the guide 13 does not have to be made of one piece but it may consist of a number of parts or pieces fig3 a is a side view of the solution shown in fig2 the guide 13 comprises loading means 15 by which the guide 13 is supported on the central axle 12 and by whose means the guide 13 is further pressed against the inner face of the roll mantle the loading means 15 comprise a piston part 16 and a fluid space 17 placed in the stationary axle into which fluid space the pressurized fluid is introduced in which connection the fluid acts upon the piston 16 then by means of the fluid pressure the guide 13 is pressed against the inner face of the roll mantle as is shown in the figure the cross sectional shape of the guide 13 is a construction that includes a curved guide face 13 a by means of which guide face in the way shown in the figure the fluid is made to flow smoothly away from the connection with the roll mantle and fitted to fall into the fluid collecting trough 19 in the figures the guiding of the fluid by means of the guide 13 is denoted with the arrows l 1 the sense of rotation of the.