Dual-valve contrast fluid delivery system

1. A disposable set ( 5 ) for establishing a fluid connection between a fluid dispensing unit ( 17 ) and a dosing device adapted to dispense a fluid into a patient's vein, the disposable set comprising a length of a tubing ( 15 ) for establishing the fluid connection from the fluid dispensing unit towards and into the dosing device, wherein the tubing ( 15 ) comprises a first ( 1 ) and a second ( 10 ) tubing part, the first tubing part ( 1 ) being provided to establish at a first end part ( 4 ) a connection to a second end part ( 9 ) of the second tubing part ( 10 ), and at a second end part ( 14 ) a connection towards the fluid dispensing unit, the second tubing part ( 10 ) being provided to establish at a first end part ( 6 ) a connection towards the dosing device and the patient and at a second end part ( 9 ) a connection to the first tubing part ( 1 ), wherein the first tubing part ( 1 ) comprises a first one-way valve ( 3 ) which is provided to permit a fluid flow from the dispensing unit ( 17 , 18 ) towards the dosing device and to prevent a backward fluid flow from the dosing device towards the fluid dispensing unit, wherein the first end part ( 4 ) of the first tubing part and the second end part ( 9 ) of the second tubing part ( 10 ) are in fluid connection with each other in a liquid tight manner by means of a releasable connection device ( 11 , 12 ), of which a releasable connection is adapted to permit a backflow from the patient into the second tubing part ( 10 ) in a direction of the releasable connection device in a released position of the releasable connection and to prevent a backflow from the patient in the direction of the releasable connection device ( 11 , 12 ) in a closed position of the releasable connection, characterized in that the first tubing part comprises one or more second one-way valves ( 24 ) which are provided to permit a fluid flow from the second end ( 14 ) of the first tubing part ( 1 ) towards the first end ( 4 ) of the first tubing part ( 1 ) and to prevent a backward fluid flow from the first end ( 4 ) of the first tubing part ( 1 ) towards the second end ( 14 ) of the first tubing part ( 1 );

wherein the second end ( 14 ) of the first tubing part ( 1 ) comprises a connector ( 7 ) to connect the dosing device to a manifold ( 20 ), which intervenes in dosing the fluid contained in the fluid dispensing unit ( 17 ) and

wherein said one or more second one-way valves ( 24 ) are arranged at a distance of 3 cm or more from the first one-way valve ( 3 ).

2. The disposable set as claimed in claim 1 , characterized in that the disposable set comprises only one second one-way valve ( 24 ).

3. The disposable set as claimed in claim 1 , characterized in that the releasable connection device comprises a first ( 11 ) and a second connector part ( 12 ), in that the second connector part ( 12 ) is fastened to a second end part ( 9 ) of the second tubing part ( 10 ) and in that the first connector part ( 11 ) is mounted to an outlet side ( 2 ) of the first one-way valve ( 3 ), to permit a fluid flow from the fluid dispensing unit through the first one-way valve ( 3 ) into the second tubing part ( 10 ) when the first ( 11 ) and second connector part ( 12 ) have been engaged.

4. The disposable set as claimed in claim 3 , characterized in that the first connector part ( 11 ) is positioned on an end part of the first one-way valve ( 3 ) on a side oriented towards the second tubing part ( 10 ).

5. The disposable set as claimed in claim 1 , characterized in that the one or more second one-way valve ( 24 ) is mounted on the first tubing part at a predetermined location between the first and the second end parts of the first tubing part, about an equal distance from the first and second end parts of the first tubing part, respectively.

6. The disposable set as claimed in claim 1 , characterized in that the releasable connection device ( 11 , 12 ) is a luer connector.

7. The disposable set as claimed in claim 1 , characterized in that the first connector part ( 11 ) comprises a first luer lock flange which is adapted to be at least partly received within in a corresponding duct ( 13 ) of the second connector part ( 12 ) so as to form a liquid tight connection, to establish the fluid connection between the first and the second connector part.

8. The disposable set as claimed in claim 7 , characterized in that the liquid tight connection of the first and second connector part ( 11 , 12 ) is achieved by means of a bayonet coupling or a threaded connection on an outer wall of the duct ( 13 ) and an inner face of a circumferential wall ( 16 ) surrounding the first luer lock flange.

9. The disposable set as claimed in claim 1 , characterized in that the second tubing part ( 10 ) has a length which is longer as compared to a length of the first tubing part ( 1 ).

10. The disposable set as claimed in claim 1 , characterized in that the dosing device is an injection needle.

11. The disposable set as claimed in claim 1 , characterized in that the first and/or second tubing part comprise one or more clips ( 30 ).

12. A fluid dispensing system containing the disposable set as claimed in claim 1 .

13. A method for verifying blood backflow from a patient towards a fluid dispensing reservoir using the disposable set of claim 1 , comprising the steps of:

1) connecting the second tubing part ( 10 ) to a dosing device which has previously been inserted into a patient's vein;

2) temporarily loosening or disengaging the releasable connection between the first and second connector part ( 11 , 12 ) to permit a backflow of blood into the second tubing part;

3) establishing the blood backflow into the second tubing part; and

4) re-connecting the first and second connector part ( 11 , 12 ) to permit a flow from the reservoir to the dosing device.