Automatic emptying of a dialyzer following a blood treatment therapy

An extracorporeal blood treatment device for use in a blood treatment therapy, the extracorporeal blood treatment device comprising:

• an extracorporeal circuit;
• a dialysis liquid circuit including an air separator;
• a dialyzer comprising a blood side fluidically connected to the extracorporeal circuit and a dialysis liquid side fluidically connected to the dialysis liquid circuit;
• and
• a control unit,
• the blood side and the dialysis liquid side being separated from each other via a membrane provided in the dialyzer,
• the control unit being configured to automatically empty the dialyzer after an end of the blood treatment therapy by setting a negative pressure in the dialysis liquid circuit and a concomitant transfer of a liquid from the blood side via the membrane into the dialysis liquid side,
• the control unit being configured, when the liquid has completely transferred from the blood side via the membrane into the dialysis liquid side and the blood side of the dialyzer has been emptied, to cause, by a continued setting of the negative pressure in the dialysis liquid circuit, a transfer of air from the blood side via the membrane to the dialysis liquid side and a displacement of the liquid out of the dialysis liquid side of the dialyzer to a dialysis liquid outflow, in order to also automatically empty the dialysis liquid side of the dialyzer, and
• the control unit being configured to stop automatic emptying of the dialysis liquid side in a sensor-controlled manner when the air separator detects or measures that a liquid level of the air separator has fallen below a predetermined liquid level or gauge height.