Apparatus for transferring process material between a first container and a second container, having: a) at least one tensioning unit (11,21,31), which has a first tensioner (111,211,311) and a second tensioner (112,212,312), which can be actuated independently of one another; wherein: b) the at least one tensioning unit (11,21,31) is intended to temporarily fix, in a sealed-off manner: ba) just an end portion, facing towards the tensioning unit in question (11,21,31), of a tubular liner piece (8,9), which extends indirectly between the containers (A,B), in order to seal off the transition between the containers (A,B) from the exterior; bb) just an end portion, facing towards the tensioning unit in question (11,21,31), of a tubular liner remainder (8',8",9') left over from a previous transfer operation, which liner remainder is closed at the other end by a first crimp (81',82",91'); and bc) the end portion of the liner piece (8,9) simultaneously with the end portion of the liner remainder (8',8",9') left over from a previous transfer operation; and c) both tensioners (111,112;211,212;311,312) of the respective tensioning unit (11,21,31) are intended to temporarily fix, in a sealed-off manner, jointly the facing end portion of the liner piece (8,9) or jointly the facing end portion of the liner remainder (8',8",9') left over from a previous transfer process, characterized in that d) both tensioners (111,112;211,212;311,312) of the respective tensioning unit (11,21,31) are arranged circularly and concentrically with one another in relation to the longitudinal extension of the liner piece (8,9). a) at least one tensioning unit (11,21,31), which has a first tensioner (111,211,311) and a second tensioner (112,212,312), which can be actuated independently of one another; wherein: b) the at least one tensioning unit (11,21,31) is intended to temporarily fix, in a sealed-off manner: ba) just an end portion, facing towards the tensioning unit in question (11,21,31), of a tubular liner piece (8,9), which extends indirectly between the containers (A,B), in order to seal off the transition between the containers (A,B) from the exterior; bb) just an end portion, facing towards the tensioning unit in question (11,21,31), of a tubular liner remainder (8',8",9') left over from a previous transfer operation, which liner remainder is closed at the other end by a first crimp (81',82",91'); and bc) the end portion of the liner piece (8,9) simultaneously with the end portion of the liner remainder (8',8",9') left over from a previous transfer operation; and ba) just an end portion, facing towards the tensioning unit in question (11,21,31), of a tubular liner piece (8,9), which extends indirectly between the containers (A,B), in order to seal off the transition between the containers (A,B) from the exterior; bb) just an end portion, facing towards the tensioning unit in question (11,21,31), of a tubular liner remainder (8',8",9') left over from a previous transfer operation, which liner remainder is closed at the other end by a first crimp (81',82",91'); and bc) the end portion of the liner piece (8,9) simultaneously with the end portion of the liner remainder (8',8",9') left over from a previous transfer operation; and c) both tensioners (111,112;211,212;311,312) of the respective tensioning unit (11,21,31) are intended to temporarily fix, in a sealed-off manner, jointly the facing end portion of the liner piece (8,9) or jointly the facing end portion of the liner remainder (8',8",9') left over from a previous transfer process, characterized in that d) both tensioners (111,112;211,212;311,312) of the respective tensioning unit (11,21,31) are arranged circularly and concentrically with one another in relation to the longitudinal extension of the liner piece (8,9).