Unit and method for deaeration of drainage water

A unit (3) for deaeration of drainage water from a paper machine, said unit (3) comprising:

• an inlet (8) for receiving the drainage water in a first flow direction;
• an outlet (39) for removing the drainage water to a subsequent deaeration channel;
• and
• a first chamber (5) that is arranged downstream of the inlet (8), said first chamber (5) comprising a first chamber part (18), and a second chamber part (19) that is arranged downstream of the first chamber part (18), wherein the first chamber part (18) comprises:
• a guide wall portion (37) for redirecting the drainage water in a predetermined second flow direction that differs from the first flow direction, said guide wall portion (37) being formed by a plurality of curved guide walls (10, 23) which define a plurality of curved and substantially parallel flow channels (15) for the drainage water and that the guide walls (10, 23) are arranged to interact with the drainage water in such a way that air is forced out of the drainage water;
• and
• two substantially planar end walls (25, 26), which are substantially parallel to the first flow direction and which are arranged on respective sides of and substantially orthogonally to the guide walls (10, 23), wherein each end wall (25, 26) of at least one of the flow channels (15) exhibits an opening (27) that communicates with the flow channel (15) for removing at least part of the air, which has been released from the drainage water in the flow channel (15) by said interaction, from the first chamber part (18).