What is Water Filtration?
Filtration (particle filtration) separates and removes solids from water.
Why is Water Filtration Required?
Whether water is required for drinking, industrial processes or irrigation, it usually requires some degree of filtration. The type of filter selected depends on the water source (surface or sub-surface water) which have different characteristics and quality. While water quality can be analyzed according to its chemical, biological and physical characteristics, our focus is on the physical composition of the water as well as the type and the quantity of the solids.
Taking a look at the filtration spectrum, we see that water can contain salts, viruses, bacteria, helminth eggs, clay, silt, algae, sand and gravel.
To effectively cope with the wide range of materials that need to be filtered, Amiad has developed diverse filtration solutions:
Particle filtration is a statistical process: Due to elongated biological bodies and compressible particle materials, the filtration process is one of statistical probability. Particles larger than a certain size (according to the specific application) must be removed in order to protect the water systems and downstream processes and equipment.
Filtration of coarse and fine particles is mainly a process of mechanical filtration. The particles are retained on the filtration element by lodging on its solid parts and fully or partially covering the water passages.
What Types of Mechanical Filtration are Available?
Here are the three most popular types of fine particulate filters which have different size pores (measured in mm or micron):
• Surface filtration (screen filters)
• Depth filtration (media filter)
• Semi-depth filtration (disc filter)
What is the filtration degree and why is it important?
The degree of filtration required is defined by the irrigation system manufacturer to protect the system from damage.
The Nominal filtration degree is an actual linear dimension of the shortest straight-line distance (length or width) across an individual opening or pore of the filter medium.
The Absolute filtration degree is the length of the longest straight-line distance across an individual opening of the filter medium.
The effective filtration area is the total area of the filter medium which is exposed to flow and is usable for the filtration process. In surface filtration, particles larger than the pore size of the filtration medium are stopped at the upstream surface of the filter.
How Do You Select the Right Screen Filter to Protect your Irrigation System?
There are two main criteria for choosing the correct filtration system from the many filter types available:
1. Efficiency in separation of particles larger than the filtration size.
2. Simple and effective cleaning technology.
Example of before and after screen filtration with an Amiad screen filter
Amiad’s Screen Filtration Process:
The filtration process works as follows:
Raw water enters through the filter’s inlet, first passing through the coarse screen for removal of large debris and sediment and then through the inner fine screen for removal of the remaining smaller particles.
A differential pressure switch (DPS) monitors the pressure caused by the accumulation of debris on the inner screen and initiates the self-cleaning process when the pressure changes. The buildup from the screen is then discharged.
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.
The forced backwash ensures powerful, efficient and complete cleaning of every point in the screen due to small nozzles with high velocity and suction forces. Efficient cleaning enables the filter to operate continuously without downtime. An efficient cleaning process cleans the screens, returning the DP to its original value.
An efficient cleaning process cleans the media, thus returning the DP to its original value.
An inefficient cleaning leaves some of the solids on the filter’s screen, so the DP does not return to its initial value. With inefficient cleaning, clogging of the filter is inevitable.