Vacuum Filtration with a Drum Filter

BoVac Drum filter – excellent with regard to filtration, washing and dewatering.

BoVac Drum filters by BOKELA are most modern vacuum drum filters. They show top performances in the filtration, washing and demoisturing of products in the minerals, salt, chemical, pharmaceutical and food industries. Replaceable filter cells make these drum filters unique. They enable an unrivaled fast cloth change during production.

Drum filters are the oldest, most versatile and therefore, the most common type among continuous rotary filters. With the BoVac Drum filter series, BOKELA has created a modern drum filter with an innovative, distinctive profile. BoVac Drum filters have replaceable filter cells. They allow a cloth change in only about 1–2 hours, without stopping the production. This improves occupational health and safety and maximizes production.

The ingenious design of the filter hydraulic system ensures excellent operating results of these vacuum filters. BoVac Drum filters are also convincing in demanding applications with outstanding results in filtration, washing and demoisturing. They are very compact and have only small space requirements.

BoVac Drum filters work fully automatically and are characterized by reliable operation and easy maintenance. Various optional features enable optimal adaptation to individual product and process conditions. BoVac Drum filters can also be operated at high temperatures and in hazardous areas. They are available with filter areas from 1 m² to 9 m².

BoVac Drum filters are characterized by:

  • non-stop production through unparalleled quick cloth change
  • excellent cake washing without increasing the residual moisture
  • individual design for specific product and process conditions
  • high availability and flexibility
  • easy operation and easy maintenance

Due to the modular design, BoVac Drum filters can be individually adapted to specific product and process characteristics. The main target is to achieve superior performance, best operating characteristics and high availability . The basis is the well-calculated filter hydraulic system, which is tailored to the special features of the separation task, and the modular design with optional features.

The hydraulically optimized design of the control head and filter cells with filtrate pipes at the leading and trailing edge of each cell guarantee fast filtrate removal and complete emptying of the filter cells. These are the prerequisites for high filter speeds or a high throughput and for efficient washing of the filter cake with exact separation of the individual filtrates. The number and size of the filter cells allow the formation of a homogeneous filter cake, which is evenly flowed through by the wash liquid. This is an important precondition for a good cake washing.

Special features of the BoVac Drum filter design:

  • exchangeable single cells for quick re- clothing
  • leading and trailing filtrate pipes
  • control head with pre-separation function
  • cake removal by compressed air blow-back
  • large process zones for cake formation, washing and demoisturing
  • encapsulated bearings
  • water lubrication, meaning no grease or oil lubrication
  • modular design with optional features:
    • washing system for cake wash
    • encapsulation
    • exhaust hood
    • CIP system

The replaceable BoVac Drum filter cells allow each cell to be replaced individually. The filter cloth is made as a bag for which different types of filter media are available. This way, a second set of filter cells already equipped with filter bags can be prepared.

The advantages:

  • unparalleled simple and quick cloth change in approx. 1–2 hours, including shutdown, cleaning and restart of the filter
  • filter cloth change during production
  • improved work safety through simple and easy handling
  • in the case of tissue damage, individual cells can be exchanged immediately
    • no production stop
    • no product loss
    • no deterioration of the filtrate quality

The purity of solids and/or liquids is a quality attribute which is of great importance in many processes in the chemical, pharmaceutical and food industries. BoVac Drum filters are thus often used if the filter cake needs to be washed to obtain clean solids.

The hydraulically optimized filter design ensures the formation of homogeneous filter cakes through which the wash fluid passes evenly. This is an important precondition for intensive replacement wash of the cake. The exact separation of the filtrates from cake-forming, washing and demoisturing allows effective countercurrent washing.

Due to the precise division of the process zones, the available angular range is optimally utilized for the individual process steps cake formation, cake washing and cake demoisturing. Wash ratios WR are realized, which are typically in the range WR = 0.2 to 2 [kg wash water/kg solids].

The results are:

  • clean filter cake by high washout in up to 3-stage countercurrent washing
  • low wash medium consumption
  • wash ratio WR: 0.2 to 2 [kg wash water/kg solids]
  • sharp separation and separate removal of the individual filtrate streams.

