Patent ID: 7273554

Claim:
A crossflow-filtration method for beverages, in particular beer, which are fed as the feed liquid at filtration intervals to a filter module with at least one membrane, which is cleaned with a cleaning solution and flushed with water from the filtrate side at cleaning intervals lying between the filtration intervals, characterized in that the following steps are carried out: a) introduction of the feed liquid ( 8 ) into the filter module ( 2 ) via a first connection ( 10 ) on the unfiltrate side ( 7 ) over a predeterminable flowing-over time period with an entry pressure created by a recirculation pump ( 4 ) located on said unfiltrate side which is adequate to keep the filtrate flow on the filtrate side ( 19 ) of the filter module ( 2 ) within predetermined limit values, and evacuation of the concentrate via a second connection ( 13 ) on the unfiltrate side ( 7 ) of the filter module ( 2 ), b) reduction of the entry pressure at the first connection ( 10 ) and backflushing by surges of filtrate by means of reversal of the direction of flow transversely to the membrane ( 6 ) by means of a filtrate backflushing pump ( 5 ) with a backflushing valve ( 23 ) arranged upstream toward the filter module ( 2 ) for generating a pressure surge and wherein the opening time of the backflushing valve ( 23 ) is between 100 and 700 ms, c) repetition of steps a) and b) until the filtrate flow goes below the lower predetermined limit value, d) emptying of the filter module ( 2 ) by applying pressure, e) backflushing of the filter module ( 2 ) from the filtrate side ( 19 ) with water and subsequently with a solution containing chemicals, f) leaving the filter module ( 2 ) filled with the solution containing chemicals to rest for a predetermined exposure time, g) flushing of the filter module ( 2 ) with water until neutrality is established, h) filling of the filter module ( 2 ) with degassed water, i) forcing out the degassed water from the filter module ( 2 ) with filtrate and j) continuation with steps a) to i).