candle filter

Candle filter is a fully closed filter system. Its main parts are the material tank, air storage tank, feeding pump, candle filter, pipes, valves, PLC electric control system.
While filtering, filter material will be sent into the filtering housing by feed pump first; when it passes through filter cloth, solid particles will be stopped on the filter cloth. And as the solid particles growing, they will become filter cakes. The holes between solid particles are very small, so they can keep more solid particles, thus get clear liquid. Before solid particles becoming cakes, the filtration will be sent back to filter material tank and resend to vessel again. When filter cakes are formed (and reaches required requirement), PLC will send a signal to stop the circulation, and the clear liquid will pass the filter valve and go to next process to start the normal filtering process.
After certain time normal filtering, the cake thickness is increasing to high level, the filtering speed is slow down, filtering efficiency is decreased, and the filter pressure is >0.5MPa, then the pressure sensor will send a signal to PLC to stop feed pump, close feed valve and open forward blowing valve to remove the filtrate in vessel. When the liquid level in vessel is lower than filter cartridge, PLC will open drain valve to discharge filtrate, the pressure will drop swiftly. When PLC received low pressure signal, it will close forward blowing valve and open back blowing valve (compressed air, nitrogen or steam) to back blow until cakes fall down. Stop blowing after 30 seconds, and open cake discharging outlet to discharge cakes. When cakes are discharged, close the cake discharging outlet to finish the filtering cycle. The candle filter will be ready for next cycle.