and 7 has the same object the centrally and coaxially located feeding and discharging channels 7 8 lead to a smooth equal distribution of the flow inside the treatment chamber fig6 and 7 illustrate 2 specimen carrier inserts 3 which can be mounted selectively the embodiment illustrated in fig6 is intended for receipt of a textile roll having a rigid material specimen carrier bush 60 at the left hand of the fig or a flexible material specimen carrier bush 61 having an adjustable height the specimen carrier bush includes perforations for the through flow of the treatment liquid it is supported by means of a closed distance holder tube 62 adapted to conform to the height of the respective bush and via a sealing ring 63 accordingly the height of the roll spool can be accordingly selected by maintaining the same displacement body 18 a flow bush 64 which is open at its top is provided at the outside of the specimen supporting bush 60 61 which bush 64 extends roughly up to the height of the specimen carrier bush or the roll respectively accordingly the flow path of the treatment liquid is definitely defined the returning of the flow from the central inlet 8 to the cylinder 4 does not proceed in and through the specimen roll but rather through the flow tube.