Patent ID: 7186342

Claim:
A method of filling and washing a filter of a dialysis machine, comprising the steps of: providing a dialysis machine having: a filter comprising a dialysate compartment, a blood compartment, and a semi-permeable membrane to separate the dialysate compartment from the blood compartment; a blood circuit comprising an arterial branch connected to the blood compartment, a venous branch connected to the blood compartment, a first dropper located in the arterial branch, a second dropper located in the venous branch, and a vent tube connected to one of said first and second droppers, a peristaltic pump connected to the blood circuit; a dialysate circuit comprising a first branch connected to the dialysate compartment to supply a fresh dialysate to the filter and a second branch connected to the dialysate compartment to remove a spent dialysate from the filter; a first pump located along the first branch to provide a flow rate of fresh dialysate to an inlet of the filter; a first pressure sensor located along the first branch between the first pump and the filter; a second pump located along the second branch to provide a flow rate of spent dialysate from an outlet of the filter; a second pressure sensor located along the second branch between the filter and the second pump; a supplying device connected to the first branch for supplying a fresh dialysate for a dialysis treatment as a solution of salts in purified water, and a control unit connected to the first pump, the second pump, the peristaltic pump, the first pressure sensor, the second pressure sensor, and the supplying device; configuring the blood circuit to form a loop connected by said vent tube to the exterior of the blood circuit, whereby the pressure in the blood compartment is equal to the atmospheric pressure; operating the first pump and the second pump to fill and wash the dialysate compartment with a priming liquid at a first pressure, the priming liquid being supplied by said supplying device; when the dialysate compartment has been filled and washed with the priming liquid, operating the first pump and the second pump to supply the dialysate compartment with the priming liquid at a second pressure, the second pressure being greater than the first pressure and greater than atmospheric pressure, and the second pressure defining a pressure difference between the dialysate compartment and the blood compartment such that the priming liquid is transferred from the dialysate compartment to the blood compartment through the semi-permeable membrane, during said transfer, the control unit receiving information related to a pressure in the blood circuit in said loop, and the control unit processing pressure signals supplied by said first and second pressure sensors to regulate said first and second pumps; operating the peristaltic pump to circulate said priming liquid in the blood circuit in said loop, and discharging air contained in the blood circuit in said loop through the vent tube.