Filters

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 flows through the filter medium under gravity or under pumped pressure and the floc material is trapped in the sand matrix. These filters are typically designed as part of multi-stage treatment systems used by large municipalities.

Pressure Sand Filters (Multi-grate Sand Filters)

These filters are the most popular method for removal of turbidity from water. The pressure sand filter consists of multiple layer of sand with a variety in size and specific gravity. These filters are designed to remove turbidity and suspended particles present in the feed water with a minimum pressure drop. These filters vary in design to suit the process & system requirements. These filters are offered in FRP, Mild Steel with Frontal Pipe Works and associated valves.

Construction

Pressure sand filter consists of a pressure vessel-this could be either vertical or horizontal-fitted 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 collect filtered water.

Process

Raw water flows down wards through the filter bed and as the suspended matter- which has usually been treated by addition of a coagulant like alum- is retained on the sand surface and between the sand grains immediately below the surface. There is steady rise in the loss of head as the filter process continues and the flow reduces once the pressure drop across the filter is excessive.

The filter is then taken out and cleaning of the filter media is effected by flow reversal also called as back wash. To assist in cleaning the bed, the backwash operation is sometimes preceded by air scouring by way of agitation through the water 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.

Activated Carbon Filters

Activated Carbon Filter are designed and manufactured with dual filtering media like sand and activated carbon. These filters can be used as initial unit for industrial water treatment. It is also used as pre-treatment and tertiary treatment of waste water. These filters comprises of a steel pressure vessels of FRP Vessels containing activated carbon granules as filter media. Activated carbon is porous carbon material. Due to its highly developed porous structure and huge specific surface area, activated carbon has very strong adsorption capacity. It removes bad odour of water. It is used as a catalyst or catalyst carrier, to find wide applications in industrial production, agriculture environmental protection.

These filters are fitted with no of valves for inlet, outlet, drain and backwash with suitable piping size to meet the specification of customer and capacity designed by customer. It is used in sugar industries, Distilleries, Food Industries, Water Boards etc.

Dual Media Filters

A sand-anthracite filter or dual media filter/multi-media filter is primarily used for the removal of turbidity and suspended solids as low as 10-20 microns. Dual media filters provide very efficient particle removal under the conditions of high filtration rate. Inside a sand-anthracite filter is a layered bed of filter media.

The bed is graded from bottom to top as follows: Having the filter media graded this way enables the sand anthracite Filter to run for longer times before a backwash is necessary. A sand anthracite filter or multi-media filter consists of 2 main parts:

  • A composite pressure vessel with Multiport Valve.
  • Graded beds of sand and anthracite.

Internally, the dual media filter is fitted with an inlet distributor and a bottom Colleting system. Externally, the system is fitted with frontal pipe work and isolation valves. Sand is used to remove the suspended particles and anthracite is used to remove the odor and color etc. to make the water fit for different applications. Gravels and pebbles are provided to support to both the media. Periodically, the sand-anthracite filter will backwash, which changes the water flow through the sand-anthracite filter.

Applications:

  • Side stream filtration of cooling tower
  • Potable water treatment
  • Waste Water treatment
  • Boiler feed water

Salient Features

  • High Filtration efficiencies
  • Filter up to 10 – 20 Microns
  • FRP, MSRL, MSEP & SS Vessel available.
  • Standard and effective sand- anthracite media
  • Low Pressure drop across the vessel
  • Air scouring available for high flow pressure vessel
  • Manual, Semi Automatic and Automatic features are provided

SIDE STREAM FILTER

Cooling towers scrub large volumes of air and effectively remove solids consisting of dust, microbiological organisms, and various airborne debris. Makeup to the tower adds suspended solids in the form of corrosion products, microbiological growths and wood fibers from the tower, and process leaks. If allowed to settle out, these solids can and do generate many problems within the system. With heavy solids loading, even the best treatment program can be severely strained. Under these circumstances, significant improvement might be realized with the use of a sidestream filter.

A proven method to help manage these and other issues surrounding cooling towers is to install a properly designed side stream filter. This can benefit your system through:

  • Reduced Corrosion Rates
  • Increased Equipment Life
  • Better System Efficiency
  • Reduced Maintenance Costs
  • Better Chemical Control

Iron Removal Filter

The process through which iron is removed from water is known as Oxidation Filtration that involves the oxidation of the soluble forms of iron (Fe) and manganese (Mn) to their soluble forms and then removal by filtration. The oxidant chemically oxidizes the iron and manganese (forming a particle), and kills iron bacteria and any other disease-causing bacteria that may be present after that the filter removes the iron and manganese particles.

Products