Abstract: A method and an apparatus are provided for carrying out integrity tests of at least one filter element, arranged within a filter housing, with porous filter materials. Sensors are provided for measuring the sound generated by a test fluid when it flows through the filter element. The method includes applying a test fluid to a first side of the filter materials of the filter element while maintaining a constant fluid pressure, measuring the body-borne sound and/or the vibrations caused by test fluid flowing through the filter materials by sensors, and comparing the body-borne sound and/or the vibrations with the body-borne sound and/or the vibrations of an integral, identical filter element, measured under identical conditions.

Abstract: A method and an apparatus are provided for carrying out integrity tests of at least one filter element, arranged within a filter housing, with porous filter materials. Sensors are provided for measuring the sound generated by a test fluid when it flows through the filter element. The method includes applying a test fluid to a first side of the filter materials of the filter element while maintaining a constant fluid pressure, measuring the body-borne sound and/or the vibrations caused by test fluid flowing through the filter materials by sensors, and comparing the body-borne sound and/or the vibrations with the body-borne sound and/or the vibrations of an integral, identical filter element, measured under identical conditions.

Abstract: In the method for mixing-free transport of homogeneous liquids in microchannels a heterogeneous liquid flow (14) is autonomously divided into portions, transported over a distance and then autonomously recombined. When the flow is divided into portions, individual volumes of a second liquid (16), which may be but must not be homogeneous, are introduced between volume fractions lying one behind the other of the heterogeneous liquid flow (14). While the volume fractions of the heterogeneous liquid (14) that lye close to one another would mix with each other without this measure being taken, separation of the individual volume fractions allows these volume fractions, and thus the heterogeneous liquid (14), to be transported over large distances without any mixing occurring.

Abstract: In the method for mixing-free transport of homogeneous liquids in microchannels a heterogeneous liquid flow (14) is autonomously divided into portions, transported over a distance and then autonomously recombined. When the flow is divided into portions, individual volumes of a second liquid (16), which may be but must not be homogeneous, are introduced between volume fractions lying one behind the other of the heterogeneous liquid flow (14). While the volume fractions of the heterogeneous liquid (14) that lye close to one another would mix with each other without this measure being taken, separation of the individual volume fractions allows these volume fractions, and thus the heterogeneous liquid (14), to be transported over large distances without any mixing occurring.