Flow control valves for leakage detection, free-flow prevention and occlusion detection

1. An injection device for injecting a fluid into an organism, the injection device comprising:

a fluid providing section including a container for storing the fluid and a pump unit for supplying the fluid, the pump unit comprising a displacement member, a driven member and a driving unit; and

a fluid injecting section for injecting the fluid provided by the fluid providing section into the organism and a catheter means, wherein

the fluid injecting section is provided with a pressure recognition arrangement for detecting at least one of a pressure increase and a pressure loss in the fluid injecting section, the pressure recognition arrangement comprising a fluid pressure sensor, a control unit, a permanent memory, and at least one control valve, the at least one control valve is a cracking valve that opens the at least one control valve above a cracking pressure, permitting flow through the at least one control valve, and closes the at least one control valve below the cracking pressure, wherein the control unit is configured to extrapolate a time series of measured pressure values in the fluid injecting section and to send a signal to an alarm device if the extrapolated values attain a certain relation to at least one given reference pressure value.

2. The injection device according to claim 1 , wherein the control unit is configured to operate the pressure recognition arrangement.

3. The injection device according to claim 1 , further comprising a plurality of control valves, the plurality of control valves are cracking valves that open and permit flow through the plurality of control valves above the cracking pressure, and closes the plurality of control valves below the cracking pressure, wherein the plurality of control valves are configured to have different cracking pressures at which flow through the plurality of control valves will occur.

4. The injection device according to claim 1 , wherein the permanent memory is configured to store at least one reference value for the pressure of the fluid.

5. The injection device according to claim 1 , wherein the fluid pressure sensor senses at least one of pressure, occlusion and leakage in the fluid injecting section and sends a measured value to the control unit, wherein the control unit compares the measured value to at least one reference value and outputs a result of the comparison of the measured value and the at least one reference value, based on the result an information signal is supplied.

6. The injection device according to claim 5 , wherein the information signal is sent to an alarm device, wherein the information signal can give rise to a corresponding information emitted by the alarm device.

7. A method of controlling an injection device according to claim 1 comprising:

providing the control unit to operate the pressure recognition arrangement of the injection device, said control unit measures the pressure in the fluid injecting section and compares the measured pressure value to at least one reference pressure value and a predetermined interval around the reference pressure value, and if the measured pressure value is not equal to the at least one reference pressure value or does not lie within a predetermined interval around the reference pressure value, the control unit stops the driving unit which is operably connected to the fluid providing section of the injection device.

8. The method of claim 7 , further comprising issuing an alarm from the control unit to an alarm device.

9. The method of claim 7 , further comprising:

checking whether the pressure recognition arrangement is in a state to detect the pressure increase or the pressure loss; and

if the pressure recognition arrangement is not in a state to detect the pressure increase or the pressure loss, enable the pressure recognition arrangement to detect the pressure increase or the pressure loss.

10. The method of claim 7 , further comprising:

stopping the driving unit if the position of the driven member of the injection device is not in accordance with a predetermined position of the driven member relative to the measured pressure value;

driving the driven member such that the pressure in the fluid injecting section is reduced; and

emitting a signal based on the comparison of the measured pressure value to at least one of the reference pressure value and a predetermined interval around the reference pressure value.

11. The injection device according to claim 3 , wherein the plurality control valves are arranged such that the cracking pressures of the plurality of control valves increase with increasing distance from the pump unit downstream along the fluid injecting section.