Apparatus for extracorporeal blood treatment and method for monitoring the fluid flow of an extracorporeal blood treatment apparatus

An apparatus for extracorporeal blood treatment comprising

• a blood supply line leading to a unit for obtaining one or more blood constituents,
• a blood return line leading away from the unit for obtaining one or more blood constituents,
• a line leading to a treatment unit for treating the obtained blood constituent or constituents,
• a line which leads away from the treatment unit and which comprises a first line segment leading to the blood return line and a second line segment leading to a collection container, and
• means for changing over the fluid flow between a first direction, in which fluid flows through the first line segment of the line leading away from the treatment unit, and a second direction, in which fluid flows through the second line segment of the line leading away from the treatment unit,
• wherein a device is provided for monitoring the fluid flow through the first or second line segment of the line leading away from the treatment unit, and wherein the monitoring device comprises a means for determining the weight of the collection container and an evaluation unit, which is constituted in such a way that, in order to monitor the fluid flow, a change in the weight of the collection container can be ascertained.