TOVEKO Sand Filters
TOVEKO sand filters are gravity-fed units that operate continuously so long as there is a flow that requires filtration. This and other elements of their design offer you some significant advantages:
No standby filter required
The solids removed from the incoming flow are then cleaned from the sand bed at the same time as the filter is operating. This means that it does not need to be taken “off-line” for backwashing like a conventional sand filter, which therefore means that you do not need a standby filter and all the large tanks, pumps etc. that is required for backwashing.
TOVEKO filters are only 2.3m high
This means that they fit into a normal height room. This makes frost protection and installation in “visually sensitive” sites very straightforward. It also commonly allows gravity flow into the filter from the preceding treatment step (for example settlement). This not only avoids the need for an expensive pumping stage, but also delicate solids are not broken-up within the pump. This therefore makes their subsequent removal in the filter more efficient and so gives you better quality filtered water.
Unique Sand Washer
The rotation of the unique sand washer in TOVEKO filters means that the sand grains “roll” over each other. This gently abrasive “rubbing” improves the sand cleaning process, efficiently removing whatever is on the sand surface.
This difference is really important where the solids removed are at all sticky (for example where polyelectrolyte is used for flocculation) or indeed where there is oil present in the water. Actually, TOVEKO filters are used quite commonly for the removal of oil in wastewater. Of course, any sand filter will remove oil, but TOVEKO is unique in its ability to remove it from the sand again so that the filter continues to operate efficiently.
For details of the range of sizes and advantages of Toveko Filters you can download a leaflet here
Any continuous gravity sand filter relies on a “head” of wastewater above the sand bed to “push” the water through the sand. Uniquely, TOVEKO filters constantly monitor this so-called head loss and this enables automatic control of filter operation::
- When flow through the filter stops and the head loss falls to zero, the filter automatically stops washing the sand. This means that the filter does not “keep going” when it doesn’t need to and is therefore more energy efficient.
- When flow re-starts, the head loss increases to its “normal” level and filter operation re-starts. This “stop and start” process just continues, completely automatically.
- If head loss increases above its “normal” level (normally due to a far higher concentration of incoming solids causing the filter bed to block) the rate of sand washing is automatically increased. This normally deals with the problem, the head loss decreases, and sand washing rate falls to its normal level.
- But, if this does not solve the problem, the head loss across the filter bed continues to increase until it reaches a final switch point, when the sand washing rate increases even further and also generates an alarm.
Stainless Steel construction
TOVEKO filters are normally constructed in 304 grade stainless steel (1.4301).
For higher chloride concentrations, 316 grade is used (1.4401).
For even higher concentrations (for example sea water), duplex alloys are available.