Fully automatic filter with no driving unit simple structure
The IHI-Fundabac Filter filters materials through filter cloths attached to the numerous candles placed inside the vessel. Post-filtration processes can be fully automated, including drying and discharging the cake to cleaning the filter cloths. It has a simple structure without a drive unit, so this filter can be applied to large filtration areas. Sealing components are critical in the filtration process, and IHI has developed a unique seal hose to achieve leak-free and stable operation.
The filter is filled with the raw material through a pump. The air inside the filter is released from the top.
2Circulation
The filtrate is returned back to the raw material tank, and the filtration is circulated until the liquid is clarified. Overflow is generally used to prevent the sedimentation of solids.
3Filtration
Clear filtrate is extracted from the system. Each candle can hold up to 20 mm of cake.
4Withdrawal
Raw material is drawn using pressurized air (N2).
5Air blowing
Cake on the filter cloth is dewatered using air (N2). Air blowing is conducted for each filtrate line to reduce the instantaneous usage of utilities.
6Draining
Pressurized air (N2) from above drains any remnants at the bottom of the filter.
7Pressure release
The air (N2) in the filter is released until there is no internal pressure.
8Cake discharge
The cake discharge valve at the bottom of the filter is opened to discharge the cake using the back blow of air (N2). Discharge is conducted for each register to reduce the instantaneous usage of utilities.
9Backwashing→Backflow
Filter cloths are cleaned with backwash liquid and air (N2). Backwashing is divided into filtrate lines to reduce the instantaneous usage of utilities.
Efficacy of Riser Pipes
Drying
Fundabac Filter
With IHI-Fundabac Filter, compressed air passing through the cake layer carries the liquid contained in the cake into the candles. Then, the liquid rises up the riser pipe together with the filtrates remaining within the candles and is discharged outside the filter. This method allows for the cake to dry evenly from top to bottom before discharge.
Conventional Circular Candle Filter
In a conventional filter without riser pipes, the compressed air passes through the cake layer and takes a shortcut from the top. As a result, the lower cake and any remaining filtrate inside the element are drained away. This makes it impossible to discharge dry cake.
Backwashing and Back Blow
Fundabac Filter
With IHI-Fundabac Filter, backwash liquid is fed into the filter with an amount slightly more than the riser pipe capacity. Compressed air is blown into the riser pipe immediately after. Backwash liquid rises to the top of the element by the air lift effect, resulting in effective backwashing.
(Even during cake drying and discharge, the riser pipe and unique shape of the candle pieces facilitate the expansion of filter cloths to allow effective cake discharge.)
Conventional Circular Candle Filter
In a conventional filter without riser pipes, simply feeding the backwash liquid into the element is insufficient to fill it to the top. Even when compressed air is subsequently supplied, it only washes the bottom of the element. The compressed air will also follow a shortcut from the top, making effective backwashing impossible.
