Sample preparation system for an analytical system for determining a measured variable of a liquid sample

1. A sample preparation system for an analytical system for determining a measured variable of a sample liquid, comprising:

a first fluid conducting line;

a second fluid conducting line;

a transport unit with a pump connected with a sample taking location via said first fluid conducting line;

a sample collecting unit with a container, which serves the analytical system as a staging area for automated removal of liquid samples, based on which the measured variable is determined;

a filter unit arranged between said sample taking location and said transport unit, the filter unit fluidly connected to the sample collecting unit via the first fluid conducting line; and

at least one reservoir connected via said second fluid conducting line with said filter unit for providing a cleaning medium for cleaning said filter unit, the second fluid conducting line configured to bypass the transport unit, wherein said transport unit is embodied to transport sample liquid from said sample taking location through said filter unit via said first fluid conducting line into said sample collecting unit and wherein the cleaning medium comprises an oxidizing agent.

2. The sample preparation system as claimed in claim 1 , further comprising:

a first valve unit structured to include a first state and a second state, wherein in the first state, the first valve unit connects a first section of said first fluid conducting line extending between said filter unit and said first valve unit with a second section of said first fluid conducting line extending between said valve unit and said transport unit, while the first valve unit blocks flow through the first section of the first fluid conducting line into the second fluid conducting line, and

wherein in the second state, the first valve unit connects the first section of said first fluid conducting line with said second fluid conducting line, while the first valve unit blocks flow through the first section of the first conducting line into the second section of the first fluid conducting line.

3. The sample preparation system as claimed in claim 2 , further comprising:

a second valve unit structured to include a first state and a second state of the second valve unit, wherein in the first state, the second valve unit connects said second section of said first fluid conducting line with said sample collecting unit, and in the second state, the second valve unit connects the second section of said first fluid conducting line with an outlet leading to a waste container.

4. The sample preparation system as claimed in claim 1 , wherein:

said filter unit extends, at least partially, into liquid present at the sample taking location.

5. The sample preparation system as claimed in claim 1 , wherein:

the cleaning medium comprises a liquid, a gas or a gas mixture

comprising ozone as the oxidizing agent.

6. The sample preparation system as claimed in claim 1 , wherein the at least one reservoir for a cleaning medium comprises an apparatus for producing the oxidizing agent.

7. The sample preparation system as claimed in claim 1 , wherein said transport unit is a peristaltic pump.

8. The sample preparation system as claimed in claim 6 , wherein:

said reservoir for providing a cleaning medium includes a container containing a liquid cleaning agent and a pump, which is embodied to transport the cleaning medium from container into said second fluid conducting line.

9. The sample preparation system as claimed in claim 2 , wherein:

in a first operating mode of the sample preparation system, said first valve unit connects said first section of said first fluid conducting line with said second section of said first fluid conducting line; and

said second section of said first fluid conducting line is connected with said sample collecting unit via the transport unit for transporting sample liquid from said sample taking location via said filter unit into said sample collecting system.

10. The sample preparation system as claimed in claim 2 , wherein in a second operating mode of the sample preparation system, said first valve unit connects said first section of said first fluid conducting line with said second fluid conducting line for transporting cleaning medium through said filter unit in the direction of the sample taking location.

11. An analytical system for determining a measured variable of a liquid sample, comprising:

a sample preparation system, comprising: a first fluid conducting line; second fluid conducting line; a transport unit with a pump connected with a sample taking location via said first fluid conducting line; a sample collecting unit with a container, which serves the analytical system as a staging area for automated removal of liquid samples, based on which the measured variable is determined; an analyzer; a filter unit arranged between said sample taking location and said transport unit, the filter unit fluidly connected to the sample collecting unit via the first fluid conducting line, and at least one reservoir connected via said second fluid conducting line with said filter unit for providing a cleaning medium for cleaning said filter unit the second fluid conducting line configured to bypass the transport unit, wherein: said transport unit is embodied to transport sample liquid from said sample taking location through said filter unit via said first fluid conducting line into said sample collecting unit; and the cleaning medium comprises an oxidizing agent; and

an analytic device, comprising:

a measuring cell;

at least one liquid container containing a treatment liquid for treating the liquid sample;

a processing system comprising a transport- and dosing apparatus for transporting and metering the liquid sample from the sample collecting system and the treatment liquid from the liquid container into the measuring cell; and

an optical measuring transducer for providing at least one measurement signal correlated with the measured variable of the liquid sample contained in the measuring cell and treated with the treatment liquid.

12. The sample preparation system as claimed in claim 6 , wherein the apparatus for producing the oxidizing agent is an ozone generator.

13. The analytical system as claimed in claim 11 , wherein the measuring transducer is an optical measuring transducer.