Patent ID: 8409127

Claim:
A method for emptying a blood tubing set of a blood treatment device that includes an extracorporeal blood circuit with a membrane filter having a first chamber and a second chamber separated therefrom by a membrane, said first chamber conveying blood in operation of the blood treatment device and said second chamber conveying filtrate in operation of the blood treatment device, and said blood tubing set including an arterial blood tube and a venous blood tube which are both in communication with the first chamber of the membrane filter and which conduct the blood from a patient to the membrane filter and from the membrane filter to the patient in operation of the blood treatment device, and including a substituate line which opens into at least one of the arterial blood tube and the venous blood tube, and a substituate pump which is in communication with the substituate line to convey substituate from a substituate source through the substituate line, said method comprising: connecting the arterial blood tube and the venous blood tube to one another to provide a circuit that includes the membrane filter, the arterial blood tube, and the venous blood tube; disconnecting the substituate line from the substituate source; and pumping air or gas into the blood tubing set with the substituate pump to provide an excess pressure in the blood tubing set by which liquid is displaced, via the membrane, into the second chamber of the membrane filter.