?Automatic Back flush Gravity Rapid Sand Filter Product Description ? Gravity Sand Filters
The gravity sand filter or rapid gravity filter are most commonly used in Municipal water purification plants worldwide. They use relatively coarse sand and other granular media to remove particles and impurities that have been trapped in a floc through the use of flocculation chemicals. Water and flocs flows through the filter medium under gravity and the flocculated material is trapped in the sand matrix. ? These filters are typically designed as part of multi-stage treatment systems used by large municipalities. ?
working principle ? Construction
The Pressure sand filter consists of a pressure vessel either vertical or horizontal, with a set of frontal pipe work and valves, graded silica quartz sand supported by layers of graded under bed consisting of pebbles and gravels, a top distributor to distribute the incoming water uniformly throughout the cross section of the filter, and an under drain system to uniformly collect the filtered water. ? Process
Raw water flows down wards through the filter bed and as the suspended matter, which is treated by addition of a coagulant like alum or poly electrolyte, is retained on the sand surface and between the sand grains immediately below the surface. There is steady rise in the loss of head over a period of time and the flow reduces once the pressure drop across the filter is excessive. ? ? The filter is then taken out of service and cleaning of the filter media is effected by flow reversal also called as backwash. To assist in cleaning the bed, the backwash operation is sometimes preceded by air scouring by way of agitation through the under drain system. The air scouring agitates the sand with a scrubbing action, which loosens the intercepted particles. The filter is now ready to be put back into service. ? ? ? ?? Packaging & Shipping Package: wooden cases into container Delivery: 7-10 working days after deposit received in advance Shipping methods: FOB Shanghai or by air ? Our Services We provide 24 hours online customer service. Any inquiry about water treatment system, please feel free to contact me for further details! Contact information: Mobile phone: +86 15295068302 Email: lucy AT jsyld.com.cn Alibaba website:?http://js-yilida.en.alibaba.com Official website: WWW.jsyld.com.cn ? ?