Device for changing the number of part streams of a flowing medium

A device for changing the number of part streams of a flowing medium, comprising a tube (7) with a plurality of holes (11) through the tube wall arranged one after the other in the length direction of the tube, a piston (12), which divides the interior of the tube into a first compartment (13), through which the medium is intended to flow, and a second compartment (14), which is closed from the first compartment (13), and a piston rod (15), which extends from the piston (12) through the second compartment (14) and with an end portion extends a distance outside the tube (7), the number of part streams being determined by the number of holes (11) through the tube wall communicating with the first compartment (13), characterized by

• a first stop member (16), which is arranged axially displaceable on the end portion of the piston rod (15) extending out from the tube (7) and which is adapted to abut against an end surface of the tube (7),
• a second stop member (17), which is arranged to keep the first stop member (16) axially pressed against said end surface of the tube, and
• a determined number of sleeve members (18-21) of different axial extension, which are removably applied one after the other around the piston rod (15) within the tube (7) and which together have such an axial extension that they serve as spacing means between the piston (12) and said first stop member (16), when the latter is pressed against said end surface of the tube by the second stop member (17), a change of the number of part streams being possible by at least one of the sleeve members (19-21) being movable to and clampable as a spacing means in a position between the two stop members (16, 17), and the remaining sleeve members being clampable between the piston (12) and the first stop member (16).