TOVEKO Sand Filters
TOVEKO sand filters are gravity-fed units. They 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 cleaned from the sand bed while the filter is operating. So, the filter does not need to be taken “off-line” for backwashing like a conventional sand filter. Therefore you do not need a standby filter and all the large tanks, pumps etc. that are required for backwashing. Consequently, both the space required and the associated costs are minimised.
TOVEKO filters are only 2.3m high
Each Toveko filter will fit into a normal height room So, frost protection and installation in “visually sensitive” sites is very straightforward. It also commonly allows gravity flow into the filter from the preceding treatment step (for example settlement). This therefore avoids the need for an expensive intermediate pumping stage. It also ensures that the delicate solids are not broken-up within the pump. As a result, their subsequent removal in the filter is easier and more efficient and therefore 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. The resulting, 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 sticky. This is common where polyelectrolyte is used for flocculation, or where there is oil present. Actually, TOVEKO filters are often used for the removal of residual oil in wastewater. Of course, any sand filter will remove oil. However, 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”. This enables automatic control of filter operation:
- The filter automatically stops washing the sand when flow through the filter stops and the head loss falls to zero. As a result, the filter does not “keep going” when it doesn’t need to. It is therefore more energy efficient.
- When flow re-starts, the head loss again increases to its “normal” level and filter operation therefore re-starts. This “stop and start” process just continues, completely automatically.
- Occasionally an upstream problem may cause a far higher concentration of incoming solids. The filter bed may then start to block and head loss then increases above its “normal” level. When this happens 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.
- If it does not solve the problem, the head loss across the filter bed continues to increase until it reaches a final switch point. This is 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.