Candle filter (CF)

Fully clarify turbid liquids

A complete CF 24-113 candle filter plant with 76 m² filter area to desulfurizing the natural gas in the amine sweetening process
Complete BHS candle filter plant

The BHS candle filter (type CF) is a fully automatic, batch-operated filter whose filter elements are arranged vertically inside a pressure vessel. It is used for clarifying liquids with a low solids content. The candle filter is a compact unit that allows for high throughput rates, dry cake discharge and a wide range of cake treatment options.

The suspension is fed into the pressure vessel and continuously pumped until the required cake thickness has been reached. The filter cake is formed on the outside of each filter candle. The filtrate is discharged from the inside of the candles through immersion pipes. After filtration, the filter cake can be washed, reslurried or dried. Finally, the cake is lifted by a blast of compressed air and discharged.

BHS also provides complete candle filter installations including fittings, instrumentation, piping, pumps, tanks, steel structures, and control systems. The plants have a modular design for easy transport and assembly.

Machine design of a candle filter
Machine design of a candle filter
Structure of a filter candle and cake formation
Structure of a filter candle and cake formation
Discharge of the filter cake
Discharge of the filter cake

Assembly of six BHS filter systems

For the mega gas plant project in Saudi Arabia, BHS-Sonthofen installed a total of three pressure plate filter skids and three candle filter skids and packed them for transport. The tasks are shown in time lapse.

Operating criteria:

Operating method intermittent
Operating pressure up to 10 bar (g)
Operating temperature up to 250°C
Solids content (suspension) up to 10% (wt.)
Cake thickness up to 30 mm
Particle size 0.5 µm and above
Filter performance – suspension 0.1 to 10 m³/m² h
Filter performance – dry solids
Active filter surface (total) 1 to 150 m²
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Brochure "Candle filter (CF)" (PDF / 3.4 MB)
Brochure "Candle filter (CF)"

Product brochure for candle filter (CF)

Size: 3.4 MB
‘Liquid clarification systems’ brochure (PDF / 4.0 MB)
‘Liquid clarification systems’ brochure

Product brochure for ‘Liquid clarification systems’

Size: 4.0 MB
Technical data sheet "Candle filter (CF)" (PDF / 103 KB)
Technical data sheet "Candle filter (CF)"

Technical data for candle filter (CF)

Size: 103 KB
Filtration application questionnaire (PDF / 129 KB)
Filtration application questionnaire

The PDF form includes a questionnaire that asks for information we require to assess your filtration challenge. The information you provide allows us to plan industrial-scale filters and prepare lab trials, if applicable.

Size: 129 KB


  • High throughput rates
  • Fully automatic operation
  • Low investment costs
  • GMP design is possible (pharmaceutical & food industry)
  • Modular turnkey system concepts


BHS filtration technical center

Link to tests at BHS technical center

Technical article

Continuous Pressure And Vacuum Filtration Technologies as Alternatives to Batch Filtration Operations

Chemical Industry Digest
Sept 2017
September 2017
PDF (1.8 MB)
Continuous Pressure And Vacuum Filtration Technologies as Alternatives to Batch Filtration Operations

This paper discusses the selection of the filtration process systems: continuous pressure and/ vacuum filtration through a process of laboratory and pilot testing. These tests enable problem analysis, technology selection and scale up which help in optimum filter selection.

Size: 1.8 MB

Removing contaminant fines from process water

ptq Petroleum Technology Quarterly
Q2 | 2016 (April-May-June)
April 2016
PDF (8.6 MB)
Removing contaminant fines from process water

Careful analysis and creative approaches are required for optimum applications of filtration technologies. The article discusses filtration technologies, applications for grey water and water scrubbing as well as troubleshooting.

Size: 8.6 MB

Choosing a Fine-Particle Filtration System

Chemical Engineering Progress (CEP)
December 2014
December 2014
PDF (4.4 MB)
Choosing a Fine-Particle Filtration System

Filtration technology has advanced to meet the demand to remove small particles at low concentrations. When designed ocrrectly, a candle filter or a pressure plate filter may be a more-efficient replacement for a traditional filtration scheme.

Size: 4.4 MB
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