BoVac Drum filters work fully automatically and as plug & play technology, they can be easily integrated into the process automation:

  • automated startup and shutdown processes
  • automated filter operation
  • automated cleaning (CIP)
  • shortest installation and commissioning times (Plug & Play)

BoVac Drum drum filters are easy to operate and have features which facilitate maintenance:

  • easy disassembly of the control head
  • supply of lubrication points with water (no grease or oil lubrication)
  • disassembly of the agitator without disassembling the filter drum
  • individually replaceable filter cells.
Filter Type [–] XS1 XS3 S5 M9
Filter Area [m²] 1 3 5 9
Drum Diameter [m] 0.9 0.9 1.4 1.9
Length of Drum [m] 0.375 1.0 1.2 1.6
Number of Single Cells [–] 24 24 36 36

Crystallization and Precipitation Suspensions

Tailored Solutions for Smooth Solid Separation, Washing and Dehumidification.

In crystallization and precipitation processes, solids have to be separated from suspensions. The BOKELA filter series BoHiBar Drum and BoVac Drum allow a product-friendly, fully automatic solution for the often sensitive suspensions, while also reducing drying costs.

Plastic Precursors

Filtration Apparatuses for High Product Quality and Consistently Low Costs.

Filtration is often an important step in the production of plastics. BOKELA products such as BoHiBar Drum, BoVac Drum or BoCross Micro Screen provide reliability, long service life and excellent process results. Minimal energy consumption and reduced drying costs ensure an improved economy.

Pharmaceutical Precursors

For Maximum Hygienic and Economic Standards.

The production of pharmaceutical products naturally faces high regulatory standards. Apparatuses, process and filter technology have to meet those demands. BoCross Dynamic and BoVac Drum are unique solutions for different fields of application.

Pigments, Fillers & Dyes

BOKELA filters for Sensitive Solids and Smallest Particle Sizes.

Pigments, fillers and dyes are used very differently in the various fields of application. A feature all of them share is the very small size of particles, usually smaller than one micrometer. The technologies of the BoCross Dynamic, Boris MicroScreen, BoVac Drum and BoHiBar Drum series ensure a reliable and product-friendly separation.

Filtration, Washing and Dewatering of Gypsum

The BoVac Drum filter with 1 m² filter area is operated in parallel to a 12 m² belt filter for filtration and washing of gypsum.

Filtration, Washing and Dewatering of an Organic Pharma Intermediate

The BoVac Drum filter is operated for filtration, washing and dewatering of an organic pharma intermediate. The filter is encapsulated and equipped with 3 adjustable wash bars with full cone spray nozzles and with a CIP system.

Filtration, Washing and Dewatering of a Textile Dye Product

The BoVac Drum filter is operated for filtration, washing and dewatering of a textile dye product. The filter is equipped with a wash hood and adjustable wash bars with spray nozzles and with a CIP system for clean & safe operation.

Filtration, Washing and Dewatering of Pigments

Four BoVac Drum drum filters are operated for filtration, washing and dewatering of fine sized tarnishing pigments. Each of these modern 5 m² vacuum drum filters replaces one 8 m² drum filter of old design.

Vacuum Filtration. State-of-the-Art Design for High Performance.

BoVac Disc, BoVac Drum and BoVac Pan – those are continuously working disc, drum and pan filters for vacuum filtration. They are used especially with regard to continuous production processes with high throughputs.


Low residual moisture is important for the further processing of the filter cake. With mechanical drying, an intelligent filter design and the right operation mode, production costs can be considerably reduced.

Filter Cake Washing

Filter cake is the name for the solids filtered from a suspension and collected at the surface of the filter medium. The washing of the filter cake is essential to the purity of the filtered solids and thus, for the reusability.

Solid Separation

Solid separation is the first process step with regard to separating solids from fluids. The driving force behind the process is the pressure difference with which the suspension flows through the filter medium.

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© 2024 BOKELA GmbH Karlsruhe, Germany

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