# US 8,465,641 B2 · Dialysis liquid circuit, dialysis apparatus comprising a dialysis liquid circuit, method for detecting air in a dialysis liquid flowing through a dialysis liquid circuit, and use of a gas sensor in a dialysis liquid circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,465,641 B2 - Document ID: US8465641B2 - Status: Granted - Kind: B2 - Application number: 12/452,956 - Filed: 2008-07-30 - Published: 2010-06-03 - Granted: 2013-06-18 - Earliest claimed: 2007-07-31 - Assignees: Fresenius Medical Care Deutschland GmbH - Applicants: Andreas Maierhofer; Alfred Gagel; Malte Gross - Inventors: Andreas Maierhofer; Alfred Gagel; Malte Gross - Web page: https://patentgrep.com/patent/US8465641B2 ## CPC - A61M 1/1656: {Apparatus for preparing dialysates} - A61M 2205/15: Detection of leaks - A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)} ## Abstract A dialysis liquid circuit with conduits for conducting dialysis liquid and elements for detecting air in the dialysis liquid. The elements includes at least one gas sensor traversed continuously by the dialysis liquid, which is configured such that it measures at least one property of the dialysis liquid which depends on the presence of air bubbles in the dialysis liquid, and which is arranged downstream of a region to be monitored of the dialysis liquid circuit. During operation of the dialysis liquid circuit a negative pressure exists with respect to atmospheric pressure, and the elements includes an evaluation unit which is connected with the gas sensor and which is configured such that the property measured by means of the gas sensor is evaluated with regard to the presence of air bubbles in the dialysis liquid. ## Claims ### Claim 1 A dialysis liquid circuit comprising: conduits for conducting a dialysis liquid, and elements for continuously detecting air in the dialysis liquid and leakage in the dialysis liquid circuit, the elements including at least one gas sensor traversed continuously by dialysis liquid, the at least one gas sensor being configured such that it measures at least one property of the dialysis liquid which depends on the presence of air bubbles in the dialysis liquid, and being arranged downstream of a region to be monitored of the dialysis liquid circuit in which during operation of the dialysis liquid circuit a negative pressure exists with respect to atmospheric pressure, and an evaluation unit which is connected with the gas sensor and is configured such that the property measured via the gas sensor is evaluated with regard to the presence of air bubbles in the dialysis liquid and based thereon, with regard to the presence of leakage in the dialysis liquid circuit. ### Claim 2 (depends on 1) The dialysis liquid circuit according to claim 1, further comprising a dialyser arranged in the dialysis liquid circuit, and wherein the gas sensor is arranged downstream of the dialyser. ### Claim 3 (depends on 1) The dialysis liquid circuit according to claim 1, wherein the gas sensor is a conductivity sensor. ### Claim 4 (depends on 1) The dialysis liquid circuit according to claim 1, wherein the gas sensor is configured such that via the gas sensor individual signal peaks of the property of the dialysis liquid can be detected. ### Claim 5 (depends on 1) The dialysis liquid circuit according to claim 1, wherein at least one of the gas sensor and the evaluation unit is configured such that a mean value of the at least one property of the dialysis liquid is determined and taken as a basis for evaluation. ### Claim 6 (depends on 1) The dialysis liquid circuit according to claim 1, wherein the evaluation unit is configured to at least one of emit a signal and initiate a particular mode of operation of the dialysis liquid circuit when it is detected during the evaluation that air bubbles are present in the dialysis liquid. ### Claim 7 (depends on 6) The dialysis liquid circuit according to claim 6, wherein the particular mode of operation is a pressure holding test of the dialysis liquid circuit or of the region to be monitored. ### Claim 8 (depends on 1) The dialysis liquid circuit according to claim 1, further comprising a bypass conduit, which bypasses the region to be monitored, and at least one shut-off valve, in whose open condition the dialysis liquid can flow through the bypass conduit for performing a reference measurement. ### Claim 9 (depends on 1) The dialysis liquid circuit according to claim 1, further comprising, arranged upstream of the region to be monitored of the dialysis liquid circuit, another gas sensor for performing a reference measurement. ### Claim 10 (depends on 1) The dialysis liquid circuit according to claim 1, further comprising an element for varying the pressure in the region to be monitored. ### Claim 11 (depends on 10) The dialysis liquid circuit according to claim 10, wherein the element for varying the pressure includes a pressure regulator arranged upstream of the region to be monitored and a pump arranged downstream of the region to be monitored. ### Claim 12 (depends on 11) The dialysis liquid circuit according to claim 11, wherein the pressure regulator is configured as an adjustable valve or an adjustable pump. ### Claim 13 (depends on 1) The dialysis liquid circuit according to claim 1, wherein in the dialysis liquid circuit at least one pressure sensor is arranged for detecting the pressure existing in the dialysis liquid. ### Claim 14 (depends on 1) A dialysis apparatus with at least one dialysis liquid circuit according to claim 1.