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Self-Cleaning Screen Filters: How Do They Work?

Luda Hazan<br>Regional Sales Manager - CIS
Luda Hazan
Regional Sales Manager - CIS // 26 Jul. 2018
Luda has years of experience in leading global irrigation projects.
(Updated May 2023)
screen filter on filed background

In previous blog posts, we discussed how to protect your irrigation system from clogging so that you can produce the highest possible yield while minimizing costs and the multiple benefits of using automatic self-cleaning irrigation filters.

In this blog post, Dotan will go into more detail on how the automatic self-cleaning filtration technology works and how switching from manual filtration can save precious resources.

Manual vs Self-Cleaning Automatic Filtration

Managing your land involves a continuous learning process of trial and error. Each soil type has its own unique composition and needs, and every water source used for agricultural irrigation has its advantages and disadvantages.

An agricultural irrigation filtration system, just like the irrigation system it protects, requires a lot of maintenance. Moreover, as high-quality potable water sources become more and more scarce, reclaimed water and non-potable fresh water, such as well water, are increasingly used for agricultural irrigation. These water sources often contain a variety of clogging factors like sand, silt, clay particles and organic matter. These clogging factors gradually build up on the inner surface of the filter screen and cause a filter cake to develop.

This filter cake needs to be tended to and cleaned by farming personnel, otherwise it may continue to accumulate and become thick enough to clog the filter. This then leads to reduced filtration performance, and in turn can lead to clogged emitters, which amongst other things, can interrupt the uniform distribution of water to your crops, or even stop the irrigation completely. Needless to say, crops that do not receive the irrigation they need will not thrive.

This manual maintenance and cleaning of your filtration system takes up precious time and manpower – and you can save on both with automatic self-cleaning agricultural irrigation filters. In addition, self-cleaning screen filters are more water efficient as they use the precise amount needed and no water is wasted on manual flushing and cleaning. As a result, labor and water costs are reduced.

Mini Sigma screen filter in greenhouse
This photo shows the Mini Sigma – Amiad’s newest automatic self-cleaning screen filter

The technology behind the Amiad self-cleaning filters

The filtration process

The Amiad self-cleaning filtration process

The self-cleaning process

The self-cleaning cycle is initiated by any one of the following conditions:

  • Signal from the DP switch, which is preset at 7 psi (0.5 bar)
  • Time interval parameter set at the controller
  • Manual start, triggered by the ADI-P mobile app (within Bluetooth® range*)

adi p controller









The flush valve opens to the atmosphere to create a strong suction force at the scanner nozzles, effectively removing dirt particles from the screen and discharging them from the filter.

Amiad’s suction-scanning technology

One of the features that make Amiad automatic self-cleaning screen filters truly stand out is their unique suction-scanning technology, which provides 100% cleaning of the screen area and uses less than 1% of the total process water. This is the lowest ratio of process to exhaust water of all competing automated self-cleaning methods (this ratio can vary depending on specific application conditions).

When the self-cleaning cycle is activated, the flush valve opens. This creates a powerful back-flush stream and a high-force suction effect at the suction-scanner nozzle to completely remove the dirt particles from the screen.

The backwash water flows through the hydraulic turbines causing them to rotate and the scanners to spin. The pistons’ pressure drop forces the suction-scanners into an axial movement. This, combined spinning and axial motion, moves the suction-scanners upward, ensuring that the nozzles sweep and clean the entire inner side of the fine screens. The suction force causes water to flow backward through the nozzles, removing the filter cake from the screen and driving it out of the filter through the flushing valve.

The self-cleaning cycle is triggered when suspended solids accumulate into a filter cake on the screen surface (measured by the pressure differential). This means that cleaning is performed “as needed”, resulting in minimal energy and water waste.

Amiad’s suction-scanning technology eliminates the need to isolate the filter during the self-cleaning cycle, and this, together with the minimal exhaust required, enables an uninterrupted process flow.

All this and more with Amiad’s Sigma Pro and Mini Sigma

Amiad’s Sigma Pro and the Mini Sigma are multi-screen, polymeric, automatic self-cleaning agricultural irrigation screen filters designed to be user-friendly, durable, efficient and easy to install. Both filters have flexible inlet-outlet configurations for versatile installation options. They come in three different models, with the Sigma Pro sizes ranging from 4″ to 8″ and the Mini Sigma (which is considerably smaller) sizes ranging from 2” to 4″.

The Sigma Pro and the Mini Sigma both have unique cleaning mechanisms that use minimal energy. The cleaning cycle uses only 1.5 bar in comparison to other automatic self-cleaning screen filters on the market that use between 2 and 2.5 bar. 

The Sigma Pro and Mini Sigma are equipped with Amiad’s ADI-P Controller. The controller interacts with Amiad’s smartphone app and sends detailed filtration performance and data reports. The cleaning cycle is triggered by a DPS switch, but unlike other filters, the ADI-P controller allows the user to choose specific time intervals or initiate the cleaning cycle at any time.

The video above shows the cutting-edge Mini Sigma automatic, self-cleaning screen filter powered by Amiad’s unique suction-scanning technology.


What can happen if the filter cake continues to accumulate debris?

If the filter cake is not cleaned on a regular basis, it may become thick enough to clog the filter, eventually leading to reduced filtration performance and clogged emitters. Clogged irrigation emitters will not deliver the required water to your crops.

Which water sources are used for agricultural irrigation?

High-quality water sources for agricultural irrigation are becoming more and more limited in their availability and increasingly expensive. This has led to the use of more economical and more accessible reclaimed water and/or non-potable fresh water, for example, well water.

Are self-cleaning screen filters more economical?

Yes! Having to manually maintain and clean filters is both time-consuming and labor-intensive. Automatic self-cleaning irrigation filters save time and manpower expenses and since they use the exact amount of water needed for cleaning, water isn’t wasted.


*The Bluetooth® word mark and logos are registered trademarks owned by the Bluetooth SIG, Inc. and any use of such marks by Amiad Water Systems is under license. Other trademarks and trade names are those of their respective owners.

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Case Study Mini Sigma Pecan Grove