Cross Flow Filtration for Craft Beer?

Gretta Beer News, Technical Article







Crossflow filtration using ceramic membranes – means no filter medium is required when filtering your beer. This is done by high-velocity parallel flow of the liquid in relation to the module ensures a continuous cleaning the membrane, thus allowing for very lengthy filtering cycles without the need to use chemical additives, compared to other filters that need some sort of medium for filtration (such as Diatomaceous Earth (DE) for DE filters). Keeping the cost of filter mediums non-existent and saving a lot of time and money ordering these during the course of the year and beyond.

The CFK-B Crossflow has been in development and testing for several years now – with the technology getting better over year on year. Fully automatic operation gives you the time you never had to do tasks in your brewery. Filtering is done automatically and continuously, by connecting your tanks from the receiving tank of the filtered product. To further prolong the filtering cycle, an incorporated backwash system periodically removes the thin fouling layer that deposits on the membrane. This helps avoid blockages on the ceramic membrane for keeping the flow rate consistent during the filtering run. Cleaning cycles can be set up with chemicals used for cleaning the crossflow filter automatically also – meaning more time for other necessary activities in the brewery, meaning less labour costs associated with running your business. Membranes can come as fine as 0.45 micron for sterile filtration of your product but can also come is in a range of micron sizes. This can give your beer a filtered but not polished visual appearance and can be filtered to whatever specifications needed. Sizes of the filters come from a small filtering surface area on a standalone unit to bigger connected crossflows. They are also are modular and can be connected together for medium to larger volumes in the future when volumes increase.

Filtering surface areas- sizes range from 20m2 up to 170m2 for a range of small to large breweries


Technical Specifications include: –

  • Centrifugal product feed and pressurizing pump.
  • Stainless steel pre-filter (which can be inspected) with a 1mm2 mesh to retain any gross impurities that might obstruct the channels of the membranes, with sight glass.
  • Main recirculation circuit consisting of stainless steel piping of suitable cross-section connecting the recirculation pump to the containers of the membranes.
  • Multiple-channel ceramic membranes comprising a porous supporting material coated with titanium oxide of the required porosity, fixed by means of easily-removable gaskets onto one or two containers depending on the filtering surface area being used. The particular shape of the containers enables large surfaces areas to be obtained while reducing the overall dimensions to a minimum.
  • High-efficiency centrifugal recirculation pump for ensuring the crossflow of the product inside the channels of the membranes.
  • Backflow system consisting of an elastomeric membrane inserted in a special stainless steel housing and moved at programmable intervals by a pneumatic system.
  • Service tank of adequate capacity, used for washing and as a plenum for the product, complete with washing system, inspection hatch, level detector and various couplings to the process.
  • Piping for connecting the various machine components, complete with electro-pneumatic product cut-off valves, a sight glass on the product outlet, sample collectors, an electronic flowmeter, pressure sensors, a temperature sensor, solenoid valves for the delivery of inert gas, electro-pneumatic valves for draining the circuit, and safety valves.
  • An electric switchboard in a stainless steel cabinet with a degree of protection to IP 55, containing the electric power components for the control and protection of the various motors, the inverter for controlling the feed pump, the PLC- based section with digital-analogical inputs and outputs, the section for controlling and displaying the selectors, pushbuttons, pilot lights and operator touch screen for configuring and selecting the various working parameters.
  • Pneumatic system for the compressed air and nitrogen, complete with manual on-off valves, filters, pressure regulators, pressure switches, means for controlling the flow to the valves, detectors of any presence of liquids in the backflow outlet and solenoid valves.
  • Wheel-mounted frame made of stainless steel profiles, on which all the above-mentioned components are rationally arranged and suitably fixed to create an integrated structure that is easy to position and install.












– Membranes 0.45 micron – With range of other micron size available
– isobaric kit
– heat exchanger on the filtration loop
– external recirculation on the brewery tank
– prefilter with sight glass at inlet
– valve with spiral for beer sampling at filtrate outlet and loop

Starting from just two parameters input by the customer (filtering difficulty and quantity to filter), the software for managing the CFKN crossflow filters offers the following options:

  • Dynamic control of the transmembrane pressure
  • Dynamic control of the backflow rate
  • Automatic definition of the frequency of intermediate emptying cycles
  • Automatic definition of the type of chemical washing cycle to adopt
  • Auto compensation for filtering difficulty in the event of a stoppage due to the maximum viscosity or minimum flow rate being reached
  • Monitoring with the display on a graphic screen of the status of the pumps, valves, pressures, instantaneous and mean flow rates, temperature, filtering time, liters filtered, viscosity and status of the alarms
  • Control, signalling and stoppage on reaching the programmable maximum product viscosity setting
  • Signalling and stoppage when the product runs out
  • Signalling when the minimum flow rate is reached, with the optimization of any stoppages
  • Monitoring of the integrity of the backflow membranes
  • Monitoring of the compressed air and nitrogen pressures, with signalling and stoppage in the event of low pressures
  • Stoppage after a programmable number of liters have been filtered
  • Suction of the volumes of concentrate previously emptied before completing a filtering process
  • Drainage with the recovery of the filtered product at the end of the filtering process through a dedicated valve
  • Fully automated performance of the selected washing cycle
  • System for metering the detergent complete with a pneumatic dosing pump and electropneumatic valves for enabling and disabling the delivery of the alkaline, acid and neutralizer products used in the washing cycle
  • Filling with any mixing of hot/cold water to avoid abrupt temperature differences in excess of 60°C
  • Tests with a differentiated historical record of the permeability after chemical washing cycles
  • Automatic restart after programmed washing cycles
  • Historical records of the main processing data (date and time, selected and actual mean flow rate, selected and actual total volume filtered, filtering time, number of emptying procedures, number of rinsing procedures, number of viscosity alarms, number of minimum flow rate alarms, selected and actual filtering difficulty, maximum viscosity, temperature, type of washing cycle, permeability test).


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