Editing Disc filter

{{Short description|Type of water filter}}
<!-- NOT a COPYVIO. See talk page -->

A '''disc filter''' is a type of [[water filter]] used primarily in [[irrigation]], similar to a [[screen filter]], except that the filter cartridge is made of a number of plastic discs stacked on top of each other like a pile of [[poker]] chips.  Each disc is covered with small grooves or bumps.  The discs (or rings) each have a hole in the middle, forming a hollow cylinder in the middle of the stack. The [[water]] passes through the small passages in between and the impurities are trapped behind.<ref name="Tomatoes" /><ref name="Stryker">{{cite web|last1=Stryker|first1=Jess|title=Irrigation Water Filtration & Filter Recommendations|url=http://www.irrigationtutorials.com/filters.htm|website=Irrigation Tutorials|accessdate=7 August 2017}}</ref>
  
The filtration quality is based on the quantity and size of particles that the filtering element is able to retain.  Higher quality filtration simply means cleaner water.  This depends on the geometry of the channels, including the size, length, angle, and number of generated intersection points.<ref name="CarrowDuncan2008">{{cite book|author1=Robert N. Carrow|author2=Ronny R. Duncan|author3=Michael T. Huck|title=Turfgrass and Landscape Irrigation Water Quality: Assessment and Management|url=https://books.google.com/books?id=dFN1K8k8FmcC&pg=PA275|accessdate=7 August 2017|date=17 December 2008|publisher=CRC Press|isbn=978-1-4200-8194-7|page=275}}</ref>  The discs are typically color coded to denote the level of filtration.<ref name="Burt & Styles">{{cite book|last1=Burt|first1=Charles M.|last2=Styles|first2=Stuart W.|title=Drip and Micro Irrigation for Trees, Vines, and Row Crops|date=1999|publisher=ITRC, Cal Poly|location=San Luis Obispo, California|isbn=0-9643634-2-9|pages=140–142|edition=2nd}}</ref>  Filtration quality is usually measured in [[micron]]s, based on the smallest size particle filtered.  The typical range is from 25 microns for the finest level of filtration to 400 microns for the coarsest.<ref name="Allhands & Prochaska" />  Sometimes the filtration quality is given as the equivalent [[mesh size]] of a comparable screen filter.  Typical mesh sizes range from 40 to 600.<ref name="Tomatoes" />  When using mesh sizes, 40 is the coarsest and 600 is the finest or highest level of filtration.{{citation needed|date=October 2011}}

Disc filters range in size from small units with a 3/4" inlet and outlet used for landscape [[drip irrigation]] systems to very large banks of multiple filters manifolded together used for filtering large volumes of water for agricultural and industrial applications.<ref name="Allhands & Prochaska" />

Some disc filters, especially the smaller ones, must be taken apart and cleaned by hand.<ref name="Stryker" /><ref name="Maintaining Microirrigation" />  Many of the larger ones can be backflushed in such a way that the discs are able to separate and spin during the cleaning cycle.<ref name="Tomatoes">{{cite book|title=Drip Irrigation of Processing Tomatoes|url=https://books.google.com/books?id=R7jn7l75kYMC&pg=PA46|accessdate=7 August 2017|year=2008|publisher=UCANR Publications|isbn=978-1-60107-436-2|page=46}}</ref><ref name="CarrowDuncan2008">{{cite book|author1=Robert N. Carrow|author2=Ronny R. Duncan|author3=Michael T. Huck|title=Turfgrass and Landscape Irrigation Water Quality: Assessment and Management|url=https://books.google.com/books?id=dFN1K8k8FmcC&pg=PA275|accessdate=7 August 2017|date=17 December 2008|publisher=CRC Press|isbn=978-1-4200-8194-7|page=275}}</ref><ref name="Maintaining Microirrigation">{{cite book|title=Maintaining Microirrigation Systems|url=https://books.google.com/books?id=b32OIhEpqFoC&pg=PA37|accessdate=7 August 2017|year=2008|publisher=UCANR Publications|isbn=978-1-60107-488-1|pages=33, 37–38}}</ref> In some cases, a [[booster pump]] may be required for backflushing.<ref name="Burt & Styles" />  Disc filters can be used for many types of contaminants, including fine sand and organic matter.  However, when used to filter organic matter, they will clog more quickly than a [[media filter]] and will have to be cleaned more often.  One advantage that the disc filter has over the media filter is that it can backflush more quickly with less flush water.<ref name="Tomatoes" /><ref name="Maintaining Microirrigation">{{cite book|title=Maintaining Microirrigation Systems|url=https://books.google.com/books?id=b32OIhEpqFoC&pg=PA37|accessdate=7 August 2017|year=2008|publisher=UCANR Publications|isbn=978-1-60107-488-1|pages=33, 37–38}}</ref>

Disc filters used in agricultural irrigation are covered by the ISO 9912-2 standard.<ref name="ISO 9912-2">{{cite web|title=ISO 9912-2:2013 Agricultural irrigation equipment -- Filters for microirrigation -- Part 2: Strainer-type filters and disc filters|url=https://www.iso.org/standard/39769.html|website=International Organization for Standardization|accessdate=7 August 2017}}</ref>

== History ==
The disc filter was originally developed in 1936 to filter [[hydraulic fluid]] in the [[B-17 bomber]].  In these filters, the discs were made of stainless steel and brass. In the 1960s, this type of filter began to be used in [[Israel]] to filter irrigation water.<ref name="Allhands & Prochaska">{{cite web|last1=Allhands|first1=Marcus|last2=Prochaska|first2=James|title=Disc Filtration: Something Old, Something New|url=https://www.ksre.k-state.edu/sdi/abstracts/discfiltration.pdf|website=K-State Research and Extension|accessdate=8 August 2017}}</ref><ref name="US 20080257801 A1">{{cite web|title=Device For Filtering Solid Particles For Liquids Containing Such Particles|url=https://patents.google.com/patent/US20080257801|website=Google Patents|access-date=8 August 2017}}</ref>

==References==
{{reflist}}

[[Category:Water filters]]
[[Category:Irrigation]]

{{tech-stub}}