Today's a tough challenge. Same function: cleaning water. Whether we're talking about manual or automatic filtration systems, the goal is the same: to protect our irrigation system from small and large impurities that could clog it.
From an economic point of view, an automatic filter entails higher costs compared to a manual cleaning filter, but if we consider the inherent advantages of an automatic filter, that cost difference will be compensated by the improved performance efficiency of the filter.
Specifically, automatic cleaning filters are divided into two categories: screen filters and gravel filters. Both perform a flush whenever the filter fills with enough impurities to reduce or even block the water flow.
The working concept of an automatic filter is simple. It "reads" the pressure difference between the filter's inlet and outlet (as is done using pressure gauges in a manual filter) and initiates a flush until the filter returns to optimal working conditions. This process provides two advantages. First, it eliminates the risk of impurities clogging the drippers of our system, but more importantly, it reduces the maintenance required for the filters themselves.
Let's use an example to better understand the advantages of an automatic filter.
If we consider a manual flush gravel filter working in fairly dirty water because the supply source is a channel full of algae, this filter will need to be cleaned much more frequently to prevent it from clogging.
As is known, the water cleaning process within a gravel filter occurs through the quartzite (gravel) present inside, which blocks impurities and allows clean water to pass through. Therefore, if the filter were to work, as in this case, in the presence of many impurities, the gravel inside would be subject to greater wear and consequently would need to be replaced even annually. In many cases, the filter continues to be used with unsuitable gravel, and therefore the filtration is reduced, allowing the passage of particles that will then clog the irrigation system.
That said, let's imagine working with an automatic filter under the same conditions mentioned above. We will notice that the filter will be cleaned whenever the sensors detect a pressure difference between the inlet and outlet, reducing the wear of the quartzite inside and consequently the risk of dripper clogging will be almost zero. Moreover, with an automatic flush filter, another aspect to consider, in addition to less maintenance of the filter itself, is time. The time that must be dedicated to cleaning the filter, which in the case of large quantities of impurities in the water can be very high, could be utilized and saved in other ways.
As we have seen, the economic advantage comes from the reduced wear of the gravel, which can therefore be replaced less frequently, and there will also be a lower risk of dripper clogging, meaning they will have a longer lifespan and thus a lower probability of needing replacement in a short period of time.
It remains clear that a filter, whether automatic or manual, must always be sized to the flow rate of your system. A system with an undersized filter (e.g., 2") and high water volumes passing through it (e.g., 10lt/s) will have reduced cleaning times, especially in the presence of varying amounts of impurities, as well as a high pressure loss due to the small size of the filter.
Given all of the above and considered in this article, we could say that when choosing the filtration system to use for your irrigation system, you must first consider the type of impurities present in the water, which will determine the choice of filter type to use, whether screen, disc, or gravel. Subsequently, you will need to understand the water flow rate of your irrigation system, which will determine the choice of filter size, and finally, the possibility of installing an automatic filtration system.
Good luck with your choice ;-)