Blood treatment device and disposable kit for a blood treatment device

A blood treatment device comprising:

• a blood treatment unit having an inlet and an outlet;
• a blood feed line connected to the inlet of the blood treatment unit, the blood feed line having a first branch line and a second branch line, wherein the first branch line and the second branch line are connected in parallel;
• a blood return line connected to the outlet of the blood treatment unit;
• a first positive displacement pump connected in the first line branch, the first pump divides the first line branch into a first section and a second section, a first closure member provided in the first section of the first line branch, a second closure member provided in the second section of the first line branch;
• a second positive displacement pump connected in the second line branch, the second pump divides the second line branch into a first section and a second section, a third closure member provided in the first section of the second line branch, a fourth closure member provided in the second section of the second line branch;
• and
• a connection line that branches off from the blood return line and connects the outlet of the blood treatment unit to one of the first line branch and the second line branch, a fifth closure member provided in the connection line.