Method and device for heating solutions, preferably dialysis solutions

• US 8,350,195 B2
• Filed: 02/27/2009
• Issued: 01/08/2013
• Est. Priority Date: 02/29/2008
• Status: Active Grant

• Current Assignee: Fresenius Medical Care Deutschland GmbH (Fresenius Medical Care AG)
• Original Assignee: Fresenius Medical Care Deutschland GmbH (Fresenius Medical Care AG)
• Inventors: Hedmann, Frank L., Klatte, Stephan
• Primary Examiner(s): Ho, Hoai V
• Application Number:
  US12/735,891
• Publication Number:
  US 20110000902A1
• Time in Patent Office: 1,411 Days
• Field of Search: 219/494
• US Class Current: 219/494
• CPC Class Codes: A61M 1/1656 Apparatus for preparing dialysates
• CPC Class Codes: A61M 1/166 Heating for sterilisation A61M1/1686
• CPC Class Codes: A61M 1/1664 with temperature control
• CPC Class Codes: A61M 1/167 Flexible packaging for solid concentrates
• CPC Class Codes: A61M 1/287 Dialysates therefor
• CPC Class Codes: A61M 5/445 the media being heated in the reservoir, e.g. warming bloodbags

Abstract

A method and an apparatus for the heating of a solution, such as a dialysis solution, to a desired temperature includes heating the solution presented in a bag. The heating is effected with a heater system, which includes a heater, by means of a two-step control. The temperature forming the lower switch-on threshold of the heater and the temperature forming the upper switch-off threshold of the heater vary.

Claims

1. A method of heating a solution contained in a bag to a desired temperature, comprising:

heating the solution with a heater system having a heating element via a two-step control,

including varying a temperature that constitutes a lower switch-on threshold of the heating element and a temperature that constitutes an upper switch-off threshold of the heating element by iteratively increasing the temperatures during the heating.

2. The method in accordance with claim 1, wherein a temperature T₁ of the bag containing the solution is measured via a first temperature sensor, and a temperature T₂ of a heating element arranged in the heater system is measured via a second temperature sensor.

3. The method in accordance with claim 1, wherein a previously fixed precontrol temperature T_V is used as a temperature T₂ that constitutes the upper switch-off threshold.

4. The method in accordance with claim 1, wherein a precontrol temperature for a discrete bag temperature T₁ is determined in advance.

5. The method in accordance with claim 1, wherein the two-step control includes the following steps taking place iteratively:

measuring a temperature T₁ of the bag containing the solution;

setting a precontrol temperature T_V; and

heating the heating element until the precontrol temperature T_V is reached.

6. The method in accordance with claim 3, wherein the precontrol temperature is selected such that an overshooting of a temperature beyond a maximum heater temperature T_max is not possible.

7. The method in accordance with claim 1, wherein a switch-on point for the switching on of the heating element is determined such that a predetermined ratio of a temperature T₂ that constitutes the upper switch-off threshold to a temperature T₁ of the bag containing the solution is reached.

8. The method in accordance with claim 1, wherein a temperature T₁ of the bag containing the solution is determined when an influence of the heating element on a sensor measuring the temperature T₁ has fallen below a limit value.

9. The method in accordance with claim 8, wherein the temperature T₁ of the bag containing the solution is determined from a gradient of the sensor measuring the temperature.

14. The method according to claim 1, wherein the solution is a dialysis solution.

15. The method according to claim 1, wherein a temperature T₁ of the bag containing the solution is measured and is employed in a fixed ratio to a previously fixed precontrol temperature T_v which constitutes the upper switch-off threshold.

10. A heating system for heating a solution contained in a bag to a desired temperature via a two-step control by varying a temperature that constitutes a lower switch-on threshold of a heating element and a temperature that constitutes an upper switch-off threshold of the heating element by iteratively increasing the temperatures during the heating, said heating system comprising:

an element configured to make variable the temperature that constitutes the lower switch-on threshold of the heating element and the temperature that constitutes the upper switch-on threshold of the heating element.

11. The heating system in accordance with claim 10, wherein the element that makes variable the temperatures is configured to store discrete temperature values which correspond to the temperatures that constitute the upper switch-off threshold of the heating element.

12. The heating system in accordance with claim 10, wherein a first temperature sensor is embedded in the heating element.

13. The heating system in accordance with claim 10, wherein a temperature sensor is arranged on the heating element.