TECHNOLOGIES

SCREENING (SIEVE FILTER SYSTEMS)

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A sieve filter is a type of filtration using a fixed or flexible sieve to separate sand and other small particles from water for irrigation or industrial applications. These are generally not recommended for filtering out organic matters such as algae. Common sieve materials include stainless steel (mesh), polypropylene, nylon and polyester. Drop SA chooses the most environmentally friendly material. Thus, stainless steel and polypropylene are preferred more, and more easily, as they are recyclable materials.

The self-cleaning sieve filters incorporate an automatic washing cycle to overcome these limitations. Washing cycles are much more frequent compared to a media filter (gravel filters) of similar capacity, and each backwashing requires much less water to be carried out. Their ability to rapidly remove contaminants from water before washing their nutrients out makes such filters a popular choice for the recycling of aquaculture systems. They have also become popular in closed-loop industrial systems such as cooling towers, heat exchangers and other equipment protection applications. Similar devices with larger gaps, designed only to hold large objects are called filter aids. Stainless steel filters are used in industrial, municipal and irrigation applications and can be designed for very high flow rates. When combined with a controller and a flushing valve, a filter can be automated. Suspended particles are collected inside the sieve and the flushing valve opens to discard the coacervation. This eliminates the need for manual cleaning of the filter. There is a wide variety of mesh, to decide from, which can be used based on custom needs and requirements. Briefly, these are: 80, 120, 140, 160 up to 250 mesh (additional options upon request).

DISC FILTRATION SYSTEMS

A disc filter is a type of water filter, used primarily in irrigation, similar to a sieve filter, except that the filter cartridge is made of a number of plastic discs stacked on top of each other. Each disc is covered with small keyways. The discs (or rings) each have a hole in the middle, forming a hollow cylinder in the middle of the stack. Water passes through the small passages and impurities are trapped behind. Filtration quality is based on the quantity and size of particles that the filtration element is able to restrain. Higher quality filtration means cleaner water.

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This depends on the geometry of the channels, including the size, length, angle and number of crossing points created. The discs are color coded to indicate the level of filtration. Filtration quality is usually measured in microns, based on the smallest particle size filtered. The typical range is from 10 microns for the best filtration level to 200 microns for the bulkiest. Sometimes the filtration quality is given as an equivalent of the mesh size of a comparable sieve filter. Disc filters range in size from small units with a 2-inch inlet and outlet, used for horizontal stand irrigation systems, to very large systems used to filter large volumes of water for agricultural and industrial applications.

Some disc filters, especially the smaller ones, must be removed and cleaned manually. The larger ones can be suctioned in such a way that the discs can be separated and rotated during the cleaning cycle. In some cases, a booster pump for supplementation may be necessary. Disc filters can be used for many types of contaminants, including fine sand and organic matter. However, when used for filtering organic matter, they will clog faster than a media filter and they’ll need to be cleaned more frequently. One advantage a disc filter has over a media filter is that it can be inverted faster, using less water. Disc filters used in agricultural irrigation are covered by the ISO 9912-2 standard. Drop SA can provide many different options relative to the size of the micron, based on your needs.

MEDIA FILTRATION SYSTEMS

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A media filter is a type of filter that uses a layer of sand, gravel, anthracite, decomposed granite or some other type of media for filtering drinking water, swimming pools, aquacultures, irrigation, stormwater management, oil and gas operations and other applications. The system works as follows: A pipeline brings the water on top of a vessel through a distributor, which distributes the water evenly.

The filter starts with fine sand on top and then – gradually – the sand becomes coarser in a series of layers followed by gravel in progressively larger sizes, at the bottom. The sand on top removes natural particles from the water. Subsequent layers are used to support the above finer layer and provide effective drainage. While particles get trapped in the subsequent layers, the differential pressure increases.

Periodically, a wash may be initiated to remove the solids trapped in the vessel. During backflow, the water is directed towards the reverse direction from the normal flow. In multi-media filters, the layers in the media re-stratify due to density differences prior to resuming to normal filtration. Drop SA offers media filters in many different sizes and types, including dual chamber media filters, which allow a continuous filter operation. Moreover, our company can provide you with automatic media filters, which require minimal human maintenance and their backwashing operates automatically. The range of the different media type filters and their respective combinations are extremely precise based on the requirements of each need. You can find the detailed overview with the chemical and physical characteristics upon request.