Candle Filter

Our candle filter allows the cake to be discharged in a semi-liquid form (sludge) or in a dry form (mechanical dry). The filter offers advantages to our clients as it not only can be used as a filter but also as a thickener, eliminating in this case need for a separate machine to thicken the cake. Consequently, deploying our candle filter in the field helps to reduce space needs at the manufacturing plants of our clients.
The operation of our candle filter is fully automated and can be programmed (and manually interfered with) with the aid of a PLC or central process control unit.


Our candle filter is a closed system consisting of a pressure vessel and vertically installed spiral candles.

  1. Pressure vessel
  2. Emptying
  3. Discharge flange
  4. Productinlet
  5. Spiral candle
  6. Paw
  7. Support tube
  8. Filter cover
  9. Reserve flange
  10. Instrument connection
  11. vent connection
  12. Attachments eyelet
  13. Gas connection
  14. Filtrate connection

Main Advantages

  • No moving parts
  • Closed system
  • Modular construction
  • Full automation of the process
  • Use at high temperatures and highest corrosion load
  • Mechanical dry and wet cake discharge

Process engineering features

0,5 – 3 m

0,025 – 200 m2


Candles length: 0,5 – 3 m
Filter area: 0,025 – 200 m²
Cake washing: Spray washing or displacement washing.
Cake drying: Gas or steam drying.
Mechanical dry or thick sludge. Mechanical dry or thick sludge.
Automation: Fully automated using pressure transmitters, clarifier probes and flow meters.

Spiral shape of the candle

Our candle filters use a special helical shape of the candle, which offer additional advantages:

  • The helix gives extra support to a cake and thus supports falling-prone cakes
  • The helical shape allows a better cake discharge, as the cake undergoes an additional twist
  • The candle shape offers a soft touch of a filter cloth to the support body, without sharp buckling, which guarantees a longer life of the filter cloth

Depending on the application, our candles can be made out of a stainless steel or a plastic.

Function of the filter elements

Filtration Mode


  1. Filtrate
  2. Central tube
  3. Support tube
  4. Filtercloth
  5. Cake


Suspension flows in the direction of the candle.
The cake forms around the candle.
Through the central tube, the filtrate exits.


Discharge Mode


  1. Gas
  2. Central tube
  3. Support tube
  4. Filtercloth
  5. Cake


The compressed gas flows from the inside to the outside.
The filter cloth is inflated by the compressed gas.
The cake breaks and falls down.

Application examples

  • Filtration and drying of activated carbon and bleaching earth from vegetable oil
  • Filtration of catalysts, for example: Pd, Pt, Rh and Raney nickel
  • Cleaning of electrolyte baths e.g. Zn and Sn and precious metals
  • Filtration of PTA wastewater (Purification Terephthalic Acid)
  • Filtration of polyols
  • Filtration of antibiotics
  • Chloralkali filtration
  • Spin bath and rinse bath filtration
  • Filtration of cellulose fibres
  • Titanium dioxide filtration
  • Metal oxide filtration e.g. iron oxide, chromium oxide etc.
  • Caffeine filtration
  • Potash filtration