Disc type Pre-coat filter
In this filter, there are discs assembled one on the other & made a stack. This helps in getting more filtration area in less volume. It is a vertical filter. The filter media used is a stainless steel mesh.
Complete indexing cycle i.e. Scraping, backwashing, Pre-coating is totally automatic.

Flat bed type Pre-coat filter
There are two shells in the filter. One is called top shell & other is bottom shell. Dirty oil is fed to the top shell. There is a filter paper sealed between two shells to filter the oil. Pre-coat layer is given on the filter paper for fine filtration. Rubber sealing have been provided between two shells to avoid leakages through the shells.

Indexing of the filter media
Filter media indexes on the backpressure developed in the filter because of clogging of filter media.

There is a pressure switch to sense backpressure & further to give signal for subsequent indexing cycle.

Indexing Cycle
Backpressure Signal
Closes in let valve of Upper shell & stops transfer pump.
Let's compressed air in upper shell to pass residual oil in upper shell & makes the sludge dry.

After preset time upper shell goes up & indexes the filter media for predetermined length to dispose the sludge along with filter paper. After disposal of the sludge fresh paper comes in & upper shell goes down. Inlet valve opens & transfer pump starts.

During indexing the powder feeding in dirty oil tank takes place simultaneously & keeps the slurry ready for further Pre-coating.

Candle type Pre-coat filter
This filter is basically a product of our technical collaborator M/S Water & mechanical Technologies, Milan (Italy).

Vertical candles made of stainless steel are assembled in one vessel. This gives you more filtration area in small volume.

These candles are Pre-coated before filtration process is started.

This is a pressure filter. Coolant from semi clean coolant pump is passed to self-cleaning filter. This filter operates on differential pressure created across the filter. Filter media is cleaned automatically when differential pressure reaches 1 bar.

Wedge wire screen having the slit size of 200 microns is used in this filter to give effective filtration of 50 to 70 microns when differential pressure reaches to 1 bar. Flow direction is from in to out through filter media. All the sludge is collected on inner surface of the wedge wire screen. There is motorized scraping system mounted on the center shaft to wipe out sludge from inner surface. Further cleaning takes place with pressurized incoming coolant when drain line of the filter is opened up to atmospheric pressure with help of the pneumatically operated drain valve. Operations of this valve have been synchronized with the drive motor.

Drained coolant along with sludge is further passed through the cartridge filters to trap sludge & collect coolant back to the tank. There are duplex cartridge filters to avoid any stoppage of the system during cleaning of clogged filters. Change over from one cartridge filter to another could be done easily with help of the valves. Pressure switch has been provided on cartridge filters to give an indication of clogging of the filter.