dust such as carbon, nickel, iron and so on. This is caused by the filter not working properly and so it will not be removing such conductive dust from the air that enters a cabinet.
- Difficulties with moving elements inside the cabinet such as internal fans and more. These will be affected by the entry of particles, causing performance problems.
- The useful life of the equipment inside the enclosure will be shortened because of the higher temperature.
- The cabinet will enter a low performance state due to an inefficient fan.
The features of an ideal solution
So, those are the problems that can result. What’s the solution?
Ideally, this would be something that would address the weakest parts of a fan in a control cabinet. As outlined above, this means there must be:
- A way to remotely determine how dirty a filter is and the temperature of the air crossing the filter.
- A means to adjust fan speed and set it where desired via a controller.
- A method to measure and report fan reliability, as well as other important preventative maintenance factors, to a control system.
The first of these – determining how dirty a filter is – lays a foundation for the rest. As soon a filter goes in, it begins to accumulate dirt. At some point, it will become dirty enough to warrant changing. Exactly when that happens will depend upon the industrial environment. So, the optimum solution will have sensors set to trigger an alert of the need for a replacement when the filter reaches a percentage of dirtiness, with this set by the end user.
The second requirement – adjusting fan speed – builds upon this by controlling the movement of flowing air. This ensures proper temperature control, which is the main objective. When combined with measurements of fan temperature and current, this leads to an ideal situation in which little problems with the fan itself can be spotted before they become big ones.
Lastly, by combining these direct measurements with advanced algorithms, a control system can predict the current and remaining lifetime of the fan. So, it can help determine when will be the best moment to replace the next filter, using a filter’s dirtiness, a fan’s speed, and the delta T between two grids or filters as inputs.
Such a solution will minimize the headache of changing filters, prolong the life of equipment and cut energy usage.
An example solution
For an example of such an ideal solution, consider Schneider Electric’s ClimaSys™ Smart Ventilation System (CSV) equipped with Smart Filters and Dust Sensors. These allow absolute control of the ventilation and air function, including percentage of filter dirt from 0% to 100%. All of this is managed with the new FilterStat Controller.
For more information, watch this video: