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Enviroquip Filtration
Eimco Water Technologies
•Brochure: Filter Underdrains
This new design follows years of proven performance of the folded plate underdrains providing uniform distribution in low headloss gravity backwash systems and filter retrofits with pumped backwash systems.
Media retaining underdrain eliminates support gravel. The 0.25mm wide punched openings allow the filter media to sit directly on the underdrain and air scour laterals. Low profile design, 6 to 8 inch vertical height, and no support gravel allows deeper media stacks than previously considered with other underdrain designs.
Uniform introduction of air and water through separate conduits provides superior simultaneous air/water backwash. Simultaneous air/water cleaning of the filter is done over a short time period with low waterwash/ air rates resulting in reduced volume of wash water usage.
Separate uniform distribution of air and water provides the vigorous agitation required for effective media cleaning. Most other systems introduce air and water through the same orifices creating a surging action and non-uniform distribution of air and water resulting in irregular cleaning of the filter media.
Air Scour
Uniform cleaning of the filter media with auxiliary air scour and water wash is essential for peak filter performance. Enviroquip''''s air scour and underdrain system provides this uniform cleaning whether as separate operations or simultaneous air/water. Separate air/water conduits eliminates opportunity for blowouts. The overall efficiency of our air scour system is evident by the lower air scour rates utilized. Lower air rates means reduced blower and piping costs and lower long term operating costs. Air is introduced at the lowest point in the valley between folded plates for best scouring of the media layer prior to media fluidization. Air is introduced above the underdrain eliminating the possibility of high pressures when compressible air and non-compressible liquid are mixed.
Ideal for Retrofits
Fabricated construction makes it the ideal system for filter retrofits; clay tile blocks, wheeler bottoms, header laterals and walker camp nozzles have been replaced with stainless steel folded plate underdrains. Low profile underdrain means more room for filter media to meet today's stringent effluent requirements. The headloss for each filter system is designed specifically for that system. Headloss is calculated based on years of filter underdrain experience to provide uniform distribution of wash water at maximum backwash rates.
Backwash Systems
The fact that we can vary the headloss through the underdrain allows us to offer underdrains for conventional pumped backwash filters or inner filter gravity backwash systems. Conventional pumped backwash filters required a higher underdrain headloss to insure uniform distribution of wash water. The principal behind inner filter backwash design is to provide a lower headloss through the underdrain and the piping to allow utilizing throughput from several filter cells to backwash an adjoining filter cell.
•Brochure: Filter Underdrains
